REGULATION OF BREATHING AND COUGH

Question 1

What is Dalton’s law?

Answer 1

Total partial pressure = partial pressure of each gas added together

Question 2

What is partial pressure?

Answer 2

The concentration of a gas in a mixture of gases

Question 3

Which nerve innervates the diaphragm?

Answer 3

The phrenic nerve C3-C5

Question 4

Which muscles can help with breathing?

Answer 4

Accessory muscles - abdominal muscles

Question 5

What is hypercapnia?

Answer 5

A rise in partial pressure of CO2

Question 6

What is hypocapnia?

Answer 6

Fall in partial pressure of CO2

Question 7

What is hypoxia?

Answer 7

Fall in partial pressure of oxygen

Question 8

Describe the carbonic acid-bicarbonate buffer system?

Answer 8

Carbon dioxide dissolves to form carbonic acid which dissociates and forms hydrogen ions and bicarbonate ions.

Question 9

What is respiratory acidosis?

Answer 9

When hypoventilation causes increased partial pressures of carbon dioxide so plasma pH falls

Question 10

What is respiratory alkalosis?

Answer 10

Hyperventilation leads to a decrease in partial pressures of CO2 so plasma pH increases

Question 11

What are peripheral chemoreceptors?

Answer 11

They are found in carotid and aortic bodies and monitor partial pressures of oxygen in the blood. They only react when pO2 falls close to 8kPa and then they signal to the brain stem to increase Br and Hr and change the distribution of blood to prioritise more crucial tissues

Question 12

What are central chemoreceptors?

Answer 12

Receptors sitting in CSF and detect minuscule changes in pH so that ventilation rates can be altered to maintain homeostasis of pH

Question 13

What are the 2 types of respiratory failure?

Answer 13

Type 1 = hypoxia and normal to low pCO2

Type 2 = hypoxia and hypercapnia

Question 14

What is a productive cough?

Answer 14

A cough that produces mucus

Question 15

Describe the cough reflex?

Answer 15

Cough receptors are triggered and I put,she’s then travel via the vagus nerve to the medulla. The efferent neural pathway is then via the vagus, phrenic nerves and spinal motor neurones to all the effector organs (larynx, trachea, bronchi, diaphragm, exploratory muscles)

Question 16

Outline the mechanics of a cough?

Answer 16

The diaphragm and external intercostal, muscles contract to create a negative pressure around the lungs
Air rushes into the lungs to equalise this pressure
The glottis closes and vocal cords contract to shut the larynx
Abdominal muscles and other exploratory muscles contract to increase the pressure of the air within the lungs
Glottis and vocal cords reopen and air is forces out, clearing any irritants attached to the respiratory lining