Biology Lesson Note SS2 Second Term
Biology Note for Senior Secondary school – Edudelight.com
SCHEME OF WORK FOR SECOND TERM
WEEK ONE-Excretion
WEEK TWO-Tissues and supporting systems/skeleton and supporting systems.
WEEK THREE-Components of the mammalian skeleton.
WEEK FOUR-Joints.
WEEK FIVE-Alimentary canals/Digestive systems/Alimentary tracts of animals.
WEEK SIX-Practical on digestion and skeletal system. Dissection of rabbit/rat/fowl.
WEEK SEVEN-Feeding Habits.
WEEK EIGHT-Feeding in amoeba,hydra and man.
WEEK NINE-Transport system.
WEEK TEN-Circulatory system in mammals.
WEEK ELEVEN-Mechanisms of transport in higher plants
1st WEEK
EXCRETION
Excretion is defined as the process by which toxic metabolic wastes are being removed from the body of a living organism.
Reasons for Excretion.
1. To maintain water balance in the living organisms.
2. To remove poisonous and unwanted substances from the body of the living organism.
3. It helps in controlling body temperature.
4. It helps to maintain salt balance (homeostasis).,
5. It saves some protozoa such as amoeba from bursting.
| 1. Protozoa e.g. Amoeba | Body surface and contratile vacuole | CO2,water,excess mineral salts ammonia. | Contractile vacuole body surface. | Carbon (iv) oxide, water excess mineral salt and ammonia | ||
| 2. Flat worm e.g. Tape worm | Flame cell | Water,urea,CO2,urea and nitrogenous wastes. | Flame cell | Water, Urea, CO2 and Nitrogenous waste (ammonia) | ||
| 3. Annelids e.g. earthworm | Nephridium | Carbon-dioxide, urea and nitrogenous waste. | nephridium | Water, Urea, CO2 and nitrogenous wastes. | ||
| 4. Insects e. g Cockroaches | Malpighian tubule | Carbon-dioxide,water, and uric acid. | Malpighi an tubule | Water, CO2 AND Uric acid | ||
| 5.crustacea | Green gland | Carbon-dioxide, water and nitrogenous waste. | ||||
| 6.vertebrates.eg mammals,fish, lizard e.t.c | Lungs, kidneys,skin,liver | Water,carbon-dioixde,mineral salt,sweat,nitrogenous waste. | ||||
| 7.flowering plants | Stomata and lenticel | gum,mucilage Water,oxygen,carbon(iv)oxide,tannins,alide de alkaloid,lipid,latex,resins and oil. |
Explain the process of excretion in Amoeba.
Excretion in Amoeba is carried out by the contractile vacuole. Water constantly enters the amoebic cell through its selectively permeable membrane by osmosis. The excess water collects in a contractile vacuole. The contractile vacuole expands as it is filled with water and then empties its content to the exterior.
Excretory products, like ammonia and CO2 leave the Amoeba by diffusion across the selectively permeable cell membrane mechanism for excretion of metabolic wastes the surface area : volume is large for the amoeba.
EXCRETION IN PROTOZOA
Excretion in most protozoa is by contractile vacuole. This is a simple cavity found in the cell of fresh water protozoa that help to eliminate water from the cell. Some contractile vacuoles are spherical while others are star shaped. The cell membrane of protozoa such as amoeba is semi- permeable. The osmotic pressure inside the cytoplasm is greater than that of the water surrounding its water plasma. As water enters into the cytoplasm, a contractile vacuole is formed and water flows into it when it reaches, the maximum size it contracts and discharge the excess water through a temporary break in the cell membrane at regular intervals. Excretion of waste product such as carbon dioxide and ammonia is by diffusion through the cell membrane.
EXCRETION IN EARTH WORM
STRUCTURE OF A NEPHRIDIUM
Nephridia are the organ of excretion in earthworm. A pair of nephridia is located in each segment except the first three and the last segment. Each nehridridium consists of five (5) portions namely: nephrostome, , narrow tube, middle tube, , wide tube and muscular tube. The nephrostome is ciliated and funnel shaped and it lead to a narrow coiled and ciliated tube which in turn lead to middle ciliated tube .. The middle ciliated tube finally leads to muscular bladder- like tube with an opening to the exterior by the nephridiopore.
MECHANISM
Each nephrotome is located in the body cavity. The gut muscles in the body cavity is lined with CHLORAGOGENOUS cell deaminate unwanted amino acid into urea and GUANIN and other compounds. The waste nitrogenous compounds are secreted into the fluid of the body cavity. The fluid therefore contains both useful material (Glucose) and waste material (urea). The beating of the cilia of nephrostome draws the fluid which is pushed along the tube by the cilia and muscular contraction. As the fluid passes along the tube,useful materials such as glucose is reabsorbed into the blood circulation. Also, some nitrogenous compounds are absorbed by the secretory cell of the tubule. Finally, the waste fluid is pushed into the muscular bladder where it is temporarily stored before being discharged to the outside through the nephridiopore. Carbon (iv) oxide is excreted from the body by diffusion through the moist skin.
EXCRETORY SYSTEM IN FLATWORM STRUCTURE OF FLAME CELL.
The excretory organ in flat worm is called flame cell which consists of two longitudinal canals with network of ducts. The ducts branch to all parts of the body and end up in flame cells. The two main canals open on the dorsal surface of the body by excretory pores. Each flame cell is a bulb cavity and funnel shaped. Projecting from the cell lumen is a brush of long cilia. The cell lumen end up as a narrow tube called duct. The beating of the cilia resemble a flame which give the entire structure the name flame cell.
MECHANISM
Liquid wastes containing Ammonia and Carbon(iv)oxide diffuse into the cell lumen. The continuous beating of the cilia drives the wastes into the excretory duct and from there to the excretory pores on the surface of the body where they are eventually removed. Flame cells are found in flat worms such as Schistosoma, Planaria and Tapeworm.
EXCRETORY SYSTEM IN INSECT
The Malpighi an tubule is the excretory system in insect. They arise from the junction between the mid gut (small intestine) and hind gut (large intestine). Each tubule consists of two parts namely: distal end and proximal end. The distal end is free and closed. Malphighian tubules are lined with glandular epithelium and are arranged in group of six. The tubules lie in the body cavity called haemocoel where it can be bathed with blood.
MECHANISM
Since, the Malpigh an tubules are already laid in the haemocoel of insects, soluble nitrogenous wastes such as potassium urates are produced by the tissue of the insect and sent to the blood. The distal end of the tubule absorb the potassium urates from the blood. Inside the tubules, the potassium combines with carbon(iv)oxide and water to produce potassium and sodium bicarbonates and uric acid. These waste products move along to the proximal end of the tubules, where the bicarbonates and the water are reabsorbed, leaving the concentrated crystalline uric acid which is passed to the hind gut to mix with faeces. The uric acid are then again passed into the rectum where water is reabsorbed again.
The dry faeces and uric acid are passed out through the anus.
FORMS IN WHICH WASTE PRODUCTS ARE EXCRETED
Liquid form
Waste product which are of liquid form include water, uric acid, sweat, urea, urine, dissolved nitrogenous wastes, dissolved mineral salt, latex and gum.
Gas form
Waste product which are excreted in gaseous form include carbon(iv)oxide, oxygen and ammonia gas.
Solid form
Waste products which are excreted in solid form include uric acid in some animals tannin, alkaloid, mucilage in all plants.
Excretion In Mammals
The four types of excretory organs used by mammals are Lungs, Skin, Liver and Kidney.
The lungs excrete water vapour and carbon(iv)oxide
The Liver excrete bile pigment called Bilirubin. The bilirubin is derived from the decomposition of haemoglobin.The Skin excretes water, salt and urea through sweat while the kidney excrete water, mineral salt, urea, uric acid and creatinine. In mammals, Kidney is the major excretory organ.
STRUCTURE OF THE KIDNEY
The mammalian kidney is a bean-shaped and reddish brown organ located in the posterior end of the abdomen. The kidney has two distinct regions, an outer cortex and inner medulla. Over one million fine narrow tubules called urinary tubules or nephron pass through both regions. Each urinary tubule is linked to a funnel-shaped cavity called pelvis. The kidney has many tiny capillaries which are branches of the renal arteries and renal veins.
The excretory system of mammals include the kidney, ureter, bladder, urethra and the associated renal artery and vein. The kidney is supplied with blood vessels. The renal artery supply blood to the kidney while the renal vein takes blood away from the kidney.
