Neural control of breathing

Question 1

Why is ventilation regulated?

Answer 1

Regulated to meet varying O2 demand/CO2 production

Question 2

What is breathing initiated by and what do they provide?

Answer 2

Breathing is initiated by neural activation of respiratory muscles, which provide the movement required for ventilation

Question 3

What do resp muscles consist of and what do they require to contract?

Answer 3

As Resp muscles consist of skeletal muscle, they require neural inputs/stimulation to contract

Question 4

What provides the contractile signal?

Answer 4

Innervation from motor neurons synapsing from descending spinal tracts provide the contractile signal

Question 5

Muscles utilized in quiet breathing during inspiration

Answer 5

Diaphragm

Question 6

Muscles utilized in quiet breathing during expiration

Answer 6

Elastic recoil

Question 7

Which respiratory muscles are utilized in increased/forced ventilation during inspiration?

Answer 7

External intercostals

Question 8

Which respiratory muscles are utilized in increased/forced ventilation during expiration?

Answer 8

Elastic recoil

Internal intercostal

Question 9

Which accessory muscles are utilized in increased/forced ventilation during inspiration?

Answer 9

Pectorals
Sterno-mastoid
Scalene

Question 10

Which accessory muscles are utilized in increased/forced ventilation during expiration?

Answer 10

Abdominal

Question 11

What is the basic breathing pattern generated by?

Answer 11

Generated by neuronal systems within the brainstem

Question 12

How does the central pattern generator determine how often and hard to breathe?

Answer 12

Higher brain centers-Cerebral cortex(voluntary control over breathing)
Other receptors-Emotional stimuli acting through the hypothalamus
Respiratory centers-Medulla and pons
Peripheral chemoreceptors
Stretch receptors in lungs
Central chemoreceptors
Receptors in muscles and joints
Irritant receptors

Question 13

What does the CPG integrate?

Answer 13

The CPG integrates data from various neuronal inputs to regulate ventilation

Question 14

What do central chemoreceptors respond to?

Answer 14

Central chemoreceptors respond indirectly to changes in arterial PCO2

Question 15

What monitor changes in arterial CO2?

Answer 15

Central respiratory chemoreceptors present in medulla indirectly monitor changes in arterial CO2

Question 16

What does CRC respond to and why and what do they not directly respond to?

Answer 16

Although CRC respond to changes in [H+] within cerebrospinal fluid, as H+ doesn’t cross the blood brain barrier, CRC do not directly respond to changes in blood pH

Question 17

What do peripheral chemoreceptors respond to?

Answer 17

Peripheral chemorecceptors respond to changes in arterial O2, CO2 and pH

Question 18

What are carotid and aortic bodies activated by?

Answer 18

Activated by a decrease in PaO2, increase in PaCO2 and acidaemia

Question 19

What do carotid and aortic bodies signal to and what do they do?

Answer 19

Signal to respiratory centers in medulla via sensory nerves to increase ventilation(negative feedback)

Question 20

In a hypercapnic drive, what is ventilation proportional to?

Answer 20

Ventilation is proportional to PaCO2

Question 21

In a hypoxic drive, what happens?

Answer 21

Hypoxaemia(low PaCO2) stimulates increased ventilation

Question 22

What is central sleep apnoea?

Answer 22

Temporary cessation of breathing during sleep caused by dysfunction of the processes that initiates breathing

Question 23

What are central sleep apnoea negative effects?

Answer 23

Include:

• tiredness
• CV compoliations

Question 24

What are the causes of central sleep apnoea?

Answer 24

• Stroke
• Drugs
• Altitude