Chapter 14 - Cardiovascular

Question 1

primary function of the CV system

Answer 1

transport of nutrients, water, gases, wastes, and chemical signals to and from all parts of the body

Question 2

blood flows down a ____

Answer 2

pressure gradient (delta P)

Question 3

driving pressure for blood flow

Answer 3

the pressure created when the ventricles contract

Question 4

resistance of a fluid flowing through a tube increases as the length of the tube and the viscosity of the fluid ___ and as the radius of the tube ___

Answer 4

increase; decrease

Question 5

fluid flow through a tube is ___ to the pressure gradient

Answer 5

proportional

Question 6

flow rate

Answer 6

the volume of blood that passes one point in the system per unit time

Question 7

velocity

Answer 7

the distance a volume of blood travels in a given period of time

Question 8

at a constant flow rate, the velocity of flow through a small tube is ___ than the velocity through a larger tube

Answer 8

gaster

Question 9

autorhythmic cells

Answer 9

noncontractile myocardium. the signal for contraction originates here

Question 10

intercalated disks

Answer 10

link myocardial cells. contain gap junctions. the junctions allow depolarization to spread rapidly from cell to cell

Question 11

calcium-induced calcium release

Answer 11

in contactile cell excitation-contraction coupling, an action potential opens Ca2+ channels. Ca2+ entry into the cell triggers the release of additional Ca2+ from the sarcoplasmic reticulum through calcium-induced calcium release

Question 12

the force of cardiac muscle contraction can be graded according to

Answer 12

how much Ca2+ enters the cell

Question 13

the action potentials of myocardial contractile cells have a rapid depolarization phase created by ___ influx, and a steep repolarization phase d/t ___ efflux. the action potential also has a plateau phase created by ___ influex

Answer 13

Na+; K+; Ca2+

Question 14

pacemaker potential

Answer 14

an unstable membrane potential in autorhythmic cells. it is d/t If channels that allow net influx of positive charge

Question 15

the steep depolarization phase of the autorhythmic cell action potential is caused by ___ influx. the repolarization phase is f/t ___ efflux

Answer 15

Ca2+; K+

Question 16

electrical pathway through the heart

Answer 16

SA node -> AV node -> bundle of His (AV bundle) -> bundle branches -> Purkinje fibers -> myocardial contractile cells

Question 17

What sets the pace of the heartbeat?

Answer 17

the SA node. if the SA node malfunctions, other autorhythmic cells in the AV node or ventricles take control of HR

Question 18

ECG

Answer 18

surface recording of the electrical activity of the heart; provides info on heart rate and rhythm, conduction velocity, and the condition of cardiac tissues

Question 19

P wave

Answer 19

represents atrial depolarization

Question 20

QRS complex

Answer 20

represents ventricular depolarization; atrial repolarization is incorporated in the QRS complex

Question 21

T wave

Answer 21

represents ventricular repolarization

Question 22

most blood enters the ventricles when…

Answer 22

the atria are relaxed. only 20% of ventricular filling at rest it d/t atrial contraction

Question 23

the first heart sound is d/t

Answer 23

the closure of the AV valves during ventricular contraction

Question 24

the second heart sound is d/t

Answer 24

the semilunar valves closing when ventricles relax and ventricular pressure falls

Question 25

isovolumic ventricular contraction

Answer 25

ventricular blood volume does not change but pressure rises

Question 26

stroke volume

Answer 26

the amount of blood pumped by one ventricle during one contraction

Question 27

cardiac output

Answer 27

the volume of blood pumped per ventricle per unit time. it is equal to HR x stroke volume. the avg CO at rest is 5 L/min

Question 28

homeostatic changes in cardiac output are accomplished by varying:

Answer 28

HR, stroke volume, or both

Question 29

___ activates ___ receptors to hyperpolarize pacemakers

Answer 29

ACh; muscarinic

Question 30

the longer a muscle fiber is when it begins to contract, the ___ the force of contraction

Answer 30

greater

Question 31

the Frank-Starling law of the heart says that an increase in end-diastolic volume (EDV) results in a ___ stroke volume

Answer 31

greater

Question 32

end-diastolic volume (EDV)

Answer 32

the maximum volume of blood that the ventricles hold during a cardiac cycle

Question 33

end-systolic volume (ESV)

Answer 33

the amount of blood left in the ventricle at the end of contraction

Question 34

preload

Answer 34

the degree of myocardial stretch created by venous return

Question 35

afterload

Answer 35

the combined load of blood in the ventricle (the EDV) and arterial resistance during ventricular contraction. AKA the load placed on the ventricle as it contracts. it reflects the preload and the effort required to push the blood out of the arterial system. mean arterial pressure is a clinical indicator of afterload

Question 36

ejection fraction

Answer 36

the percentage of EDV ejected w/ one contraction (stroke volume/EDV). used to evaluate ventricular function

Question 37

mean arterial pressure (MAP

Answer 37

average blood pressure in the arteries, estimated as diastolic pressure plus 1/3 of the pulse pressure. a clinical indicator of afterload.