1. National 5 Biology Unit 2 – Cell Biology
Section 12
Transport in Animals

2. We will be learning…
Be able to describe the components of blood including; plasma, red blood cells and white blood cells.
Be able to describe the function of blood as a transport system for nutrients, oxygen and carbon dioxide.
Be able to describe the shape and structure of red blood cells and how this is related to the function of transporting oxygen in the form of oxyhaemoglobin.
Be able to describe the mechanism for white blood cells destroying pathogens such as phagocytes during phagocytosis, and other lymphocytes that produce antibodies.
State that each antibody is specific to a particular antibody.
Describe the structure of the heart - include names of chambers, blood vessels entering and leaving the heart
Describe the position and the function of valves in the heart
Describe the pathway of blood through the heart, lungs and body
Describe the structure and function of arteries, veins and capillaries
Explain how the structure of a capillary network is related to its function

3. Blood is mostly water, with cells and other substances suspended in it.
Red blood cells
White blood cells
Plasma
Platelets
National 4/5 Biology Course Unit 2

4. Red Blood Cells and Plasma
Blood is made up of cells floating in a liquid called plasma.
The plasma also carries dissolved substances such as carbon dioxide, digested food and waste products.
Red blood cells carry oxygen
carbon dioxide
food
oxygen
Red blood cells are adapted to carry out their function.
They have a biconcave shape which increases their surface area – allowing them to pick up oxygen by diffusion much faster.
No nucleus
They contain haemoglobin

5. Plasma
Contains proteins such as antibodies and other substances such as the products of digestion e.g. glucose, hormones, vitamins, minerals and amino acids.
These substances are transported to within diffusion distance of living cells.
Carbon dioxide is carried away from the cells in the plasma

6. White blood cells
Far fewer w.b.c compared to r.b.c, approx 4,000-13,000 per mm3
They have a nucleus and can squeeze through capillary walls to the site of an infection.
Their function is to defend the human body
They have an irregular shape and can change shape, allowing them to squeeze through capillary walls to the site of microbial infection.

7. White blood cells
Two types of white blood cell are monocytes and lymphocytes
Nuclear shape varies from rounded to lobed
Nuclei large and rounded

8. Phagocytosis
Phagocytosis is the process by which bacteria are engulfed and digested by cells such as monocytes and macrophages.
(macrophages are made from monocytes)
Dead bacteria and phagocytes accumulate at injuries forming pus.

9. This digests the bacterium which is then absorbed by the cell.
Phagocytosis
The macrophage approaches a bacterium and engulfs it by infolding its membrane .
Once inside the macrophage, lysosomes (enzymes) fuse with the food vacuole containing the bacterium, and deposit digestive enzymes into it.
This digests the bacterium which is then absorbed by the cell.

10. Phagocyte e.g. macrophage -nucleus not shown
Lysosome containing digestive enzymes
Vacuole forming
Some lysosomes move towards and fuse with vacuole
Bacterium digested by enzymes
Breakdown products pass into cytoplasm
Bacterium giving
out chemical
Trapped bacterium

11. Specific Immune Response (antibody formation)
An antigen is a complex molecule (e.g. protein) that is recognised as foreign to the body.
White blood cells called a lymphocyte responds to the presence of antigens by producing specific chemicals - antibodies - against that antigen.
Each type of lymphocytes is capable of recognising and responding to one antigen only.

12. Immune Response
Immunity is an organisms ability to resist infectious disease
Phagocytosis is an example of non-specific immune response and provides general protection against a wide range of micro-organisms

14. Heart Structure
The heart is made of a special type of muscle called cardiac muscle, which doesn’t get tired.
The job of the heart is to pump blood around the body.
The heart can be thought of as a muscular pump.

16. Chambers of the Heart Left atrium right atrium left ventricle
right ventricle
The heart has four chambers. The heart is shown from the front. Like it is in your body…the left hand side is nearest your left arm etc…

17. Heart Structure
Blood contains (as well as many other things) dissolved food, and gases (e.g. oxygen and carbon dioxide.
Every cell in the body needs food and oxygen.
The coronary artery supplies food and oxygen to the cells of the heart muscle. When these blood vessels get blocked, you can suffer a heart attack.
coronary artery
The blood from the heart must reach all cells, so that means the heart needs its own blood supply too .

18. to lungs to body from body from lungs
The ventricles have thicker walls than the atria.
to lungs
to body
from body
The left ventricle has a thicker wall than the right ventricle because the left ventricle has to pump blood right around the body and the right ventricle only has to pump blood to the lungs.
from lungs
left ventricle
right ventricle
left atrium

19. pulmonary artery aorta vena cava pulmonary vein
Arteries go away from the heart.
aorta
vena cava
pulmonary vein
Veins return to the heart.
A pulse indicates that blood is flowing through an artery.
Can you find your own pulse?

