chapter 30

Question 1

what is the cardiovascular systems vital role in maintaining homeostasis depends on

Answer 1

continuous, controlled movement of blood through capillaries

Question 2

hemodynamics

Answer 2

A collection of mechanisms that influence the dynamic (active and changing) circulation of blood

Question 3

Circulation control mechanisms must accomplish what functions

Answer 3

Maintain circulation
Vary the volume and distribution of the blood circulated

Question 4

perfusion pressure

Answer 4

pressure gradient needed to maintain blood flow through a local tissue

Question 5

what is P1-P2

Answer 5

symbol used to represent a pressure gradient, with P1 representing the higher pressure and P2 the lower pressure

Question 6

Blood circulates from the left ventricle to the right atrium of the heart

Answer 6

because a blood pressure gradient exists between these two structures

Question 7

Aortic reflex

Answer 7

sensory fibers extend from baroreceptors located in the wall of the arch of the aorta through the aortic nerve and through the vagus nerve to terminate in the cardiac control center

Question 8

Peripheral resistance

Answer 8

resistance to blood flow imposed by the force of friction between blood and the walls of its vessels

Question 9

Factors that influence peripheral resistance

Answer 9

blood viscosity
high plasma protein
high hematocrit

Question 10

Vasomotor mechanism:

Answer 10

muscles in walls of arteriole may constrict (vasoconstriction) or dilate (vasodilation), thus changing diameter of arteriole

Question 11

Vasomotor control mechanism:

Answer 11

controls changes in the diameter of arterioles; plays role in maintenance of the general blood pressure and distribution of blood to areas of special need

Question 12

Vasomotor chemoreflexes:

Answer 12

located in aortic and carotid bodies are sensitive to hypercapnia(too much carbon dioxide), hypoxia(too little of oxygen), and decreased arterial blood pH

Question 13

Medullary ischemic reflex:

Answer 13

acts during emergency situation when blood flow to the medulla is decreased; causes marked arteriole and venous constriction

Question 14

Vasomotor control by higher brain centers:

Answer 14

impulses from centers in cerebral cortex and hypothalamus transmitted to vasomotor centers in medulla to help control vasoconstriction and dilation

Question 15

Local control of arterioles: several mechanisms produce localized vasodilation;

Answer 15

relative hyperemia

Question 16

Venous return:

Answer 16

amount of blood returned to the heart by the veins

Question 17

Stress-relaxation effect:

Answer 17

occurs when a change in blood pressure causes a change in vessel diameter (because of elasticity) and thus adapts to the new pressure to keep blood flowing (works only within certain limits

Question 18

Venous pumps

Answer 18

blood-pumping action of respirations and skeletal muscle contractions facilitate venous return by increasing pressure gradient between peripheral veins and venae cavae

Question 19

Total blood volume

Answer 19

changes in total blood volume change the amount of blood returned to the heart

Question 20

Antidiuretic hormone mechanism

Answer 20

decreases the amount of water lost by the body by increasing the amount of water that kidneys reabsorb from urine before it is excreted from the body; triggered by input from baroreceptors and osmoreceptors

Question 21

Renin

Answer 21

released when blood pressure in kidney is low; leads to increased secretion of aldosterone, which stimulates retention of sodium, causing increased retention of water and an increase in blood volume

Question 22

Angiotensin II

Answer 22

intermediate compound that causes vasoconstriction, which complements the volume-increasing effects of renin and promotes an increase in overall blood flow

Question 23

Atrial natriuretic peptide mechanism

Answer 23

adjusts venous return from an abnormally high level by promoting the loss of water from plasma, causing a decrease in blood volume; increases urine sodium loss

Question 24

Arterial bleeding(more critical)

Answer 24

blood escapes from artery in spurts because of alternating increase and decrease of arterial blood pressure

Question 25

Venous bleeding

Answer 25

blood flows slowly and steadily because of low, nearly constant pressure

Question 26

Cariogenic shock

Answer 26

Results from any type of heart failure(decrease CO, usually comes from heart attack)

Question 27

Hypovolemic shock

Answer 27

Results from loss of blood volume in the blood vessels (low volume of blood, losing blood internally or externally very quickly)

Question 28

Neurogenic shock

Answer 28

Caused by widespread dilation of blood vessels (activating parasympathetic, caused by damage to spine or head injury)

Question 29

Anaphylactic shock

Answer 29

Results from anaphylaxis(allergic reaction, decrease BP, swelling)

Question 30

Septic shock

Answer 30

Results from septicemia complications (infection of blood, toxins dilate bp)

Question 31

shock

Answer 31

decrease blood flow to the tissues (Shock leads to weakness, increase HR, respiration rate, sweat, anxiety, thirst)

Question 32

hypertension(HTN)

Answer 32

High blood pressure
Occurs when force exerted by the arterial blood vessel exceeds 140/90 mmHg

Question 33

Hypotension

Answer 33

Lower than normal blood pressure