Lecture 10-Neural regulation of the heart and vasculature Flashcards
what is autoregulation?
intrinsic ability of an organ to maintain a constant blood flow despite changes in perfusion pressure
-intrinsic to the organ –> occur in absence of neural / hormonal influence
what is reflex neural control
adjustment of cardiovascular function to meet the bodies needs
- allows rapid change in BP / CO
- essential to meet demand of brain / heart
where does parasympathetic and sympathetic afferents go to
medullary regulatory center
where do PNS and SNS efferents go to?
autonomic ganglia
sympathetic also goes to spinal centers`
what does the autonomic ganglia act on?
intrinsic nerves of the heart and vessels
what does sympathetic activity do to the heart?
increases HR and contraction rate
increases strength of contraction
releases adrenaline
vasoconstriction and vasodilation in certain places
what does parasympathetic activity do to the heart?
slows HR
slows rate of conduction
dilation in some vascular beds
what leads to HTN and heart failure
imbalance of sympathetic and parasympathetic NS
what receptors does the sympathetic nervous system act on?
B1
B2
A1
A2
what receptors does the parasympathetic nervous system act on
Muscarinic receptors
M1-3
What receptors are cardiac specific
Sympathetic = adrenergic B1 receptors Parasympathetic = M2 receptors
What receptors act peripherally?
SNS =B2 + A1 + A2
How does the Vagus nerve affect the heart?
Role in the parasympathetic efferent Slow rate of conduction / lower HR / relax smooth muscle 1. Right Vagus -innervates SA node 2. Left vagus -AV node
what other cranial nerves relax smooth muscle?
III , VII , IX
what are the characteristics of parasympathetic efferent fibres?
- maintain physiological rest
- long preganglionic fibres
- short post-ganglionic fibres
- ganglia near or in visceral organ
- released AcH