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52 Cards in this Set

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List the three components of a reflex.
Afferent signal (input), processor/controller, efferent signal (ouput), effector organ
What generates the afferent signal for a cardiovascular reflex?
Mechanoreceptors (stretch receptors)
What serves as the processor/controller for a cardiovascular reflex?
Brainstem is the primary integrator
What are the 3 effector systems which are the pathways for efferent signal?
Sympathetic NS, Parasympathetic NS, and endocrine system
What is the name given to mechanoreceptors in the walls of the arteries?
baroreceptors
What is the name given to mechanoreceptors in the walls of the heart chambers?
cardiopulmonary receptors
What are the 2 effector targets?
Heart and blood vessels
How does the kideny participate in long term regulation of the CV system?
Adjusts blood volume
What receptor types, which effect the CV system are sensitive to blood chemistry?
Chemoreceptors
Where is the highest concentration of the most sensitive baroreceptor found?
In the carotid sinus at the bifurcation of the internal and external carotid arteries
Besides the carotid sinus list two other locations where baroreceptors can be found.
Other parts of the carotid artery and around the aortic arch
Define: the pressure differential across the wall of the vessel.
transmural pressure
What is the critical parameter measured by baroreceptors?
transmural pressure
An increase in mean arterial blood pressure will result in an ____ in the rate of nerve impulse generation of the baroreceptor (sinus nerve).
Increase
True/False, systolic and diastolic pressure difference produce the same sinus nerve response.
False, impulse generation is greater during rises in pressure (systole) than during decreases (diastole)
If the wall is stiffened by contraction of smooth muscle, what is the effect on the sensitivity of the baroreceptors?
Sensitivity will decrease because the transmural pressure will not change.
Mechanoreceptors are a type of _________ receptor.
Stretch
When the wall of the carotid artery expands (or contracts) how does the baroreceptor respond?
Increases impulse generation
Locate the primary locus for integration of the cardiovascular reflex system in the brain.
Upper medulla
List the four major areas for cardiovascular control in the brain.
Upper medulla, hypothalamus (temperature reg, volume etc), cortical areas (i.e. blushing), and spinal cord (primitive reflexes)
True/False, in the upper medulla when the more laterally located sympathetic nervous system is activated, the more medially located parasympathetic (vagal) nervous system is simultaneously inhibited.
TRUE
What nervous system is the dominant effector in baroreflex responses?
Sympathetic NS
Sympathetic nervous activity is directly __________ to the amount of baroreceptor input to the brain.
opposite
What nervous system is activated by rising blood pressure and results in decreased heart rate and reduces the contractile state of the heart?
Parasympathetic NS
What are the two fold effects of the sympathetic NS on the venous system?
1. decreasing of reservoir space (venous volume) 2. Increase venous return to the heart (by increasing mean systemic filling pressure and/or decreasing the resistance to venous return.)
An increase in sympathetic activity will cause an _________ in vascular resistance.
Increase
A decrease in sympathetic activity will cause a ___________ in vascular resistance.
Decrease
An increase in sympathetic activity creates a ___________ heart.
hypereffective
Heart rate is __________ with increased sympathetic activity.
increased
What two effects does sympathetic activity have on the heart?
Increases heart rate and makes the heart hypereffective
Will the parasympathetic Nervous system cause a small or great depression in contractile state?
Small depression
An increase in parasympathetic activity will cause a ___________ in heart rate.
decrease
What is the primary endocrine organ involved in the baroreceptor reflex?
Adrenal gland
What are the two hormones released by the adrenal medulla which both effect blood pressure?
Norepinephrine and epinephrine
What two effects does epinephrine have on the myocardium?
increases heart rate and contractile state
What neurotransmitter is shared by the adrenal medulla and the sympathetic nervous system?
norepinephrine
What does Renin (produced by the kidneys) stimulate?
The formation of angiotensin
What is the effect of angiotensin on the blood vessels?
Very strong angiotensin
What two conditions need to be met for the kidney to release renin?
Low blood pressure and/or sympathetic activity is elevated
Vasopressin is a vasoconstrictor or a vasodilator?
Vasoconstrictor
What brain structure releases vasopressin?
hypothalamus
What is the short term and long term purported function of the atrial mechanoreceptor reflex?
short-term vasoconstriction (through release of vasopressin, aka ADH) and long-term response for fluid conservation.
Describe the components of the atrial mechanoreceptor reflex.
Stretch receptors located in the walls of both the left and the rigth atria, consisting of a type A and Type B. Send information to brain and modulate the release of vasopressin.
When are Type A atrial mechanoreceptor reflex receptors active?
During atrial contraction (called such because they are associated with the "a" wave of atrial pressure)
When are Type B atrial mehcanoreceptor reflex receptors active?
During atrial filling (called such because they are associated with the "v" wave in atrial pressure)
Besides the baroreceptor reflex and the atrial mechanoreceptor reflex, list two other cardiovascular reflexes.
CNS Ishemic reflex and Diving reflex
What elicits the CNS Ishemic reflex?
When the blood pressure falls below 40 mmHg (inadequate for brain perfusion)
What is the dominant reflex effect of the CNS ischemic reflex?
sympathetic vasconstriction (additionally, an increase in heart rate)
If CSF pressure approaches within 30-40 mmHg what occurs?
CNS Ishemic reflex (as well as cushing response and sometimes accompanies by a vagally induced bradycardia)
Describe the Cushing response/reflex.
When CSF pressure > Mean Arterial Pressure, sympathetic nervous system activated resulting in a sudden change in blood pressure causing the baroreceptors to induce bradycardia (Cushing's triad)
Describe the diving reflex.
Elicited by exposing the nasopharynx to wet cold stimuli, trigeminal nerve carries signal and induces bradycardia and vasoconstriction (especially in the abdominal organs).
What is the use of the diving reflex?
Conserves energy while diving, increasing submersion time/depth, may be used clinically to retard tachycardia