Exam 2: Lecture 17 Flashcards
Whare the effects of the autonomic nervous system on the heart rate called
Chronotropic effects
does + or - chronotropic effects increase the heart rate
+
Does the SNS or PNS work on + chronotropic effects
SNS
- NE released from S nerve fibers and activates Beta-1 receptors in the SA node
What receptor in the SA node produces an increase in I subscrpit f (If)
Activation of Beta 1 receptors
What happens in phase 4 depolarization and decreasing the threshold AP?
the SA node is depolrized to threshold potenital more frequently and fires more AP’s = increased HR
Does + or - chronotropic effects decrease HR
-
Does the SNS or PNS use negative chronotropic effects on the heart to decrease HR
PNS
What neurotransmitter is used in PNS to decrease HR and activates muscerinic receptors in the SA node
Acetylcholine
Does negative chronotropic effects in I subscript f (If)
decrease HR due to inhibition of adenylyl cyclase system from Gi protein
what is dromotrophy
effects of the autonomic nervous system on conduction velocity
What is the outcome of a positive dromotrophy on conduction velocity
increases in conduction velocity
What is the outcome of negative dromotrophy on conduction velocity
decrease in conduction velocity
What is the most important physiological effects on the autonomic nervous system on conduction velocity and can alter the rate at which AP are conducted from the atria to the ventricles
AV node
Stimulation of the SNS or PNS can increase condution velocity
SNS
- increase HR
Stimulation of the SNS or PNS can decrease conduction velocity
PNS
- decrease HR