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TRANSPORT
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EXAMPLES OF MATERIALS TRANSPORTED
INTO THE CELL
-OXYGEN
-NUTRIENTS
-WATER
-HORMONES
OUT OF THE CELL
-CARBON DIOXIDE
-UREA
-HEAT
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TRANSPORT IN UNICELLULAR ORGANISMS
-TRANSPORT MATERIALS OVER SHORT DISTANCE, SUCH AS BETWEEN
ADJACENT CELLS.
- BY SIMPLE DIFFUSION, OSMOSIS, ACTIVE TRANSPORT OR CYCLOSIS
(CIRCULATION OR STREAMING OF CYTOPLASM WITHIN THE CELLS)http://www.youtube.com/watch?v=PFtzs_cUddI&feature=player_detailpage
- ITS CELL MEMBRANE IS IN FULL CONTACT WITH ITS ENVIRONMENT.
SO, THE MATERIALS NEEDED ARE TRANSPORTED DIRECTLY INTO THE
CELL.
-IN Paramecium sp., GASEOUS EXCHANGE OCCURS BY SIMPLE DIFFUSION.
MATERIALS ARE TRANSPORTED WITHIN ITS CYTOPLASM BY CYCLOSIS.
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TRANSPORT IN MULTICELLULAR ORGANISMS
-CELL DO NOT CONTACT WITH EXTERNAL ENVIRONMENT
- THERE ARE LAYERS OF CELLS BELOW THE EPIDERMAL CELL LAYER
-SIMPLE DIFFUSION CANNOT TRANSPORT SUBSTANCES (OXYGEN,
NUTRIENTS, CO2 AND WASTE PRODUCTS) TOB THE BODU CELLS.
-NEED TRANSPORT SYSTEM TO TRANSPORT OXYGEN AND FOOD TO THE
CELLS AND REMOVE CO2 AND METABOLIC WASTES FROM THEM.
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EPIDERMAL LAYER IN MULTICELLULAR ORGANISMS
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LIVING ORGANISMS AND THEIR TOTAL SURFACE AREA TO VOLUME
RATIOS
-THE TOTAL SURFACE AREA TO VOLUME (TSA/V) RATIO : THE TOTAL
EXTERNAL SURFACE AREA OF A STRUCTURE TO ITS CAPACITY
-TSA/V RATIO OF A CELL : THE TOTAL SURFACE AREA OF ITS PLASMA
MEMBRANE TO THE VOLUME OF THE CELL.
-TSA/V OF A MULTICELLULAR ORGANISM : TOTAL SURFACE AREA OF THE
SKIN TO VOLUME OF ITS BODY
-TSA/V IS USED TO MEASURE :A) SURFACE AREA AVAILABLE FOR GASEOUS EXCHANGE
B) RATE OF MOVEMENT OF SOLUTES TO THE INTERIOR OF AN ORGANISM
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- By using a cube, we found that the TSA/V ratio of a cube is
inversely proportional to its size.
Size 1
tsa/v
-The physical implications are :a) smaller living organisms have larger TSA/V ratios. A large
TSA/V ratio helps in the efficient gaseous or solutes diffusion
b) larger living organisms have very small TSA/V ratios. A smallTSA/V ration limits the rate of gaseous or solutes diffusion.
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- How to overcome the transport problem?
- Organism A : a)unicellular organism
b)has very high TSA/V ratio
c)has cells where nutrient and oxygen molecules
can easily diffuse into the cell and waste products
diffuse out of the cells through its entire cell
surface
A
B
C
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-Organism B : a) multicellular organisms
b) has a very low TSA/V ratio
c) less surface area per unit cell for diffusion of
nutrient and oxygen molecules into its
epidermal cells
d) impossible for simple diffusion to occur
-Organism C : a) same size as organism Bb) has transport tube linking to the interior cells
c) increasing TSA/V ratio of organism
d) tube transport nutrient, oxygen and unwanted
waste molecules in and out of cells
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CIRCULATORY SYSTEM
-Circulatory system transports substances such as nutrients,
water and oxygen to the body cells and removes carbon dioxide
and other nitrogenous wastes from the body cells.
-The circulatory systems of humans and animals consist of 3
components:
a) a medium/fluid required to carry materials around the
circulatory system (blood, haemolymph)
b) vessels tubes for the medium to flow through
c) pump heart that help to propel and circulate the medium
around the body
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HUMAN BLOOD
Blood cells Plasma
Erythrocytes
(red blood cell)
Leucocytes
(white blood cell)
Thrombocytes
(platelets)
Granulocytes
basophil
Neutrophil
eosinophil
Agranulocytes
monocytes
Lymphocytes
Fibrinogen
Serum
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ERYTHROCYTES
- 5 million per mm3 of blood
-Tiny (8m), biconcave, disc shape
-Do not have nucleus, mitochondria or
ribosomes
-Full of haemoglobin
- made in the bone marrow, live for about 120
days
- Destroyed and recycled in the liver
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-Adaptations of erythtocytes:
a) have no nucleus provide more space for haemoglobin
b) transport oxygen haemoglobin combine to oxygen and form
oxyhaemoglobin
c) transport CO2 haemoglobin combine to CO2 as hydrogen-
carbonate
d) biconcave, disc shape increase the TSA/V ratio for optimum
gaseous exchange
e) small and flexible can diffuse through narrow capillary walls
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LEUCOCYTES
Leucocytes in blood
-colorless, do not have haemoglobin
-Larger than erythrocytes, fewer in number
-7000 per mm3 of blood. Raised the number
of leucocytes (leucocytosis), decrease thenumber of leucocytes ( leucopenia)
-Irregular shape, have nucleus
-Important in body defence mechanisms against disease
- divided into 2 basic types : granulocytes and agranulocytes
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Granulocytes
-Have granular cytoplasm and
lobed nucleus.
granules
Bi-lobednucleus
-Amoeboid
movement and
engulf bacteria by phagocytosis
-Produce in bone
marrow
-Divide into 3 types:
a) Neutrophils form 70% of
total leucocytes
- has multi-lobed
nucleus
- engulf bacteria byphagocytosis
b) Eosinophils 2-4% of total
leucocytes
- detoxify chemical,
reduce inflammation
c) Basophils 1% of leucocytes
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GranulocytesAgranulocytes
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AGRANULOCYTES
Have non-granular cytoplasm,
compact nucleus
Divide into 2 typesa) Monocytes
- Largest of the five types of
white blood cell
- Produce in bone marrow
- Consist 5-8% of all leucocytes
- Have bean-shaped nucleus
- Ingest bacteria by phagocytosis
b) Lymphocytes
- Has large, rounded
nucleus and small
amount of non-granular
cytoplasm
- Large nucleus contain
genes for antibody
protein production
- Produced in lymph
glands and lymphatic
nodes
- Produced antibodies
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THROMBOCYTES (PLATELETES)
- Are tiny fragments of megakaryocytes (bone
marrow cell) found in the bone marrow.
