Pulmonary Function

Question 1

Differentiate between internal and external respiration.

Answer 1

• External respiration is the exchange of gases with the external environment, and occurs in the alveoli of the lungs.
• Internal respiration is the exchange of gases with the internal environment, and occurs in the tissue respiratory membrane The actual exchange of gases occurs due to simple diffusion.

Question 2

Can you list the four steps involved with oxygen transport

Answer 2

• Pulmonary ventilation
• Pulmonary diffusion
• Gaseous transport
• Capillary diffusion

Question 3

Define diffusion

Answer 3

• Diffusion is the process by which atoms or molecules move from an area of high concentration to low concentration

Question 4

What examples could you use to explain diffusion in human physiology?

Answer 4

• A tea bag immersed in a cup of hot water will diffuse into the water and change its colour.
• A spray of perfume or room freshener will get diffused into the air by which we can sense the odour.

Question 5

Detail the mechanics of ventilation

Answer 5

• Divided into conducting zones, trachea.
• Transitional and respiratory zones, bronchioles, aleovli
• Ventilation, or breathing, is the movement of air through the conducting passages between the atmosphere and the lungs. The air moves through the passages because of pressure gradients that are produced by contraction of the diaphragm and thoracic muscles

Question 6

• What is a common position assumed after strenuous exercise and how might this aid breathing?

Answer 6

• The tripod position
• muscles of the neck and upper chest work to get more air into the lungs. With the position of the arms secure, contraction of the pectoralis results in elevation of the anterior wall of the chest.

Question 7

Define tidal volume, residual lung volume and forced vital capacity

Answer 7

• Tidal volume is the volume of air inhaled in a single, normal breath.
• while residual volume is the amount of air left in the lungs after forceful respiration
• Vital capacity is the maximum amount of air a person can expel from the lungs after a maximum inhalatio

Question 8

Explain the function of residual lung volume in pulmonary function.

Answer 8

• it keeps the small airways open
• prevents the complete emptying of the lungs during each respiratory cycle.
• If there is no FRC, the alveolar PO2 and PCO2 will vary widely during breathing and will interfere with the diffusion of the respiratory gase

Question 9

• Example common obstructive and restrictive pulmonary conditions and describe how these alter common spirometric tracings

Answer 9

• chronic obstructive pulmonary disease (COPD), asthma, and bronchiectasis.
• Your FEV1 will fall between 50 percent and 79 percent of the predicted normal values with an FEV1/FVC of less than 70 percent

Question 10

What is FEV

Answer 10

Force expiratory volume

Question 11

Identify the physical activity implications of gender differences in lung function measures.

Answer 11

• reduced airway diameter, and a smaller diffusion surface than age- and height-matched men.
• The volume of adult female lungs is typically 10–12% smaller
• Smaller vital capacity and maximal expiratory flow rates

Question 12

Describe the relationship between pulmonary ventilation and exercise intensity.

Answer 12

• As exercise commences pulmonary ventilation (breathing) increases in direct proportion to the intensity and metabolic needs of the exercise
• resting values of around 5–6 litre min−1 to >100 litre min−

Question 13

Define physiologic dead space.

Answer 13

• total dead space is equal to anatomic plus alveolar dead space which is the volume of air in the respiratory zone that does not take part in gas exchange

Question 14

Detail how athletes maintain alveolar ventilation during intense aerobic exercise

Answer 14

Increases in the rate and depth of breathing

- . In moderate exercise, increasing tidal volume and only minimally increasing breathing rate

Question 15

• Explain how, when and why the Valsalva maneuver alters blood pressure.

Answer 15

increase in intrathoracic pressure, leading to a reduction in preload to the heart. Cardiovascular changes occur during and after this maneuver due to baroreflex and other compensatory reflex mechanisms that are initiated by decreased preload.
- venous return to the heart is decreased and peripheral venous pressures become increased.

Question 16

What is the pathway in which oxygen diffuses across the alveolar wall

Answer 16

partial pressure of oxygen is high in the alveoli and low in the blood of the pulmonary capillaries. As a result, oxygen diffuses across the respiratory membrane from the alveoli into the blood

Question 17

Pathway of oxygen from the air to the lungs

Answer 17

• Nostrils →→ Nasal Cavity →→ Pharynx →→ Trachea →→ Bronchi →→ Bronchiole →→ Alveoli.

Question 18

List the 5 factors that govern the rate of gas diffusion into a liquid

Answer 18

• he partial pressure difference across the diffusion barrier.
• The solubility of the gas.
• The cross-sectional area of the fluid.
• The distance molecules need to diffuse.
• The molecular weight of the gas

Question 19

Ambient air is made up of oxygen, carbon dioxide and nitrogen. Describe how their physical properties and solubility in different bodily fluids differ

Answer 19

• Carbon dioxide is more soluble in blood then oxygen
• Nitrogen as a low solubility in blood
• O2 is twice as soluble as N

Question 20

How may alveolar gas transfer be impaired

Answer 20

• diffusion coefficient of the gas, which is influenced by: molecular size, temperature , fluid viscosity/chemical properties of the membrane

Question 21

What is anaemia

- and how can it affect exercise performance

Answer 21

• a condition in which there is a deficiency of red cells or of hemoglobin in the blood, resulting in pallor and weariness.
• a reduction in oxygen-transport capacity of blood cells and a decrease in maximal consumption of oxygen peripheral

Question 22

Define oxygen cascade

Answer 22

• The oxygen cascade describes the transfer of oxygen from air to mitochondria.

Question 23

• Outline the relationship between the partial pressure of oxygen and the oxygen transport cascade.

Answer 23

• In each step of the cascade the PaO2 falls. It demonstrates that oxygen delivery to tissues relies on the passive transfer of gas

Question 24

• What role does myoglobin pay in gas exchange

Answer 24

• it stores oxygen for use during heavy exercise, and it enhances diffusion through the cytosol by carrying the oxygen. By binding O2, myoglobin (Mb) provides a second diffusive pathway for O2 through the cell cytosol

Question 25

• How is ventilation regulated during exercise?

Answer 25

• increases in ventilation are proportional to the increase in carbon dioxide production (V̇co2) and oxygen consumption (V̇o2).
• Ventilation is controlled by a complex cyclic neural process within the respiratory centers located in the medulla oblongata of the brain stem