Chapter 20 Homework

4 September 2022
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question
Which term refers to the feedback response to blood pressure changes?
answer
baroreflex
question
Which of the following does not move substances across capillary walls?
answer
Group transport
question
What is the most important force driving reabsorption at the venous end of a capillary?
answer
Blood colloid osmotic pressure
question
In people who stand for long periods, blood tends to pool in the lower limbs and this may result in varicose veins. What causes the varicose veins?
answer
Failure of the venous valves
question
Which of the following would decrease the velocity of blood flow?
answer
Increased viscosity
question
How is increased muscle perfusion during exercise accomplished? Check all that apply.
answer
During exercise, 1. the arterioles dilate in response to epinephrine and norepinephrine from the adrenal medulla and sympathetic nerves. 2. Precapillary sphincters, which lack innervation, dilate in response to muscle metabolites such as lactic acid, CO2, and adenosine. 3. Blood flow through the muscles can increase more than 20-fold during strenuous exercise, which requires that blood be diverted from other organs such as the digestive tract and kidneys to meet the needs of the working muscles. Muscular contraction compresses the blood vessels and impedes flow.
question
Why do fluids leave the capillaries at the arterial end?
answer
The net filtration pressure of the blood is higher at the arterial end than it is at the venous end.
question
Approximately what percent of fluid that exits the capillaries at the arterial end reenters the capillaries at the venous end?
answer
90%
question
Which of the following is not detected by chemoreceptors in the carotid and aortic bodies?
answer
Blood pressure
question
Which of the following contains chemoreceptors?
answer
Medulla oblongata
question
Which of the following will not increase the heart rate?
answer
increased blood pressure
question
Where are baroreceptors found?
answer
Carotid sinuses
question
Action potentials are conducted from the baroreceptors to the brain via which nerve?
answer
Glossopharyngeal nerve
question
The action potential from the brain to the heart travels along which nerve(s)?
answer
Vagus nerve
question
A nurse takes your blood pressure and tells you the numbers are 110/70. What are your blood pressures?
answer
Systolic = 110 mmHg, Diastolic = 70 mmHg, Pulse Pressure = 40 mmHg, MAP = 83 mmMg
question
Which of the following occur during a period of exercise? Check all that apply.
answer
1. The sympathetic nervous system can selectively reduce blood flow to the kidneys and digestive tract. 2. The sympathetic nervous system can increase perfusion of the skeletal muscles. 3. Metabolite accumulation in a tissue can stimulate local vasodilation.
question
Which of the following decreases blood pressure?
answer
Natriuretic peptides
question
Which of the following does not aid in venous return?
answer
Venule suction
question
How is venous return to your heart affected when you go for an easy jog?
answer
It is increased due to increased skeletal muscular pump activity
question
Neurogenic Shock:
answer
form of Venous pooling (vascular) shock that results from a sudden loss of vasomotor tone, occurs when the body has a normal total blood volume, but too much of it accumulates in the lower body.
question
Circulatory Shock:
answer
Circulatory shock is any state in which cardiac output is insufficient to meet the body's metabolic needs. All forms of circulatory shock fall into two categories: (1) cardiogenic shock, (2) low venous return (LVR) shock,
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Anaphylactic Shock:
answer
Anaphylactic shock results from exposure to an antigen to which a person is allergic, such as bee venom.
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Cardiogenic Shock:
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cardiogenic shock, caused by inadequate pumping by the heart, usually as a result of myocardial infarction,
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Septic Shock:
answer
Septic shock occurs when bacterial toxins trigger vasodilation and increased capillary permeability.
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Hypovolemic Shock:
answer
Hypovolemic shock, the most common form, is produced by a loss of blood volume as a result of hemorrhage, trauma, bleeding ulcers, burns, or dehydration.
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Obstructed Venous Return Shock:
answer
Obstructed venous return shock occurs when any object, such as a growing tumor or aneurysm, compresses a vein and impedes its blood flow. (
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Low Venous Return Shock:
answer
low venous return (LVR) shock, in which cardiac output is low because too little blood is returning to the heart. There are three principal forms of LVR shock: Hypovolemic shock Obstructed venous return shock Venous pooling (vascular) shock
question
What is taken up by the capillaries at their venous end?
answer
Waste products
question
How do materials get from the blood to the surrounding tissues?
answer
Diffusion, filtration and absorption, and transcytosis
question
arteries...
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loosely termed "resistance vessels" loosely termed "pressure reservoirs" Pulsatile flow of blood Usually carry oxygenated blood from the heart to the body Exhibit greater ability to alter vessel diameter
question
veins...
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loosely referred to as "capacitance vessels" Contain the majority of blood at any one time Collapsed when empty provide for relatively consistent velocity of blood flow rely on the respiratory and skeletal muscular pumps to propel blood
question
During exercise, the adrenal medulla and sympathetic nerves cause which of the following to occur?
answer
Arterioles dilate in response to epinephrine and norepinephrine.
question
Which of the following are powerful vasoconstrictors?
answer
Norepinephrine and angiotensin II
question
What is the best way to estimate the MAP?
answer
Take the diastolic pressure and add one-third of the pulse pressure. MAP is not simply an arithmetic mean of systolic and diastolic pressures, however, because the low-pressure diastole lasts longer than the high-pressure systole. The best estimate of MAP is diastolic pressure plus one-third of the pulse pressure. For a blood pressure of 120/75, MAP ≈ 75 + 45/3 = 90 mm Hg.
question
Which of the following does not contribute to venous return?
answer
Widespread vasodilation
question
What type of shock can be produced by hemorrhage, severe burns, or dehydration?
answer
Hypovolemic
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What type of shock occurs when bacterial toxins trigger vasodilation and increase capillary permeability?
answer
Septic
question
Which of the following is not a mechanism that assists venous return?
answer
Central venous pressure being greater than pressure in the venules
question
What is(are) the physiological purposes of vasoreflexes?
answer
To cause a generalized raising or lowering of blood pressure throughout the body and to selectively modify the perfusion of a particular organ by rerouting blood from one region of the body to another
question
Blood usually passes through one network of capillaries from the time it leaves the heart until the time it returns, but there are exceptions, notably the __________.
answer
portal systems and anastomoses
question
Which of the following is not a possible circulatory route from the heart?
answer
Heart → arteries → capillary bed → vein → capillary bed → arteries → heart
question
increased flow
answer
increasing vessel radius increasing blood pressure Aldosterone hypersecetion increasing blood velocity
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decreased flow
answer
increasing blood velocity increasing vessel length dehydration increased resistance increasing red blood cell count vasoconstriction
question
decompensated shock
answer
life threating positive feedback loops occur poor cardiac output results in myocardial ischemia and infarction half of those who go into this type of shock die from it ischemia/acidosis of brainstem depresses the vasomotor and cardiac centers slow circulation of the blood can lead to DIC
question
compensated shock
answer
brings about spontaneous recovery hypotension triggers the baroreflex when a person falls to a horizontal position, gravity restores blood flow to brain hypotension triggers the production of angiotensin II
question
What is the most important force driving filtration at the arterial end of a capillary?
answer
Blood hydrostatic pressure