cardiac output and blood flow in muscle tissues

Question 1

define cardiac output

Answer 1

quantity of blood pumped into the aorta each minute by the heart
quantity of blood that flows through the circulation
sum of all the blood flows to all the tissues of the body

Question 2

define cardiac index

Answer 2

cardiac output per square meter of body surface

Question 3

what happens to cardiac output and oxygen consumption when you exercise

Answer 3

they both increase

Question 4

what is the fick principle used for

Answer 4

used to calculate blood flow through an organ

Question 5

what is the equation for the fick principle of blood flow

Answer 5

cardiac output= O2 consumption/ [O2]pul vein-[O2]pul art

Question 6

what determines how much blood the heart pumps out

Answer 6

the amount of blood returning to the heart

Question 7

how are the 2 circuits of the cardiovascular system connected

Answer 7

series

Question 8

are pressures higher in systemic or pulmonary circuits

Answer 8

systemic

Question 9

what factors directly affect cardiac output

Answer 9

basic level of body metabolism
whether the person is exercising
age
size of the body

Question 10

what is the frank-starling law

Answer 10

heart automatically pumps whatever amounts of blood that flows into the right atrium

Question 11

define ohm;s law

Answer 11

anytime the long-term level of total peripheral resistance changes the cardiac output changes quantitatively in exactly the opposite direction

Question 12

what does the bainbridge reflex do

Answer 12

responds to changes in blood volume as detected by stretch receptors in the right atrium

Question 13

what factors cause hyper effective heart

Answer 13

nervous stimulation
hypertrophy of heart
exercise via nervous system

Question 14

what factors cause hypo effective heart

Answer 14

increased arterial pressure (hypertension)
inhibition of nervous excitation of the heart
pathological factors causing abnormal heart rhythm/rate
coronary artery blockage
valvular heart disease
congenital heart disease
cardiac hypoxia

Question 15

cardiac factors causing decreased cardiac output

Answer 15

severe blood vessel blockage--> myocardial infarction
severe valvular disease
myocarditis
cardiac tamponade
cardiac metabolic arrangements

Question 16

what is beriberi

Answer 16

caused by insufficient quantity of the vitamin thiamine of the tissues to use some cellular nutrients, and the local tissue blood flow mechanisms in turn cause some marked compensatory peripheral vasodilation

Question 17

what is atriovenous fistula

Answer 17

when fistula occurs between a major artery and vein=a lot of blood flows direction from artery to vein. This greatly decreases the total peripheral resistance and increase the venous return and cardiac output

Question 18

what is hypothyroidism

Answer 18

metabolism of most tissues of the body becomes greatly increased. oxygen usage increases and vasodilator products are released from the tissues. Total peripheral resistance decreases markedly because of the local tissue blood flow control reactions throughout the body=venous return and cardiac output often increased to 40-80% above normal

Question 19

what is anemia

Answer 19

2 peripheral effects greatly decreased the total peripheral resistance (1st reduced viscosity of the blood result in form the decreased concentration of RBC. 2nd diminished delivery of oxygen to the tissues, which causes local vasodilation). due to both of these, the cardiac output increases greatly

Question 20

non-cardiac factors that decreased cardiac output

Answer 20

decreased blood volume
acute venous dilation
obstruction of large veins
decreased tissue mass
decreased metabolic rate of tissues

Question 21

what factors affect venous return to the heart from the systemic circulation

Answer 21

right atrial pressure
degree of filling of systemic circulation (when heart pumping stops, all blood flow ceases, pressure everywhere in the body become equal)
the greater the difference between the mean systemic filling pressure and the right atrial pressure, the greater the venous return
resistance to blood flow
right atrial pressure
mean systemic filling pressure
blood flow resistance between peripheral vessels and right atrium

Question 22

define pressure gradient for venous return

Answer 22

the difference between the mean systemic filling pressure and the right atrial pressure

Question 23

what is the equation to calculate venous return

Answer 23

(mean systemic filling pressure-right atrial pressure)/resistance to venous return

Question 24

how is the resistance to blood flow determined (factors that affect venous return to the heart from the systemic circulation)

Answer 24

about 2/3 of the resistance to venous return is determined by venous resistance
about 1/3 of the resistance to venous return is determined by arteriolar and small artery resistance

Question 25

how does right atrial pressure affect venous return

Answer 25

impedes flow of blood from veins into right atrium

Question 26

how does the mean systemic filling pressure affect venous return

Answer 26

forces systemic blood toward heart

pressure when arterial and venous pressures come to equilibrium and systemic circulation flow comes to a stop

Question 27

what does a decrease in resistance do to blood flow (venous return curves)

Answer 27

allows more blood to flow (more venous return)

Question 28

what does increasing Psf do to vascular volume and venous compliance

Answer 28

increases vascular volume

decreases venous compliance

Question 29

what does an increase in Psf do to the vascular return curve

Answer 29

shifts it to the right and enhances filling of the ventricles

Question 30

what does decreasing Psf do to vascular volume and venous compliance

Answer 30

decrease vascular volume

increase venous compliance

Question 31

what does decreased Psf do to the vascular return curve

Answer 31

shift to the left and reduces filling of the ventricles

Question 32

what are the local controls of blood flow regulation to skeletal muscle

Answer 32

large blood flow during skeletal muscle activity is due mainly to chemicals that act directly on muscle arterioles to dilate them (reduction in oxygen, adenosine, potassium ion, ATP, lactic acid, carbon dioxide

Question 33

what are the nervous controls of blood flow regulation to skeletal muscle

Answer 33

sympathetic vasoconstrictor nerves (secrete norepinephrine, can decrease blood flow through resting muscles to as little as one half to one third normal)
adrenal medullae (secrete norepinephrine and epinephrine, epinephrine also has a slight dilator effect)

Question 34

what happens when there is a mass discharge of the sympathetic nervous system

Answer 34

heart rate increases
most peripheral arteries are strongly contracted except (those in active muscles, coronary arteries, cerebral arteries)
muscle walls of veins are contracted

Question 35

what does the sympathetic stimulate cause when there is an increase in arterial pressure

Answer 35

vasoconstriction of arterioles and small arteries in most tissues
increased pumping activity of the heart
increase in mean filling pressure caused mainly by venous contraction

Question 36

what happens to blood flow during contractions

Answer 36

decreases

Question 37

what happens during systole in coronary flow

Answer 37

coronary blood flow in the left ventricle falls to a low value (opposite to flow in vascular beds elsewhere in the body)

Question 38

what happens during diastole in coronary flow

Answer 38

the cardiac muscle relaxes and no longer obstructs blood flow through the left ventricular capillaries

Question 39

what is the primary controller of coronary flow

Answer 39

local muscle metabolism

Question 40

what can cause coronary occlusion and death

Answer 40

decreased cardiac output
damming of blood in pulmonary blood vessels and death resulting from pulmonary edema
fibrillation of heart
rupture of heart