ANS control of the heart Flashcards
HR, BP, temp etc
Response to exercise
Response to stress
are all controlled by what?
Autonomic nervous system - involunatry
What are the effectors of the ANS?
Smooth muscle
Exocrine glands
Heart- rate and force
What is the enteric nervous system?
Network of neurones found in GI tract controlled by sympathetic and parasympathetic fibres.
Which branch of the ANS predominates in Basal conditions?
Parasympathetic
Do the parasympathetic and sympathetic nervous systems work together?
Yes the oppose one another to achieve a balance.
In the eye which receptors are found in the iris muscle and what neurotransmitter innervates them to do what action?
alpha 1- adrenaline- dilation
M3- Acetyl choline - contraction
What do M3 receptors in the lungs do?
Broncho-constrict
What neurotransmitter is at NMJ of parasympathetic nerves?
Acetyl choline
What receptor type is at the NMJ of most parasympathetic nerves?
mAChR
What is Qiss Qiq
A memory aid to help remember what receptor is where.
alpha1 Q vasoconstriction
alpha2 I inhibits nerotransmitter release
beta 1 S heart (inc, HR and inotropy)
beta 2 S lungs bronchodilation
M1 Q glands
M2 I heart (decrease HR and force)
M3 Q lungs (bronchoconstriction)
What does parasympathetic innervation do to sweat glands?
No effect
What causes sweat gland activity?
Sympathetic effect
Is the sympathetic effect systemic or localised?
More often than not it is localised but in fight or flights its systemic.
Which nerve slows the heart?
Vagus nerve pre-ganglionic fibres innervate post-ganglionic cells on the epicardial surface or with n the walls at the SAN or AVN.
Which nerve speeds up heart rate?
Sympathetic trunk feeds into cardiac accelerator nerve
Does the ANS initiate the heart beat?
NO
SAN is automated. The vagal nerve slows the intrinsic heart rate down in normal circumstances but does not initiate it.
Venoconstriction is controlled by?
ANS
How do M2 slow heart rate?
Slow AVN conduction velocity.
What neurotransmitter is released at M2 receptors?
Acetyl choline
B1 stimulation has positive inotropic and chronotropic effects where are the receptors in the heart and what stimulates it?
Noradrenaline
SAN, AVN and myocardium