Central control of Respiration

Question 1

What is respiration controlled by

Answer 1

Respiration controlled by nerve cells or neurones in the medulla oblongata
Medullary neurones set the basic rhythm of respiration, but is influenced by inputs from other parts of the brain and by peripheral sensory receptors.

Question 2

What are the 2 regions of the respiratory centre.

Answer 2

The inspiratory centre

The expiratory centre

Question 3

Define the inspiratory centre

Answer 3

2 dorsally situated regions of the medulla oblongata.
Neurones show a spontaneous rhythmicity and have a cyclic form of activity that arises every few seconds.
This activity sets the basic rhythm of respiration.
Action potentials pass along the intercostal nerves and phrenic nerve to muscles of inspiration.

Question 4

Define the expiratory centre

Answer 4

2 groups of neurones more ventrally either side of the medulla oblongata

Mostly inactive, but during heavy breathing, send action potentials to muscles of expiration.

Question 5

Define apneustic centre and pneumotaxic centre

Answer 5

1) Apneustic centre = scattered neurones in the pons, send action potentials to the inspiratory centre.
2) Pneumotaxic centre = neurones in the superior region of the pons, inhibitory effect on the inspiratory and apneustic centres.

Question 6

What are the hiring Breuer reflex

Answer 6

Stretch receptors in the walls of the bronchi.
Activated during inspiration and send action potentials via the vagus nerve to the medulla oblongata.
Inhibit the inspiratory centres and allow expiration.

Question 7

What are the 2 types of chemo receptors.

Answer 7

cental and peripheral

Question 8

Where are the central chemoreceptors found

Answer 8

Central = medulla oblongata, influence the respiratory centres.

Question 9

Where are the peripheral chemoreceptors found

Answer 9

Peripheral = carotid and aortic bodies, connect to the respiratory centres by glossopharyngeal nerve and vagus nerve.

Question 10

What is the function of chemo receptors

Answer 10

Respond to changes in the concentrations of hydrogen ions (pH) and oxygen.

Question 11

What effect does pH and CO2 have in the blood.

Answer 11

Excessive PCO2 = hypercapnia

Lower PCO2 = hypocapnia.

CO2 conc of blood is not directly detected by the chemoreceptors, instead the chemoreceptors detect changes in the bloods pH.

pH is detected by the chemoreceptive area in the medulla oblongata and by the peripheral chemoreceptors.