Question

Identify five (5) factors that influence the brain stem respiratory centers. Discuss the specific effect of each of these factors on the brain stem respiratory centers.

Answer 1

Respiratory centre present in the brainstem regulates respiration by sending motor signals to respiratory muscles that results in suppress or stimulation of rate of respiration through altered activity.
The chemoreceptors present in the blood vessels senses the change in chemical composition of blood and sends sensory impulses to respiratory centre.
The main factors that affect respiratory centre are :

1. decreased oxygen content in blood : decreased oxygen content in blood activates the chemoreceptors. The sensory signals are send to respiratory centre that causes increased contraction of muscles of inspiration resulting in increased respiratory rate and depth. This sets the homeostasis of oxygen content in blood.
2. increased CO2 : increased CO2 content in blood activates the chemoreceptors. The sensory signals are send to respiratory centre that causes increased contraction of muscles of inspiration resulting in increased respiratory rate and depth. This increases removal of CO2 from blood.
3. Decreased blood pH : Decrease in blood pH results in acidic blood which activates the chemoreceptors. The sensory signals are send to respiratory centre that causes increased contraction of muscles of inspiration resulting in increased respiratory rate and depth. This increases removal of CO2 from blood resulting in increase in blood pH.
4. Increased lung volume : this stimulates the stretch receptors in lungs. The sensory signals are send to respiratory centre. This suppresses the respiratory centre resulting in decreased respiratory rate.
5. Temperature: at increased temperature cellular respiration increases. This increases oxygen demand. The respiratory centre in brainstem is stimulated that cause increase in respiratory rate to increase oxygen supply to cells