Mass Transport In Humans

Question 1

What happens when muscle contracts in arteries?

Answer 1

Narrows lumen.

Question 2

Why is pressure higher in the atrium than the ventricle?

Answer 2

Due to filling/contraction.

Question 3

What does higher pressure in the atrium cause?

Answer 3

Atrioventricular valve opens.

Question 4

What causes the atrioventricular valve to close?

Answer 4

Ventricle has higher pressure than atrium.

Question 5

When is ventricular pressure higher than aorta pressure?

Answer 5

During ventricular contraction.

Question 6

What happens when ventricle pressure exceeds aorta pressure?

Answer 6

Semilunar valve opens.

Question 7

What happens when aorta pressure becomes higher than ventricular pressure?

Answer 7

Semilunar valve closes.

Question 8

What causes pressure to rise during the cardiac cycle?

Answer 8

Muscle contraction.

Question 9

What does diaphragm contraction cause?

Answer 9

Diaphragm flattens.

Question 10

What does flattening of the diaphragm do to lung volume?

Answer 10

Increases lung volume.

Question 11

What happens to pressure inside the lungs during inhalation?

Answer 11

It becomes lower than atmospheric pressure.

Question 12

Why does air move into the lungs?

Answer 12

Pressure inside lungs is lower than atmospheric pressure.

Question 13

What increases surface area in the lungs?

Answer 13

Many alveoli.

Question 14

What increases surface area in capillaries?

Answer 14

Many capillaries.

Question 15

What is the purpose of a large surface area in lungs/capillaries?

Answer 15

Fast diffusion.

Question 16

What makes the alveoli-capillary barrier efficient for diffusion?

Answer 16

Alveoli or capillary walls are thin/one cell thick.

Question 17

What type of epithelium allows fast diffusion in alveoli?

Answer 17

Flattened/squamous epithelium.

Question 18

What maintains a concentration gradient in the lungs?

Answer 18

Ventilation / circulation.

Question 19

Name the structures in order for air movement in the respiratory system.

Answer 19

Trachea → bronchi → bronchioles → alveoli.

Question 20

What happens during inhalation (breathing in)?

Answer 20

Diaphragm contracts, external intercostals contract → Volume increases, pressure decreases in thoracic cavity.

Question 21

What happens during exhalation (breathing out)?

Answer 21

Diaphragm relaxes, internal intercostals contract → Volume decreases, pressure increases.

Question 22

Name the two layers oxygen diffuses across in gas exchange.

Answer 22

Alveolar epithelium and capillary endothelium.

Question 23

What does reduced surface area or increased distance in alveoli do?

Answer 23

Reduces rate of gas exchange.

Question 24

How does elastic tissue in arteries function during heartbeats?

Answer 24

Stretches under pressure / recoils to even out pressure.

Question 25

What does muscle contraction in blood vessels do?

Answer 25

Vasoconstriction which reduces diameter & changes pressure and flow.

Question 26

How does smooth epithelium benefit blood vessels?

Answer 26

Reduces friction / blood clots / resistance.

Question 27

Why does the aorta stretch during systole?

Answer 27

Because ventricle contracts and pressure increases.

Question 28

Why does the aorta recoil?

Answer 28

Because ventricle relaxes and pressure falls.

Question 29

What is the purpose of aorta recoil?

Answer 29

Maintains smooth flow/pressure.

Question 30

What should you include when drawing biological diagrams?

Answer 30

* Labels * Annotations * Title * Magnification * Scale bar * Same size parts * No shading

Question 31

Name two safety rules when using sharp instruments in dissection.

Answer 31

Hold by handle/point away; Disinfect instruments/surfaces.

Question 32

What should be done with used biological material?

Answer 32

Put in a separate bag/bin/tray to dispose.

Question 33

What causes tissue fluid to form?

Answer 33

High hydrostatic pressure forces fluid out.

Question 34

Why do proteins remain in capillaries during tissue fluid formation?

Answer 34

Because they are too large.

Question 35

Why does water return to capillaries from tissues?

Answer 35

Low water potential in capillaries due to plasma proteins → Water enters by osmosis.

Question 36

What system returns excess tissue fluid to circulation?

Answer 36

Lymph system.

Question 37

Why do smaller mammals lose more heat per unit mass?

Answer 37

Greater surface area to volume ratio.

Question 38

How do small mammals compensate for heat loss?

Answer 38

Greater rate of respiration/metabolism.

Question 39

Why do small mammals require more oxygen?

Answer 39

For increased respiration/metabolism.

Question 40

What happens to haemoglobin in small mammals?

Answer 40

Lower affinity for oxygen.