Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
42 Cards in this Set
- Front
- Back
are there any parasympathetics to peripheral vasculature?
|
no, only SNS
|
|
what is active vasoconstriction?
|
dilation of vasculature due to a stimulus
|
|
what is active vasodilation?
|
dilation of vasculature due to a stimulus
|
|
what is passive vasoconstriction?
|
return to normal tone after a dialatory stimulus has been removed
|
|
what is passive vasodilation?
|
the return to a normal tone after constrictive stimuli have been removed
|
|
what causes vasoconstriction?
|
increase in:
myogenic activity O2 concentration endothelin vasopressin angiotensin II cold Decrease in: CO2 metabolites |
|
what causes Vasodilation?
|
increase in:
NO CO2 Metabolites heat histamine Decrease in: SNS O2 myogenic activity |
|
what are intrinsic factors?
|
active and reactive hyperemia
autoregulation |
|
what are extrinsic factors?
|
hormones
neural influences |
|
what causes active hyperemia?
|
increased metabolic activity decreases O2 concentration and increases local metabolite concentration. this dilates the vessels and increases blood flow
|
|
what are the local metabolites and electrolytes that effect vasodilation?
|
K+
PO4 prostaglandins lactic acid H+ adenosine NO |
|
what is the only difference between reactive and active hyperimia?
|
reactive hyperimia is induced by an occlusion
|
|
what are the organs that autoregulate?
|
Kidney
heart Brain Skeletal Muscle |
|
what is the primary goal of autoregulation?
|
to maintain a constant blood flow despite changes in pressure
|
|
what is the myogenic hypothesis?
|
if Pressure increases, smooth muscle in arterial walls will constrict to compensate
if pressure decreases, the smooth muscle will relax to compensate |
|
where is vasopressin released from and what does it do?
|
it is released from the pituitary and it is a vasoconstricter and increases water retention
|
|
where does angiotensin II come from and what is its function?
|
it comes from a stepwise process that converts angiotensinogen into angeotensin I and then angiotensin II via the use of renin and ACE
it is a vasoconstrictor |
|
where does atrial natriuretic peptide come from and what is its function?
|
atria
vasodilator |
|
what does the SNS use for vasodilation? vasoconstriction?
|
dilation- B2
constriction- a1 |
|
are there sympathetic cholinergic fibers?
|
yes, M3 SNS fibers
|
|
what does angiotensin II bind to on vascular bed smooth muscle cells?
|
AT1 receptors
|
|
what is another name for vasopressin?
|
ADH
vasoconstrictor and causes water retention |
|
what does ADH bind to?
|
V1 receptors on the distal convoluted tubule of nephron
|
|
what do ANPs and BNPs do?
|
they are vasodilators
stimulate guanylyl cyclase activity |
|
what are the effects of ANP in the kidney
|
increased water and Na+ secretion
|
|
what is the effect of epinephrine release on the system>?
|
vacoconstriction of most arterioles via a1 and a2
Vasodilation of skeletal muscle arterioles via B2 |
|
how is NO release stimulated?
|
neurotransmitters
shear stress causes an increase in cGMP |
|
what is EDHF?
|
causes endothelial cell dilation by hyperpolarizing the cell
|
|
what is prostacyclin?
|
released by the same stimulus for NO.
causes dilation and inhibits platelet formation |
|
what is endothelin?
|
most powerful vasoconstrictor yet discovered
|
|
what are the effects of prostaglandins?
|
induces vasoconstriction in arease with platelet aggregation
i.e. blood loss |
|
what is the role of kinins?
|
vasodilators
|
|
what effect does histamine have on vasculature?
|
vasodilator
but also stimulates the release of prostoglandins |
|
where is the velocity of blood flow the slowest?
|
in the capillaries
|
|
what type of vessel contains precapillary sphincters?
|
metarterioles
|
|
what are the factors that influence bulk flow?
|
capillary blood pressure (Pc)
Plasma osmotic pressure (pieP) interstitial fluid hydrostatic pressure (Pif) interstitial fluid osmotic pressure (pie if) |
|
what is capillary blood pressure (Pc)?
|
the pressure exerted on the inside of a capillary wall
|
|
what is plasma osmotic pressures (pie P)
|
the force caused by plasma proteins (fluid movement into the capillary)
|
|
what is interstitial fluid hydrostatic pressure(Pif)?
|
the fluid pressure exerted on the outside of the capillary by interstial fluid
|
|
what is the interstitial fluid osmotic force (pie if)?
|
the small force exerted by proteins that have leaked into the interstitial fluid. (fluid flow outward)
|
|
what is the equation for net exchange pressure?
|
NEP= (outward forces) - (inward forces) = (Pc + pie if) - (Pif + pieP)
|
|
what happens to bulk flow during a hemorrhage?
|
the net flow of fluid will be from interstitial fluid to plasma
|