- Colourless, irregular shape, no nucleus.
- Measures about 2-3m across.
- Made in the bone marrow and last for about
6-7 days.
- Have amoeboid movement
- Important in blood clotting, repairing damaged tissues and
maintain the integrity of blood vessel wall.
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PLASMA
- Yellowish liquid which the blood cells are suspended.
- Consist about 90% water, 10% dissolved substances.
- Dissolved substances consist of plasma proteins, dissolvedgases, absorbed food molecules, excretory waste products,
hormones and salts.
- Heat produced by respiration is being absorbed by plasma.
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Content Composition
Water 90% of the plasma
As a solvent and transport mediumProteins Albumins for viscocity and osmotic balance
Antibodies e.g. globulin for immunity
Clotting factors such as fibrinogen and
prothrombin
Dissolved gases Consist of CO2 and O2
Absorbed food
molecules
Consist of glucose, amino acids, fatty acids,
vitamins
Excretory waste
products
Consist of CO2, urea, uric acid, creatinine
Hormones Adrenaline,insulin,glucagon, antidiuretic hormone
Salts Consist of dissolved ionic salts; sodium,potassium,
calcium,magnesium
Content of blood plasma
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FUNCTION OF BLOOD AND HAEMOLYMPH IN TRANSPORT
- Functions of blood:
a) transport of materials
b) defence against diseases
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FUNCTIONS OF BLOOD IN TRANSPORT
Materialstransported
Examples Transported in Transportedfrom
Transported to
Gases
Oxygen Haemoglobin
in erythrocytes
Lungs Respiring
cells
CO2 Haemoglobin
in erythrocytes Respiringcells LungsHydrogen
carbonate ions
in plasma
Absorbedfood
Amino
acidsPlasma Intestines
Liver andbody tissuesGlucose
Vitamins
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Mineral salts
Iron
Plasma Intestines
Bone marrow
Calcium Teeth and
bonesIodine Thyroid
glands
Hormones Insulin
Plasma
Pancreas Liver
Antidiuretic
hormonePituitary
gland
Kidney
Excretory
products
Urea, uric
acid,
ammonium
salts
Plasma Liver Kidney
Heat Metabolic
heat
Whole
blood
Liver,
muscles
Whole body
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FUNCTION OF HAEMOLYMPH IN TRANSPORT
- Haemolymph is the circulatory fluid in the body cavities of insects
that have an open circulatory system.
- Known as insect blood.
- Contains water, amino acids, sugars, salts and white blood cells
- Help to transport hormones, nutrients, salts and metabolic wastes
around the body.
- Does not contain haemoglobin
- Does not transport oxygen and CO2 in insects, these gases are
transported by the tracheal system.
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OPEN AND CLOSED CIRCULATORY SYSTEM
a) Open circulatory system- found in insects, crustaceans (prawns) and molluscs (snails).
- blood pump from heart aorta arteries body
cavities.
- Haemolymph reach the body cells directly
- Haemolymph diffuses between body cells and re-enters the
heart through open-ended veins.
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b) Closed circulatory system
- found in all vertebrates (human, fish) and invertebrates
(earthworms).
- blood is pump within a vessel and never comes in direct
contact with the body cells.
- can transport oxygen and other materials faster
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THE STRUCTURE OF HUMAN BLOOD VESSELS
- The heart is connected to a series of tubes called blood vessels.
-The main types of vessels : artery, arterioles, capillary, venule and
vein.
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ARTERIES
-Carry blood away from the heart at high pressure.
-Carry blood that is rich in oxygen (except in the pulmonary artery)
- have 3 layered walls consisting of:
a) endothelium inner layer, single flatten
cellb) smooth muscles and elastic fibres
thick middle layer
c) fibrous connective tissue external layer
-Able to transport blood under high pressuredue to the strength of the thick elastic fibres
-Contract their smooth muscles to decrease
the diameter of the lumen, decreasing the volume of blood flow.
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- Relax their smooth muscles to increase the diameter of the lumen
and increase the volume of blood flow.
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ARTERIOLES
-Smaller thin walled, branches of the arteries that end in capillaries.
- carry blood from arteries to the capillaries.
-Constrict and dilate to regulate blood flow and pressure.
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CAPILLARIES
-Microscopic thin-walled (one-cell thick) blood vessels.
-Carry blood from arterioles to venules.
-Have diameters of about 7-9m
-Form capillary networks in most of the organs and tissues of thebody.
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VENULES
-Small veins which carry blood from capillaries to the veins.
-Have 3 layered wall : inner endothelium, inner layer of muscle and
elastic tissue, outer layer of fibrous connective
tissue.
- Have thinner walls than arterioles.
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VEINS
-Carry a slower-flowing blood at low pressure towards the heart.
-Carry deoxygenated blood (except in pulmonary vein).
-Have 3 layered walls, but these layers are thinner and less
muscular than those in the arterial wall. So, they collapse when
empty.
-Have internal valves (semi-lunar valves) to prevent a backflow
of blood.
- Have skeletal muscle to move the blood more quickly.
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Vessels
Aspect
Artery Capillary Vein
Structure of
wall
3 layers
endothelium,
smooth muscles,fibrous connective
tissue
Single layer-
endothelium
3 layers-
endothelium,
smooth muscle,fibrous
connective tissue
Thickness of
wall
Thick Very thin Thinner than
artery
Direction of
blood flow
Away from the
heart
From arteries to
veins
Towards the heart
Valve Absent Absent Present
Oxygenated
blood
Yes (except
pulmonary artery)
Arteriole carry
oxygenated
blood.
Venule carry
deoxygenated
blood
Carries
deoxygenated
blood (except
pulmonary vein)
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Blood pressure High Decreases from the
arteriole to the
venule
Low
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STRUCTURE AND FUNCTION OF THE HUMAN
HEART
-Enveloped by a membrane called pericardium.
