Reflex Control Of The CVS

Question 1

What types of reflexes response are there

Answer 1

Reflexes can be in response to excitatory signals or inhibitory inputs.

Question 2

What does the stimulation of arterial chemoreceptors cause

Answer 2

The
stimulation of arterial chemoreceptors (detect chemical signals like CO2 concentration) and muscle
metaboreceptors (detect physical signals like stretching) causes reflexes that increase cardiac output,
TPR and blood pressure (pressor response)

Question 3

What does the stimulation of cardiac-pulmonary receptors and cardiac bareceptors cause

Answer 3

whilst the stimulation of baroreceptors and cardiac-
pulmonary receptors cause reflexes that decrease cardiac output, TPR and blood pressure (depressor
response).

Question 4

What blood flow is vital

Answer 4

It is vital to maintain blood flow to the brain and myocardium.

Question 5

Where is blood flow not monitored - how does the body compensate

Answer 5

There are however no blood flow
sensors that monitor blood pressure in the carotid or coronary arteries. The body compensates for
this by using pressure sensors in the aorta and carotid artery that send information on pressure
changes in these key vessels back to the brain.
A decrease in pressure will result in a decrease in
either blood flow or TPR.

Question 6

What detects co2 and o2 concentration in the body -where are they located

Answer 6

There are also chemoreceptors around the CVS that detect CO2 and O2 concentration. They are
located in the aorta as aortic bodies and in the carotid arteries as carotid bodies sending their signals
up the vagus nerve and the carotid sinus that joins up to the glossopharyngeal nerve respectively.

Question 7

What are the two types of drive that regulate breathing

Answer 7

There are two types of drive that regulate breathing. Hypoxia is the lack of O2 and hypercapnia is
high CO2. The hypercapnic drive is the main reason why one breaths and not hypoxia (CO2 build up
detected before lack of O2). The levels of oxygen and carbon dioxide in the blood are constantly
being measured in the chemoreceptors and these measurements drive the autonomic nervous
system.

Question 8

What do chemoreceptors also measure

Answer 8

These chemoreceptors also measure potassium and hydrogen ion levels. They are well
supplied with blood flow (around 20 ml/g/min) and regulate ventilation. They can also drive cardiac
reflexes during asphyxia (low O2/high CO2), shock and haemorrhage.

Question 9

What happens when blood pressure falls below the range baroreceptors can detect

Answer 9

When blood pressure falls
below the range that baroreceptors can detect it (not stretched at all), the chemoreceptors are still
somewhat active and can partially compensate for the lack of the baroreflex.