Regulation of BP Flashcards by Rachel Muxlow

What are the general classifications of CV regulators?

Neural
Vascular
Hormonal
Local

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What are the two general classifications of neural regulators of the CVS?

Autonomic
Reflex

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What a reflex mechanisms for neural regulation of the CVS?

Baroreceptor
Bainbridge
Volume
Chemoreceptors
Pulmonary
Somatosympathetic

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Where are the baroreceptors?

Carotid sinus
Aortic arch

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What are the medullary CV centers?

Nucleus ambiguus
Pressor area
Depressor area
Vasomotor centers
Nucleus of tractus solitarius

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What is the CV function of nucleus of tractus solitarius?

Medullary relay center for cardiorespiratory and afferents

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What is the CV function of the nucleus ambiguus?

Cardioinhibitory center
Receives afferents from nucleus of tractus solitarius

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What is the CV function of the pressor area?

Glutaminergic neurons that exert excitatory effect on spinal sympathetic neurons

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What is the CV function of the depressor area?

Stimulate GABA-secreting inhibitory neurons to decrease sympathetic activity

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What are the vasomotor centers associated with CVS and their main functions?

Caudal ventrolateral medulla - depressor area
Rostral ventrolateral medulla - pressor area

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When is carotid sinus massage used clinically?

To interrupt paroxysmal atrial tachycardia

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What will happen to BP if NTS is destroyed bilaterally?

Severe HTN, possibly fatal

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How quickly can baroreceptors reset if exposed to a new pressure continuously?

1-2 days

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What are atrial stretch receptors and their function?

Low pressure receptors that provide information about circulating blood volume
Type A - during atrial systole only
Type B - during late atrial diastole

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What is the Bainbridge relfex?

Initial slow HR or infusion increases venous return which stimulates tachycardia producing stretch receptor to increase HR

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What is the volume reflex?

Decreased blood volume in atria decreases atrial stretch which decreases the release of ANP –> decreased secretion in kidney and increased ADH production –> increased ADH increases kidney retention
Main result: increase blood volume to increase BP

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What is another name of the coronary chemoreflex?

Bezold-Jarisch reflex

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What is the coronary chemoreflex?

Chemical stimulation of afferents in LV baroreceptors stimulates respiratory center and cardiac depressor area –> results in tachypnea, hypotension, and bradycardia which then results in reflex apnea due to CO2 loss in hyperventilation

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What are the general distributions of ANS to the heart?

R vagus to SA node
L vagus to AV node
R SyNS trunks to SA node
L SyNS trunks to AV node

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What are the results of sympathetic stimulation of heart?

Increased HR/chronotropy
Increased force of contraction/inotropy
Increased conduction/dromotropy
Increased excitability/bathmotropy

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What are the results of parasympathetic stimulation of the heart?

Decreased HR
Decreased force of contraction of atria
Decreased conduction
Decreased excitability

What is the result of cutting vagal supply to the heart?

Increased HR to 150-180 bpm

What will occur if both adrenergic and cholinergic systems are blocked to the heart?

HR stabilizes around 100 bpm

What is the response to sympathetic stimulation to the vessels?

Skeletal muscle vessels dilate
Secretion in sweat glands
Release of epinephrine
Skin, renal and GI vessels constrict

What is the effect of arteriolar constriction on BP?

Increase diastolic BP by increasing peripheral resistance

What is the effect of venoconstriction on BP?

Increases systolic BP by increasing venous return and therefore increasing CO

What is the effect of arteriolar dilatation on BP?

Decreases diastolic BP by decreasing peripheral resistance

What is the effect of venodilatation on BP?

Decreases systolic BP by decreasing venous return and therefore decreasing CO

Where are peripheral chemoreceptors located?

Carotid bodies Aortic bodies

Where are the central chemoreceptors located?

Ventrolateral medullary surface near the exit of CN IX and X

What are Meyer waves?

Slow, regular oscillations in arterial pressure that occur about 1 every 20-40 seconds during hypotension

What are Traube-Hering waves?

Fluctuations in BP synchronized with respiration

What acts as an emergency arterial pressure control system?

CNS ischemic response

What is the Cushing reflex?

Increased intracranial pressure that constricts arterioles causing ischemia results in baroreceptor reflex induced bradycardia

What are the main points that indicate a Cushing reaction?

Triad of HTN, bradycardia, and respiratory depression

What is the general function of pulmonary baroreceptors?

Minimize arterial pressure changes in response to change in blood volume

What is the capillary fluid shift mechanism in relation to BP?

Significant decrease in BP decreases hydrostatic pressure in capillaries drawing more fluid in from interstitial spaces to increase blood volume and thereby increase BP

What is another name for the hormonal mechanism of BP regulation?

Renin-angiotensin-aldosterone system

What is renin?

Production in kidneys stimulated by low BP Catalyzes the change of angiotensinogen from the liver into angiotensin I

What is angiotensin converting enzyme?

Converts angiotensin I into angiotensin II

What are the functions of angiotensin II?

Vasoconstriction Increases free fluid to preserve renal function in hypovolemia Increases aldosterone secretion from adrenal glands Increases ADH release form posterior pituitary Increases PCT Na/H exchanger activity Stimulates hypothalamus to increase thirst

What is pressure natriuresis?

Effect of arterial pressure on renal excretion of sodium Long-term control of HTN

What are conditions that can trigger renin release?

Coarctation of aorta Renal A stenosis CKD

What are the rapid control mechanisms of BP?

Baroreceptors Chemoreceptors CNS ischemic response

What are the intermediate control mechanisms of BP?

Capillary fluid shift Stress relaxation and reverse stress relaxation

What are the long-term control mechanisms of BP?

Hormonal mechanism Renal mechanisms - changing excretion

What is the Valsalva maneuver?

Forcefully expiring against a closed glottis to change intrathoracic pressure to effect venous return, CO, arterial pressure, and HR

What is phase 1 of the Valsalva maneuver?

Intrathoracic pressure becomes very positive due to compression from contracting rib cage and full lungs

What is the result of phase 1 of the Valsalva maneuver?

Venous compression and increase in RA pressure impedes venous return --> reduces preload Decrease in CO Transient increase in aortic pressure Decrease in HR

What occurs during phase 2 of the Valsalva maneuver?

HR increases Aortic pressure falls

What occurs during phase 3 of Valsalva maneuver?

Normal breathing resumes Aortic pressure briefly decreases reflexively HR briefly increases reflexively