Physiology 3

Question 1

What name is given to space in the lungs filled with air which is not available for gas exchange?

Answer 1

Anatomical dead space

Question 2

Give a word equation for pulmonary ventilation.

Answer 2

Pulmonary ventilation = Tidal volume x Respiratory rate (L/min)

Question 3

Give a word equation for alveolar ventilation.

Answer 3

Alveolar ventilation = (Tidal volume - dead space volume) x Respiratory rate (L/min)

Question 4

Why is alveolar ventilation LESS than pulmonary ventilation?

Answer 4

Anatomical dead space

Question 5

What is pulmonary ventilation?

Answer 5

The volume of air breathed in and out per minute

Question 6

What is alveolar ventilation?

Answer 6

The volume of air exchanged between the atmosphere and alveoli per minute

Question 7

Why is the value for alveolar ventilation more important than that of pulmonary ventilation?

Answer 7

It represents the new air available for gas exchange with the blood

Question 8

How does one increase their pulmonary ventilation?

Answer 8

1. Increase the depth of breathing (tidal volume)

2. Increase the rate of breathing (respiratory rate)

Question 9

Because of dead space, it is more advantageous to increase (depth of breathing / respiratory rate).

Answer 9

depth of breathing

Question 10

What is ventilation?

Answer 10

The rate at which GAS passes through the lungs

Question 11

What is perfusion?

Answer 11

The rate at which BLOOD passes through the lungs

Question 12

Arterial partial pressure and alveolar partial pressure are at equilibrium when the ventilation/perfusion ratio is _.

Answer 12

1

Question 13

In most of the lung, partial pressures (are / are not) the same.

Answer 13

are not

Question 14

What is alveolar dead space?

Answer 14

Ventilated alveoli which is not adequately perfused with blood

Question 15

Alveolar dead space increases in ____.

Answer 15

disease

Question 16

Give a word equation for physiological dead space.

Answer 16

Physiological dead space = anatomical dead space + alveolar dead space

Question 17

___ ___ acts on the airways and arterioles to match airflow to blood flow.

Answer 17

Smooth muscle

Question 18

What must be matched in the airways and arterioles?

Answer 18

Airflow and blood flow

Question 19

Why may carbon dioxide accumulate in the alveoli?

Answer 19

Increased perfusion

Question 20

What occurs in the airways in response to alveolar carbon dioxide accumulation?

Answer 20

Dilation of airway / decrease in airway resistance –> Increased airflow

Question 21

Why may oxygen accumulate in the alveoli?

Answer 21

Increased ventilation

Question 22

What occurs in the pulmonary vessels in response to alveolar oxygen accumulation?

Answer 22

Vasoconstriction / increase in vascular resistance –> Decreased blood flow

Question 23

What happens to pulmonary arterioles when oxygen concentration of adjacent alveoli decreases?

Answer 23

Vasoconstriction

Question 24

What happens to pulmonary arterioles when oxygen concentration of adjacent alveoli increases?

Answer 24

Vasodilation

Question 25

Name four factors influencing the rate of gas exchange across the alveolar membrane.

Answer 25

1. Partial pressure gradients of O2 and CO2 2. Diffusion Coefficients 3. Surface area of alveolar membrane 4. Thickness of alveolar membrane

Question 26

What is Dalton's Law of Partial Pressures?

Answer 26

The total pressure exerted by a gaseous mixture = The sum of partial pressures of each gaseous component

Question 27

What is the partial pressure of a gas (e.g Gas X)?

Answer 27

The pressure that Gas X would exert if it alone occupied the total volume

Question 28

What is the partial pressure gradient?

Answer 28

Gases move from higher to lower partial pressures

Question 29

What are the two units of measurement for partial pressure?

Answer 29

1. kilopascals (kPa) | 2. mm Hg (to convert to kPa, divide by 7.5)

Question 30

What is the diffusion coefficient of a gas?

Answer 30

The solubility of that gas in membranes

Question 31

The diffusion coefficient of carbon dioxide is __ times that of oxygen.

Answer 31

20

Question 32

The higher diffusion coefficient of carbon dioxide offsets its smaller ___ ___ ___.

Answer 32

partial pressure gradient

Question 33

___ amounts of oxygen and carbon dioxide are transferred across the membrane.

Answer 33

Equal

Question 34

What is Fick's Law of Diffusion?

Answer 34

The amount of gas which moves across a sheet of tissue per unit time is: 1. Directly proportional to the surface area of the sheet 2. Inversely proportional to the thickness of the sheet

Question 35

What are two properties of the lungs which make them favourable for gas exchange?

Answer 35

1. Large surface area | 2. Thin membranes

Question 36

The extensive pulmonary capillary network of the lungs receives the entire ___ ___.

Answer 36

cardiac output

Question 37

The walls of alveoli consist of what type of alveolar cell?

Answer 37

Type I

Question 38

Which type of alveolar cell produce pulmonary surfactant?

Answer 38

Type II

Question 39

Alveoli are encircled by ____ ____.

Answer 39

pulmonary capillaries

Question 40

Name two non-respiratory functions of the respiratory system.

Answer 40

1. Water loss and heat elimination 2. Enhances venous return 3. Maintains acid-base balance 4. Enables speech and articulation 5. Defence against foreign material 6. Nose - function of smell