The ureter connects the kidney to the urinary bladder which leads to the urethra which also open to the exterior from which the urine is finally passed out.
The urinary tubule or NEPHRON is the functional unit of the kidney each urinary tubule starts in the cortex as a cup- shaped structure called Bowman capsule which surround capillaries called glomerulus. The bowman capsule lead into a coiled tubule called proximal convoluted tubule. This goes down to form a u- shape structure called Henle’s loop before re- entering the cortex. In the cortex the tubules become coiled again to form distal convoluted tubule. The tubule bends once again and completes its course in the medulla where it empties into the collecting duct.
Mechanisms of excretion in mammal (urine formation)
The process involved in formation of urine occurs three (3) phases which are:
1. Ultra filtration.
Selective re-absorption.
Hormonal control of re-absorption
ULTRA -FILTERATION takes place in the Bowman’s capsule and is made possible by two processes namely.
1. The pressure created by the narrowness of the capillaries, the barrier formed by the ENDOTHELIAL lining of the glomerular capillaries and the basement membrane of the Bowman’s capsule which retain molecules above a certain size while allowing smaller ones to pass through.
Blood in the renal artery and the arteriole is always under pressure, when it reaches glomerulus, it slows down by the narrowness of the capillaries and by the fact that the arterioles leading from the glomerulus in narrower than the one leading into it. A high pressure is developed and the blood containing dissolved substances like urea, water, glucose and mineral salt are filtered through the wall into the bowman’s capsule from the capsule in process is called ULTRAFILTRATION. Ultra filtration is the process by which waste and useful substance such as glucose, vitamin & mineral salt are filtered from the glomerulus to the bowman capsule as a result of the pressure created by the blood inside the capsule.
SELECTIVE REABSORPTION: The fluid in the capsule of the glomerular filtrate flows down the tubule certain substances are passed back into the blood while others are retained, such as water, sugar, amino acid and salt like Sodium, Potassium, Calcium which are useful to the body are reabsorbed into the blood capillaries against concentration gradient or active transport. This process of reabsorbing useful material back into the blood is called SELECTIVE REABSORPTION.
HORMONAL CONTROL OF REABSORPTION OF WATER : The reabsorption of water can be linked partly to osmosis and to a hormone known as ANTI- DURETIC HORMONE (ADH). After reabsorption, the resulting fluid known as urine then trickles down the ureter and collect in the bladder which stretches to accommodate it, when the bladder is full, it contracts and discharge the urine through the urethra.
EXCRETION IN PLANTS
Plants are much less active than animal and produce waste product at a much slower rate. They have no need of specialized excretory organ. Plant waste product include water carbon (iv) amino, acid, mucilage, alkaloid, latex, resin, crystal of salt, oil and anthocyanin. The main excretory organ of flowering plants is the stomata in the leaves and lenticels in the stem.
STOMATA
These are pores in the epidermis bounded by specialized epidermal cell known as guard cell. Stomata are usually found on the aerial part of the stem and leaves and on flower parts. They may be irregularly scattered or arranged in parallel rows. The guard cells are bean- shaped and fit together with the pore between them. The size of the pore alters according to how turgid the guard cell is which in turn depends on the osmotic pressure with the guard cell. When the pressure is low, the guard cells are flabby and the stoma is closed. When it is high, the guard cells are swollen and the stoma opens.
LENTICEL
The lenticels are structurally differentiated part of the periderm which stand out because of the loose cell arrangement. In a stem undergoing secondary thickening the first lenticel usually arise beneath the stomata in the epidermis
Carbon (iv) oxide and oxygen are excreted by diffusion through stomata or lenticels: water is excreted by diffusion out of the stomata or lenticels through the process of GUTTATION OR TRANSPIRATION.
Oil and resin: these are stored in the cell of the cytoplasm where they are kept in the system until they are eliminated latex is stored in tube like system in tissue and are kept harmless until they ooze out the plant when the plant is damaged.
Tannins, mucilage, gum crystals, alkaloid, anthocyanin, calcium oxalate and calcium carbonate. These pigment are converted into resoluble compounds are deposited in dead tissue like the bark of stem and leaves and petals which are shed periodically.
ASSIGNMENTS
(i)Define excretion
(ii)state reasons for excretion
(iii)state the excretory organs of the following organisms;amoeba,tapeworm,grasshopper,lizard,crab and monkey
(iv)Make a labelled drawing 8-12cm long of the longitudinal half of mammalian kidney
WEEK 2
SKELETON AND SUPPORTING SYSTEMS
Skeleton is the bony framework of the body which provide support, shape, rigidity and protection to the soft tissue and organ in animal. The skeleton of any animal depend on the position of the organism in the evolutionary trend help to determine the advancement and development of organism e.g. man is able to stand erect than other organism due to their sophisticated skeletal build up.
FORMS OF SKELETON
I. Cuticle:
Cuticle is composed of protein called chitin and a thin waterproof layer of wax. Chitin is a non-living substance, hence animal with this type of skeletal structure undergo moulting or ecdysis. Cuticle is an exoskeleton which is located externally on the body of the animal. Examples of organisms with this kind of the body structure are mainly Arthropods e.g. insect, crab, scorpion, prawn and crayfish.
II. Bones:
Bones consist of a living bone cell called osteocytes, protein fibres called collagen and minerals which are mainly of calcium phosphate and calcium carbonate. A bone consists of a hard outer layer called shaft and a spongy or hollow cavity filled with bone marrow. Animal that has bones include bony fish, toad, lizard and mammals.
III. Cartilage:
A cartilage is a tissue found in the skeleton of complex vertebrates. It consists of living cell called chondroblast, carbohydrate and protein fibre. It is a very tough and flexible tissue that has great tensile strength. Examples of organisms which possess cartilage are: cartilaginous fishes such as: Shark, rays and mammal.
Types of cartilage.
a. Hyaline cartilage : Trachea, bronchi and surface of moveable joint, nose.
b. Fibro- cartilage: between inter vertebral column.(c) Elastic cartilage: ear, epiglottis.
Types of skeleton.
1. Hydrostatic of fluid skeleton.
2. Exoskeleton.
3. Endoskeleton.
Hydrostatic Skeleton is a type of skeleton possessed by soft bodied animal examples of organism with this type of skeleton are earthworm and sea anemones.
Exoskeleton is a type of skeleton which is found outside or external part of the body of some animals. Most invertebrates do possess cuticle which is composed of chitin.
Endoskeleton is the type of skeleton which is found inside the body of the animal. Endoskeleton exists in toad, lizard, birds and mammals.
Endoskeleton in mammal include the skull, the vertebral alumni or backbone, ribs, and the bones of the fore and hind limbs.
ASSIGNMENT
(i)Which of these type of skeleton is most appropriate to the cockroach?(A)hydrostatic skeleton(B)endoskeleton(C)exoskeleton(D)bony skeleton
(ii)Name one animal each that possess;hydrostatic,exoskeleton and endoskeleton.
WEEK 3
THE COMPONENT OF THE MAMMALIAN SKELETONS.
The mammalian skeletal system is group into two major parts:
1. Axial skeleton which comprises of the skull, vertebral column, ribs and sternum.
2. Appendicular skeleton is made up of the limbs girdles, pectoral and pelvic girdles and the limbs which is fore limbs and hind limbs. The skull is made up of several flat bones joined together by means of joint called sutures. The three major parts of the skull are: (i) Cranium or brain box.
(ii) Facial skeleton (iii) Jaws (upper & lower)
Functions of the skull
1. It protects the brain.
2. It gives shape to the head.
3. It protects vital organs in the head e. g eye, nose, ear.
4. It bears the teeth which help in grinding of food.
VERTEBRAL COLUMN
The vertebral column is the central supporting structure of the skeleton, it is made up of five group of bones called vertebrae in mammals. In human it consists of 33 vertebrae. The vertebrae are held to one another with a strong ligament having compressible cartilage pads called intervertebral disc between the consecutive vertebrae.
| Types of vertebrae | Man | Rabbit | Rat |
| Cervical | 7 | 7 | 7 |
| Thoracic | 12 | 12 | 13 |
| Lumbar | 5 | 7 | 6 |
| Sacral | 5 | 3-4 | 4 |
| Caudal | 4 | 16 | 27-30 |
FEATURES OF A TYPICAL VERTEBRAE
All vertebrae even though they have different function, have certain features in common.
