Control Of Respiration

Question 1

Neural regulation

Answer 1

• activity of respiratory muscles are transmitted to and from the brain via phrenic and intercostal nerves
• neural centres: medulla and pons, control rate and depth

Question 2

Medulla and Pons

Answer 2

• dorsal ventral group: integrates sensory input and communicates with central respiratory group
• ventral respiratory group: sets rhythm
• pons: smooths out the rhythm set by the medulla

Question 3

Ventral respiratory group

Answer 3

• two sets of neuroma that inhibit each other to generate a rhythm of breathing
• (inspiratory 2s, expiratory 3s)

Question 4

Neural passageway

Answer 4

-medulla > phrenic / intercostal nerves > diaphragm / external intercostals > bronchioles / alveoli stretch receptors > vagus nerve > medulla
(Which stops inspiration, inflation reflex, protective, puts more regularity)

Question 5

Depth and rate of breath

Answer 5

Depth: how actively motor neurons are stimulated
Rate: how long an inspiratory system is active and how quickly it is turned off

Question 6

Factors that modify basic rhythm

Answer 6

• physical factors: exercise, increased body temp, talking, coughing
• volition (limited)
• emotional factors (fear, anger, excitement) via the hypothalamus

Question 7

High altitude

Answer 7

• could produce acute motion sickness

- from low partial pressure at high altitudes

Question 8

Acute motion sickness

Answer 8

• headaches nausea, shortness of breath

- pulmonary and cerebral edema

Question 9

Acclimatization to high altitude

Answer 9

• chemoreceptors become more responsive to PCO2 when PO2 declines
• when PO2 is <60mmHg, peripheral chemoreceptors stimulated, increasing ventilation and stabilizes in a few days to 2-3 L/min higher than sea level
• kidneys stimulated to accelerate the production of EPO
• increased RBC slowly provide long-term compensation