Transport systems - animals

Question 1

Describe the components of blood in mammals

Answer 1

Blood contains plasma, red blood cells and white blood cells. It transports nutrients, oxygen and carbon dioxide.

Question 2

Describe how red blood cells are specialised to transport oxygen

Answer 2

Red blood cells are specialised cells, so they efficiently transport oxygen.

Red blood cells contain no nucleus
Red blood cells are biconcave in shape
Red blood cells contain the protein haemoglobin
It is haemoglobin that binds to oxygen. This process happens in the alveoli in the lungs, where the oxygen concentration is high.

Oxygen + Haemoglobin → Oxyhaemoglobin

This is a reversible reaction and oxygen will dissociate from haemoglobin in body tissues, where there is a low concentration of oxygen.

Oxygen + Haemoglobin ← Oxyhaemoglobin

Question 3

Explain the term pathogen

Answer 3

Pathogens are disease-causing micro-organisms (bacteria, viruses and fungi).

Question 4

Name the two different types of white blood cells

Answer 4

The two types of white blood cells are:

Lymphocytes
Phagocytes

Question 5

Describe the process of phagocytosis

Answer 5

Phagocytosis is the process by which phagocytes will engulf and digest the pathogen.

Phagocyte surrounds the pathogen

Phagocyte engulfs the pathogen and encloses it in a vacuole

Digestive enzymes within lysosomes in phagocytes digest the pathogen

Question 6

Describe the role of antibodies when destroying a pathogen

Answer 6

Lymphocytes produce antibodies which will bind to a specific protein on the pathogen, called an antigen.

Antibodies will bind to several pathogens preventing the pathogen from spreading and allowing phagocytes to engulf the pathogen.

Antibodies are specific and only one antibody is specific to one pathogen.

Question 7

Label of the main structures within the heart

Answer 7

1. Left/right ventricle
   2.Left/right atrium
2. vena cava
   4.pulmonary artery
   5.aorta
   6.pulmanory vein

Question 8

Describe the functions of the main structures within the heart

Answer 8

Atria - pump blood into the ventricles

Ventricles - pump blood out of the heart

Vena cava - brings deoxygenated blood from the body into the right atria

Pulmonary Vein - carries oxygenated blood to the left atria from the lungs

Pulmonary artery carries deoxygenated blood from the right ventricle to the lungs

Aorta carries oxygenated blood from the left ventricle to the rest of the body (except the lungs)

Valves - prevents the backflow of blood into the heart

Coronary arteries - provide the heart muscle with oxygen, glucose and amino acids

Question 9

Describe the pathway of oxygenated and deoxygenated blood through the heart

Answer 9

Deoxygenated blood enters the right side of the heart through the vena cava and enters the right atrium. It is pumped into the right ventricle and is pumped out of the heart through the pulmonary artery to the lungs.

Oxygenated blood returns from the lungs to the left side of the heart, it enters through the pulmonary vein into the left atrium. It is pumped out of the left atrium into the left ventricle and out of the left side of the heart to the rest of the body through the aorta.

Question 10

Describe the structure and function of arteries and veins, including the function of valves in veins

Answer 10

Artery
The Lumen of an artery is smaller than that of a vein and it has a thicker layer of smooth muscle to withstand the high pressure of blood. Arteries carry oxygenated blood from the heart to the body (1 exception).

Veins
Veins have a larger lumen, a smaller layer of smooth muscle and carries deoxygenated blood (1 exception) under lower pressure. Veins also contain valve.

Valves prevent backflow of blood.

Question 11

Describe the structure and function of capillaries

Answer 11

Capillaries have a large surface area and form a dense capillary network. They are only 1 cell thick to allow fast exchange of substances between the blood and body tissues.