- Made up of cardiac muscles
-Cardiac muscles are made up of muscle fibres
-Each muscle fibre is made up of
interconnecting muscle cells.
-Muscle cells are joined one to another by
intercalary disc that allow the rapidtransmission of nervous impulses from cell to
cell through the tissue.
-Myogenic, it can relax and contract on its own (do not need nerve
to stimulate).
Contractile cell
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Muscle fibre of a heart
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-Has 4 chambers :
a) 2 upper auricles / atria
b) 2 lower ventricles
-A thick muscular wall, called medium septum completely separate
the right side of the heart from its left side.
-The heart functions as 2 separate pumps side by side:
(a) The right side of the heart pumps deoxygenated blood
(b) The left side of the heart pumps oxygenated blood
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-Contraction of the atria:
(a) when the right atrium contracts, blood passes into the lower right
ventricle.
(b) when the left atrium contracts, blood passes into the lower left
ventricle.
-Contraction of the ventricle:
(a) when the right ventricle contracts, it pumps blood out into the
pulmonary arteries.
(b) when the left ventricle contracts, it pumps blood out into theaorta
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-Thickness of the muscular walls:
(a) Atria have thinner and less muscular walls because they only
pump blood down the ventricles.
(b) Right ventricle has to pump blood to the lungs, and therefore
has a thick wall.
(c) Left ventricles has to pump blood to the body and has thickest
wall.
-Has 4 valves :
(a) Tricuspid valve on the right side of the heart
has 3 flaps
prevents the backflow of blood into
the right atrium when the
right ventricle contracts.(b) Bicuspid valve/ mitral valve
on the left side and has 2 flaps
prevents the backflow of blood into
the left atrium when the left
ventricles contracts.
Tricuspid
valve
Bicuspid
valve
Aorta
Pulmonary
artery
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(c) Semi-lunar valves
found at the base of pulmonary artery and aorta
prevent the backflow of blood into the right and the left
ventricles when they relax.
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Bicuspid valve (3D)Upper part tricuspid valve
Lower part bicuspid valve
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TESTING YOURSELF
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THE CIRCULATION OF BLOOD IN HUMAN
-Humans have closed, double circulatory system:
a) It is closed because the blood is contained within the heart and
the blood vessels, does not come in direct contact with the
respiring body cells.
b) It is double circulatory system because the blood passes
through the heart twice for each complete circuit of the body.
-Consist of 2 sub-circuits:
(a) Pulmonary circulation heart lung heart
(b) Systemic circulation heart rest of the body heart
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Pulmonary
circulation
Systemic
circulation
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PULMONARY CIRCULATION
- Deoxygenated blood from the heart is pumped from the right
ventricle through the pulmonary artery.
-Oxygenated blood from the lungs then return to the left atrium
through pulmonary vein.
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SYSTEMIC CIRCULATION
- Supplies blood to all parts of the body, except the lungs.
-Oxygenated blood is pumped from the left ventricle into the aorta
before it is distributed by:
(a) subclavian arteries to the arms
(b) carotid arteries to the neck and head
-Superior vena cava collects deoxygenated blood from the upper
part of the body and return it to the right atrium.
-Inferior vena cava collects deoxygenated blood from the lower
part of the body and returns it to the right atrium.
-Heart receives blood form a pair of coronary arteries leading from
the aorta.
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THE PUMPING OF HEART
- Two atria contract simultaneously:a) blood from the right atrium is forced into the right ventricle
b) blood from left atrium is forced into the left ventricle
- Two atria relax simultaneously:
a) left atrium receives blood from the pulmonary veinsb) right atrium receives blood from the superior upper part of
body) and inferior (lower part of body) vena cavae.
- After a slight pause, two ventricles contract (systole)
simultaneously :
a) blood in the right ventricle is forced into the pulmonary artery
and blood in the left ventricle is forced into the aorta.
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b) Blood in the right ventricle and the left ventricle is prevented
from flowing back into the atria by the closure of bicuspid
tricuspid valve.
c) The simultaneous closure of the two valve will produce lubsound.
- When 2 ventricles relax (diastole):
a) the volume of the ventricles increase; drawing in blood from
the atria.
b) blood in the arteries (pulmonary artery and aorta) is prevented
from flowing back to the ventricles by the closure of both the
two semilunar valves, produce dub sound.
- A heartbeat consist of a systole (lub sound) and a diastole
(dub sound).
- Normal heartbeat 72 times/minute
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BLOOD PRESSURE AND THE REGULATORY MECHANISM
- Blood pressure is the force that blood exerts on the walls of the
blood vessels, which is measured in millimetres of mercury
(mmHg).
- Caused by the contraction of the heart and by the muscles thatsurround blood vessels.
- Blood pressure in the arteries is highest when the ventricles
contract (systole) and force the blood into the pulmonary artery
and the aorta.
- Blood pressure decreases when the two ventricle relax (diastole).
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-Normal blood pressure : 120/80 mmHg , 120 over 80
- The first number represent the pressure when the ventricles
contract.
-The second number represents the pressure when the ventricle
relax.
-In human, blood pressure is regulated by:a) nervous system send impulse to speed up or slow down the
heart rate
b) kidney regulate blood pressure by controlling the amount of
fluid in our blood. When blood pressure is too high, kidneysremove water from the blood (less volume of blood), blood
pressure become lower.
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REGULATION OF BLOOD PRESSURE BY THE NERVOUS SYSTEM
-Baroreceptor / stretch receptors groups of nerve fibres within
the walls of the carotid sinus (a swelling of the internal carotid
artery) and the aortic.
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-If blood pressure in the arteries is high:
a) the baroreceptors detect it and send impulses from the sensory
nerves to the cardiovascular centre in the medulla oblongata ofthe brain.
b) Cardiovascular centre of the brain sends impulses (in the vagus
nerve of the parasympathetic nervous system) to the heart to
decrease the heart rate and also the cardiac output (volume of
blood pumped by the heart).
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c) At the same time, the cardiovascular centre sends nervous
impulses to relax the smooth muscles of the arterioles,causing the arterioles to dilate (vasodilation) and reduce the
resistance to blood flow.
d) A reduced heart rate, a lowered cardiac output and a
vasodilation of the arterioles will help to reduce the blood
pressure.
