Electrical Activity Of Heart Part 3 Flashcards
What nerves or glands are norepinephrine and epinephrine secreted by?
Sympathetic nerves
Adrenal medullar glands
What neurotransmitters bind to beta-adrenergic receptors?
Norepinephrine and epinephrine
How to epinephrine and norepinephrine affect the heart?
Elevate heart rate
What neurotransmitter is secreted by the parasympathetic nerves?
Acetylcholine
What neurotransmitter binds to muscarinic cholinergic receptors?
Acetylcholine
What neurotransmitter decreases heart rate?
Acetylcholine
What is the name of the heart rate in the absence of any neural influence or when sympathetic and parasympathetic effects are equal?
Intrinsic rate
All cardiac muscle cells have _-________ receptors
Beta- adrenergic
Norepinephrine and epinephrine leads to ______, ______ duration action potentials and, quicker, stronger, and shorter ________ of contractions?
Taller
Shorter
Duration
What type of action potentials produced by norepinephrine and epinephrine cause an increase in the number of L-type Ca2+ channels open during the platue of an action potential?
Taller action potentials
What type of ion channels open that leads to more positive plateaus?
Ca2+
What type of ion channels are opened during shorter duration action potentials?
K+
What type of ion channels lead to shortened action potential and speeds repolarization?
K+
What type of contraction is produced when more Ca2+ channels are opened to increase the entry of Ca2+ from the extracellular space and SR?
Quicker and stronger contractions
What type of contraction is when the pump that moves cytosolic Ca2+ back into the SA and back out of the cell into the extracellular fluid is sped up?
Shorter duration contraction