1. Neural canal: This is the passage of the spinal cord.
2. Neural spine: This project upward dorsally for the attachment of muscles.
3. Trans verse processes: They project from the side of each vertebra for the attachment of muscles and ligament.
4. Centrum : It is a solid piece of bone below the neural canal.
5. Facet: This a small, smooth, flat or slight depressed on the bone usually in point of contact with another bone.
6. Zygapophysis : These are articular surfaces for the articulation of successive vertebrae, They are grouped into two parts namely:
(a) Pre- zygapophysis facing inward and upward. (b) Post- zygapophysis facing outward and downward.
CERVICAL VERTEBRAE.
The cervical vertebrae are found in the neck region. The First vertebra is called atlas while the second one is called axis. The third to the seventh bones are similar and they are the normal cervical bones. The atlas allows the head to nod and it fits into the occipital condyles of the skull.
Characteristics of atlas.
1. It has a large neural canal.
2. It has a flat and broad transverse process.
3. The neural spine is very short, in some cases it may even be absent.
4. Centrum is absent.
5. It has a vertebrarterial canal for the passage of blood vessels.
ATLAS
Characteristics of Axis vertebrae.
1. It has a broad and flat centrum.
2. It articulates with the atlas through odontoid process.
.
3. It has a large flattered neural spine.
4. The transverse process is reduced to pin- like structure.
5. It has a vertebrarterial canal.
THORACIC VERTEBRAE
Thoracic vertebrae are found in the chest region.
Characteristics
1. It has a long and prominent neutral spine which project upward and backward.
2. It has a pair of short transverse processes.
3. There is presence of demifacet and articular surfaces for attachment of ribs.
4. It has a large neural canal.
5. It has a large centrum.
Functions of the Thoracic vertebrae
1. It aid the attachment of the ribs.
2. It provides space for attachment of muscles of the shoulder and back to the neural spine.
3. It assists in breathing along side with the ribs.
LUMBAR VERTEBRAE
The lumbar vertebrae are found in the upper abdominal region.
Characteristics
1. It has a large flattened transverse process.
2. It has a broad and flat neural spine.
3. It has a large and thick centrum.
4. It has well developed pre and post zygapophysis.
5. It also have two extra- paired projections called anapophysis & metapophysis for attachment of abdominal muscles.
Functions of the lumbar vertebrae.
1. The lumbar vertebrae provide attachment for abdominal muscles.
2. They bear considerable weight of the body.
SACRAL VERTEBRAE
These bones are found in the lower abdominal region. In man, they are 5 in number and they are fused together to form the sacrum.
Characteristics
1. It has a narrow neural canal.
2. It has neural spine which is reduced to a small notch.
3. It has a large centrum.
4The first sacral vertebra has a pair of transverse process which is large and wing like but the others are attached to the muscles of the back.
5. The first sacral vertebrae has a small neural canal which gradually become narrower in the other vertebra.
They are joined with the pelvic girdle to provide support rigidity and strength.
CAUDAL VERTEBRAE
The caudal vertebrae are fused together is a solid mass of bone are found in the tail region.
RIBS AND STERNUM.
Twelve pairs of ribs and sternum form the rib cage in humans, the sternum is a single bone which consist of seven small bones. The ribs articulate with the thoracic vertebrae; however, in humans only the first ten pairs are attached to the sternum. The last two pairs remain free and are known as floating ribs
Functions
1. The ribs and sternum protect the heart and the lungs.
2. They assists in respiration.
APPENDICULAR SKELETON PECTORAL/ SHOULDER GIRRDLE.
The pectoral girdle holds the upper limbs or arms to the axial skeleton. It consist many of four separate bones, two large flat, triangular, bones called shoulder blade or scapula at the back and two small slender bone called collar bone or clavicle in front. The scapula are attached to the vertebral column by muscles, each scapula has a depression called the glenoid cavity into which the head of the upper humerus fits to form the shoulder joint. The calvicles are attached to the scapula at one end and to the sternum and the other end.
The pelvic griddles consist of two half which have joint to each other ventrally to form a sacrum. The line of fusion of two half bones is called pubis symphysis .Each half is made up three bones namely ilium, ischium and pubis. The ilium is the largest and the longest of the three bones.
Pelvic griddle or hips
Pelvic girdles or hip consist of two bones, the right and the left pelvic. These are joined to form sacrum at the back and held together by cartilage at the back and in front to form a complete hip girdle. At the outer edge of each pelvic is a deep cavity called acetabulum cavity into which the bone of the thigh bone or( femur )fits to form the hip joint.
The pelvic girdle consist of two halves which are joined to each other ventrally to form a sacrum. The line of fusion of the two halves bones is called pubis symphysis, each halve is made up of three bones namely ilium, ischium and pubis . the ileum is the largest and longest of the three bones. At the lower and of ischium and of ischium and pubis encloses an opening or a hole called obturator foramen. It is through this hole blood vessels and muscles pass.
The limbs are made up of fore limbs i.e bones of the arm and limbs. The limbs of most vertebrates are built on the same basic plan called pentadacty limb plan < 5 digit plan>.The fore limbs of mammals is made up of an upper arm bone which a long bone called humerus. The humerus has a rounded head which fix to the glenoid cavity of scapula of the pectoral girdle. The humerus are grooved- like surface called trochlea which join with ulna and radius are foliated by the bones of the wrist called carpals which are followed by the bones of the digit called metacarpals or phalanges.
HIND LIMBS
The hind limbs is made up of the tight bone called Femur. The femur is the largest and the strongest bone in the body. Very close to the femur and three projections called TROCHANTERS, they are important for the attachment femur to muscle. At the distal end of the femur are two rounded knobs called condoyle for articulation. The Shank is made up of two bones called Tibia and Fibula. The knee joint is found at the junction of the femur with tibia and fibular ,the there is a short bone called patella or knee cap . the inner tarsal’s project backward to form the heel bone .
THE FEMUR
IMPORTANT OF SKELETON
1. it gives support, shapes and rigidity to the body
2. Skeleton protect delicate organs of the body e.g the cranium protects the brain while the sternum
3. Protect the heart and the hung
4. Skeleton makes the body to move
5. The ribs and the sternum take part in respiration
5. The long bone marrow manufacture the raw blood cell
6. The skeleton provide space for attachment of muscle
7. The skeleton stores some mineral salt e.g calcium and phosphorus
ASSIGNMENT
1Which vertebra has a projection called odontoid process?(a)atlas (b)axis (c)thoracic(d)lumbar.
2Which of the following vertebra lacks centrum?(a)atlas(b)axis(C)thoracic(d)lumbar
3.What are the bones that make up the pectoral girdle?(a)hip bone(b)sacral vertebra (c)scapula and clavicle(d)caudal vertebra
4.The thoracic vertebra can be readily recognized by its (a)long neural spine (b)large centrum(c)long transverse processes (d)small neural canal(e)short neural spine
5.The appendicular skeleton is composed of the pectoral girdle.(a)pelvic girdle, fore and hind limb(b)pelvic and fore-limb(c)lumbar vertebrae and pelvic girdle(d)lumbar vertebrae, fore and hind
6.Make a labelled drawing of the anterior view of a lumbar vertebra
7.State five of functions of skeleton
WEEK FOUR
THE JOINTS
A joint is a place where two or more bones meet or articulated.
Types of Joint
Immovable joint
These are joints or regions where two or more bones are firmly attaches to one another or firmly fixed by ligament in such a way that movement of these bones are not possible. Example of some places in the body where
Immovable joints are present are skull and pelvic girdle.
The immovable joint of the skull are called suture
MOVABLE JOINTS
They are joint or region of the body where movement of joint is possible. Most of the bones are held together by movable joint
Types of movable joint
1. Ball and socket joint
These are joints that allow movement in all directions <3600>the joint are found in the shoulder and hip joint
2. Hinge joints
It is found at the elbows and knee it allow movement in only one direction
Gliding and sliding joint
It allows gliding of the bones over one another. Example of this joint are found in the wrist and ankle
Pivot joint
Pivot joint are found in the neck between the atlas and axis. It permits nodding and rotation of one part of the body on another
Structure of joint
The main part of the joint consist of the followings
Ligament
These are though partly elastic bands of tissue which hold two bones together at a joint
Tendons are extension of connecting tissue which join muscle to the bones
Articular cartilage these are found at the surface of the bones at joint plays the role of cushioning by protecting them from wear and tear during movement
Synovial Membrane is responsible for the secretion of synovial fluid
Synovial fluid is the fluid which lubricate the joint and thus reduce shock as well as friction between bone.