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If bl d d t l
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-If blood pressure drops too low:
i) The baroreceptors detect it and stimulate the cardiovascular
centre to send the nervous impulse (via the sympathetic nervous
system): to increase the heart rate (via the sympathetic nerve)
to stimulate the smooth muscles in the arterioles to contract
(vasoconstriction) to decrease flow of blood.
ii) An increased heart rate and a vasoconstriction of the arterioleswill help to increase blood pressure.
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(Baroreceptor)/medulla
Stimulatesmooth
muscle
in the
arterioles
to contract
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-Single circulation blood passes through the heart only once in
a complete circulation of the body
-Double circulation blood passes through the heart twice in acomplete circulation of the body
lizards, snakes, and turtles have incomplete septums,
oxygenated blood and deoxygenated blood may
mix to some degree.
In crocodiles a complete septum and a valve prevent this
from happening.
FISH
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FISH
- Has a simple two-chambered heart, consisting of an atrium and
ventricle that are separated by atrio-ventricular valve.
-Atrio-ventricular valve prevents the backward flow of the blood
from the ventricle into the atrium.
-Blood circulation:
a) ventricle of the heart pumps deoxygenated blood to the capillary
network of the gills to be oxygenated.
b) Arteries carry the fully oxygenated blood from the gills to
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b) Arteries carry the fully oxygenated blood from the gills to
various parts of body capillaries.
c) Deoxygenated blood from the body capilaries returns to the
atrium of heart.
Heart
(ventricle)Gills Body
Heart
(atrium)
-Fish have a
a) single circulation blood is pumped through the heart only
once.
b) closed circulation blood is always contained within the
heart and blood vessels.
-Disadvantage of the single circulation single heart has to pump
blood through the gill capillary network and the body capillary
network. Thus, reduce blood pressure and sluggish flow of blood
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AMPHIBIANS
- Has 3 chambered heart, consist two atria and one ventricle
(partially divided).
-Blood circulation:
Pulmonary artery carries blood
from the ventricle to the
pulmonary capillary network,where gas exchange occurs.
Pulmonary vein returns
oxygenated blood from the lungs
to the left atrium of the heart
Vena cava returns deoxygenated
blood from the systemic capillaries
to the right atrium.
Single ventricle receives both
oxygenated blood and
deoxygenated blood.
Pulmonaryartery Pulmonary
vein
Vena
cavae
Aorta
When the ventricle contract a mixture of oxygenated and
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When the ventricle contract, a mixture of oxygenated and
deoxygenated blood is pumped into both the pulmonary artery
and aorta.
-Amphibians have: incomplete double circulation although blood is pumped through
the heart twice in a circulation,
there is a mixing of oxygenated
and deoxygenated blood in the
ventricle. closed circulation blood is contained within the blood vessel
-Advantage for incomplete double circulation is higher blood
pressure, so the flow of blood is more efficient compared to fish.
BIRDS
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BIRDS
-Have 4-chambered heart that completely separate oxygenated and
deoxygenated blood.
-Septum of the heart is complete, providing 2 separate circulatory
systems:
Pulmonary circulation right atrium and right ventricle
receives deoxygenated blood fromthe body and send it to the lungs
Systemic circulation the left atrium and left ventricle receive
oxygenated blood from the lungs and
sends it to the body tissues.
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-Birds have higher metabolic rate than humans, the pulse rate of
chicken can reach 400 beats/minute.
-Its ventricle have more muscle mass and less chamber space than
human.
BLOOD CLOTTING
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BLOOD CLOTTING
-Importance of blood clotting:
a) prevents excessive blood loss which make blood pressuredangerously low.
b) prevents the entry of microorganisms and foreign particles
into the body
c) forms scabs and helps in the healing of wounds
d) maintains the circulation of blood in a closed system
MECHANISM OF BLOOD CLOTTING
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MECHANISM OF BLOOD CLOTTING
- Blood flowing in blood vessels is prevented from clotting by asubstance called heparin (family of carbohydrate) found in the
blood plasma.
-Blood clotting is initiated by the:
a) clotting factors from damaged cells e.g. fibrinogen, prothrombin, thromboplastin, calcium ions
b) Collagen fibres from damaged blood vessel wall
- Mechanism of blood clotting:
Damaged blood vessel,I th f l i
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Damaged blood vessel,tissue or platelets releasean enzyme,thrombokinase (also
known as thromboplastin,which is a protease)
In the presence of calciumions and vitamin K,thrombokinase convertsthe protein prothrombin to
thrombin
Thrombincatalyses theconversion of thesoluble proteinfibrinogen toinsoluble fibrin
Fibrin, a fibrous
protein, form ameshwork of fibresover the woundtrapping the red bloodcells and seals thewound
The trappedcells dry andharden forminga protectivescab.
IMPAIRED BLOOD CLOTTING MECHANISM
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IMPAIRED BLOOD CLOTTING MECHANISM
a) Deficient in calcium and vitamin K:
o It will take a longer time than normal
o cause bleeding
b) Haemophilia
Blood is unable to clot because the deficiency of blood
proteins
Cause bleeding or death
c) Thrombosis
Thrombosis is the formation of a clot or thrombus inside a
blood vessel, blocking the flow of blood. The blockage stops the tissues from receive blood flow and
oxygen
cause damage to the tissues in that area
A l t f d i t h t tt k
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A clot formed in coronary artery cause heart attack.
A clot formed in the brain cause strok.
Heart attack Strok
LYMPHATIC SYSTEM
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LYMPHATIC SYSTEM
-The space between tissue cells
interstitial space
-Interstitial space is filled with a
colourless liquid interstitial fluid
-The formation of interstitial fluid andlypmh :
a) Blood enters the arterial ends of the
capillary network under high pressure
b) Endothelial cell walls of the capillaries act as filter. Large cellularcomponents (red blood cell) and large protein molecules cannot
pass through. Only water and dissolved substances of
the plasma (oxygen, products of digestion and hormone) can
diffuse out of the cell.
c) Blood plasma diffuse out into the interstitial spaces to form
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c) Blood plasma diffuse out into the interstitial spaces to form
interstitial fluid.
d) The process of producing interstitial fluid from the blood is
called ultrafiltration.
e) The interstitial fluid circulates among the tissue cells and
returns to the blood circulatory system in two ways:
(i) passes into the venous end of the capillaries
ii) drain into the lymph capillaries as lymph
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ii) drain into the lymph capillaries as lymph
f) Lymph and interstitial fluid have the same composition, thedifference is interstitial fluid is found between the cells, while
lymph is found inside the lymph vessel.
