Autonomic Regulation of the Heart - Quiz 1 Flashcards
role of SA node on actions on the heart
- changes nodal action potential
- changes heart rate
parasympathetic role on heart rate
- decreases heart rate
sympathetic role on heart rate
- increases heart rate
sympathetic role on contractility
- increases contractility
sympathetic role on vasculature
- constricts smooth muscle of blood vessels
autonomic role of baroreceptor reflex
- regulates autonomic response to changes in pressure and volume in the vasculature
NE or EPI binds to
- beta1 adrenergic receptors on SA nodal cells
beta receptors on SA nodal cells have what kind of receptor
- G protein coupled receptor
NE or EPI binding to B1 adrenergic receptor causes what?
- increases open state probability of HCN (mostly Na+) - due to cAMP
- increases opening of T type Ca channels - due to more negative membrane potential
- increases opening of L-type Ca channels - due to cAMP -> PKA which opens DHP
opening of HCN and T-type Ca channels causes
- faster rate of phase 4 depolarization
- major effect
opening of L-type Ca channels causes
- less positive threshold
additional sympathetic effect of NE or EPI binding to B1 adrenergic receptor
- increased conduction velocity of action potentials
- increased heart rate
increased conduction velocity of action potentials is what kind of effect
- positive dromotropic
increased heart rate is what kind of effect
- positive chronotropic
parasympathetic effect Ach binds to
- muscarinic receptors
what type of receptor are muscarinic receptors
- G coupled protein receptors
results of Ach binding to muscarinic receptor
- increases permeability to K+
result of increased permeability to K+
- hyper polarization maximum diastolic polarization more negative
- slows depolarization
additional parasympathetic effect of Ach binding to muscarinic receptor
- decreased conduction velocity
- decreased heart rate
decreased conduction velocity is what kind of effect
- negative dromotropic
decreased heart rate is what kind of effect
- negative chronotropic
sympathetic stimulation effects on cardiac muscle contractility
- increased tension developed
- increased rate of tension increase
- increased rate of relaxation
sympathetic stimulation effects on cardiac muscle contractility a result of
- L-type channels increasing permeability to Ca2+
- increasing activity of Ca2+ pumps to make myocyte ready for next depolarization and increase amount of Ca2+ in stores for next release burst
where are the baroreceptor sensory receptors located?
- aortic arch
- carotid sinus
integrators in maintenance of blood pressure/volume
- brainstem and hypothalamus determine response
afferent pathway travels by
- cranial nerves
efferent pathway travels by
- ANS pre- and post-ganglionic neurons
effects of maintenance of blood pressure/volume are
- ANS outflow to targets
- blood vessels, SA node, ventricles, endocrine tissues
what do baroreceptors due in response to increases or decreases in mechanical stretch
- alter firing
what organ center receives the synapses from the baroreceptors and other nuclei
- brainstem cardiovascular control center
hemorrhage pathway
- decrease arterial pressure
- decrease firing by arterial baroreceptors
- decrease parasympathetic discharge to heart
- increase sympathetic discharge to heart
- increase heart rate
parasympathetic efferent pathway travels via
to where
result
- vagus nerve
- SA node of heart
- decrease heart rate
sympathetic efferent pathway travels via
- sympathetic chain ganglia
sympathetic efferent pathway travels to where
- SA/AV node
- adrenal medulla
- blood vessels
sympathetic efferent pathway result
- increase heart rate
- secrete Epi/NE
- constrict blood vessels using NE
