Cardio - The Vascular System Flashcards
Which blood vessel contains a lot of elastic tissue?
arteries
Whose diameter is adjusted to regulate blood flow?
arterioles
The ___ serves as a physical lining that blood cells do not normally adhere to in heart and blood vessels.
endothelium
T/F. The endothelium serves as a permeability barrier for the exchange of nutrients, metabolic end products, and fluid between ___ and ___ fluid. It regulates transport of macromolecules and other substances.
plasma; interstitial fulid
The endothelium secretes ___ agents that act on adjacent vascular smooth muscle cells; including vasodilators (prostacyclin and nitric oxide) and vasoconstrictors (endothelin-1).
paracrine
In response to pulsatile contraction of the heart, what happens to the vasculature?
pulses of pressure move throughout the vasculature, decreasing in amplitude with distance
Compliance = change in ___ / change in ___.
volume; pressure
The maximal arterial pressure reached during peak ventricular ejection = ___ ___. The minimum arterial pressure that occurs just before ventricular ejection = ___ ___.
systolic pressure; diastolic pressure
Pulse pressure = ___ - ___
systolic pressure (SP) - diastolic pressure (DP)
What determines pulse pressure?
stroke volume
speed of ejection of the stroke volume
arterial compliance
Because the arterial pressure continuously changes throughout the cardiac cycle, the average pressure during the cycle is referred to as the ___ ___ ___.
Mean Arterial Pressure (MAP)
This is the pressure driving blood into tissues averaged over the cardiac cycle
T/F. The mean arterial pressure is equal to the diastolic pressure plus 2/3 of the pulse pressure.
False, The mean arterial pressure is equal to the diastolic pressure plus 1/3 of the pulse pressure.
MAP = DP + 1/3(SP-DP)
or
MAP = DP + 1/3(pulse pressure)
The blood moved in a single heart contraction (during systole) ___ (stretches/relaxes) the arteries, so that their ___ continues to push on the blood, keeping it moving during diastole.
stretches; recoil
What are the two major roles that arterioles play?
- in individual organs they are responsible for determining the relative blood flows to those organs at any given mean arterial pressure.
- The arterioles, together, determine the mean arterial pressure itself
Flow = change in ___/___.
pressure; resistance
change in pressure = (MAP-venous pressure [ which is close to 0])
Therefore, Flow (to an organ) = MAP/Resistance (organ)
T/F. The dynamic adjustments in the blood distribution to the organs is accomplished by relaxation and contraction of circular smooth muscle in the arteries.
False, The dynamic adjustments in the blood distribution to the organs is accomplished by relaxation and contraction of circular smooth muscle in the ARTERIOLES.
Arterioles have smooth muscle cells that can relax (___) or constrict (___). The intrinsic tone is controlled by ___ and ___ controls.
vasodilate; vasoconstriction; local; extrinsic
Define active hyperemia.
Most organs and tissues manifest and increased blood flow (hyperemia) when their metabolic activity is increased.
What organs undergo active hyperemia?
heart
skeletal muscle (exercising)
brain
Increased metabolic activity of an organ causes a decrease in ___ and an increase in ___ into the interstitial fluid. Local changes cause the arterioles to ___ in order to increase blood flow to that organ.
oxygen; metabolites; dilate
T/F. With flow ___, a decrease in ___ ___ ___ reduces blood flow and therefore, ___ to the organs. There is decreased ___ to the vessel walls due to ___ responses. Arteriolar ___ occurs and blood flow to the organ is restored.
autoregulation; mean arterial pressure; oxygen; stretch; myogenic; dilation
Describe reactive hyperemia.
When an occluded vessel is relaxed, and then there is a rush of blood flow
What controls extrinsic effects?
sympathetic system
What types of receptors are found on the vasculature that respond to the sympathetic system?
alpha receptors will vasoconstrict to decrease blood flow to that location
Sympathetic stimulation of beta-adrenergic receptors leads to ___ to cause an ___ in blood flow to that location.
vasodilation; increase
What are the extrinsic controls on arterioles?
- sympathetic nerves
- parasympathetic nerves
- Noncholinergic, Nonadrenergic Autonomic neurons (release NO - enteric and penile)
- Hormones (Epi and NE)
What are the endothelial controls on arterioles?
- paracrine effects (vasodilators and vasoconstrictor)
2. flow induced arterial vasodilation
Epi and NE increase heart blood flow, but they are vasoconstrictors. Why do they increase when they are vasoconstrictors?
Beta-1 receptors increase heart rate and increase contractility (SV via Ca2+). Therefore, it increases heart blood flow and metabolic activity of heart which causes vasodilation.
Review Table 12.5
serious do it!
What is functional hyperemia?
Usually the GI is under extrinsic control however after eating a meal there is increase blood flow. This is called functional hyperemia
The skin is under ___ control except during times of intense exercise when there is increased blood flow for ___. The vessels will ___ to help cool down.
extrinsic; thermoregulation; vasodilate
The ___ is the primary exchange between the blood and the interstitial fluid. Intercellular ___ assist the exchange. There walls are a single ___ cell in thickness.
capillary; clefts; endothelial
T/F. Increased surface area and decreased blood flow allow for more exchange in a capillary.
True.
T/F. There are many, many capillaries, each with slow-moving blood in it, resulting in adequate time and surface area for exchange between the capillary blood and the ISF.
True.
What is the movement of fluid and solutes out of the blood?
Filtration
___ is the movement of fluid and solutes into the blood.
Absorption
Net filtration = what???
Net filtration = Pc + #if - Pif - #c
Pc or the capillary ___ pressure is due to ___ ___ and causes ___.
hydrostatic; blood pressure; filtration
Pif or the ___ hydrostatic pressure is determined by ___ and favors ___.
interstitial; albumin; absorption
Blood pressure ___ (increases/decreases) as you move thru the capillaries. Therefore, Pc ___ (increases/decreaes) and favors ___ (filtration/reabsorption) at the venous end of capillaries.
decreases; decreases; reabsorption
If an accident victim loses 1 L of blood, why would an intravenous injection of a liter of plasma be more effective for replacing the lost volume than injecting a liter of an equally concentrated crystalloid solution?
plasma contains proteins which increase the oncotic pressure. This will keep water in the capillary and favors absorption. Therefore, blood volume will increase.
At rest, aprox. ___% of the total blood volume is in the ___. Sympathetically mediated ___ can substantially increase venous return to the heart.
60; veins; venoconstriction
Sympathetic ___ receptors on veins cause ___, which returns more blood to the heart. The ___ system is not in veins.
alpha; venoconstriction; parasympathetic
How do skeletal muscles assist venous flow?
venous flow is assisted by skeletal muscle pump mechanism working in combination with one-way valves.
T/F. Alterations in “venous return” alter end-diastolic volume (EDV) and increased EDV directly decreases stroke volume and cardiac volume.
False, Alterations in “venous return” alter end-diastolic volume (EDV) and increased EDV directly INCREASES stroke volume and cardiac volume.
What are three ways to increase blood going back to the heart?
- blood volume
- venoconstriction (increase sympathetic on vein [alpha receptors])
- skeletal muscle pump
What system is permeable to all interstitial fluid constituents, including proteins, that returns interstitial fluid to the cardiovascular system?
lymphatic system
What happens when the lymphatic system becomes occluded?
there is an accumulation of proteins in the interstitial fluid and this leads to massive edema.