Fluid
CharacteristicBlood Plasma Interstitial fluid Lymph
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Characteristic
Appearance Red Light yellow Pale brown
colour
Clear watery
fluid, sometimes
yellowish
Location Within the heart, arteries, veins
and capillaries
Interstitial
space
Within the
lymph vessel
Originate from Bone marrow,
lymph nodes,
thymus gland
Water and
dissolved
substances
absorbed byalimentary
canal
Plasma Interstitial fluid
and fatty acids
absorbed by the
ileum
Function Transport and
defence
Transport
over long
distance
Transport over
short distance
Transport and
defense
Moved by Pumping of the heart, muscle
contraction, breathing action
Hydrostatic and
osmotic forces
Hydrostatic
forces, muscle
contraction,
breathing action
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Direction of
flow
Circulates around the
body and back to the
heart
Out of the arterial
end and returns into
the venous ends of
the capillaries
From the tissues
and towards the
heart
Contents Blood Plasma Interstitial fluid Lymph
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y p
Water
Plasma
proteins(albumin,
globulin,
fibrinogen)
X (proteins
remain inblood
capillaries)
Platelets X X X
Leucocytes X X (lymphocytes)
erythrocytes x x x
Ions
(Na+,K+,Ca2+)
Nutrients
(glucose,
amino acids,
fatty acids,
vitamin)
(more fats
from lacteal)
Waste products
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Waste products
(urea, uric acid)
Gases
Hormones
- The importance of interstitial fluid:
a) tissue fluid fills the interstitial spaces between the tissue cells,
providing them with a stable external environmentb) nutrients and oxygen from the bloodstream in the capillary
network diffuse across the capillary walls into the interstitial fluid
and then into the tissue cells.
c) waste products that accumulate within the active cells diffuse
in the opposite direction across the interstitial fluid from the cells
to the capillaries.
STRUCTURE OF THE LYMPHATIC SYSTEM
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-Lymph is found inside the lymph vessels.
-The composition of lymph is similar to interstitial fluid but with
more fats.
-Main structures of the lymphatic
system:a) Lymphatic capillaries:
- larger in diameter than the
blood capillaries
- located next to blood
capillaries in tissue spaces
- very permeable to tissue
fluid
- found as lacteals in the villi
of the small intestine
b) Lymphatic vessel
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b) y p at c esse
- formed from lymph capillaries
- similar as veins (have 3 layered walls), but have thinner
walls and more valves
- carry lymph away from the tissues
c) Lymph node
- small round or oval structures
- contains a network of fibres and irregular channels acting
like a filter- filter lymph when it
flows through the
nodes
- eliminates bacteria
and cellular debris byphagocytosis
d) Spleen
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) p
- an organ located on the left side of the abdomen near the
stomach
- produce lymphocytes, filters the
blood, store blood cells, destroy oldblood cells.
e) Lymph ducts (larger lymph vessel)
- lymph vessels drain their contents
back into the bloodstream- Thoracic duct (left lymphatic duct)
and right lymphatic duct.
-Movement of lymph within the lymphatic system;
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Movement of lymph within the lymphatic system;
a) interstitial fluid drains into the lymph capillaries to form lymph
b) lymph capillaries join together to form larger lymphatic vessel
c) the walls of the lymphatic vessels contain
valve-like pores that allow the entry of cell
debris and bacteria
d) the contraction and relaxation of the
skeletal muscle contract and relax the
lymphatic vessel, pushing lymph to the
lymph nodes
e) Semilunar valves within the lymphatic
vessels keep the flow of lymph in one
direction
f) Lymph nodes remove the suspended solid and bacteria from
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) y p p
the lymph by phagocytosis
g) The lymphatic vessels return the lymph to the heart via two ducts:
i) Right lymphatic ducts- drain lymph from the right arm, right side of head and the
thorax and opens into
the right subclavian vein
near the heart
ii) the thoracic duct (leftlymphatic ducts) drains
lymph from the rest of the
body into the left
subclavian vein near the
heart
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Right subclavian vein
- Lymph is moved along the lymph vessel by:
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a) Hydrostatic pressure of interstitial fluid- push lymph along the
lymphatic capillaries
b) Contraction of skeletal muscle lymph flow along the lymphaticvessel
c) Valves within lymphatic vessel lymph flow away from the tissue
to the heart in one direction
d) Inhalation reduce pressure in thoracic cavity and drawing lymph
towards the thorax.
Lymphatic capillaries Lymphatic vessel Lymphatic nodes
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Lymphatic capillaries Lymphatic vessel Lymphatic nodes
Lymphatic vessel
Right lymphatic duct
Left lymphatic duct
Superior vena
cavaeHeart
Right subclavian
vein
Left subclavian
vein
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-Function of lymphatic system:
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a) transport interstitial fluid back to the bloodstream
b) distributes fluids and nutrients in the body and drains excess
fluids and protein so that tissues do not swell upc) transport fat and fat-soluble vitamin from small intestine into
the blood circulation
d) provides immunological defence against disease by:
(i) produce lymphocytes and antibodies to fight and destroy
microorganisms(ii) filtering out microorganisms and other foreign substances
from the lymph by the lymph nodes and from the blood by
the spleen.
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WHEN INTERSTITIAL FLUID FAILS TO RETURN TO THE
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CIRCULATORY SYSTEM
-Too much interstitial fluid is produced, but little or none isreabsorbed back into the circulatory system.
-Cause the organs and tissues of the body to swell up- oedema
-Oedema can be caused by:a) increase in the capillary blood
pressure, forcing an excess fluid
leakage to the interstitial space
b) blockage of the lymphatic vessel
which slows down the drainage
of excess interstitial fluid.
-Elephantiasiscaused by the blockage of the bodys lymphatic
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system by certain parasitic round worms leading to oedema.
ROLE OF THE CIRCULATORY SYSTEM IN BODY DEFENCE MECHANISM
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Line of defencemechanism
Inborn, nonspecificdefence mechanism
First line ofdefence
- Skin
-mucous
membrane
Second line ofdefence
-White blood cell
Acquired, specificdefence mechanism
Third line of defence- Lymphocytes
- Antibodies
-First and second lines of the defence mechanism:
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a) nonspecific they do not distinguish infectious pathogens
b) inborn they are natural built-in defences
- for example :skin act as barrier to the pathogens
: phagocytesengulf pathogens
c) provide immediate protection against invading pathogens.