Capsule is the space which contain the synovial fluid
Movement
The skeleton can be move due to the muscular contraction. Muscle are joined to the bone by means of tendons . Tendon transmit the pull from a muscle into the bone, antagonist pair of muscle work against each other moving the same limb into opposite direction, thus the biceps bend the arm while the triceps straightened. The contraction of the flexor muscle attains elongation of the biceps. The flexor muscle antagonistic pair i.e triceps the limbs while the extensor muscle e.g triceps straighten the arm.
FUNCTIONS OF SKELETON
1.It gives support ,shape, and rigidity
2.It protects the delicate organs of the body such as the brain, spinal cord and heart
3.It helps in movement
4.The bone marrows manufacture the red blood cells
5.It provides space for the attachment of the muscles
6.The ribs and sternum help the respiration
7.The skeleton stores some mineral salt e.g calcium and phosphorus
SUPPORTING TISSUE IN PLANTS
1. Parenchyma
2. Collenchyma
3. Sclerenchyma
4. Xylem
5. Phloem
Parenchyma
It is made up of living unspecialized plant cell that are rough spherical in shape. Parenchyma tissues are founds in the cortex of stem, phloem. Root, leaf mesophyll, storage tissue and xylem
Function
1. It gives firmness and rigidity to the stem of herbaceous plant
2. It can store food and water
They are present in the leaf mesophyll to partake in the synthesis of food.
Collenchyma are found in the primary tissue of plants. The cell of collenchyma are living elongated and unevenly thickened at the corner. The cell are flexible and this allow the bending and twisting strain to which the stem , root and leaves of plant are often subjected. The collenchyma tissue are location in the cortex of stem and in the hypo dermis just beneath epidermis.
Function
1.They provide strength and support in young drawing plant part such as stem, petiole and leaf
2.They give flexibility and resilience to the plant i.e enable the plant to bend without breaking
Sclerenchyma Tissue is composed of two type of cell namely sclerenchyma fiber and sclerenchyma sclereid. Both of them consist of deal cell in which the cell wall are heavily thickened with deposit of lignin. ( A lignin is a substance that provide mechanical strength). The cells of the fiber are narrow polygonal, elongated with tapering end.
The lumens are small because of the thickened wall. The s-fiber are present in the outer region of the cortex and pericycle of stem and in the vascular tissue
Sclerenchyma slereid are heavily lignified cells which are spherical. They are present in all part of the plant e.g cortex, pith, phloem, fruit and seed coat.
Function
-They provide mechanical strength
-They give flexibility to plant and prevent them from breaking easily
-They provide strength, rigidity, hardness and support to plants
XYLEM TISSUE
The xylem tissue are found in the vascular bundle especially the plant that undergo secondary growth. There are four types of xylem tissues namely:
-Xylem tracheid
-Xylem vessel
-Xylem fiber
-Xylem parenchyma
Of the four, first three are lignified and so provide mechanical support.
Xylem tracheid are non- living elongated tapering cell with thickened lignified wall with pith that allow the passage of water and dissolve mineral salt.
Xylem vessel :- are long tubular structure that are formed by the fusion of several elongated cells which are joined
one on top of another.
Xylem fibers– are similar to the sclerenchyma fiber , they have narrow elongated cell with very thick wall.
Xylem parenchyma– are similar to parenchyma tissue. They are composed of cell with large vacuoles
Function of Xylem Tissue
1. The xylem tissue provide support and shape to the plant
2. The major function of xylem tissue is to conduct water and dissolved mineral salt from the root to the leaves.
PHLOEM TISSUE
The phloem tissue are located within the vascular bundle of all plant, be it in the root, stem and leaf , they are made up of four type of cells namely
1. P. sieve ( phloem sieve tube)
2. Phloem parenchyma
3. Phloem companion cell
4. Phloem fiber
The phloem sieve tubes– are made up of elongated row of cylindrical cell which are arranged vertically. The cell are living and they conduct mainly manufacture food.
Phloem parenchyma– are made up of parenchyma cell which offer strength and support to plant. The cell also help in food storage
Phloem fibers– are special cells which are concerned with strengthening of the organs in which they are present.
Phloem companion cells– are small and short cell which are vertically elongated like the seive tube. They assist in conduction of food substance.
FUNCTION OF THE PHLOEM
1.The general function of the phloem is to conduct manufactured food from area of the synthesis ( leaf) to the area
where they are needed ( i.e stem root)
2.They also assist to provide support to the entire plant .
EPIDERMIS
The protective tissue of plant is the epidermal cell found on the leaf and stem and as piliferous cell in the root.. The epidermal layer is one cell thick with a protective cell. It prevents the inner cell from injury, infection and water less.
The epidermis cell does not contain chloroplast except in the guard cell which possess chloroplast and therefore can photosynthesis
CORTEX
The part of the stem between the epidermis and vascular bundle of a dicotyledonous stem is called
Cortex. The cortex is made up of three tissue which are( collenchyma) on the outside, a middle( parenchyma) and inner( endoderm). The collenchyma is about three to four times thick while the parenchyma is made up of thin wall cell with many spaces . Both cells provide strength and support. The endodermis is a single layer which is also referred to as starch sheet.
Sclerenchyma.
This layer is found on the outer part of the vascular bundle. It consists of dead lignified cells. It aids to strengthen the cell.
Vascular Bundles.
These are found in the inner part of the stem. It consist of the xylem, phloem and cambium. The xylem is responsible for conduction of water and dissolved minerals salt from soil to the leaf through the root and stem. The phloem is responsible for the conduction or transfer of manufactured food from the area of their synthesis to the other part of the plant.
Cambium is found between the phloem and xylem. The cambium cell are constantly dividing cell. This increases the size of cell which is called secondary thickening which is responsible for the increase in size of the trunks of many trees.
Pith
It is the central part of the stem, it is large and made up of parenchyma and extend between the vascular tissue.
Transverse section {T/S} dicotyledonous stem.
Difference between Dicot and Monocot plant.
| No | Dicto stem | Monocot stem |
| 1. | The tissue below the epidermis is collenchyma | The tissue below the epidermis is sclerenchyma |
| 2. | The size of cortex is wide | The size of the cortex is narrow |
| 3. | The pericycle is made up of sclerenchyma which caps the individual bundle | Sclerenchyma completely surround each vascular bundle |
| 4. | The vascular bundle is few which arrange in a ring of cambium | The vascular bundle are scattered all over the ground tissue |
| 5. | Cambium is present | Cambium is absent |
| 6. | Secondary growth occurs | Secondary growth does not occurs |
| 7. | Pith is present | Pith is absent |
T/S OF MONOCOTYLEDONOUS STEM.
Different between Dicot and Monocot Root
| No | Dicot Root | Monocot Root |
| 1. | It has only one star shaped xylem bundle centrally located. | It has many xylem bundle radially arranged |
| 2. | Pith is absent | Pith is present |
| 3. | Few phloem bundles are present | Many phloem bundles are present |
| 4. | Cambium is present | Cambium is absent |
INTERNAL STRUCTURE OF A LEAF
The internal structure of a leaf consist of three main tissues:
1. The epidermis ( the upper and lower epidermis)
2.The mesophyll consist of palisade and spongy mesophyll
3.The vascular bundle consists of mid –rib and veins
The epidermis is a single layer of closely packed cell found both on the lower and upper surface of the leaf. The epidermis is lined with cuticle which prevent too much evaporation of water and protect the inner cell from mechanical damage and diseases. The mesophyll is made up of parenchyma cell. The tissue between the upper and lower epidermis is called mesophyll. The palisade mesophyll consist of one or two layers of elongated cell closely packed. The cell contains numerous chloroplast which are used for photosynthesis. The spongy mesophyll is made up of irregular cells that are loosely packed with lots of intercellular air spaces, air diffuse into the space. The carbon (iv) oxide is absorbed for photosynthesis and oxygen is used respiration. The spongy cell contain fewer chloroplasts. The mid- rib and vein are the vascular tissue consisting of xylem and phloem surrounded with few parenchyma. The stomata are the opening in the epidermal layer of leaves through which air passes in and out of the leaves, the opening and closing of the stomata are guarded by guard cell
ASSIGNMENTS
i.The joint between the atlas and axis allows for (a)rotatory movement only(b)up and down or nodding movement(c)rotatory and nodding movement(d)no movement at all
ii.Jointed skeleton is absent in the (a)cockroach(b)spider(c)millipede(d)snail
iii.The substances manufactured by the leaves are transported other parts of the plants through the.(a)xylem(b)companion cells(c)sieve tube(d)cambium
iv.The bones are joined together by(a)tendon(b)cartilage(c)ligament(d)synovial fluid
v.Which of the following is not a tissue found in plant?(a)epidermis(b)phloem(c)xylem(d)dermis
2.(a)What is a joint?
b.List four type of movable joints and mention one location in the mammalian body they can be found.
