L24. Gas Transport

Question 1

Which is more diffusible, CO2 or O2?

Answer 1

CO2

Question 2

Name 2 gas diffusion properties in the respiratory and circulatory systems.

Answer 2

1. Large surface area for gas exchange

2. Mechanisms to transport CO2 and O2 between lungs and tissues

Question 3

Describe the relationship between the partial pressures of O2 and CO2.

Answer 3

They are generally opposites

Question 4

Complete the sentence:

The sum of the partial pressures of a gas (in mmHg or torr) must _________________________________

Answer 4

be equal to the total pressure

Question 5

Give the abbreviation and value for barometric pressure at sea level.

Answer 5

760mmHg

Question 6

Give the pressure of water vapour at 37 degrees c

Answer 6

47mmHg

Question 7

How do you calculate the internal pressure of O2?

Answer 7

P I O2 = (Barometric pressure - water pressure) x fraction of O2

Question 8

Describe the 2 methods that oxygen can travel in the blood

Answer 8

Dissolved or bound to haemoglobin

Question 9

Name the type of sample which measures dissolved blood.

Answer 9

Arterial blood sample (PaO2)

Question 10

What is arterial blood pressure at rest?

Answer 10

3ml/L

Question 11

How much oxygen is needed per minute of strenuous exercise?

Answer 11

3L/minute

Question 12

Haemoglobin is composed of a protein with 2-alpha and 2-beta chains with how many haem groups?

Answer 12

4

Question 13

How many haemoglobin units are in each blood cell?

Answer 13

280 million

Question 14

Name the reader which can detect O2 saturation on your finger. Give a range of values for a healthy/unwell person.

Answer 14

Pulse oximeters
A healthy person should have 96-100%
An unwell person has 70-80% saturation

Question 15

What is the normal respiratory exchange rate?

Answer 15

0.8 (80 CO2 to 100 O2)

This becomes greater than 1 during strenuous exercise

Question 16

Name the 3 ways that CO2 can be transported

Answer 16

1. Dissolved
2. Bound to haemoglobin
3. as bicarbonate

Question 17

In a dissociation curve, which variable is ALWAYS on the x-axis?

Answer 17

Partial pressure of oxygen

Question 18

As temperature decreases, what happens to the speed of haemoglobin’s oxygen saturation?

Answer 18

speeds up

Question 19

As blood becomes more acidic, what happens to the speed of haemoglobin’s oxygen saturation?

Answer 19

speeds up

Question 20

What is the total O2 capacity for each litre of blood?

Answer 20

211ml

Question 21

In P O2 in mmHg, what state of oxygen-ation is the blood at before 100 and at 100?

Answer 21

Before 100 = deoxygenated

At 100 = oxygenated