EX 2: The Vascular System Flashcards
These are the main transporters of oxygenated blood
arteries
In these, the diameter is adjusted to regulate blood flow
arterioles
There is where diffusion occurs across thin walls
capillaries
What are three functions of the endothelial cell monolayer of capillariers
physical lining
permeable barrier for exchange
secrete paracrine agents that induce vasodilation or vasoconstriction
Pulses of pressure move throughout the vasculature decreasing in what with distance
amplitude
What is the maximum arterials pressure
systolic pressure
What is the minimum arterial pressure
diastolic pressure
What is pulse pressure
systolic pressure - diastolic pressure
What three things is pulse pressure determined by
stroke volume
speed of ejection of the stroke volume
arterial compliance (resist recoil)
What is the equation for compliance
change in volume
divided by
change in pressure
What is the long equation of MAP
DP + 1/3(SP+DP)
spend most of our time in diastole, only 1/3 in systole
The blood moved in a
single heart contraction
stretches out the arteries,
so what happens during diastole
their recoil
continues to push
on the blood, keeping it
moving during diastole.
This is the pressure driving blood into the tissues averaged over the cardiac cycle
MAP
In arterioles, the flow of an organ equals what
MAP/resistance of the organ
The smooth muscle cells of the arterioles can do what two things
relax
contract
Dynamic adjustments in the blood distribution to the organs is accomplished by what
relaxation and contraction of circular smooth muscle in the arterioles
The intrinsic tone of the arterioles is controlled by what two things
local controls
extrinsic controls
Active hyperemia and flow autoregulation differ in their cause but both result in what
the production of the same local signals that provoke vasodilation
What would happen with decreased metabolic activity or increase arterial pressure?
If you decrease MAP you will decrease flow to 2 different organs, unless you change resistance
In active hyperemia, an increase in metabolites in organ interstitial fluid and a decrease in O2 will have what affect
vasodilation
In flow autoregulation, a decrease in O2 and an increase in metabolites of an organ will cause what
vasodilation
What two things control the intrinsic tone of the arterioles
local controls; active hyperemia and flow autoregulation
This is the accumulation of Co2, H, K, eicosanoids, adenosine, bradykinin, and NO. Which controls intrinsic control of the arterioles
active hyperemia
What are the two responses of flow autoregulation
myogenic response
reactive hyperemia
This is when some arteriolar smooth muscle responds to increase stretch caused by an increased pressure by contracting to a greater extent
myogenic response (flow autoregulation
This the response to cessation of blood flow
reactive hypermia (flow autoregulation)
Sympathetic stimulation (NE) of these receptors causes vasoconstriction to decrease blood flow to that location
alpha-adrenergic
Sympathetic stimulation (E) of these receptors leads to vasodilation to cause an increase in blood flow to that location
beta-adrenergic
Where are the alpha receptors located
vessels
Where are beta receptors located
atraia and ventricles
What are the four extrinsic controls of the arterioles
sympathetic nerves
parasympathetic nerves
non-cholinergic, non-adrenergic autonomic neurons
hormones
What are the two paracrine effects of the arterioles
vasodilators
vasoconstrictors
What are two vasodilators with paracrine function
endothelium derived relaxing factor; EDRF
prostacyclin
What is a vasoconstrictor with paracrine effects
endothelin-1
What are the two endothelial controls on the arterioles
paracrine effects
flow induced arterial vasodilation
Diversity among signals that influence contraction/relaxation in circular smooth muscle implies what
a diversity of receptors and transduction mechanisms
What are the two locally controlled organs
brain and heart
What are four the neurally controlled organs
skin
muscle
GI
kidney
When do the skin and muscles become under local control
when exercising
Capillaries lack this
smooth muscle
What detrained the volume of blood each capillary receives
contraction/relaxation of circular smooth muscles in upstream met arterioles and pre-capillary sphincters
There are many, many capillaries, each with slow-moving blood in it, resulting in what
adequate time and surface area for exchange between the capillary blood and ISF
This is the movement of fluid and solutes out of the blood
filtration
This is the movement of fluid and solutes into the blood
absorption
These two things favor fluid movement out of the capillary
capillary hydrostatic pressure (PC)
osmotic force due to interstitial fluid protein concentration (Ħif)
These two things favor movement into the capillary
interstitial hydrostatic pressure (Pif)
osmotic forse due to plasma protein concentration (Ħc
These are low molecular weight penetrating solutes
crystalloids
These are non-penetrating plasma proteins
colloids
What is the net filtration pressure equation
Pc + Ħif - Pf - Ħc
If an accident victim loses 1L of blood, why would IV injection of plasma be more effective for replacing the lost volume
protein gets into capillaries therefore keeping the water in the capillaries
At rest, approximately what percentage of the total blood volume is in the veins
60%
This can substantially increase venous return to the heart
sympathetically mediated venoconstiriction
Venus flow is assisted by what
the skeletal muscle pump mechanism working in combination with one-way valves
Alterations in “venous return” can alter what
end-diastolic volume
An increase in EDV directly increases what
stroke volume and cardiac output
This is formed by the slight mismatch between filtration and absorption in the capillaries, returns the blood in the veins
lymphatic fluid
What three things can cause abnormalities of the lymphatic system
congenital traumatic or infectious etiologies
