1. Circulatory
system.

2. What’s in the
red blood
cells
digested
food
white blood
cells
oxygen
waste
(urea)
platelets
carbon dioxide
plasma
hormones

3. •
•
•
Functions of
Blood
Replenishing tissue fluid
Transport: to and from tissue cells
– • Nutrients from small intestine to cells: amino acids, glucose, vitamins,
minerals, lipids (as lipoproteins).
– • Oxygen: by red blood corpuscles (oxyhaemoglobin - 4 x O2
molecules/haemoglobin)from lungs to tissues
– • Waste products from cells: urea, CO2 (from liver kidneys / from
tissueslungs)
– Hormones to their target organs
– Heat from muscles/brain/abdominal organs to head and limbs
Defence against infection/Immunity: protection against pathogens blood
clotting; phagocytes, lymphocytes and antibodies distributed in blood.
What is HOMEOSTASIS, Sheldon?
•Homeostatic functions Maintain constancy of internal environment
(Temperature Regulation:by alter the blood flow through the skin.)

4. Blood
red blood cell
platelets
The fluid that circulates
in the
heart, arteries, capillaries
, and veins of a
vertebrate animal
carrying nourishment
and oxygen to and
bringing away waste
products from all parts
of the body. white blood cell
plasma

5. Red Blood Cells
a biconcave disc that is
round and flat without a
nucleus
contain haemoglobin, a
molecule specially designed
to hold oxygen and carry it
to cells that need it.
(oxyhaemoglobin)
can change shape to
an amazing extent,
without breaking, as
it squeezes single
file through the
capillaries.
After 4 months
breakdown in the LIVER
Iron (stored)
Bilirubin 
excreted in
the BILE

6. Platelets
Platelets are bits of cell
broken off larger cells.
No nucleus
Made in the red bone marrow
Platelets produce
tiny fibrinogen
fibres to form a net.
This net traps other
blood cells to form a
blood clot.

7. White Blood Cells
there are many different types and all
contain a big nucleus.
the two main ones are the
lymphocytes and the phagocytes.
Antibodies
lymphocytes T and
B
‘eat’ and digest
micro-organisms
Made in white bone marrow/lymph
nodes.
Mature in Thymus/ Spleen
/Lymph Nodes
some lymphocytes fight disease by making antibodies to destroy invaders
by dissolving them.
other lymphocytes make antitoxins to break down poisons.

8. Lymphocytes
*B (from Bone marrow)  short- lived plasma cells
May
Lymphocytes
attack antigens
stick to the surface membrane of the alien cell
*T (from Thymus) KILLER T  damaging cell
membrane of
infected cell
HELPER T  stimulate B cells to %
IMMUNITY
* Natural Acquired
* Innate
* Artificially Acquire  Vaccine

10. Plasma
It also contains
useful things like;
• carbon dioxide
• glucose
A strawcoloured
liquid that
carries the
cells and the
platelets
which help
blood clot.
• lipids
• amino acids
• proteins
• minerals
(sodium/potassium/calcium)
• vitamins
• hormones
• waste materials
like urea.

11. HEART
+ BLOOD VESSELS
CIRCULATORY
SYSTEM

12. External view of the heart
superior
vena cava
pulmonary
artery
aorta
pulmonary
vein
pulmonary
vein
left atrium
coronary
artery
right atrium
inferior
vena cava
left
ventricle
right ventricle

13. Explanation of Heart
Left
Atrium
Right
Atrium
Which
side of
the heart
is thicker
What kind
of blood
does each
side
pump?
Right
Ventricle
Valves
Left
Ventricle
The heart has 4 chambers:
2 on the Right: received blood and 2 on the left: pumps the blood out
How does the heart pump?

14. The vena cava carries deoxygenated
blood from the body to the right
atrium
superior
vena cava
(transports blood
from the head)
inferior
vena cava
(transports blood
from rest of body)

15. The right atrium collects deoxygenated
blood and pumps it to the right
ventricle
right atrium

16. The right ventricle pumps
deoxygenated blood to the lungs
right ventricle

17. The pulmonary artery carries
deoxygenated blood from the right
ventricle to the lungs
aorta

18. The septum separates the left and
right sides of the heart
septum

19. The pulmonary veins carry
oxygenated blood from the lungs to
the left atrium
Pulmonary
veins

20. The left atrium collects the
oxygenated blood and pumps it to the
left ventricle
Left atrium

21. The left ventricle pumps oxygenated
blood to the body via the aorta
Left ventricle

22. The aorta carries the oxygenated from
the left ventricle to the rest of the body
Aortic arch
Aorta

23. Blood doesn’t flow Backwards
because of 4 sets of valves
RIGHT
Tricuspid valves
semi-lunar
valve
Tendon
LEFT
Bicuspid valve
(mitral valve)
semi-lunar
valve

24. The Heart
Artery to Lungs
Vein from Head and Body
Right Atrium
valve
Right Ventricle
Artery to Head and Body
Vein from Lungs
Left Atrium
valve
Left Ventricle

25. The
* receives FOOD and O2 from CORONARY ARTERIES
•NORMAL RATE  50-100
beats per minute
Depends on AGE
SEX
EXERCISE
ADRENALINE
The
beat is initiated by the PACEMAKER
Receives 2 sets of
nerves from BRAIN
1set speeds up the
1set slows down the
RIGHT ATRIUM
Specialized
muscle cells
rate
rate
Has IMPUT from receptors
in the circ. System for
BLOOD PRESSURE and
levels of O2 and CO2

26. How does the Heart work?
STEP ONE
blood from the
body
blood from
the lungs
The heart beat begins when the
heart muscles relax and blood
flows into the atria.

