The document summarizes mammalian circulatory and transport systems. It describes how oxygenated blood moves from the lungs to the heart and body through pulmonary and systemic circulation. It explains the roles of arteries, arterioles, capillaries, and veins in transporting blood and oxygen throughout the body. It also discusses the lymphatic system's role in returning fluid to blood and maintaining fluid balance.

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