-Third line of defence mechanism:
a) specific distinguish specific pathogens. For example,
lymphocytes produce specific type of antibody to fight
pathogens.
b) Acquired and developed
c) takes a longer time to be effective, but remember the pastinfections. So, it can be better prepared for future invasions by the
same type of pathogens.
FIRST LINE DEFENCE
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-Skin
provides a continuous layerprotect a whole body.
Few microorganisms canpenetrate the layers of deadcells at the surface of the skin.A cut in the skin allow themicroorganisms to enter the body.
Blood clots plug the wound and prevent the entryof microorganisms.
-Mucous membrane
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lines all tissues and organs such as respiratory,digestive, urinary and reproductive tracts.
secrete mucus, which is thick, slippery liquid thatprotect the membrane and keep it moist and soft.
protect the interior surfaces of the body that may beexposed to pathogens
-Both the skin and mucous membrane are nonspecificdefence because:
a) use the same barrier against all types ofmicroorganisms
b) not directed against any particular pathogens
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CHEMICALS USE BY SKIN AND MUCOUS MEMBRANE
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CHEMICALS USE BY SKIN AND MUCOUS MEMBRANE
-Perspiration/sweat Excreted from sweat glands contains lysozyme and
acids that destroy harmful bacteria and inhibits thegrowth of fungi.
-Lysozyme
also present in tears, saliva and nasal secretion
-Sebum low pH prevents the growth of certain microorganisms
and fungi
- Mucus trap microorganisms and dirt particles
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trap microorganisms and dirt particles.
-Cilia little hair that carry the mucus,trapped microorganisms and dirttowards the glottis to the throat
- Acid in gastric juice kills microorganisms present infood or water on in swallowedmucus.
SECOND LINE DEFENCE
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-Take action when pathogens can penetrate the skin
or mucous membrane.
-Nonspecific immune response because use samemethod of defence to all type of pathogens.
-The nonspecific immune response include:a) phagocytosiscarried out by white blood cells such
as neutrophils, macrophages andoccasionally eosinophil.
b) natural killer cellsdestroy infected cells and pre-cancerous cells.
c) Inflammationinvolve redness, heat, swelling, pain
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d) Feverhigh temperature kill bacteria bydenaturing their protein and help healing
process
PHAGOCYTOSIS
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-Phagocytosis (phago = eat; cyte = cell) attack,
engulf and destroy pathogens
-Two common types of phagocytes are neutrophils andmacrophages
-Neutrophils: circulate freely through the blood vessels squeeze between cells of the capillary wall to reachthe site of infection, attracted by the chemicals
released by the microorganisms (chemotaxis). first phagocytes to arrive at the injured tissues beforemacrophages.
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-Macrophages
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p g another type of phagocyte developed frommonocytes (white blood cells)
longer-lived and arrived at the inflamed site some3-7 days later after the neutrophils.
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Phagocytes extendits plasmamembrane(pseudopod) aroundthe pathogens
Bacterium engulfedand enclosed in aphagocytic vesicle(phagosome)
Lysosome, amembrane-boundorganelle containing
hydrolytic enzyme,fuse with phagosometo formphagolysosome
Bacterium is
destroyedby enzymes
Afterdigestion,indigestiblematerial is
dischargedfromphagocytes
PROCESS OFPHAGOCYTOSIS
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NATURAL KILLER CELLS
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NATURAL KILLER CELLS
INFLAMMATION
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THIRD LINE OF DEFENCE
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- Immunity : ability of the human body to resist infection
- Immune response : bodys defence reaction when anantigen is recognized and specific antibodies are
produced by lymphocytes to defend againstpathogens
- Antigen : foreign protein molecule (bacteria, virus,fungi) that enter the body and stimulate the
production of antibodies
- Antibody : a protein substance produced by immunesystem to recognize antigen.
: Y shaped protein molecule that also knowni l b li
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as immunoglobulin.: functiondestroy or weaken a pathogen and
neutralise its toxin
- 2 white blood cells that involved:a) lymphocytesproduce antibodiesb) macrophages - phagocytosis
- Antigen recognition and the production of antibodiestakes place when:
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takes place when:
When pathogens enter the humanbody, it stimulate lymphocytes toproduce specific antibodies
Lymphocytes recognize thetype of pathogen by the uniqueantigen on the surface ofpathogen
Lymphocyte produceantibodies to match themolecular shape of antigens
Antibodies attack antigens bybi di t th i ti
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binding to them, using antigenbinding sites
Antibodies start to kill thepathogen in several waysbefore it is digested bymacrophages
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WAYS WHICH ANTIBODIES HELP TO DEFENSE BODY
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a) Agglutinationb) Opsonisationc) Neutralisationd) Precipitation
AGGLUTINATION
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-Antibodies and antigens stick together and the
microorganisms clump together in large numbersmaking the antigens harmless.
-The inactive pathogens are then ingested by
phagocytes.
OPSONISATION
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- An antigen is covered with antibodies which make it
easier for ingestion by phagocytes.
-An antibody-coated pathogen can be made to burst(cell lysis), killing it before being ingested by phagocytes.
Cell produce fromdifferentiation of
monocytes
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NEUTRALISATION
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- Antibodies bind to the toxins (antigens), neutralise the
poison of the toxin.
-When an antibody binds to a toxin, it is called antitoxin
-The neutralised toxin is then ingested by thephagocytes
-Virus and bacteria are similarly neutralised to preventthem from attach and penetrate the body cells.
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PRECIPITATION
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- Antibodies bind to the soluble antigens, cause them
to precipitate.
- Then, they will be ingested by phagocytes.
VARIOUS TYPES OF IMMUNITY
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-
After an initial infection, some lymphocytes are keptin the body as a memory. This helps the body todefend itself against further attacks by the sameantigens.
-As this memory may last for years, the body is said tobe immune to the disease.
-There are 2 types of immunity:
a) active immunityb) passive immunity
Active immunity Passive immunity
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Active immunity Passive immunity
Acquired when
lymphocytes in thebody are activated byantigens to produceantibodies
Occur when a person
becomes temporaryimmune to an antigen byreceive ready-madeantibodies from anotherperson or animal.