3(a)Make a well labelled diagram of a dicotyldonous stem showing the arrangement of the tissue.
b.Make a labelled drawing of 10-12cm long of a typical movable joint.
WEEK FIVE
DIGESTIVE SYSTEM OR ALIMENTARY SYSTEM CANAL
Type of Alimentary system
The alimentary system a collection of organs which perform the function of digestion of food in various animal, there are different type of alimentary in various animals
1. Alimentary canal in lower Animals
Planaria – Flat worm
The planaria are free living flat worms which feed on small microorganisms. They have a simple gut with a single opening leading to the outside i.e the mouth which is situated on the ventral side of the flat body . The mouth opens into a large muscular pharynx that can be averted suddenly to catch their prey . During feeding, the food is sucked into the gut by means of suctorial pharynx. The gut has three branches one leading toward the anterior and the other two towards the posterior. The three main branches give out many fine branches. Digestion is partly extracellular and partly intercellular. The branches gut makes the absorption and digestion efficient, the undigested food is thrown out of the anus.
Digestion in earthworm
The earthworm feed mainly on vegetable materials which it swallows as it burrows into the soil . The straight gut is a tube with mouth at the anterior end and anus at the posterior end . The mouth opens into a walled
Buccal cavity into which the food is moistened secrete mucus that by a thick muscular pharynx which secrete mucus that lubricates the food . The pharynx opens into a narrow thin crop in which food is stored for a short time . From the crop, the food is released into a walled muscular gizzard in which there are small stones which help to grind the food this is followed by a long straight intestine in which digestion take place . Digestion in earth worm is purely intracellular and the digested food diffuses through the intestinal wall into the surrounding blood capillaries . The blood them carries the soluble food to all parts of boy
ALIMENTARY CANAL OF INSECT
The alimentary canal of insect e.g cockroach consists of three main parts ,the fore gut, the mid gut and the hind gut .The Fore gut is made up of the mouth, buccal cavity ,pharynx, crop and gizzard. The mid gut or the stomach while the hind gut is composed of the intestine and annus. At the junction of the fore gut and mid gut is a finger- like projection called gastric caecum . These secrete digestive juice into the mid gut where digestion take place .. Absorption of digested food takes places in the anterior part of the hind gut. Between the mid gut and the hind gut are numerous tubules called Malpighian tubules which absorb waste material from the body fluid and deposit them in the hind gut. The hind gut consist of ileum, colon and rectum which absorbs water and mineral salt. The faeces are later passed out through the anus.
Alimentary canal if insect (cockroach)
ALINENTARY CAVAL OF A BIRD
The digestive system of bird include the beak, mouth, pharynx, oesophagus, crop, proventriculus, gizzard, intestine, caecum, rectum and anus or cloaca. The bird uses the beak to pick up food which passes through the mouth, oesophagus and the crop where the food is temporarily stored, moistened and fermented by some bacteria. The food is now passed down to the proventriculus where enzymes are secreted on the food,. proventriculus is often regarded as glandular stomach because it has glands which secrete digestive enzymes e.g pepsin, amylase e.t.c on the food.
From the proventriculus the food moves to the gizzard where the natural grinding of the food takes places with the aid of small stones or grift with which the food is ground by the gizzard. From the gizzard the food moves to the duodenum and the intestine where further digestion and absorption of the food take place. The undigested food particles are moved through the caecum to the rectum and finally to the anus.
ALIMENTARY CANAL OF RABBIT.
The alimentary canal of rabbit consist of the teeth, mouth, salivary gland, oesophagus, stomach, small intestine, caecum, appendix and large intestine.Rabbit is a herbivorous animal, herbivores are adapted for cropping grasses and grinding plant matter to break down the cellulose cell wall. The incisors of rabbit are long and chisel shaped. They bite against each other to chop of pieces of grasses. The incisors wears away fast but the teeth can grow continuously because of a good supply of blood into the pulp cavity. There are no canines in herbivores, instead between the incisors and premolar, there is a gap called diastema which help to push the food from the front of the mouth to the grinding teeth behind. The rabbit has a large caecum and appendixes which contain numerous bacteria capable of breaking down cellulose into sugar and the rest is absorbed by the herbivore.
ALIMENTARY CANAL OF MAN
The alimentary canal of man is a tube of varying diameter running form the mouth to the anus. The canal include mouth, esophagus, stomach, small intestine or ileum, caecum, large intestine or colon and anus. Along the length of the canal, there are sections adapted to deal with various stages of nutrition and egestion.
Ingestion is the taking in of solid food by the organism through the mouth. The mouth contains the teeth, salivary gland and tongue. The teeth are used to break and grind food mechanically into tiny particles while the tongues rolls the food into bolus. It allows mixing of food with saliva which contains enzyme ptyalin which breaks down starch into maltose which is later swallowed into the gullet in form of bolus. The esophagus connects the mouth to the stomach. The food swallowed is passed down through the esophagus by peristaltic movement into the stomach.
Digestion: It is defined as an enzymatic break down of food substances into simple and absorbable form. These commences in the stomach which store the food temporarily for few hours. The food is now released at regular interval by the opening of PYLORIC SPHINCTER In the stomach, The gastric gland secret gastric juice which contain two enzymes: rennin and pepsin. The renin acts on liquid protein e.g milk or it helps to curdle milk while the pepsin break down the protein to peptone. The gastric gland also secretes hydrochloric anus ( HCL) which creates acid medium for the enzymes to act and also to kill some bacteria contained in the food. The food is churned by muscular contraction of the stomach wall which enable the mixing of the food with digestive juice. The churning movement then convert the food into a semi- liquid state called chyme.The food ( CHYME) is passed down by peristalsis to the first part of small intestine called duodenum where the pancreas secrete pancreatic Juice that contain the following
1. Amylase: This enzyme covert starch to maltose
2. Lipase: it converts fat and oil to fatty and glycerol
3. Trypsin: This enzyme converts protein and peptone to polypeptides
The pancreatic Juice is alkaline and provide the medium for the enzymes mentioned above to act. The digestion of fat and oil is carried out by the green pigment called bile produce in gall bladder which is situated in the liver. The bile is used for the emulsification of fact and oil i. e breaking down fat and oil molecules into tiny droplet before enzyme lipase acts on them
The small intestine or ileum is found between the duodenum and large intestine. The major event that take place there are:
1. Completion of digestion
2. Absorption of digested food
The intestinal wall of ileum secrete intestinal Juice which contain the following enzymes
1. Enzyme lipase
2. Erepsin
3. Maltase
4. Sucrase
5. Lactase
The LIPASE converts fat and oil to fatty and glycerol, erepsin convert polypeptide to amino and , Maltase convert maltose to two units of glucose, sucrase convert sucrose to glucose and fructose, while lactase convert lactose sugar to glucose and galactose.
Absorption is define as the passage of soluble digested food substances into the blood stream or body fluid through the wall of the ileum called villi, : The end product of digestion such as amino acid , glucose , fatty and glycerol are absorbed in the small intestine by tiny finger- like structure called villi : A villus is made up of inner surface or epithelium ,. blood capillaries and lacteal .. The inner surface of each villus is thin which allows the absorption of the end products either by diffusion or active transport through it . The glucose and amino acid are absorbed by blood capillaries through the epithelium into the blood stream wile the fatty and glycerol enter the lacteal where they are carried to the lymph vessels which eventually empties their content in to the blood vessels near the heart
Caecum or appendix has no specific function but the caecum contain some bacteria which and mine digestive of cellulose. Some vitamins especially K&B complex are partially synthesized in this region egestion :it is the discharge of the insoluble absorbable and undigested food particles passes through the anus . the indigested food particles passes through the colon or large intestine and water is aborted back into the blood stream .the absorption of water concentration the waste product and make them into faces which are passes out through the aims
Diagram of a villus
Differences Between Alimentary Canal Of Bird And Cockroach
| BIRD | COCKROACH | |
| I. | There is presence of tongue in the mouth. | Tongue is absent. |
| II. | Mouth is modified into beak. | Mouth is modified into mandible and maxillae for chewing and grinding. |
| III. | There is presence of duodenum. | Duodenum is not present. |
| IV. | It has long alimentary. | It has relatively short alimentary canal. |
| V. | The hind gut ends in cloaca. | Hind gut ends in anus distinct from the reproductive tract. |
| VI. | Malphighian tubules are absent. | Malphighian tubules are attached to aliment canal. |
| VII. | There is presence of pancreas. | Pancreas is absent. |
Similarities Between Alimentary
Canal of A Bird And Cockroach
1. Both have narrow esophagus.
2. Crop is present in both organisms
3. Muscular gizzard is present in both.
4. There is the presence of a caecum in both
5. Mid-gut is present in both organisms.
ASSIGNMENTS
1.Which of the following organs produce bile?(a)gall bladder(b)pancreas(c)liver(d)stomach.
