Cardio 4 Flashcards Preview

PHSI 208 > Cardio 4 > Flashcards

Flashcards in Cardio 4 Deck (19):
1

What two factors determine the amount of force generated by cardiac muscle?

-contractibility of the heart
-length of muscle fibres at beginning of contraction

2

inotropic agent

any chemical that affects contractibility

3

positive inotropic effect

chemicals increasing contractibility

4

negative inotropic effect

chemicals decreasing contractibility

5

Catecholamines

norepinephrine and epinephrine; positive inotropic effect

6

preload

degree of myocardial stretch prior to contraction

7

stretch

indicated by ventricular end-diastolic volume

8

frank starling law

stroke volume increases with increasing end-diastolic volume

9

skeletal muscle pump

Skeletal muscle activity compresses veins in the extremities pushing blood back to the heart

10

respiratory pump

during inspiration the chest expands and diaphragm moves down creating a subatmospheric pressure in the thoracic cavity, this draws blood into the vena cava that exist within this cavity

11

sympathetic constriction of veins

decreases their volume squeezing blood back towards that heart.

12

afterload

end load against which the heart contracts to eject blood

13

ejection fraction (EF) =

SV/EDV

14

progressive branching of vessels

Aorta>Arteries> arterioles> capillaries> venules > Veins>vena cava

15

arteries

all; mostly elastic tissue and smooth muscle

16

arteriole

endothelium and smooth muscle

17

capillary

endothelium

18

venule

endothelium and fibrous tissue

19

vein

all