Lasts for a long time Lasts only for a short timeas the antibodieseventually die off orremoved from the body asforeign proteins.
ACTIVE
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IMMUNITY
NATURALACTIVE
IMMUNITY
-Lymphocytes
are activated
by antigens
to produce
antibodies
- Natural
infection
ARTIFICIALACTIVE
IMMUNITY
- Antigens are
injected into the
body to artificially
stimulate the
lymphocyte toproduce antibodies
- Vaccination
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- Some vaccines are made from:a) live attenuated (weakened) pathogensmeasles,
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) ( ) p gmumps, rubella, chickenpox
b) killed pathogensinfluenza, Japanese encephalitis(J.E), hepatitis A, typhoid fever
c) toxoidbacterial toxin that has been weakenedand no longer toxictetanus, diphtheria
EFFECTS OF HIV ON THE BODYS DEFENCE MECHANISM
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-HIV : Hfor Human, because it infect humans
I - Immunodeficiency, because virus attack thebodys immune system, weakening it so thatit cannot fight other deadly disease
VVirus belong to the group, retrovirus
- AIDSAcquired, person get HIV from another infectedperson
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person.- Immune, refer to the bodys defence system
- Deficiency , making the immune systemdeficient
- Syndrome, refer to a group of illness
When HIV infects a person
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When HIV infects a person,HIV antibodies is producedto fight pathogens. But, HIVantibodies cannnot fight theinfection
HIV weakens the immune
system , attack thelymphocytes (T -cell)
HIV uses its RNA and DNA of T-
cells to replicate, thusdestroying the T-cells
Destruction of T-cells by HIVweakens the immunesystem making the
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system, making theinfected personimmunodeficient
A weak immune systemcannot effectively defendthe body against otherpathogens
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- When the immune system is weakened:a) the body becomes vulnerable to a variety of
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a) the body becomes vulnerable to a variety ofinfections and cancers.
b) other infections take advantage of the weakenedimmune system. These called as opportunisticinfections.
c) the body becomes so weak, and the person dies.
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TRANSPORT OF SUBSTANCES IN PLANTS
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-Transport system is necessary because:a) CO2 is absorbed and transported to
photosynthesising cellsb) O2 is released from photosynthesising cells into
the atmosphere.c) water and minerals from the roots have to be
transported to the leavesd) photosynthetic products (sugar, amino acids)
have to be transported away from the leaves
for storage and to other tissues.
- Transport functions are carried out by xylem andphloem.
VASCULAR TISSUE IN STEM, ROOT AND LEAF
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-Consist of phloem and xylem.
- Roles of vascular tissue:a) xylemtransport water
support the plantsb) Phloemtransport nutrient
- Vascular bundle strand of conducting tissue
(xylem and phloem) Stemphloem is located
outward facing theepidermis, xylem is toward the centre.
Leafphloem facing at the lower part, xylemat the upper part.
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- A mature vascular bundle consist of xylem, phloemand cambium. Cambium separate the xylem andphloem.
STRUCTURE OF VASCULAR TISSUE
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- The main tissues in a stem of a dicot :a) epidermisb) cortex, that contain collenchyma, chlorenchyma
and endodermisc) vascular bundle, that contain phloem and xylem
d) the pith
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- The pith is the tissue located inside the vascular bundlering.
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g
-
Parenchyma- cells with thin primary walls that retaintheir protoplasm- Collenchyma - cells with thick primary walls that
retain their protoplasm- Sclerenchyma- cells with lignified secondary walls
that have lost their protoplasm atmaturity, i.e. are 'dead'
- Chlorenchyma - Containing Chloroplast
VASCULAR TISSSUE IN THE LEAF OF A DICOT
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- Vascular bundle consist of:a) xylemfaces the upper epidermisb) cambiumthat divides to produce xylem and
phloem cellsc) phloemfaces the lower epidermis
VASCULAR TISSUE IN THE ROOT OF A DICOT
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- Vascular tissue is packed in the centre.
- Other structures observed in the root:a) root hairextension of the epidermal cells
- increase absorption of water by the
surface
b) epidermisabsorption of water and minerals
c) cortexconsist of endodermis and parenchyma cellthat store starch.
d) pericyclelayer of parenchyma cells inside theendodermis where lateral root originate
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RELATING THE STRUCTURE OF XYLEM TO TRANSPORT
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-
Functions of xylem:a) transport water and dissolvedminerals from the root toother parts of cell (one way).
b) provide mechanical support
- Xylem consist:a) vesselb) tracheid
c) fibre (rigid secondary cell wallfor support and protection)
d) parenchyma (store food)
- Vessels Dead cells that form hollow tube, which connect
the root to the leaf
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the root to the leaf. Deposited by lignin to strengthen it and support
the stem
The structure of xylem vessel is adapted totransport water because :
o it has continuous lumen without any walls andprotoplasm within it to allow the flow of waterand minerals salts
o the walls are lignified to provide strength andprevent the water from collapsing
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- Tracheids Dead cells when matured
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Long, slender cells with tapered, overlapping end
Have thick, hard, lignified secondary cell wall Smaller lumen than xylem vessel No sieve plates at the end walls
- The movement of water in tracheids:a) water moves sideway through the pits in adjacent
tracheid cells before going upward
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tracheid cells before going upwardb) movement of water upwards is slower than in
vessel
RELATING THE STRUCTURE OF PHLOEM TO TRANSPORT
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-Transport food such as sugars and amino acids fromthe leaves for storage in stem and root
- Transport food from storage in roots to other parts of
plants.
- 2-way flow
- Components of phloem :a) sieve tube
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b) companion cells
c) parenchymad) fibres
a) Sieve tube
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- made up of a single row
of elongated and thin-wallliving cells called sieve tubecells.
- A mature sieve tube has onlythin layer of cytoplasm, nonucleus or central vacuole,lost most of its organelles
- Sieve plates separate sievetube cells at both ends.
- Sieve plates allow cytoplasmicconnections between vertically-stacked cells that willtransport food by diffusion and active transport.
b) Companion cell
lie next to each sieve tube cell
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- lie next to each sieve tube cell- has a nucleus, endoplasmic
reticulum, ribosomes andmitochondria
- provide metabolic support for thesieve tube cells in the transport of
manufactured food
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TRANSLOCATION
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- Movement of sugars and other organic materials fromone place to another within the plant body
- The importance:a) distribute food to other parts of the plants such as
seed, root, tuber.b) without translocation, plants would not be able to
metabolise food for energy, growth andmaintenance
TRANSPIRATION
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-The loss of water by evaporation from the parts of
plants through the stomata of the leaves.
