1. HIV (human immunodeficiency virus)
First line of defence
Second line of defence
Third line of defence
skin,mucous membrane
phagocytic white blood cells
lymphocytes, the immune system
leucocytes collected in lymph nodes, thus the
lymph nodes block and destroy pathogens
immune response - the produced antibodies
attach themselves to pathogens and inactivate
them
skin
epidermis (keratin inhibits growth of
microorganisms)
dermis
sebaceous gland, sebum (inhibits growth of
certain type of bacteria)
• virus that attacks and destroy immune system
• victims may be symptom-free for many years
• victims become vulnerable to infections
• transmission
• body fluids (blood, semen, placenta)
• breastfeeding
• unprotected sex
• contaminated needles
AIDS (acquired immunodeficiency syndrome)
saliva and tears contains antibacterial enzymes
leucocytes such as neutrophils and monocytes
act as phagocytes
T-Cells - responsible for cellular immunity
B-Cells - produce antibodies
• end stage of infection caused by HIV
• no vaccine yet
• certain drugs can slower the progress of the disease
NK-Cells - detect antigens
Immunity
Innate
Acquired
Passive
Active
Given antibodies
produce antibodies
Short term
Artificial
injection of serum
Natural
anti-tetanus
through mother's milk
or placenta
against rabies, snake venom
Artificial
vaccine
to prevent diseases
BCG, polio, chicken pox
Natural
long term
chicken pox, smallpox

2. Importance of blood clotting

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Clumped platelets (platelet plug is formed)
Prevent serious blood loss
Prevent the entry of microorganisms and foreign
particles
Maintain blood pressure
Maintain circulation of blood in a closed circulatory
system
Release of thrombokinase (a.k.a. thromboplastin)
Prothrombin >thrombokinase > Thrombin
Fibrinogen > thrombin> Fibrin
Related diseases
•causes blood plasma to form the clot
Haemophilia
Thrombosis
•Hereditary
•Deficiency of coagulating factors in the
blood
Clot
•Blood clots(thrombus) within blood
vessels
•Obstructs flow of arteries
•Embolus (moving blood clot in
bloodstream)
•Can cause stroke or heart attacks
The Lymphatic System
Lymphatic
system
Lymph
interstitial fluid that has
not been absorbed into
bloodstream goes to the
lymph capillaries
Receives unabsorbed
interstitial fluid from the
spaces between the cells
and returns it to the
circulatory system
Carries leucocytes
Lymphatic
capillaries

Thoracic
duct
Blind ended tubes
One way valves to
prevent backflow
of the lymph
produce and store
lymphocyte
Connected to lymphatic
vessels from the areas
below the diaphragm and
from the left half of the
body
Blind ended tubes
resemble veins
but have thinner
walls and larger
lumen and more
valves
protect body from
infections
Empties into the
subclavian vein
The importance of the lymphatic system


