You're probably quite familiar with how the heart work as a pump to transport blood around your body by now. In AS level, you will take this understanding to the next level - understanding the intricate system and the processes that goes on every time you draw a breathe.

1. 8. Transport in Mammal
And the Circulatory System

3. Why do we need a mammalian
transport System
 Animals – far more active than
plants
 Need energy for – contraction
of muscles, brain power,
mobility (have to find their own
food), nervous system
 Evolved transport system
 Diffusion – too slow, the
surface area is not enough

4. Pulmonary Circulation
 Deoxygenated blood moving out from the right
ventricles through the pulmonary arteries to the lung.
 The now oxygenated blood then travels back into the
left atrium from the pulmonary vein.

5. Systemic Circulation
 Oxygenated blood moving out of the left ventricle
through the aorta to the rest of the body.
 Deoxygenated blood travelling back through the vena
cava into the right atrium

7. The Blood vessels
 Artery
 Capillaries
 Vein

8. Arteries
 Vessels that transport blood at
high pressure to the tissue away
from the heart
 Inner endothelium: Tunica intima
– layer of flat squamous
epithelium cells – REDUCE
FRICTION
 Middle layer: Tunica media –
smooth muscle, collagen, elastic
fiber
 Outer layer: Tunica externa –
Elastic fiber/ collagen fibers

9. Arteries
 Strong and elastic
 To withstand high pressure of blood leaving the heart
(120mmhg)
 Elastic fibers: Wall can stretch
 Allows the heart to moderate the pressure of the blood
by recoiling or stretching

10. Arterioles
 Arteries branch into smaller vessels –
Arterioles
 Arterioles’ wall have more smooth muscle
 The muscle can contract – controlling the
volume of blood moving in and out of a
certain body part
 Vasoconstriction and vasodilation occurs
with arterioles
 Blood pressure drops here from 120 to 85
as arteries branch out

11. Capillaries
 Arterioles further branch out into capillaries where cell
will receive oxygen and give out waste
 One-cell thick wall (endothelium) – 7 micrometer – just
enough for Red blood Cell
 Blood brought to 1 micrometer from the cell
 Blood pressure drops enough for slower flow with
exchange of thing
 Allow diffusion to occur

12. Venules
 Capillaries gradually join up to form Venules
 Venules join to form veins – function: return blood to
the heart

13. Veins
 Blood pressure is low – no need for elastic muscles or
thick wall
 Larger lumen
 Blood flow because the contraction of muscle around
the veins
 Backflow prevented by semilunar valves

15. THE LYMPHATIC
SYSTEM
BLOOD PLASMA, TISSUE FLUID, LYMPH

17. Blood Plasma
 Pale yellow liquid composing of 55% of the blood
 Content: 90% water – 10% : Ions, Glucose, Urea, Plasma
proteins (amino acids, hormones, enzymes, antibodies
etc.)

18. Blood plasma - Importance
 Contains hormones and other useful substances
 Maintains pH and osmotic balance

19. Tissue Fluid
 When passing through capillaries – plasma leaks into
the spaces between cells forming tissue fluid
 Proteins cannot pass through
 White blood cells can squeeze through

20. Tissue Fluid
 The process is as such:
 The high blood pressure at arterial end of capillary bed –
causes blood plasma to flow out of capillaries
 High protein concentration in plasma = lower water potential,
osmotic pressure causes plasma to flow back into capillaries
at venule ends of the capillary bed
 Hence tissue fluid maintains the osmotic balance of the cell
 If blood pressure too high – at arterial ends too much of the
plasma flow into tissue fluid and accumulates – swelling in
the form of oedema

22. Lymph
 90% of fluid that leaks out of capillary – seeps back
 Another 10% is returned by the lymphatic system
 Lymphatic systems: made up of lymph vessels
 The lymphatic will allow tissue fluid to leak in
 Lymph vessels have valves large enough for proteins
 Lymph nodes: contain antibodies
 https://www.youtube.com/watch?v=I7orwMgTQ5I

23. The Lymphatic system
 The lymphatic system’s main job is to return blood
plasma to the blood and also to maintain the osmotic
balance by allowing protein to leak in from the tissue
fluid
 The system is also where a lot of of the white blood
cells reside

24. Content of Blood
 5 dm3 blood = 5 kg
 5 x 1013 Red Blood Cells/ Erythrocytes
 6 x 1012 Platelets
 2.5 x 1011 White Blood Cells/ Leukocytes

25. Red Blood Cells
 Small size = 7 micrometers
 Biconcave shape
 Small amount of organelles
 High flexibility in membrane

26. Hemoglobin
The Dissociation curve, Transport of Carbon dioxide and the Bohr Shift

27. Haemoglobin
 Proteins found inside the red blood cells
 They combine with oxygen to form Oxyhaemoglobin
 They are tools Red blood cell uses for transporting
oxygen
 Each haemoglobin has 4 haem groups with each one
containing an iron prosthetic group
 This iron allows the molecule to combine with oxygen
and hence give a red color to blood

28. The Dissociation Curve
 This is a curve used to show how haemoglobin combine
with oxygen at different partial pressure
 It is important to show how haemoglobin pick up
oxygen but also how it releases those oxygen
molecules

30. The Dissociation Curve
 At low partial pressure of oxygen – percentage
saturation is very low – haemoglobin combines with
very little, in this case 1 oxygen molecule
 As partial pressure increases, it gets easier
 Plus haemoglobin changes shape after first
combination to make it easier for the other 3
 https://www.youtube.com/watch?v=HYbvwMSzqdY

31. The S-Curve
 We must also take in account the changes of partial
pressure of Carbon Dioxide
 Where there are high CO2 concentration (high partial
pressure) eg. Muscle cells – usually respiring cells that
actually do need oxygen
 Oxygen will be released more readily
 How so?

