Regulation of Respiration

Question 1

Regulation of respiration location

Answer 1

Medulla Oblongata

Question 2

DRG ( Dorsal Respiratory Group)

Answer 2

quiet & forceful inspiration

Question 3

VRG ( Ventral Respiratory Group)

Answer 3

forceful inspiration & expiration

Question 4

During normal quiet breathing

Answer 4

the expiratory area is inactive

Question 5

Apneustic center

Answer 5

Acts to prolong inspiration

Question 6

Pneumotaxic center

Answer 6

• inhibits the Apneustic center
• stops inspiration
• promotes exhalation

Question 7

Central Chemoreceptors

Answer 7

sensitive to:
CSF [H+], CO2

Blood Brain Barrier (BBB) is freely permeable to CO2. Arterial [H+] passes slowly across the BBB. Central chemoreceptors are not sensitive to arterial [H+], but are sensitive to [H+] in CSF.

results in hyperventilation

Question 8

Peripheral chemoreceptors

Answer 8

sensitive to low O2
(PO2 must fall below 60mmHg)

high ARTERIAL [H+] stimulates the carotid bodies

Question 9

Factors activating respiratory centers

Answer 9

peripheral chemoreceptors

central chemoreceptors

receptors in joints and muscles

Question 10

Factors inhibiting respiratory centers

Answer 10

stretch receptors in lungs

irritant receptors

Question 11

Lung stretch receptors: Herring Breuer Reflex

Answer 11

Distension of the lungs → stimulates lung stretch receptors → inhibit the Inspiratory centers

*** Tidal Volume > 1L
(DGN inhibits)

Question 12

Irritant receptors of lungs

Answer 12

stimulated by: smoke, ammonia, sulfur dioxide

reflex hyperventilation along with bronchospasm

Question 13

‘J’ Receptors of Lungs

Answer 13

stimulated by distension of the pulmonary vessels as in heart failure and pulmonary embolization

Question 14

Conditions when ‘J’ receptors are stimulated:

Answer 14

• Pulmonary congestion
• Pulmonary edema
• Pneumonia
• Overinflation of lungs
• Microembolism in pulmonary capillaries
• Stimulation by exogenous and endogenous chemical substances such as histamine, bradykinin

Question 15

Tachypnea

Answer 15

↑ in the rate of respiration

Question 16

Bradypnea

Answer 16

↓ in the rate of respiration

Question 17

Apnea

Answer 17

Temporary arrest of breathing

Question 18

Hyperventilation

Answer 18

↑ in rate and force of respiration

↑ CO2 stimulates the respiratory centers

Question 19

Hypoventilation

Answer 19

↓ in rate and force of respiration

Question 20

Hypoxic hypoxia

Answer 20

↓ Oxygen tension in arterial blood:

high altitude

Question 21

Anemic hypoxia

Answer 21

↓ Oxygen carrying capacity of blood:
↓RBCs
↓ Hb

Question 22

Stagnant hypoxia

Answer 22

↓ Velocity of blood flow:
hemorrhage
vasospasm thrombosis
embolism

Question 23

Histotoxic hypoxia

Answer 23

↓ Utilization of oxygen by the cells:

Cyanide poisoning

Question 24

During Exercise

Answer 24

Arterial PO2 & PCO2 does not change

Arterial pH does not change, but ↓ in strenuous exercise (because of lactic acid)

Question 25

Atelectasis

Answer 25

1. Deficiency or inactivation of surfactant →collapse of lungs due to ↑surface tension
2. Obstruction of a bronchus or a bronchiole.
3. Presence of air (pneumothorax), fluid (hydrothorax), blood (hemothorax) or pus (pyothorax) in the pleural space.

Question 26

*** PCO2 affects respiration primarily by stimulating

Answer 26

medullary chemoreceptors (central)