Lymph
nodes
Lymphatic
vessels
Maintain the fluid balance in the body
Excessive accumulation of interstitial fluid – Oedema
(probably caused by blocked lymphatic vessels)
Lacteal – lymph capillaries which transport droplets of
lipids and fat-soluble vitamins the bloodstream
Fluid
Red blood cells
Platelets
White blood cells
Proteins (albumin,
globulins, etc.)
Other solutes
Right
lymphatic
duct
Connected to lymphatic
vessel from right half of
the body above the
diaphragm
Empties into the right
subclavian vein
Blood
Interstitial fluid
Lymph
✓
✓
✓
✓
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✓
✓
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✓
✓
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3. The negative feedback regulation of blood pressure
The heart generates rhythmic impulses - heart muscles relax and contract
Cardiac muscle is myogenic – it is self-excitable
Two nodes that create electrical impulses in the heart:
Decrease in blood pressure
More impulses are sent to
cardiovascular control centre in the
medulla oblongata
Less impulses are sent to
cardiovascular control centre in the
medulla oblongata
Impulses sent to heart via
parasympathetic nerves
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
Increase in blood pressure
Sympathetic nerve increases
stimulation of the SA node
Result in weaker cardiac muscle
contractions and vasodilation
(widening of blood vessels)
Result in stronger cardiac muscles
contractions and vasoconstriction
(narrowing of blood vessels)
Heartbeat slows down
Increase the heartbeat rate
Blood pressure decreases to normal
level
Blood pressure increases to normal
level
Sino-atrial (SA) node - cardiac pacemaker
Atrioventricular (AV) node
Impulses of AV node are conducted by specialized muscle fibres (bundle of His and Purkinje fibres) to the
ventricular walls
Thick muscular wall of left ventricle is strong enough to create a pumping force throughout the body
Average heart rate – 72 heartbeats/min
Blood pressure
Decreases
Increases
Baroreceptors
Less stimulated
More stimulated
Nerve impulses sent to the
cardiovascular centre
Decreased rate
Increased rate
Nerve impulses sent to the
effectors
Via sympathetic nerves
Via parasympathetic nerves
Cardiac muscle contractions
and heartbeat rate
Stronger, increase
Weaker, decrease
Blood vessels
Narrows (vasoconstriction)
Widen (vasodilation)
Blood pressure
Increases to normal level
Decreases to normal level
Cardiac Cycle
a series of events that occur during one complete heartbeat which includes the contraction(systole) and relaxation(diastole) of both atria and ventricles
The SA node generates
impulses in both atria
Contraction of atria
Blood pressure in atria
increase
Diastole (contraction) of heart
Lowest arterial blood pressure
Blood is pumped into the
ventricles (deoxygenated
blood to right ventricle,
oxygenated blood to left
ventricle)
AV node is stimulated
The Purkinje fibres
conduct electrical impulses
to the heart
The ventricles contract
Blood pressure in both
ventricles increase
Systole (relaxation) of heart
Highest arterial blood pressure
Blood is pumped out of
the heart (deoxygenated
blood to lungs via
pulmonary artery,
oxygenated blood to whole
body via aorta)

4. Organisms
Type of circulatory
system
Insects
Open
Separation of
oxygenated blood and
deoxygenated blood
Number of chambers in
heart
A single blood vessel forms the heart
Two
Amphibians
Closed
Double
Pulmocutaneous
circulation and systemic
circulation
Humans
Closed
Double
Pulmonary circulation
Deoxygenated blood ->
Oxygenated blood
Systemic circulation
Oxygenated blood ->
Deoxygenated blood
Incomplete
Heart Contraction
Haemolymph flows from heart to haemocoel
Heart Relaxation
Haemolymph is draw back to heart through
ostia(pore)
Fish
Closed
Single
Gill capillaries to
systemic capillaries
Complete
Three
Four

5. ● Carries oxygenated blood (except
pulmonary artery)
● Carries blood away from heart to
various body parts
● Delivers nutrients and oxygen to cells
● Carries deoxygenated blood (except
pulmonary vein)
● Carries waste products away from cells
● Carries blood back to heart from
various body parts
● Protects body from infection
Function
Connects arterioles and veins
Blood vessels
Transport System of Human
● Water 90%
● Ions (minerals)
● Plasma proteins (albumin, globulin, fibrinogen,
antibodies)
● Hormones
● Dissolved substances (nutrients, waste product,
respiratory gases)
Circulatory System
Blood
Heart
Transport medium in animals. Its flow is
regulated by the rhythmic contractions
and relaxations of the heart.
•
•
•
•
Have nucleus
Do not have haemoglobin
Types: granulocytes and agranulocytes
Granulocytes (granular cytoplasm, lobed nuclei): nuetrophils,
basophils, eosinophils
• Agranulocytes (relatively clear cytoplasm, nuclei not lobed):
lymphocytes, monocytes)
• Produced in bone marrow
•
•
•
•
•
•
No nucleus
Have haemoglobin (red colour)
Biconcave disc shaped (increases cell's surface)
Facilitates diffusion of O2 and CO2
Produced in bone marrow
Destroyed by phagocytes in liver and spleen
Leukocytes
Erythrocytes
Structure
• Small, irregular fragments of large cells in bone marrow
• Responsible for blood clotting
Platelets
• Made of myocardium (cardiac muscle fibers)
• Consists of four chambers
• Consists of tricuspid valve and bicuspid valve (prevent back flow of blood from
ventricles to atria)
• Consists of semilunar valves (aortic valve and pulmonary valve) to prevent back flow
of blood from arteries (aorta and pulmonary artery) to ventricles
• the wall of left ventricle is thicker than the wall of right ventricle
Functions
• The heart functions as a muscular pump. Its rhythmic contractions pump
oxygenated blood into various tissues of the body.