Variations In Heart Rate Flashcards
What controls heart rate
Cardiovascular control centre in the medulla oblongata
What does the cardiovascular control centre control
Controls heart rate by controlling the rate at which the SAN fires which generates electrical impulses that cause the atria to contract which sets the rhythm of the heartbeat
What are baroreceptors
Pressure receptors in the aortic and carotid bodies, stimulated by high and low bp
How are electrical impulses sent from receptors to the medulla oblongata
Along sensory neurones
What happens when high blood pressure detected
-baroreceptors detect high blood pressure
-impulses sent to the cardiovascular control centre which sends impulses along parasympathetic neurones which secrete acetylcholine which binds to receptors on the SAN
-SAN fires impulses less frequently to slow hr and reduce bp back to normal
What happens when low blood pressure detected
-baroreceptors detect low bp
-impulses are sent to the cardiovascular control centre which sends impulses along sympathetic neurones which secrete noradrenaline which binds to receptors on the SAN
-SAN fires impulses more frequently to increase heart rate and increase bp back to normal
What happens when high blood oxygen, low CO2 or high pH to heart
Chemoreceptors detect chemical changes in the blood, impulses sent to the cardiovascular control centre which sends impulses along parasympathetic neurones which secrete acetylcholine which binds to receptors on the SAN
-the SAN fires impulses less frequently to decrease heart rate and return O2, CO2 and pH levels back to normal
What happens when low blood O2, high CO2 or low pH levels
-chemoreceptors detect chemical changes in the blood
-impulses sent to the cardiovascular control centre which sends impulses along sympathetic neurones which secrete noradrenaline which binds to receptors on the SAN
-SAN fires impulses more frequently to increase hr and return O2, CO2 and pH levels back to normal
