Quiz 10 Flashcards
Which sympathetic nerve receptor predominantly causes vasoconstriction?
Alpha 1
Which sympathetic nerve receptor predominantly causes increased contractility?
Beta 1
Definition: conduction velocity
Dromotropy
Sympathetic does what?
- inhibits bladder contraction
- Inhibits salivation
- Inhibits paristalsis
- stimulates glucose
- secretion of adrenaline/noradrenaline
- stimulates orgasm
- accelerates HR
- Relaxes bronchi
- Dilate pupils
Does the sympathetic nervous system primarily stimulate or inhibit the heart?
stimulates
What is the “second messenger” that is involved with sympathetic stimulation of a cardiac muscle cell?
Know Adenylyl converts ATP to cAMP (second Messenger) – activates protein Kinase A
Which catecholamine does the adrenal gland predominantly release with sympathetic stimulation?
Mostly epinephrine (80%) lesser amount norepinephrine (20%)
What is the Baroreceptor Reflex? Where are the receptors for this reflex located?
- Reflex responsible for rapid changes in BP
- Carotid sinus
How does the Baroreceptor Reflex help with blood pressure regulation?
Increases or decreases:
- HR
- Contractility
- SVR
During what surgery does Baroreceptor Reflex activation frequently cause hemodynamic changes?
Carotid Endarterectomy
What is the Bainbridge Reflex? Where are the receptors for this reflex located?
Low pressure sensors that respond to STRETCH - located in pulmonary vein and vena cava
Ex: fluid bolus given to dog increases heart rate
In addition to receptor activation what also contributes to the heart rate changes seen with the Bainbridge Reflex?
Stretch of heart and Stretch of SA node
Baroreceptor reflex often change heart rate in opposite direction of baseline (slow to fast, or fast to slow)
The Baroreceptor Reflex responds to changes in arterial blood pressure or to changes in blood volume?
Changes in arterial blood pressure
The Bainbridge Reflex responds to changes in arterial blood pressure or to changes in blood volume?
Blood Volume (stretch)
What are some of the effects of Atrial Stretch Receptor activation?
- Decreased sympathetic kidney activity –> increased UOP
- Decreased ADH (vasopressin) –> increased UOP & decreased water reabsorption
- Increased Atrial Natriuretic Peptide –> increase natriuretic UOP and decreased BP
What is the Bezold-Jarisch Reflex?
Strong contraction of an under-filled ventricle elicits the reflex, plays a role in blood pressure regulation, results in decreased BP and decreased HR
(could lead to vasovagal syncope or cardiac arrest during spinal)
What is the CNS ischemic response?
Result of decreased blood flow to vasomotor center in medulla:
-increases local concentration of CO2 results in SNS stimulation in medulla, which increases BP
What is the Cushing Response?
Special type of CNS ischemic response, a result of increased ICP, results in increased BP until blood flows
What is Cushing’s Triad?
- Increase ICP
- Increase HTN
- Bradycardia
What cardiovascular changes are mediated by stimulation of the Peripheral Chemoreceptors? Where are the Peripheral Chemoreceptors located?
-Increased
SVR
CO
MAP
-Aortic and Carotid bodies
What is the Diving Reflex? Where are the receptors for this reflex located?
- Cold water on face activates thermoreceptors, decreases HR and peripheral vasoconstriction causes reduced O2 consumption by the body and myocardium
- Facial thermoreceptors
Vasopressin is released from which part of the brain? What are the effects of vasopressin on blood pressure? What are the effects of vasopressin on the kidney?
- Pituitary
- Increases BP
- Renal Fluid Reabsorption= increases blood volume
What is the stimulus for release of Atrial Natriuretic Peptide? What are the effects of ANP on blood pressure? Blood volume?
Atrial Distension
Sympathetic Stimulation
Angiotensin II
Endothelin
decreases BP by decreasing blood volume
What converts angiotensinogen to angiotensin I?
Renin
What converts angiotensin I to angiotensin II?
Angiotensin-converting enzyme
What effects does angiotensin II have on blood pressure? Blood volume? Adrenal cortex?
- Angiotensin II causes vasoconstriction which leads to increased arterial blood pressure. Angiotensin II and Aldosterone promote sodium and fluid retention which leads to increased blood volume
- Angiotensin II stimulates the adrenal cortex to release Aldosterone
What are the INDIRECT effects of hypoxia on the circulatory system? What are the DIRECT effects?
-Moderate Hypoxia (Indirect Effects) Sympathetic Nervous System Activation Increased HR Increased CO Increased Contractility
-Severe Hypoxia
(Severe Effects)
Depressed Myocardial Contractility
What are the INDIRECT effects of hypercarbia on the circulatory system? What are the DIRECT effects?
Indirect- SNS activation, Increased HR, CO, Contractility
Direct= Depressed Myocardial Contractility
What is the “Fight or Flight” response?
Mass discharge of the Sympathetic Nervous System occurs during the “Alarm” or “Stress” response
What are the 2 types of acetylcholine receptors?
Muscarinic (only parasympathetic)
Nicotinic (both Para and sympathetic)
What are the differences between the innervation of the heart by the parasympathetic and sympathetic nervous systems?
Parasympathetic:
- negative effects on chrono/ino/dromotroy, resistance vessels
- zero effect on capacitance vessels
Sympathetic:
- Positive effects on chrono/ino/dromotropy, and resistance and capacitance vessels
Which cranial nerve carries parasympathetic nervous input to the heart?
Vagus Nerve
What amino acid is the precursor for catecholamine synthesis?
tyrosine
Binding of norepinephrine to which adrenergic receptor causes inhibition of neurotransmitter release?
alpha 2 receptors on nerver terminal
In which part of the brainstem is the vasomotor center located?
in the medulla and in the lower third of the pons
What is the neurotransmitter released at the junction between the pre-ganglionic and post-ganglionic sympathetic fibers? Between the post-ganglionic sympathetic fibers and the effector site? Between the pre-ganglionic sympathetic fibers and the adrenal medullae?
- Acetylcholine/nicotine
- Norepi/Epi
- Norepi/Epi
Blood vessels (except for capillaries) have predominantly sympathetic or parasympathetic nervous system innervation?
Sympathetic (norepi via Alpha 1 receptors)
relaxation - active, not passive process
lusitropy.
Parasympathetic does what?
- Constricts Pupils
- Contracts bladder
- Constricts Bronchi
- Stimulates saliva
- Slows HR
- Stimulates paristalsis
- Stimulates bile release
catecholemine order for catecholamine synthasis
tyrosine dopa dopamine secretory granules dopamine norepi epi
