Animal Transport 2 (Blood vessels, Tissue Fluid and Dissociation Curves)

Question 1

Name three substances that can pass through capillary walls

Answer 1

water, oxygen, carbon dioxide, urea, glucose, uric acid, lactic acid

Question 2

What level of protein structure is shown in haemoglobin?

Answer 2

quaternary structure- 4 polypeptide chains, each one with a haem group

Question 3

The heme groups in haemoglobin are an example of a ______ group

Answer 3

Prosthetic group

Question 4

Describe how red blood cell shape is ideal for their function

Answer 4

biconcave, optimizes the ratio of surface area to volume, facilitating gas exchange. It also enables them to fold up as they move through narrow blood vessels.

Question 5

What type of tissue is blood?

Answer 5

blood is considered part of connective tissue

Question 6

What is the structure of an artery? (Include the layers)

Answer 6

Tunica externa on outside, made of collagen. Tunica media made of smooth muscle and elastic tissue. Tunica interna/intima on inside, consisting of squamous endothelial cells that are smooth to reduce friction

Question 7

How does the structure of a vein differ from an artery?

Answer 7

The wall has the same layers but is overall thinner as they do not have to withstand high pressure. Veins also have semi-lunar valves to ensure flow in one direction

Question 8

Why do arteries need thick walls?

Answer 8

To resist the high hydrostatic pressure

Question 9

Which blood vessels can alter their diameter to increase or decrease blood flow and what is this called?

Answer 9

Arterioles. Vasoconstriction and vasodilation

Question 10

Give four reasons pressure drops in capillaries

Answer 10

Blood is spread over a larger cross sectional area. Fluid leaves the capillaries through pores. There is increased friction with the walls. Blood is further from the heart.

Question 11

List three things that help veins return blood to the heart despite having lower pressure than arteries

Answer 11

Gravity (from above heart), massaging action of skeletal muscle, negative pressure in thorax during inspiration

Question 12

What are the X and Y axes of an oxyhaemoglobin dissociation curve?

Answer 12

X partial pressure O2 (PPO2) Y % saturation of haemoglobin with oxygen

Question 13

What are the proper terms for haemoglobin binding to and releasing oxygen?

Answer 13

Associating and dissociating

Question 14

What is the proper term for haemoglobin’s level of attraction to oxygen?

Answer 14

Affinity

Question 15

How does foetal haemoglobin differ from adult haemoglobin?

Answer 15

It has a higher affinity for oxygen, meaning it can associate oxygen at lower PPO2s and will be fully saturated at a lower PPO2 than adult haemoglobin. It will not dissociate until very low PPO2. Curve shifted to left

Question 16

How do llama and lugworm haemoglobins differ from human haemoglobin?

Answer 16

Their haemoglobin has a higher affinity for oxygen due to living in areas of lower oxygen, meaning their haemoglobin can associate oxygen at lower PPO2s and will be fully saturated at a lower PPO2 than human haemoglobin. Their haemoglobin will not dissociate oxygen until very low PPO2. Curve shifted to left

Question 17

What happens to human blood when living at altitude?

Answer 17

More red blood cells are produced

Question 18

What is cooperative binding of haemoglobin?

Answer 18

When the first O2 molecule binds with one haem group it changes the shape of the haemoglobin molecule, making it easier for the second molecule to attach. The 4th O2 molecule only attaches if there is a very large increase in ppO2

Question 19

What happens to the oxyhaemoglobin dissociation curve when CO2 increases (/pH falls)?

Answer 19

The Bohr shift- curve shifts to the right. Haemoglobin is less saturated with oxygen at any partial pressure of oxygen. More oxygen is dissociated from haemoglobin for use by respiring tissues

Question 20

What are the three ways CO2 is transported back to the lungs in the blood?

Answer 20

5% dissolved in plasma, 10% combined with haemoglobin to form carbaminohaemoglobin, 85% as hydrogen carbonate ions (HCO3-)

Question 21

What happens to CO2 when it dissolves in water? And which enzyme speeds up this reaction in red blood cells

Answer 21

It dissolves to form carbonic acid CO2 + H2O-> H2CO3- this reaction is catalysed by carbonic anhydrase

Question 22

What happens to carbonic acid in a red blood cell?

Answer 22

It is unstable and dissociates into hydrogen ions and hydrogen carbonate ions (H+ and HCO3-). HCO3- ions diffuse out of the red blood cell into the plasma

Question 23

Why do chloride ions diffuse into a red blood cells?

Answer 23

To maintain the charge when HCO3- ions leave. This is called the chloride shift.

Question 24

What happens to the H+ ions produced in a red blood cell from carbonic acid?

Answer 24

They bind to haemoglobin, forming haemoglobinic acid. Haemoglobin acts as a buffer and dissociates oxygen molecules to bind to the H+

Question 25

Why does fluid leave the capillary at the arterial end? Hint talk about pressure

Answer 25

Hydrostatic pressure pushing fluid out of the capillary is higher than osmotic pressure drawing fluid back in

Question 26

Why does fluid return to the capillary at the venous end? Hint talk about pressure

Answer 26

Hydrostatic pressure pushing fluid out of the capillary is lower than osmotic pressure drawing fluid back in. This is because hydrostatic pressure drops as blood moves along the artery

Question 27

List the components of blood too large to leave the capillary through the pores

Answer 27

Large plasma proteins and red blood cells

Question 28

What is the function of tissue fluid?

Answer 28

To bathe the cells, providing them with oxygen and nutrients

Question 29

What happens to excess tissue fluid that does not return to the capillary?

Answer 29

It drains into the lymphatic system, becoming lymph. Lymph to the bloodstream via the subclavian vein in the neck