20. Circulation around the Body
Pulmonary artery
Pulmonary vein
Aorta
Vena Cava

21. Blood Flow through the Heart
Deoxygenated blood i.e. low in oxygen returns to the heart via the vena cava after travelling to all parts of the body. It enters the heart at the right atrium.
The right ventricle then pumps blood out through the pulmonary artery to the lungs.
In the lungs the blood picks up oxygen and loses carbon dioxide.
The oxygenated blood then returns to the heart via the pulmonary vein, entering the left atrium. The left ventricle pumps blood out through the aorta to the body.
vena cava
atrium
pulmonary
ventricle
lungs
oxygen
carbon dioxide
vein
left
left
aorta

22. Valves Valves between ventricles and blood vessels
The heart has two sets of valves.
Valves can be open or closed (like gates).
Valves stop blood flowing backwards (ie the wrong way).
One set of valves are found between the two atria and the ventricles – blood can’t flow back into the atrium.
Valves between atria and ventricles
The other set of valves are found between the two ventricles and the blood vessels leaving the heart – blood can’t flow back into the ventricles.

23. Valves backflow vein valve prevented open vein valve closed
blood to the heart
The valves allow blood to flow in the correct direction…
…but close if blood starts to flow in the wrong direction.
National 4/5 Biology Course Unit 2

25. The Heart and Blood Circulation
Every cell in the body needs food and oxygen.
blood vessels
arteries
veins
The blood circulation must reach all cells.
Arteries carry oxygenated blood (high in oxygen) from the heart around the body.
Veins carry deoxygenated blood (high in carbon dioxide) back to the heart.
The exception is the pulmonary artery, which carries blood high in carbon dioxide from the heart to the lungs.

26. Blood vessels There are three types of blood vessels.
blood from the heart
blood to the heart
Capillaries carry blood to and from the body’s cells
Teacher notes
There are different types of blood vessel because they perform different functions – arteries carry high pressure blood away from the heart, capillaries are small so that they can reach all of the body’s tissues and veins carry low pressure blood and therefore have valves. This is covered on the next slide.
Veins carry blood back into the heart
Arteries carry blood away from the heart
There are three types of blood vessels.
National 4/5 Biology Course Unit 2

27. Arteries
Arteries have thick muscular walls to withstand the high pressure of the blood being pumped by the heart.
Narrow central channel
Carries blood at high pressure
Arteries divide into smaller blood vessels and finally into tiny capillaries.
Blood is carried away from the heart in arteries.
These arteries carry blood to the body’s organs and tissues.
In the organs the arteries split up into a network of tiny tubes called capillaries.
arteries
organs

28. Capillaries Capillaries are in close contact with the living cells.
They are only one cell thick.
They allow water, gases and other substances, to pass to between the blood and the body’s tissues.
The capillary network allows efficient exchange of gas, food and waste because
They are narrow and thin walled which gives a greater surface area to allow fast diffusion of gases etc.
They are very long which also increases the surface area.
No cell is ever far away from a capillary thus ensuring easy exchange.

29. Veins Veins have thinner walls than arteries. Wide central channel
Carries blood at low pressure
They carry the deoxygenated blood (high in carbon dioxide) blood back to the heart.
They have thinner walls because the deoxygenated blood is at low pressure.
Veins have valves to prevent the backflow of blood.
The pulmonary vein, which carries blood high in oxygen from the lungs to the heart is the exception.

30. Gas Exchange Cellular Level in Tissues
Oxygen diffuses from the high concentration in the capillary blood across into the body cells. Carbon dioxide diffuses from the high concentration in the cells into the plasma .
diffuses
plasma
living cell
capillary
Blood from artery high oxygen low carbon dioxide
Blood to vein high carbon dioxide low oxygen
oxygen
CO2

31. Haemoglobin
Haemoglobin forms an association with oxygen to become oxyhaemoglobin
Haemoglobin has a high affinity for oxygen when the o2 concentration in the surrounding environment is high
Haemoglobin has a low affinity for oxygen when the o2 concentration in the surrounding environment is low
Haemoglobin + oxygen oxyhaemoglobin
Association (in lungs)
Dissociation (in tissues)

32. Haemoglobin + haemoglobin oxygen oxyhaemoglobin
A red pigment called haemoglobin is found in red blood cells. Its function is to combine with oxygen to form oxyhaemoglobin.
At the lungs, haemoglobin combines with oxygen to make oxyhaemoglobin.
At the tissues, oxyhaemoglobin releases oxygen and becomes haemoglobin again.
haemoglobin
at lungs +
haemoglobin
oxygen
at tissues
oxyhaemoglobin

33. In cells doing respiration
RBCs - haemoglobin
RBCs contain a protein called haemoglobin.
In the lungs
oxygen is attached
Oxy-haemoglobin
Haemoglobin
In cells doing respiration
oxygen is released
National 4/5 Biology Course Unit 2

34. Circulation of blood through the heart
Blood high in oxygen is called oxygenated blood
Oxygenated blood returns from the lungs…
pulmonary vein
in the _______ ______
enters the ____ _______
into the ___ ________
out through the _____
to the ____
left atrium
left ventricle
aorta
body
National 4/5 Biology Course Unit 2

35. Blood low in oxygen is called deoxygenated blood.
Deoxygenated blood returns from the body tissues…
vena cava
in the ____ _____
enters the ____ _______
into the _____ ________
out through the _________ ______
to the _____ where it picks up oxygen
right atrium
right ventricle
pulmonary artery
lungs
National 4/5 Biology Course Unit 2