Heart Physiology Flashcards
How does the nucleus tractus solitarius control heart rate?
NTS connects with:
sympathetic neurones - rostral ventrolateral medulla (medulla)
Parasympathetic neurones - dorsal vagule nuclus + nucleus ambiguus (medulla)
Where does the vagus nerve connect to the heart?
Sino-atrial node (right vagus nerve)
Atrioventricular node (left vagus nerve)
What effect does sympathetic stimulation have on the heart?
Positive inotropic
Postive chronotropic
What effect does parasympathetic stimulation have on the heart?
Negative inotropic
Negative chronotropic
How do sympathetic nerves reach the heart?
Via arterial vessels
What effect does sympathetic nerves have on blood vessels?
Cause vasoconstriction
Mediated by: Norephinephrine upon alpha adrenoceptors
What receptors are associated with sympathetic nerve effect? What are their function?
Beta 1 adrenoceptors: increase inotropic + chronotropic
Beta 2 adrenoceptors: increase inotropic + chronotropic
Alpha 1 adrenoceptors: increse inotropic + vasoconstriction
What is the neurotransmitter of beta receptors?
Noradrenaline
Adrenaline
What is the neurotransmitter for alpha receptors?
Catecholamines:
Noradrenaline
Adrenaline
What receptors does adrenaline act on?
Beta and alpha receptors
What receptors does parasympathetic neurones work on?
Muscarinic receptors (M2)
Neurotransmitter: Ach
How does activation of presynaptic alpha affect NT release?
Inhibit NT release ( noradrenaline)
How does activation of presynaptic beta receptors affect NT release?
Facilitates NT (noradrenaline) release
How does activation of presynaptic muscarinic receptors affect NT release?
Inhibits NT (noradrenaline) release
This is a mechanism the vagus nerve uses for negative inotropic and chronotropic effect