2.The removal of a man”s pancreas by operation can affect the digestion of(a)starch(b)starch, protein and fat(c)oil and fat(d)protein.
3.Which of the following is the accessory organs of digestion?(a)kidney(b)spleen(c)liver(d)lungs.
4.The activities of ptyalin are likely to decrease with an increase in the concentration of (a)oxygen(b)starch(c)protein(d)acid.
5.What is the end-product of a digested protein?(a)peptone(b)glycerol(c)polypeptide(d)amino acid.
6.What is the modifications and the mechanism association with the following feeding habits?
i.fiter feeding in mosquito
ii.parasitic feeding in tapeworms
iii.saprophytic feeding in bacteria and fungi.
Make a label diagram of digestive system man
WEEK SIX-PRACTICALS ON DIGESTON/SKELETAL SYSTEMS
DISSECTION OF RABBIT/RAT/FOWLSS
WEEK 7
FEEDING HABITS
Feeding habit is the method adopted by different organism to carry out their feeding mechanism.
1. Filter feeding/Microphagous:- This is a method of feeding used by some aquatic animal that feed on microscopic organism surrounding them. The microscopic organism are phytoplankton (microscopic plant) and zooplankton (microscopic animal). These two groups of microorganism are referred to as plankton. Example of filter feeders are mosquito larva, duck, prawn and tilapia fish. There are many aquatic animal and they wallow in water through sieve-like structure on their bodies in order to collect large quantity of their prey.
2. Fluid feeding: Is a method of feeding in which some animal feed on fluid substances derived either from animal or plant. If the food is a solid, it has to be converted into liquid form before it is being sucked into the gut. Example of organisms which are fluid feeder are housefly, adult mosquito and butterfly.
3. Wallower: These are organism that rest within or wallow in their food e.g. tape worm which live in the intestine of man, the organism live within the host and absorb digested food directly into it’s entire body surface to absorb digested food from the host
4. Sucker:– These are organism which feed by sucking fluid from plant or animal. They are mainly insects e.g. bug, mosquito, butterfly, aphids and tsetse fly.
5. Saprophytic feeding:- The saprophytes are mainly non-green plant which do not have chloroplast and therefore cannot manufacture their own food. They then feed on dead and decayed organic matter from which they derive their food e.g. Rhizopus, mushroom and mucor. They have the following features:
- They have hyphae or rhizoid instead through which they pour enzymes for digestion.
- They are capable of carrying out extra cellular digestion.
- The digested portion of the organic matter is later re-absorbed into their body by diffusion.
6. Parasitic feeding:- This feeding habit is carried by both plant and animal parasites. A parasite is a small organism that live in or on another large organism called host from which the parasite obtain food without contributing anything in return during which the host is harmed. Example of animal parasite are tick, lice, mite, fleas which are called ecto-parasites while tape worm, round worm, guinea worm are example of endo-parasite.
The plant parasites are cassytha, doodler and mistletoe. The plant parasites normally develop a structure called hastorium/hastoria with which they use to absorb nutrient from the host plant.
MODIFICATION AND MECHANISM OF FEEDING IN SOME ANIMALS
(1) Absorbing Mechanism
This mechanism is used by endo-parasites which practise parasitic feeding on their host. It has no mouth, but absorb digested food from the intestine of their host (man). The body of tapeworm is modified and adapted to parasitic feeding in the following ways:
- It possess hook and sucker for the attachment to the intestine of their hosts.
- The body has thick cuticle which protect the organism from being digested by the host enzyme.
- The body of tapeworm is flat to provide large surface area for absorption of digested food.
- Food is able to penetrate through the body surface.
(2) Biting And Chewing Mechanism
The method is adopted by insects such as grasshopper and cockroach. They have mouth parts for biting and chewing. These insects have different mouth parts which are modified and adapted for biting and chewing:
- Labrum:- It is a projecting upper mouth part (upper lips) which prevent food from falling off the mouth while chewing.
- Labium:- The labium is the lower lips. It is a mouth part formed from a fused pair of appendages. It is used to prevent wastage of food from the mouth.
- Mandible:- It is a pair of lower jaw which form insect mouth parts and is used for biting and cutting food.
- Maxillae:- The maxillae is a mouth part (two pairs) that is used for breaking down food which the mandibles would have chewed for easy digestion.
(3) Sucking Mechanism
The popular organism that feed in this manner are mosquito, butterfly and housefly. These insects have different modification of mouth parts for their feeding through sucking.
A. MOSQUITO
(I) Proboscis: – It is a long or tubular mouth part used for feeding, sucking of blood and other purposes.
(II) Stylet: – It is a long appendages. It is used for penetrating the skin in order to open it up and suck blood.
(III) Labium: – (Lower lip) It is a part of mouth of mosquito adapted for sucking as it can be folded back to allow stylet to function in cutting the skin open.
(IV) The mouth of mosquito can produce saliva which prevents clotting of blood while it is being sucked.
B. BUTTERFLY
Adult butterfly and moths feed mainly on flower nectar and other sugars such as those contained in the sap of wounded trees. The butterfly and moth used their distinctive mouth parts to feed on the nectar of flower. Their mouth is located between the eyes.
(I) Proboscis: – This is a long coiled-tube used for sucking nectar of flower. The insect is capable of recoiling the long proboscis under its head when not in use.
(II) Tasting hair: – Butterflies have hair-like structure on their feet to sense food and it also responsible for tasting the food.
C. HOUSEFLY
The housefly develops mouth parts that are used for specialized feeding on a wide range of materials. Other families of flies are black flies cralflies. Housefly has the following mouth parts:
(I) Proboscis: – Which is applied to wet surface and suck up fluid by means of capillary action.
(II) Labella: – It is used in collaboration with the proboscis to enhance feeding in housefly
(III) Sponging: – It is one of the special feeding mechanisms of the housefly which make the feeding very easy for the housefly.
WEEK 8
FEEDING IN MAN
GRINDING AND CHEWING MECHANISM
This method is common among mammals e.g. man, cattle, sheep, goat, e.t.c. These animals are capable of grinding their food before swallowing. The grinding is aided by the presence of hard and strong teeth make up of enamel and dentine. Mammal like man has four different type of teeth mainly incisor, canine, premolar and molar. The incisor has a sharp edge that is used to cut food, the canine are pointed and they are used for tearing of flesh or other material. The premolars and molars are flat teeth with cusps that grind and mash food. The molars are for vigorous chewing
STRUCTURE OF A TOOTH
DENTITION: – Is the arrangement of teeth dental formula shows the number of each typed of teeth possession by a mammal, the number of teeth in one side the jaw is given with the number in the upper jaw before that in the lower jaw
| Mammal | Dental formula | Total No of teeth |
| Man | I=2/2, C=1/1, P=2/2, M=3/3 | 32 |
| Dog | I=3/3, C=1/1, P=4/4, M=2/3 | 42 |
| Cow & Sheep | I=0/3, C=0/1, P=3/0 M=3/3 | 32 |
| Rat | I=1/1, C=0/0, P=0/0, M=3/3 | 16 |
(3) TRAPPING AND ABSORBING MECHANISM
This system is common among insectivorous and carnivorous plant such as bladderwort, pitcher, sundew, Venus fly trap. They have structure which enables them to adapt to this mode of feeding.
FEATURES
- The plants have special devices for attracting and trapping flies and other insect; such features are: bright colour flowers, scent and sugary secretion/nectar
- The plant possesses digestive juice which when a prey is trapped will trigger off to kill and digest the prey.
- The leaves of these plants have long hairs which carry digestive glands. Bladderwort is a floating aquatic plant with tiny leaves and small bladder.