32. The Bohr Shift
 When Carbon Dioxide enters the Red Blood cell, carbonic
anhydrase allows it to combine with water to form Carbonic
acid
 The Carbonic acid dissociates into Hydrogen bicarbonate
and hydrogen ions
 The hydrogen ion is actually taken up by the haemoglobin
 And hence the oxygen has to be released
 THIS IS PERFECT, BECAUSE NOW OXYGEN IS RELEASED
WHERE IT IS NEEDED MOST

33. Transport of Carbon
dioxide
 Because of the Bohr shift – 85% of the CO2 is now
transported in the form of hydrogen bicarbonate ions
 Another 10% of CO2 directly combines with
haemoglobin to form Carbaminohaemoglobin
 The other 5% is transported in solution

35. Problems with Oxygen
Transport
High Altitude, Carbon Mooxide

36. Effects of Carbon
Monoxide
 Haemoglobin combines very readily with
Carbon monoxide – even more so than oxygen
(250 times more)
 To form Carboxyhaemoglobin – a very stable
molecule
 Now the body cannot transport oxygen
 Carbon monoxide quickly diffuse through
alveoli
 Even 0.1% in the air may cause death by
asphyxiation
 They are found in cigarette smokes – hence
most smokers actually have 5% of their blood
permanently combined with carbon monoxide

37. Effects of High Altitude
 Partial pressure of oxygen in normal air is higher than
in air at high altitude
 Haemoglobin becomes less saturated
 Less oxygen carried around the body
 Causing breathlessness and illness

38. Altitude Sickness
 When the body doesn’t have enough time to adjust to
the change in altitude
 Increase in rate/ depth of breath
 Dizziness and weakness
 Arterials dilate for more oxygen transport – blood flow
into the capillary bed more – oedema
 Oedema in brains can lead to disorientation
 The way to cure is simple – come down

40. Adaptations
 If the body is allowed to
acclimatized – number of Red
Blood Cells increases –
usually takes 2 -3 weeks
 Permanent adaptations for
those living at high altitudes
 Broader chest – for more lung
capacity
 Larger right side of heart – to
pump blood to the lung
 More haemoglobin

41. The Heart
Heart beats and how they work

44. The Heart Structure
 Mass: 300 g
 Size: fist
 A bag of muscle filled with blood
 Muscles – cardiac muscles – interconnecting cells with
membranes tightly joined for electrical excitation to
pass through

45. Aorta
 The largest artery
 Arch shape
 Branches leading to the
head
 Main flow double back
down toward the body
 High pressure blood flow
here
 Connected to the left
ventricle

46. Venae Cavae
 2 large veins running vertically on the right side of the
heart, Connected to the right atrium
 1 vessel (superior vena cava) brings blood from rest of
the body
 Another brings blood from the head

47. Pulmonary Arteries/ Veins
 P Artery: takes blood out of the heart to
the lung – connected to the right ventricle
 P Veins: Takes blood from the lung into the
hear – connected to the left atrium
 The revers of the rest of the body – if veins
at the rest of the body carry deoxygenated
blood, pulmonary veins carries oxygenated
blood. Same goes for pulmonary arteries
 Pulmonary artery branches off immediately
to the right and left lung
 Pulmonary vein returns first into then
combine into one

48. Coronary arteries
 Branch off from aorta
 Deliver oxygen to the heart itself

49. The Cardiac Cycle
 The sequence of events which make up one heartbeat
 3 stages
 Atrial systole
 Ventricular systole
 Ventricular diastole

50. Atrial Systole
 Heart is filled with blood – muscle ready to contract
 Muscular wall of atrial are thin – contraction do not
produce much pressure
 Pressure still forces Atrioventricular valves (tricuspid/
bicuspid) open
 Blood flows from the atria into the ventricles
 Valves in the veins prevent backflow

51. Ventricular Systole
 0.1 seconds after the atria contract
 Ventricles contract
 Atrioventricular valves pulled shut due to the pressure
in the ventricles exceeding the atria
 Semi lunar valves forced open
 Blood rushes into the arteries
 This lasts for 0.3 seconds

52. Ventricular Diastole
 The whole heart muscle relaxes
 Semilunar valve shuts
 Blood from veins flow into the atria – at low pressure –
but thin wall of atria gives not much resistance
 Blood just begins flowing into the ventricles when the
atria contracts again

53. Control of heart beat
 The muscles in the heart are myogenic
 They naturally contract/ relaxes
 The heart still has its own natural pacemaker
 Sinoatrial node (SAN) - in the right atrium wall – it
can still respond to the brain
 SAN works a little faster than the heart
 It sends excitation waves across the atrial walls –
causing atrial systole

54. Control of heart beat
 Muscles of the ventricle contracts 0.1 second after – this is
because of the AVN
 The AVN (Atrioventricular node) receives excitation wave
which it withholds until the atria contracts, then it sends
down to the ventricles so that they can follow in contraction
 Between atria and ventricle – a band of fiber that does not
conduct electrical impulse is there
 The AVN send the impulse down through the purkyne
tissues in the septum which travels to the rest of the
ventricles