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40 Cards in this Set

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The walls of areteries and veins contain 3 distinct layers. What are they?
1. Tunica intima
2. Tunica media
3. Tunica externa
In general, the walls of arteries are thicker than those of veins. The tunica media of an artery contains more smooth muscle and elastic fibers than does that of a vein. TRUE/FALSE
TRUE.
What are elastic arteries?
They are large vessels with diameters up to 2.5 cm. They transport large volumes of blood away from the heart.
What is a muscular artery?
They are medium sized arteries or distribution arteries, to skeletal muscles and the bodys organs. A typical muscular artery has a lumen diameter of app. 0.4 cm.
Give several examples of muscular arteries/
1. carotid
2.brachial
3.mesenteric
4. femoral.
A typical capillary consists of an endothelial tube inside a delicate basal lining(lamina), neither a tunica media nor externa is present. The average diameter is app. 8um(close to that of a single RBC). TRUE/FALSE
TRUE.
What are the 2 types of capillaries?
1. Continuous
2. Fenestarted
What is the general pathogenesis of plaque formation?
1. When cholesterol levels are chronically elevated, cholesterol rich lipo-proteins remain in the circulation.
2.Circulating monocytes remove them from the bloodstream, and these monocytes become filled with lipid droplets.(Foam cells)
3. These foam cells attach to the endothelial walls of blood vessels, where they release cytokines.
4. These growth factors stimulate the division of smooth muscle cells near the tunica intima thickening the vessel wall.

.
Estrogens may slow plaque formation, which could account for the lower incidence of coronary disease. TRUE/FALSE
TRUE.
What is a continuous capillary?
The endothelium is a complete lining. In a large continuous artery several endothelial cells may represent the thickness. In a small one, one cell may be represented.
They permit the passage of water, small solutes, and lipid soluble materials into the surrounding interstitial fluid.(Blood brain barrier0
What is a fenestrated capillary?
These capillaries contain pores that penetrate the endothelial lining. They permit rapid exchange of water and solutes as large as small peptides between plasma and interstitial fluid. They are found in the hypothalamus, pituitary pineal and thyroid glands.
What is a sinusoid?
They resemble fenestrated capillaries that are flattened and irregularly shaped. They have gaps between adjacent endothelial cells. Permit the free exchange of water and solutes as large as plasma proteins between blood and interstitial fluid.
What are arteriovenous anastomoses?
They are direct connections between arterioles and venules. Blood can at times bypass the capillary bed and flow directly into the venous circulation.
An average venule has an internal diameter of roughly 20um. TRUE/FALSE
TRUE.
What are capacitance vessels?
veins are capacitance vessels, which expand easily. They can accommodate large changes in blood volume.
Capillary blood flow is determined by the interplay between pressure(P) and resistance(R). TRUE?FALSE
TRUE. The heart must must overcome the resistance of blood flow. Increased pressure yields increased flow, and inversely proportional to resistance(increased resistance yields decreased flow.
In formulary terms;
Flow is proportional to the difference of pressure over resistance.
What is Capillary hydrostatic pressure?
It is the pressure within capillary beds. Pressures range from 35mm/Hg to 18mm/Hg.
The pressure gradient from the venules to the right atrium is only about 18mm/Hg. TRUE/FALSE
TRUE.
Increasing the length of a blood vessel increases friction. TRUE/FALSE
TRUE. If 2 vessels are equal in diamter, but one is twice as long as the other, the longer vessel offers twice as much resistance. But for two vessels of equal, one twice the diameter of the other, the narrower one offers, 16 times as much resistance to blood flow.
In formulary terms;
Resistance is proportional to the length over the 4th power of the radius.
What is viscosity/
Is resistance to flow caused by interactions among molecules and suspended materials in a liquid.(water has a viscosity of 1)
What is turbulence?
High flow rates, irregular surfaces, and sudden changes in vessel diamter upset the smooth flow of blood creating eddies and swirls.
What is "pulse"?
A pulse is a rhythmic pressure oscillation that accompanies each heart beat. The difference between systolic and diastolic pressures is the pulse pressure.
What is "mean arterial pressure"?
It is used to report a single blood pressure value. It is calculated by adding one/third of the pulse pressure to the diastolic pressure;