- Venus fly trap have leaves which are folded inward but leaving some gap between the sensitive hairs.
- Pitcher plants have leaves that are modified with pitcher like vessels which contain a digestive juice. The rim of the vessel is brightly coloured with a sugary nectar.
FEEDING HABIT IN AMOEBAS
Amoebas are found in the bottom of muddy ponds. It feeds on food particles smaller than itself. There is no mouth or alimentary canal. When it comes across a food particle e.g. diatom, it shoots out 1 or 2 pseudopodia which flows around the food particle. On contact with the food particle, the pseudopodia becomes cup-shaped and engulf the food. The process is called PHAGOCYTOSIS or ENGULFMENT. By the retraction of the pseudopodia, the food is taken into the cytoplasm in food vacuole in which digestion of food take place. Digestion of food is intracellular and necessary digestive enzymes are poured into the food vacuole. From the surrounding cytoplasm. The absorption of the digested food into the cytoplasm mark the end of the feeding process. Undigested food material is egested from the cytoplasm into the surrounding water. Amoeba is using HOLOZOIC method of nutrition.
FEEDING HABITS IN HYDRA
Hydra is a carnivorous organism that sting its prey with specialized organelles called NEMATOCYST. It also uses the tentacles to push the food into its mouth. The organism feed on smaller micro-organism that swim around in the aquatic habita e.g. Daphina & flea & insect larvae. With the food in the gastro vascular cavity, specialized cell secrete digestive enzyme that soften the tissue of the prey into pieces. The food particles are then taken to gastro- dermal cell by phagocytosis and food molecules are hydrolyzed within food vacuoles after digestion of the meal. Undigested material remaining in the gastro- vascular cavity are eliminated through the single opening which functions as mouth and anus.
WEEK 9
TRANSPORT SYSTEM
Transport system in plant and animal refer to the movement of metabolic materials from various part of the organism where they are produced to the part where they are either used, stored or eliminated.
NEED FOR TRANSPORTATION
The primary purpose of the transport system is to transport material through the body of plant and animal
1. For regulation of body temperature by transporting and distributing heat produced in the body.
2. It is necessary for every cell of the organism to obtain all the essential materials for its metabolism e.g. Oxygen, water e.t.c.
3. For regulation of water balance in the body of the animal.
4. To move hormones both in plant and animal from where they are produced to the area where they are needed.
5. Useful substances that can stores are transported to their storage organ or tissue.
6. For the removal and disposal of waste product of metabolism such as carbon (iv) oxide, water, urea from body.
7. Regions of active cell division need substances to enable them build new protoplasm for the purpose of forming new cell.
8. Substances required by reproductive cell for development are moved to them by transport system.
MATERIALS FOR TRANSPORTATION IN ANIMAL
Materials for transportation in animal include water, gases, digested
food and other nutrients and various secretion such as enzyme, hormone,
excretory product and excess material for elimination and storage.
Materials for transportation in plant. They include excretory product,
Water, oxygen, nitrogenous waste product/latex, amino acid, glucose,
Lipids, auxin or hormone and materials.
MEDIA FOR TRANSPORTATION
CYTOPLASM:- Cytoplasm is used as medium for transportation in lower
Unicellular organisms such as amoeba and paramecium. Materials such as
Glucose, amino acid, oxygen, water, and carbon (iv) oxide are transmitted
From one part of the cell to another through the cytoplasm.
BLOOD:- The blood in its fluid state is able to move large materials over the
Entire body through the blood vessels such as arteries, vein and capillaries
From where they are produced.
LYMPH:- Lymph is a fluid similar in composition to tissue fluid although it
Contains extra lymphocyte, there is no red cell present. They return fluid to
the main vein through opening on the subclavian vein through the neck.
Examples of lymph vessels is the lacteal which transport fatty acid and
glycerol.
COMPOSITION AND FUNCTIONS OF BLOOD AND LYMPH
The transport system in man and most other vertebrates comprises of:
1. A circulatory fluid (Blood and lymph).
2. A pumping organ (Heart).
3. A system of closed vessels (Arteries, vein and capillaries).
Blood is a fluid tissue made up of about 55% fluid called PLASMA and 45%
Cell.
PLASMA
The plasma is the fluid portion of the blood which is amber or straw in
colored made up of about 90% water and 10% dissolved substances. The
substances dissolve in the plasma includes the followings.
1. Mineral salt such as bicarbonate, phosphate, chlorine sulphate, sodium, calcium and potassium
2. Food substance such as glucose, fat and amino acid
3. Blood proteins such as Albumin, Globulin, Fibrinogen Prothrombin
4. It also contains excretory substance mainly urea
5. It contains hormones
6. It contains antibodies
Function of the plasma
- It helps to transport the dissolved substances present in it such as digested food, hormones, antibodies e t c
LYMPH
Lymph is a colored liquid association with lymphatic system. It is a fluid
similar to tissue fluid. They return fluid to the main vein below the neck.
Lymph move through the vessel called located. Some swellings do exist in
group long nodes where lymph passes to be made pure before entering
into the blood stream.
Function of lymph
1. Body defense: the lymph nodes produce white blood cells to engulf disease causing micro organisms by phagocyte
2. It removes foreign bodies from the cell
3. It produces white blood cell help to fight pathogenesis organisms invading the body
4. The lymph gland filters bacteria from the body fluid thereby stopping the spread of such infection
5. The lacteal which is connected to the lymphatic system absorb fatty acid and glycerol for transportation
The second portion of the blood is solid which are called blood cell or blood corpuscle
1. Red blood cell or erythrocyte
-The red blood cells are small round or disk- like and concave In shape
-They have no nucleus or they are not nucleated
-They have short life span of 4 month before being destroyed by the liver
-They are produced by the bone marrow
-It contains red pigment called hemoglobin
FUNCTION OF RED BLOOD CELL
The red blood cells help to transport oxygen round the entire body when the hemoglobin combines with oxygen to form oxy-hemoglobin.
1.
WHITE BLOOD CELL OR LEUCOCYTE.
They are irregular or amoeboid in shape.
They are large, colorless and contain nucleus.
They are larger than red blood cells in diameter and fewer in number.
They are produced in the red bone narrow, lymph nodes or spleen.
They have a longer life span than the RBS.
There are two types of white blood cells:
1. Phagocytes: Which destroy bacteria by the process of ingestion called ENGULEMENT OR PHAGOCYTOSIS
2. Lymphocytes: They destroy microbes by producing anti- bodies which stick to the surface of the germs and kill them.
FUNCTIONS OF WBS
The white blood cells help to defend the body against disease by ingesting bacteria and viruses.
BLOOD PLATELETS OR THROMBOCYTE.
They are tiny irregular cell fragments without nucleus
They are produced in the red bone marrow.
FUNCTIONS OF PLATELET
The platelets help in blood clothing.
FUNCTION OF BLOOD
1. The blood help to transport oxygen in form of oxy-hemoglobin round the body.
2. The blood help to regulate body temperature by distribution the heat produced in the liver and muscles through out the body.
3. The blood helps to transport digested food.
4. The blood helps to transport excretory product from where they are produced to where they will be evacuated or eliminated.
5. The plasma content of the body helps to transport hormone.
6. The white blood cells defend the body against infection from microbes or pathogens.
7. The lymph help the body to produce anti-bodies which confer immunity on the body of human being.
8. The platelets in the blood help to initiate the process of blood clotting when injury is sustained.
9. The blood transport water to every part of the body.
WEEK 10
CIRCULATORY SYSTEM IN VERTEBRATE
Circulatory system is defined as continuous movement or flow of blood round the body which involves the heart and blood vessels.
TYPES OF CIRCULATION
i. Closed circulation
ii. Open circulation
iii. Single circulation
iv. Double circulation
v. Pulmonary circulation
vi. Systemic circulation.
CLOSED CIRCULATION: is a system made up of blood vessels called arteries from the heart which branch many times into a smaller unit called capillaries but eventually join up with other vessels called veins that is connected to the heart. Some invertebrate like annelids (earthworm) and all vertebrates have closed circulatory system.
OPEN CIRCULATORY: is a type of circulatory system where the blood vessels lead out of the heart end up in a blood space called HAEMOCOEL. In this space, the blood comes into direct contact with the cell after, which it is returned to the heart. Arthropods and some Mollusc use open circulation.
SINGLE CIRCULATION: is defined as a type of circulatory system in which the blood passes through the heart once every time the blood makes one complete circulation e.g. fish which has only two chambers heart i.e one auricle and one ventricle.