27. How does the Heart work?
STEP TWO
The atria then contract and
the valves open to allow blood
into the ventricles.

28. How does the Heart work?
STEP THREE
The valves close to stop blood
flowing backwards.
The ventricles contract forcing
the blood to leave the heart.
At the same time, the atria are
relaxing and once again filling with
blood.
The cycle then repeats itself.

29. 1
2 Systoles

30. What is DIASTOLE?
• The time period when the
heart is in a state of relaxation
What is SYSTOLE?
• It is a phase of the cardiac cycle
where the myocardium is
contracting

31. Summary
SYSTOLE Atria contract
Valve opens
Blood enters ventricles
Blood pressure closes
tricuspid and bicuspid valves
Semi-lunar valve opens
SYSTOLE  Ventricles
contract
Blood enters arteries
DIASTOLE  Ventricles
relax
Blood pressure in arteries
close the semi-lunar valves

32. How does this system work?
pulmonary vein
pulmonary artery
lungs
head & arms
aorta
main vein
Right
Left
liver
digestive system
kidneys
legs
Circulatory System

33. Our circulatory system is a double circulatory system.
This means it has two parts.
Lungs
the right side of
the left side of
the system
the system
deals with
deals with
oxygenated
deoxygenated
blood.
blood.
Body cells

35. Blood travels through the heart
twice before returning to the
body
The double circulatory system

37. blood from the heart gets around
the body through blood vessels
There are 3 types of blood vessels
a.
ARTERY
b.
CAPILLARY
c.
VEIN

38. The ARTERY
Arteries carry blood away from the heart.
the elastic/muscle
fibres allow the artery
to stretch under
pressure
thick muscle and
elastic fibres
Semi- lunar
valves
the thick muscle can
contract to push the
blood along.

39. The Aorta
The largest artery in the
body, originating from the
left ventricle of the heart
and extending down to
the abdomen, where it
branches off into two
smaller arteries and
arterioles. The aorta
distributes oxygenated
blood to all parts of the
body.

40. The VEIN
Veins return blood to the heart.
veins have valves
which act to stop the
blood from going in
the wrong direction.
thin muscle and
elastic fibres
body muscles surround the veins
so that when they contract to
move the body, they also squeeze
the veins and push the blood along
the vessel --

41. The CAPILLARY
Capillaries link Arteries with Veins
they exchange materials
between the blood and
other body cells.
the wall of a capillary is
*only one cell thick
*permeable
The exchange of materials
between the blood and the
body can only occur through
capillaries.

42. A collection of capillaries is known as a capillary bed.

43. Type of
blood
ARTERIES
VEINS
CAPILLARIE
S
Direction Structure
Valves
Reason
for
structure
Oxygenated
(in most
arteries)
From heart to
body
Elastic
tissues+muscle
fibres
THICK WALLS
(To resist the
pressure of
blood)
Semi-lunar
Thick walls as
arteries carry
blood with
high pressure,
this prevents
walls from
collapsing
deoxygenated
(less food more
CO2)
(in most veins)
From body to
heart
Less elastic, less
muscular
THINNER
WALLS/ WIDER
LUMEN
Valves for
blood not to
go
backwards
Less thick
walls as they
carry blood
with low
pressure
oxygenated
or
deoxygenated
Supply all the
cells with their
requirements/
take away
waste
1 cell-thick thin
walls
PERMEABLE
Narrow lumen
-------------
It allows
tissue fluid to
squeeze out
and give the
cells what
they need and
take away
waste

44. BLOOD CLOTTING
• 2 functions prevents loss of
blood
 prevents entrance of
bacteria
Stimulus  damage in blood vessels
Activates platelets (they aggregate)
Produce chemicals to activate
Prothrombin
Fibrinogen
(always in the blood)
Thrombin (enzyme) acts on Fibrinogen
(soluble)
CLOT
red cells + Fibrin(insoluble)

45. • When the
pumps  it produces pressure
• Arteries HIGH pressure
• Capillaries offer resistance to blood
flow blood pressure in VEINS is LOW
• Blood pressure  varies with sex/age/activity
• Fairly consistent for the FILTRATION process in the
KIDNEYS
• Blood pressure  heart disease/ stroke
• Blood pressure  kidney fail