What is impaired tissue perfusion? - answer A decrease in nutrition and respiration at
the cellular level due to decrease in capillary blood supply.. The cells are deprived of 02
and nutrients because blood is not getting to them.
What are some factors that can result in poor perfusion? - answer Vascular disorders
like HTN, atherosclerosis (hardening of the arteries), arteriosclerosis (thickening,
hardening, and loss of elasticity of arterial walls), aneurisms, renal failure, conditions
such as pregnancy, dehydration, and malnutrition.
What are three things which influence tissue perfusion? - answer1.Anticoagulants
2. Anesthesia
3. Antibiotics
How do tissues perfuse? - answer1.Red blood cells carry nutrition and oxygen through
the capillaries to the tissues.
2. Oxygen is inhaled from the atmosphere to alveoli.
3. Oxygen diffuses into the pulmonary capillaries carried by hemoglobin through the
systemic capillaries to the cells.
4. Hemoglobin gives up oxygen and picks up carbon dioxide by diffusion.
5. Carbon dioxide carried from venous end of capillaries to lungs where it is exhaled.
What is Hypoxia and what causes it? - answerHypoxia is when the cells lack oxygen.
Cause:
Low hemoglobin
Decreased blood flow
Decreased ability of oxygen to diffuse to tissues
Decreased ability of heart to pump
Decreased ability of lungs to exchange air
What is Blood Pressure? - answerPressure exerted by circulating blood volume on the
walls of the arteries and veins and on the chambers of the heart.
BP = cardiac output X systemic vascular resistance
Cardiac output = Heart rate X Stroke volume
What is stroke volume influenced by? - answerFluid coming into heart and fluid going
out of heart along with quality of contraction of the muscle. Condition of muscle will also
influence HEART RATE.
What is a "closed system"? - answerThe cardiac system of arteries, veins, and heart.
BP affects all these because of the fact that it is a closed system.
, What is Systemic Vascular Resistance influenced by? - answer1. Fluid volume control
(the more fluid, the greater the pressure - kidneys influence fluid volume).
2. Sympathetic nervous system (SNS) and neurohormonal.
3. Local regulators (lining of vessels/vascular tissues, local regulators control
vasodilation and vasoconstriction).
What role does the Autonomic Nervous System play in this? - answer1. The
sympathetic nervous system plays the greater role. It increases heart rate and cardiac
output and causes vasoconstriction.
2. The parasympathetic nervous system DECREASES heart rate and cardiac output.
Causes vasodilation.
You need a balance between the 2 systems.
The Renin Angiotensin Aldosterone System. How does it work? - answer1. Decreased
blood flow to kidney results in increased release of renin.
2. Producing vasoconstriction and stimulating adrenal cortex to produce aldosterone.
3. Increasing sodium and water retention.
4. Resulting in increased fluid volume.
5. Increasing blood pressure and flow to the kidney.
Another way to look at the Renin Angiotensin Aldosterone System. - answer1. Decrease
in blood flow to kidneys.
2. Kidneys put out more renin.
3. Angiotensin 1 (a vasoconstrictor) is increased
4. Angiotensin 2 (the most potent vasoconstrictor in the body) is released.
5. Stimulates aldosterone secretion from cerebral cortex.
6. ADH (anti-diuretic hormone) released from hypothalamus.
7. Increased re-absorption of water by kidneys.
What are the neurohormones that influence Systemic Vascular Resistance? - answer1.
Angiotensin
2. Norepinephrine
(both are vasoconstrictors)
What are the Local Regulators that influence Systemic Vascular Resistance? - answer1.
Prostaglandins (vasodilators)
2. Endothelin (lives in endothelial lining of blood vessels - vasoconstrictors).
What are some age-related changes affecting blood pressure? - answer1. Stiffer
vessels, not able to dilate and relax as easily.
2. Impaired function of baroreceptors
3. Decreased renal function (renin-angiotensin-aldosterone system not as efficient).
What are baroreceptors? - answerThey are in the aortic arch; they respond to different
pressure gradients. Can cause orthostatic hypotension.
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