Mass transport in animals

Question 1

What is the structure of haemoglobin?

Answer 1

> Primary structure - sequence of amino acid in 4 groups -> alpha helix
Tertiary structure - formation of hydrogen bonds to form a specific shape
Quaternary structure - associated with heam group

Question 2

How does haemoglobin release/carry oxygen?

Answer 2

Unloading - haemoglobin releases oxygen (disassociating)
Loading - haemoglobin attaches/binds to oxygen

Question 3

Why do different species have different affinities?

Answer 3

Different primary structures, so H+ bonds form in different areas leading to a different tertiary structure leading to different affinities.

Question 4

What happens further left on the oxygen dissociation curve?

Answer 4

> more loading occurs, due to a greater affinity for oxygen

Question 5

What happens further right on the oxygen dissociation curve?

Answer 5

> Futher right: more unloading occurs, due to less affinity for oxygen

Question 6

Why is it difficult for the 1st oxygen bind to hameglobin?

Answer 6

> Difficult for 1st haemoglobin to bind with oxygen; however, after binding this leads to changes in quaternary structure, leading to positive cooperativity.

Question 7

What is the effect of carbon dioxide concentration?

Answer 7

> Lower carbon dioxide concentration, leads to more loading of oxygen and higher carbon dioxide concentration leads to more unloading of oxygen
Dissolved co2, lowers the ph - causes haemoglobin to change shape - more readily unlaods o2 - more oxygen available for respiration

Question 8

What occurs during diastole?

Answer 8

> Diastole - relaxation of heart - blood flows into atria, pressure increases in the atria, which cause atrioventricles valves to open and blood to flow to ventricles. Semi-lunar valves close

Question 9

What occurs during atristole systole?

Answer 9

Atrial systole - atria contracts allowing the rest of the blood to flow into ventricles, recoil of ventricle walls - ventricle walls relaxed.

Question 10

What occurs during ventricular systole?

Answer 10

After a short delay, the walls contract, and pressure increases in the ventricles, which causes atrio-ventricular valves to close (preventing backflow) and semi-lunar valves to open, causing blood to be pushed in PA, or aorta.

Question 11

Cardaic output = ________ x __________

Answer 11

a. heart rate
b. stroke volume

Question 12

Structure and function of arteries:

Answer 12

> carries blood away from the heart, a thicker wall - withstand high BP,
muscular layer, thick elastic layer - control blood flow

Question 13

Structure and function of veins:

Answer 13

carries blood towards the heart, valves to prevent the backflow of blood, a thinner wall - lower pressure, elastic layer and a thinner muscular layer

Question 14

Structure and function of capillaries:

Answer 14

Narrow diameter, narrow lumen, slow blood through narrow lumen allowing for more time for diffusion, highly branched = larger SA:vol

Question 15

Structure and function of arterioles:

Answer 15

Control flow of blood from arteries to capillaries. Thicker muscular layer than arteries to withstand high Bp, thinner muscular layer than arteries

Question 16

Pocket valves:

Answer 16

in veins - ensure blood flows back towards heart

Question 17

Structure of heart:

Answer 17

Vena cava (deoxygenated blood from body) -> Right atrium -> AV valve -> Right Ventricle -> pulmonary artery (carries deoxugenated blood to lungs) -> pulmonary vein (returns oxygenated blood from lungs) -> aorta (oxygenated blood - body)

Question 18

What are some adaptations of atrium?

Answer 18

thin walled and elastic - stretches as it collects blood

Question 19

What are some adaptations of the ventricle?

Answer 19

thicker wall - strongly pump and contract

Question 20

What are the coronary arteries?

Answer 20

supplies o2 to heart

Question 21

Explain how water from tissue fluid is returned to the circulatory system.

Answer 21

Plasma proteins remain in the blood as they are too large to diffuse which creates a water potential gradient and lowers the water potential in the blood. Water diffuses by osmosis and is later returned to the circulatory system via the lymphatic system

Question 22

Explain how an arteriole can reduce the blood flow into capillaries.

Answer 22

Muscle in arterioles contracts which narrows the lumen

Question 23

Describe the structure of haemoglobin.

Answer 23

Globular, water soluble, conatins 4 polypeptides chains

Question 24

What are 3 factors affecting oxygen-haemoglobin binding?

Answer 24

1. partial pressure of oxygen
2. partial pressure of carbon dioxide
3. saturation of haemoglobin with o2

Question 25

What happens as partial pressure of oxygen increases?

Answer 25

affinity of haemoglobin increases, so oxygen binds

Question 26

How does the saturation of haemoglobin with o2 affect oxygen-haemoglobin binding?

Answer 26

positive co-operativity: hard first oxygen to bind, changes tertiary structure making it easier for second oxygen to bind.

Question 27

Why does oxygen bind to haemoglobin when in the lungs?

Answer 27

> high partial pressure of oxygen > low concentration of co2, so affinity high

Question 28

Why is oxygen released to respiring cells?

Answer 28

> low partial pressure of oxygen > higher co2 conc, affinity decreases

Question 29

What is meant by myogenic?

Answer 29

> The heart's contraction is initiated from within the muscle itself, rather than by nerve impulses

Question 30

When was tissue fuild formed?

Answer 30

As blood is pumped through increasingly small vessels, this creates hydrostatic pressure, which forces fluid out of the capillaries