Neurohumoral, Local and Volumetric Cardiovasular Control I & 2 Flashcards
What is a neurohormone?
Any hormone produced by neuroendocrine cells
What effect does oxytocin have?
Hypotensive effects
What is vasopressins affect?
Vasoconstricts and causes water reabsorption by kidneys
What does ANP (atrial natriuretic factor) do?
Causes the kidneys to output more sodium and water follows to decrease blood volume
What cells produce epinephrine and norepinephrine?
Chromafin cells in the adrenal medulla
What is a pheochromocytoma?
A catecholamine producing tumor which may cause paroxysmal hypertension
What is the effect of epinephrine in low concentration?
Vasodilatory
What is the effect of epinephrine in high concentration?
Beta adrenergic cardiac effects
What is the main controller of vascular smooth muscle tone?
Norepinephrine through alpha adrenergic receptors
What is the effect of dopamine?
Increases arterial pressure and heart rate
What type of receptors do catecholamines work on?
G protein-coupled receptors
What effect does serotonin (5-HT) have on vessels?
Vasoconstriction
What effect does histamine have on vessels?
Vasodilation
What does angiotensin II do?
Regulates renal sodium reabsorption and potassium excretion and vasoconstricts
What does aldosterone do?
Acts on distal renal tubule and collecting ducts, increasing Na+ reabsorption and K+ excretion; increasing blood volume
What is primary hyperaldosteronism?
Adrenal gland tumor hypersecretion of aldosterone and causing hypertension
How does the renin-angiotensin-aldosterone system work?
Liver releases angiotensinogen in response to poor kidney perfusion; renin is excreted from kidney to cleave angiotensinogen into angiotensin I; ACE converts angiotensin I into angiotensin II; angiotensin inhibits bradykinin causing vasoconstriction and release of aldosterone from the adrenal cortex leading to sodium retention
What affect does angiotensin II have on the brain?
Release of ACTH from anterior pituitary to act on the adrenal cortex
What is the long term affect of stress on the hypothalamus?
Release of ACTH from hypothalamus acting on adrenal cortex to release glucocorticoids (protein and fat metabolism occur) and release of mineralocorticoids (blood volume and pressure increase)
What is the short term affect of stress on the hypothalamus?
Hypothalamus sends as impulse to the spinal cord to the adrenal medulla to release epinephrine and norepinephrine increasing HR and BP
What do metabolites do?
They diffuse to vascular smooth muscle and cause relaxation (K, H, CO2, lactate, adenosine)
What does bradykinin do?
Binds beta 2 receptors on endothelial cells causing NO and prostacyclin release
What effect does ATP have on vsm?
Vasoconstriction
What effect does endothelin have on vsm?
Vasoconstriction
What does thromboxane do to vsm?
Vasoconstriction through increased Ca2+ concentration
What is the myogenic theory of autoregulation?
Intrinsic contraction in response to stretch
What is the metabolic theory of autoregulation?
Vasodilation is the most important mechanism of autoregulatory blood flow control
What is autoregulation?
Constant flow in the face of changing driving pressure
What do kinins and histamines do to visceral smooth muscle?
Cause contraction
How do histamines increase vascular permeability?
Increase post capillary resistance increasing hydrostatic pressure leading to extravasation
What is the rank order potency for vascular leakage?
Leukotrienes > Bradykinin > Histamine > Prostaglandins
What promotes new vascular growth?
Vascular endothelial growth factor
Fibroblast growth factor
Angiopoietin 1
Angiogenin
What inhibits new vascular growth?
Angiostatin
Endostatin
Angiopoietin 2
