Gas Exchange in Humans and Transport (Circulation)

Question 1

What is the scientific name for the wind pipe?

Answer 1

Trachea

Question 2

Describe the role of the diaphragm in inhalation

Answer 2

Diaphragm contracts and flattens (moves down), increasing the volume of the thorax and decreasing the pressure

Question 3

Describe the role of the intercostal muscles in inhalation

Answer 3

Intercostal muscles contract moving the ribcage up and out

Question 4

Describe the function of the pleural membranes

Answer 4

Contain pleural fluid which prevents friction between the lungs and the ribs

Question 5

By what process does oxygen leave the alveoli to enter the red blood cells?

Answer 5

Diffusion

Question 6

What adaptation of the alveoli provides a short diffusion distance for oxygen to enter red blood cells and carbon dioxide to leave

Answer 6

Capillaries surrounding alveoli are one cell thick

Question 7

What pigment in red blood cells does oxygen bind to?

Answer 7

Haemoglobin

Question 8

By what process is oxygen processed in cells?

Answer 8

Aerobic respiration

Question 9

Simple, unicellular organisms rely on simple diffusion for the movement of substances into and out of cells. Suggest why?

Answer 9

They have a large surface area to volume ratio, they have low metabolic demands

Question 10

Blood enters the right side of the heart through which blood vessel? Is it oxygenated or deoxygenated?

Answer 10

Vena cava; deoxygenated

Question 11

State the valves found between the atria and ventricles on both the right and left sides of the heart

Answer 11

Atrioventricular valves

Question 12

State the valves found between the ventricles and the pulmonary arteries/aorta

Answer 12

Semilunar valves

Question 13

Why is the left ventricular wall so thick with muscle?

Answer 13

To pump blood with great force and pressure around all organs in the body

Question 14

Through what major blood vessel does blood leave the left side of the heart?

Answer 14

Aorta

Question 15

Blood enters the kidney through which blood vessel?

Answer 15

Renal artery

Question 16

Blood leaves the liver through which blood vessel?

Answer 16

Hepatic vein

Question 17

Blood enters the liver from the gut through which blood vessel?

Answer 17

Hepatic portal vein

Question 18

What is the only artery in the body that carries deoxygenated blood?

Answer 18

Pulmonary artery

Question 19

Explain the importance of the shape of red blood cells

Answer 19

Biconcave shape to increase the surface area to volume ratio for haemoglobin and therefore oxygen that can be carried

Question 20

Red blood cells contain NO nucleus. Why?

Answer 20

To allow more space for haemoglobin

Question 21

Oxygenated blood returns to the left side of the heart from the lungs in which blood vessel?

Answer 21

Pulmonary vein

Question 22

Which hormone is released that increases heart rate

Answer 22

Adrenaline

Question 23

State the four main components of blood

Answer 23

Plasma, red blood cells, white blood cells, platelets

Question 24

Describe the structure of the aorta

Answer 24

Artery; narrow lumen so high pressure maintained; thick layer of muscle and elastic tissue to allow high pressure blood to recoil

Question 25

Describe the structure of a vein compared to an artery

Answer 25

Wider lumens as blood is carried under lower pressure; thinner layers of muscle and elastic tissue; contain valves to prevent backflow of blood

Question 26

Why are capillaries suitable blood vessels for exchange?

Answer 26

They are very small and have thin walls (one cell thick) to decrease diffusion distances

Question 27

State five roles of plasma related to transport

Answer 27

Carbon dioxide, digested food, urea, heat energy, hormones

Question 28

Describe the roles of lymphocytes and phagocytes in fighting infection

Answer 28

Lymphocytes produce antibodies to bind specifically to an antigen; phagocytes engulf and digest pathogens using enzymes

Question 29

Explain the importance of vaccination

Answer 29

Memory cells can be made which enables future antibody production against a specific pathogen to occur sooner, faster and in greater quantity

Question 30

Describe the role of platelets

Answer 30

They are involved in blood clotting which prevents blood loss and the entry of microorganisms

Question 31

Name three chemicals found in cigarette smoke

Answer 31

Carbon monoxide, tar, nicotine, carcinogens

Question 32

Describe the effects of carbon monoxide on the uptake of oxygen

Answer 32

CO binds irreversibly to haemoglobin in preference to oxygen, meaning oxygen cannot bind

Question 33

Which chemical in cigarette smoke is responsible for addiction?

Answer 33

Nicotine

Question 34

Describe the main visible hallmark of the disease emphysema

Answer 34

Reduces the surface area of the alveoli, reducing the efficiency of gas exchange

Question 35

Name three diseases, apart from coronary heart disease, that can be caused by smoking

Answer 35

Emphysema, cancer, chronic bronchitis