Exam 3

Question 1

What are the four purposes of breathing?

Answer 1

Exchange of O2<
Exchange of CO2
Control of blood acidity
Oral communication

Question 2

What is the difference between ventilation and respiration?

Answer 2

Ventilation: The process of moving air into and out of the lungs.
Respiration: The cellular process of converting oxygen and nutrients into energy.

Question 3

How is the rate of pulmonary ventilation expressed?

Answer 3

Pulmonary minute volume (V̇): Liters per minute.
V̇ = f x VT
f: The frequency of breathing (breaths per minute)
VT: The volume of air moved on each breath (tidal volume)

Question 4

How is oxygen transported in the blood?

Answer 4

Dissolved O2: About 0.3 ml O2 per deciliter of blood.
Bound to hemoglobin: Hemoglobin is a protein in red blood cells that can bind to oxygen. At a partial pressure of 100 mmHg, hemoglobin is nearly 100% saturated.

Question 5

What is the Bohr effect?

Answer 5

A shift in the oxygen-hemoglobin dissociation curve to the right due to increased temperature and acidity (lower pH) in the blood.
This facilitates the unloading of oxygen from hemoglobin in active muscle tissue.

Question 6

What is the Haldane effect?

Answer 6

The displacement of CO2 from hemoglobin by O2.
This facilitates the unloading of CO2 from the blood in the lungs.

Question 7

How is carbon dioxide transported in the blood?

Answer 7

Dissolved CO2: About 5-7%.
Bicarbonate ion (HCO3-): About 70%.
- Formed in red blood cells from CO2 and water.
- Transported out of the red blood cells in exchange for chloride ions.
Carbamino compounds: About 23-25%.
- Formed by the binding of CO2 to hemoglobin and plasma proteins.

Question 8

What is the role of carbonic anhydrase in CO2 transport?

Answer 8

Carbonic anhydrase is an enzyme that catalyzes the formation of carbonic acid from CO2 and water in red blood cells.
This is an important step in the formation of bicarbonate ions, which are the main form of CO2 transport in the blood.

Question 9

What are the three main factors that influence blood pH?

Answer 9

CO2 concentration
Concentrations of other weak acids
Relative electrolyte concentrations

Question 10

What is the most important buffer in the blood?

Answer 10

The bicarbonate buffer system

Question 11

How does ventilation regulate blood pH?

Answer 11

By controlling the CO2 content of the blood.
Increased ventilation leads to decreased CO2 levels, which in turn increases pH.
Decreased ventilation leads to increased CO2 levels, which in turn decreases pH.

Question 12

What is the role of breathing in talking?

Answer 12

Breathing is essential for vocal communication.
The control of speech (a voluntary activity) and breathing (an involuntary activity) are closely integrated.

Question 13

How does exercise affect pulmonary ventilation?

Answer 13

Increases pulmonary ventilation
Increases tidal volume
Increases breathing rate

Question 14

How is the efficiency of gas exchange in the lungs maximized?

Answer 14

Large surface area
Thin diffusion distance: The blood-gas barrier is very thin, allowing for rapid diffusion of gases.
Maintenance of a partial pressure gradient: Ventilation maintains a high partial pressure of O2 and a low partial pressure of CO2 in the alveoli, which promotes diffusion of these gases.

Question 15

What is meant by the term “oxygen delivery”?

Answer 15

The amount of oxygen transported to the tissues per minute.
It is determined by: Arterial oxygen content (CaO2) and Cardiac output

Question 16

What is the Fick Principle?

Answer 16

The Fick Principle is used to determine oxygen consumption (VO2).
It states that VO2 is equal to the product of cardiac output and the arteriovenous oxygen difference.
VO2 = Cardiac output x (CaO2 - CvO2)

Question 17

What is the function of myoglobin?

Answer 17

Myoglobin is an oxygen-binding protein found in muscle.
It facilitates the diffusion of oxygen from muscle capillaries to muscle mitochondria.

Question 18

What is the “chloride shift”?

Answer 18

The exchange of chloride ions (Cl-) for bicarbonate ions (HCO3-) across the red blood cell membrane.
This helps to maintain electroneutrality during CO2 transport.

Question 19

What are the different types of acid-base imbalances?

Answer 19

Respiratory acidosis: Caused by hypoventilation, leading to a buildup of CO2 in the blood.
Respiratory alkalosis: Caused by hyperventilation, leading to a depletion of CO2 in the blood.
Metabolic acidosis: Caused by an excess of non-volatile acids (e.g., ketone bodies in diabetes) or a loss of bicarbonate ions.
Metabolic alkalosis: Caused by an excess of bicarbonate ions or a loss of non-volatile acids (e.g., from vomiting).

Question 20

What is the significance of the anaerobic threshold in relation to ventilation?

Answer 20

The anaerobic threshold corresponds to the point at which lactate production increases significantly.
This leads to an increased demand for CO2 buffering, resulting in an increase in ventilation.