MAP= diastolic pressure+ pulse pressure
---------------
3
For a systolic pressure of 120mm/Hg and a diastolic pressure of 90mm/, the MAP can be calculated;

MAP= 90+ 120-90
------- = 90 + 10 = 100mm/HG 3
3
What is a concentration gradient?
Diffusion is the net movement of ions or molecules from an area where their concentration is higher to an area where their concentration is lower. The difference between the higher and lower concentrations represents a concentration gradient.
Plasma proteins are normally unable to cross the endothelial lining anywhere except in sinusoids, such as those of the liver. TRUE/FALSE
TRUE.
What is Osmotic pressure?
It is an indication of the force of osmotic water movement, the pressure that must be applied to prevent osmotic movement across a membrane. The higher the solute concentration of a solution, the greater the solutions osmotic pressure.
The osmotic pressure of the blood is also called blood colloid osmotic pressure(BCOP), because only suspended proteins are unable to cross the capillary walls.
What is "net hydrostatic pressure"?
This pressure tends to push water and solutes out of capillaries and into the interstitial fluid.
It is the difference between the "capillary hydrostsic pressure and the "hydrostatic pressure of the interstitial fluid(IHP).
What is "net colloid osmotic pressure"?
It tends to pull water and solutes into a capillary from the interstitial fluid.
It is the difference between;
blood colloid osmotic pressure(app. 25mm/Hg) and the interstitial fluid colloid osmotic pressure(ICOP).
What is "net filtration pressure"?
It is the difference between the net hydroststic pressure and the net osmotic pressure. When this value is positive, it indicates that fluid will tend to move out of the capillary and into interstitial fluid. At the venous end of the capillary, the net filtration pressure will be minus, and this indicates that fluid tends to move into the capillary, that is ,reabsorption is occurring.
If the CHP(capillary hydroststic pressure) rises or the BCOP(blood colloid osmotic pressure) declines, fluid moves out of the blood and builds up in peripheral tissues, acondition of edema exists. TRUE/FALSE
TRUE.
List three factors that influence tissue perfusion?
1. Cardiac output
2. Peripheral resistance
3. Blood pressure
List 6 factors that promote local vasodilation.
1. Decreased tissue O2 levels or increased CO2 levels.
2. Lactic acid
3. Nitric oxide(NO)
4.Rising levels of K+ ions or H+ ions in the interstitial fluid.
5. Histamine
6. Elevated temperature.
List several compounds that cause local vasoconstriction.
1.Prostaglandins/Thromboxanes-released by activated platelets and WBC.
2. Endothelins
The neurons innervating peripheral blood vessels in most tissues are adrenergic, that is they release the neurotransmitter norepinephrine(NE). The response to this is the stimulation of smooth muscle in the walls of arterioles, producing vasoconstriction. TRUE/FALSE
TRUE.
The most common vasodilator synapses are cholinergic, their synoptic knobs release ACh. ACh stimulates endothelial cells in the area to release NO, resulting in vasodilation. TRUE/FALSE
TRUE. Other vasodilator synapses are "nitroxidergic", the synoptic knobs release NO as a neurotransmitter.
The resistance of a maximally constricted arteriole is roughly 80X that of a fully dilated arteriole. TRUE/FALSE
TRUE.
What is the Valsalva maneuver?
`Exhaling forcefully against a closed glottis, causes reflexive changes in blood pressure and cardiac output due to compression of the aorta and venae cavae.
A steep rise in CSF CO2 levels will trigger the vasodilation of cerebral vessels, but will produce vasoconstriction in most other organs. the result is increased blood flow, and increased O2 delivery to the brain. TRUE/FALSE
TRUE.
Give some examples of how the endocrine system provides both short and long term regulation of cardiovascular performance.
E. and NE from the adrenal medulla stimulate CO and peripheral vasoconstriction. Other hormones important in CO regulation are; ADH/Angiotensin 11/EPO/ANP and BNP.
What is angiotensin 11?
This appears in the blood after the release of the enzyme renin by juxtaglomerular cells, in response to a fall in blood pressure.
Renin converts angiotensinogen, a plasma protein produced by the liver to angiotensin 1. In pulmonary capillaries, angiotensin converting enzyme(ACE) then modifies angiotensin 1 to angiotensin 11, an active hormone.