-Transpiration occur:a) mainly through the open stomata90% of water
b) waxy cuticlevery little water escape through thecuticle of the leaves
c) lenticels of woody stem
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PROCESS OF TRANSPIRATION
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-There are intercellular air spaces among the spongymesophyll cell.
- Spongy mesophyll cell hasmoist surface
- Water evaporates fromthese cells into theintercellular spaces and
diffuse through the stomatato the drier air outside theleaf.
- As these border of mesophyll cells lose water, their cellsap becomes more concentrated and therefore drawswater by osmosis from the cells deeper inside the leaf.
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water by osmosis from the cells deeper inside the leaf.
- These cells in turn draw water from the xylem of theplant veins by osmosis.
-Water forms an unbroken water chain (by cohesion and
adhesion force of water molecule) from the outersurface of leaves to the roots.
-As the water evaporates from the plant leaves, theyattract other water molecules which are still in the plantsto the top.
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Transpiration in plants
THE IMPORTANCE OF TRANSPIRATION
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- The roles of transpiration:
a) cooling the plants As water evaporates from the leaves, it remove
heat from the plant in the form of latent heat of
vaporisation, thereby cooling the plant
b) Provide support by turgor pressure because water diffuse from higher concentration
to lower concentration, all the cells in the plantsbecome turgid.
c) Transport water and mineral salts
Transpiration create a transpiration pull, liftingt d di l d i l lt th l t
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water and dissolved mineral salts up the plant
from the root to the leaf.
- Negative effect of transpiration:a) if the rate of transpiration exceeds the intake of
water by the roots, plants growth would be affectedb) any excess loss of water causes the plant to wilt and
die
THE PATHWAY OF WATER FROM SOIL TO THE LEAVES
Soilwater
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water
Root haircell
Cortex
Xylem
vessel ofthe root
Xylemvessel ofthe stem
Vein lo leaf
MesophyllcellStomata
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Absorption and movement of water in plant
MOVEMENT OF WATER FROM SOIL TO ROOT
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- The cell sap of root hairs is more concentrated than
soil water.
-The high solute concentration of the cell sap is due tothe active transport of the solute molecules into the
cell.
-Water moves from the soil water into the cell sap of roothair by osmosis.
-When water enter the vacuole of the root hair cell:a) the cell sap becomes dilute and its concentration
and osmotic pressure are reduced
b) the turgor pressure of the cell increase and reduceits suction pressure
c) the cell sap become hypotonic the cell sap of
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c) the cell sap become hypotonic the cell sap ofadjacent cell
- Water from hypotonic root hair cell sap move toadjacent hypertonic cells.
-Therefore, water move out from the root hair cell into theadjacent cells, cortex and then into the xylem.
PATHWAY OF WATER UP THE STEM
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-The movement of water in the xylem up the stem iseffected by:a) root pressureb) transpiration pullc) cohesion- adhesion theory of water
a) Root pressure
- the pulling of water into the xylem from the
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p g ysurrounding cells produces a hydrostatic pressure
inside the xylem, forcing water upwards.- this positive pressure is called root pressure.
b) Transpiration pull- when water evaporates from mesophyll cells, their
cell sap becomes more concentrated
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cell sap becomes more concentrated.
- these mesophyll cells in turn draw water byosmosis from the cells foundin deeper inside the leaf.
- these inner cells which areadjacent to the veins drawwater from them by osmosis.
- the column of water iscontinuous from the root upto the leaves
- as the mesophyll cells suck water from the xylemvessel, the whole column of water is pulled up fromroot to leaf (due to cohesive and adhesive of water
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root to leaf (due to cohesive and adhesive of water
molecule)
- The pulling force is called transpiration pull
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EXTERNAL CONDITIONS AFFECTING TRANSPIRATION
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- The amount of water lost from the plant in transpiration
depend on:a) light intensityb) temperaturec) relative humidity
d) air movement
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b) Temperature- High temperature increase the kinetic energy of
water molecules which increases the rate of
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diffusion through the stomata
- the rate of transpiration is directly proportionalto temperature
c) Relative humidity
- intercellular air spaces in the leaf are saturated with
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intercellular air spaces in the leaf are saturated with
water vapour.
- water vapour diffuse from the intercellular space tothe air outside.
- this saturated water vapour diffuse out of the leaf ata :
i) higher rate if the air outside is dry (higherrelative humidity)
ii) lower rate if the air outside is damp (lower ratehumidity)
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Graph humidity
d) Air movement
- In still air water vapour that diffuse out through the
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- In still air, water vapour that diffuse out through the
stomata forms a layer of still moist air around theleaf
- Moist air decrease the rate of water vapour diffusionand drop the rate of transpiration.
- Moving air carry away this layer of moist air formedaround a leaf and increase the rate of transpiration.
- The rate of transpiration is directly proportional tothe velocity of the air current.
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THE OPENING AND THE CLOSING OF THE STOMA
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-
The uneven thickening of the outer and inner wall ofthe guard cells provide a mechanism for the openingand the closing of the stoma.
- The inner concave wall of each
guard cell is very thick, butthe outer convex wall is thinner
- For high light intensity, the rate
of photosynthesis increase andthe guard cells absorb waterand become turgid.
- Water in each guard cell push the thin outer wallthat enlarge the stomata opening.
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-Under poor light, the turgor pressure of the guard cellsdrop, it become flaccid and the stoma becomesmaller or closes.
HOW STOMA OPENS IN DAYLIGHT
Photosynthesis take place in the guard cell
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- Photosynthesis take place in the guard cell
Sugaraccumulates in
guard cell
Osmoticpressurein guard
cell
increase
Waterenter theguard cellby osmosis
Guardcell
becometurgid
Stoma opens
- Photosynthesis take place in the leaf cells
Concentration of pHStarch in the
cell is
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CO2 in the leaf cell
drops
goes
up
cell is
convertedinto sugar
Stoma open
HOW STOMA CLOSES AT NIGHT
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- Photosynthesis in guard cells stop
Concentration ofsugar in guardcell decrease
Osmoticpressure in
guard celldecrease
Waterleaves
guard cellby osmosis
Guardcell
flaccid
Stoma close
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