Regulation Of Gas Concentration & Blood Pressure Flashcards
What effects does the concentration of carbon dioxide in the blood have on the breathing rate?
Any increase in CO2 results in an associated increase in hydrogen ion concentration. This increase results in the stimulation of Central/peripheral chemoreceptors which transmit nerve impulses to increase breathing rate.
What are the effects of the concentration of oxygen in the blood on the breathing rate?
When oxygen falls below normal while other factors are constant the breathing rate slightly increases. The concentration has to fall to very low levels before it has a major stimulatory effect.
How does the respiratory centre control breathing?
To coordinate breathing, messages pass back and forth between neurons in the two regions of the respiratory centre. Both O2 & CO2 are carried in the blood & their concentrations have an effect on the breathing rate.
What is the role of the aortic & carotid bodies in regulating breathing rate.
Two chemoreceptors exist in the aortic and carotid bodies.
Why is it dangerous to hyperventilate before swimming underwater?
As it allows the person to stay underwater longer due to loss of CO2. Breath holding ability could be increased to such an extent that the individual loses consciousness from lack of O2 before feeling the urge to breathe
On what factors does cardiac output depend?
Heart rate, stroke volume & venous return.
The amount of blood returning to the heart has an important influence on the amount of blood that can be pumped by the heart. Explain why the venous return is important.
Cardiac output couldn’t increase unless the supply of blood returning from the veins was maintained at levels sufficient to ensure a satisfactory flow of blood to the heart. If this did occur, any increase in stroke volume could not be maintained.