DOUBLE CIRCULATION: is a type of blood circulation in which the blood passes through the heart twice every time the blood makes one complete movement round the body. Each time the blood passes through the heart, it goes through a separate path way. This types of circulation system is found in mammals. Double circulation give rise to two pathways namely Pulmonary and Systemic circulation.
PULMONARY CIRCULATION: This is the movement of blood between the heart and the lungs for oxygenation.
IMPORTANCE OF PULMONARY CIRCULATION
1. Pulmonary circulation prevents mixing of deoxygenated blood with oxygenated blood.
2. It makes oxygen available in the life ventricles for system circulation.
3. It checks accumulation of water and enhances renewal of blood.
4. It prevents deoxygenated blood from entering the systemic and coronary circulation.
MECHANISM OF PULMONARY CIRCULATION
The superior vena cava returns blood from the head and the upper limbs into the right auricle. Blood from the lower limbs and the abdomen is brought to the right auricle by the inferior vena cava. The right auricle contract and the blood is forced through the tricuspid valves into the right ventricle. The right ventricle contact forcing the blood into the pulmonary artery. The pulmonary artery is divided into numerous arterioles which in turn are subdivided into microscopic capillaries in the lungs. With the thin walls of the capillaries and the moist nature of individual cells of the lungs, exchange of gases, nutrients and waste take place between the blood and the cell of the lungs. The capillaries unite to form VENULES. The veinules in turn from the pulmonary vein that bring back the oxygenated blood into the left auricle of the heart.
SYSTEMIC CIRCULATION
It is the movement of blood between the heart and all part of the body apart from the lungs. When oxygenated blood arrive at the left auricle from the lungs. The left auricle relaxes and the left ventricle contrasts. Blood is forced up into the AORTA, then to all part of the body. Blood rich in oxygen and other nutrients is taken to all living cells in the body. The aorta is the main artery leaving the heart, it forms anorthic arch and give out three branches before running down the truck.
BLOOD VESSELS AND THE HEART
The blood vessels are the tubes through which the bloods flows away or to the heart.
ARTERIES:- Arteries receive blood directly from the heart. To withstand the high pressure of blood that flow in them, they have thick wall which are muscular and elastic. These walls also enable arteries constrict or dilate and thus regulate the amount of blood flowing in them.
VEIN carries blood to back heart. The blood in them is at low pressure. Thus, vein is not as thick, muscular, or elastic as that of an artery of about the same size. Most veins have valves inside them to prevent backflow of blood.
CAPILARIES- capillaries are microscopic blood vessels form a network linking arteriole to venules. The blood in the capillaries at the arteriole end is at higher pressure that at the venule ends. The tiny wall of the capillaries make it easy for oxygen, nutrient and waste product to diffuse between the cell and blood
Difference between artery and vein
ARTERY VEIN
1. It has thick muscular wall It has thickness muscular wall
2. It has elastic wall Its wall is not elastic
3. It carries blood away from the heart It carries blood to the heat
4. All arteries carry oxygenated blood All veins carry deoxygenated blood except
except pulmonary artery Pulmonary vein.
5.The blood in the artery is pink or bright The blood in the vein is dark red in colour
In colour.
6. Blood at high pressure and flow fast. The blood pressure is low and flows slowly
7.Valves are absent except semi- lunar valves Valves are present
Near the heart.
8. Arteries are deeply located in the Veins are superficially located in the muscle
Muscle.
9. It has small lumen. It has large lumen
THE HEART
The heart is a muscular and the most powerful organ responsible for pumping blood round the body. The heart lies in the chest just behind the breast bone and in between the two lungs. It enclosed in a two layers tough membrane called PERICARDIUM. The space between the two layers is filled with pericardial fluid. The fluid reduces the friction caused by the pumping movement of the heart between the heart wall and special muscle called the CARDIAC MUSCLE which enable it go on pumping.
THE STRUCTURE OF THE HEART
The heart has four chambers: the two upper thin wall auricles and the two lower thick wall ventricles. The right side of the heart is completely separated from the left side by a wall called the SEPTUM. Two large veins, i.e. the superior (vena cava and the inferior vena cava bringing back red deoxygenated blood from the various parts of the body except the lungs open into the right auricle.
The Pulmonary veins bringing bright red oxygenated blood from the lungs open into the left auricle. The right auricle opens into the right ventricle. The opening is guarded by tricuspid valve. This valve has three flaps which are attached by cord-like tendon called chordate tendinae to the wall of the ventricle. The opening of the left auricle into the left ventricle is guarded by bicuspid valve. This valve is functionally and structurally similar to tricuspid valve except that it has two flaps instead of three.
The right ventricle opens into the pulmonary artery which branches into two. One leading to the right lungs and the other leading to the left lungs. These carry deoxygenated blood to the lungs. The left ventricle opens into the large AORTA which branches to distribute oxygenated blood to all parts of the body except the lungs. Semi-lunar valves in the arteries prevent back-flow of blood from the arteries into the ventricle.
MECHANISM OF TRANSPORTATION IN LOWER AND HIGHER PLANT
In a simple plant like alga, bryophyte and Thallophyte materials into the cell of the body by diffusion. Within the cell materials are distributed by circulating streaming movement of the cytoplasm..
In higher land plants, special conducting tissues known as vascular tissues carry out transportation. This vascular plants include all flowering plants and non-flowering plants such as ferns and gymnosperms. Many of these plant have additional system of latex tube. A vascular bundle or tissue consist of the xylem and the phloem tissue.
PROCESSES WHICH AID TRANSPORTATION IN PLANT
The major materials being transported within the plant are gases which is carbon (IV) oxide and oxygen, water, mineral salt, manufactured food, hormones and pigment.
Absorption Of Water And Mineral Salt
Absorption of soil water into plant is through the root hairs. Root hairs absorb water from the soil by osmosis. The cell sap within the root hair is a mineral solution in higher concentration than the external soil solution. Water enters the root hair cell form the soil with the cell membrane acting as a selectively permeable membrane. The extra water taken into the cell, dilute the sap, so that it becomes less concentrated than the sap of the neighboring cell in the root cortex and therefore the water passes into the neighboring cell by osmosis and again dilutes it’s sap. This process is repeated endlessly from cell to cell until the water eventually reaches the xylem vessel in the centre of the root. Some water also reaches the xylem vessel through the cell and cytoplasm by diffusion and capillarity.
ACTIVE TRANSPORT
Active transport is the transport/ transfer of heavy metallic ion, such as heavy minerals e.g. iron and copper from the soil into the plant. This process involves expenditure of energy and against osmotic gradient. It has been determined, that this energy comes from respiration. It has been experimentally supported that the uptake of mineral is greater when the root are supplied with adequate oxygen.
Water Transport In Xylem
If herbaceous plant such as sunflower is uprooted carefully and washed clean in water, then place in a beaker containing a dilute solution of EOSIN. It will be seen that the red liquid passes through the xylem tissue only. This can be seen by examining the transverse section of the root, stem and leaf. Transport of water through the xylem tissue is brought about by the combination of:
I) Root pressure
II) Capillarity
III) Transportation pull
TRANSPIRATION: – Is the loss of water vapour from difference part of the plant shoot into the atmosphere. These part include the stomata of leaves, the cuticles of both leaf and young stem and the lenticel of the tree truck.Water loss through the stomata is called stomata transpiration while water loss through the cuticle and lenticel are called cuticular or lenticular transpiration.
Factors Affecting The Rate of Transportation
1. Plant factor
2. Atmospheric factor
3. Soil factor
Plant factor
- Leaf area
- Leaf structure
- Root system
Atmosphere factor
- Sunlight
- Humidity
- Temperature
- Wind
Soil Factor
- Availability of soil water
- Temperature
Importance Of Transpiration
- Cooling effect: – It brings about cooling effect
- It enhances translocation of mineral salt
- It enhances growth of plants
GUTTATION: – Is the loss of water in liquid form through the margins of the leaves of plants growing in a warm or moist soil in a humid atmosphere. Guttation is usually experienced at the early hours of the morning and is common among grasses. Such plants have specialized duct at the tip of the vein in the leaves. These special ducts are known as HYDATHODES.
TRANSLOCATION: – Is the transport of manufactured food substances from the leaf to all other parts of the plant. The movement is usually described as downward from the leaf to the root but it is also know to occur on the reverse direction especially in the non-growing season. Translocatiosn takes place through the phloem tissues.
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