Hormonal and nervous control of heart rate Flashcards
SAN
initiates contractions
Rate of SAN contractions is controlled by…
…-hormones acting directly on SAN
-messages from autonomic nervous system
2 centres in medulla oblongata
cardiacceleratory centre and cardioinhibitory centre
each centre is linked by a
motor neurone to the sino-atrial node
Accelerator nerve
Sympathetic system
Vagus nerve
Parasympathetic system
Accelerator nerve what it does
-accelerates HR
-increases force of contractions
Vagus nerve what it does
-reduces HR
Chemoreceptors
-CO2/O2/pH
-located in aortic and carotid bodies, medulla
-detect changes in level of particular chemicals in blood
Baroreceptors
-pressure (mechanoreceptors)
-located in aortic arch and carotid sinus
-detect changes in blood pressure