cardiac A&P patho - E3

Question 1

cardiac output equation

Answer 1

CO = SV x HR

Question 2

why is CO diminished in HF

Answer 2

left ventricle is weakened and cannot adequately pump blood out of the chamber

Question 3

3 major factors of stroke volume

Answer 3

1) preload: volume of blood in the heart
2) afterload: force opposing ejection of the blood from the ventricle
3)contractility: contractile capabilities of the heart

Question 4

Preload

Answer 4

“stretch of cardiac muscle cells before contraction” -> r/t chamber volume just prior to contraction
a lower preload leads to a lower SV which leads to a lower CO

Question 5

frank starling law

Answer 5

this law states that an increase in resting muscle fiber length results in greater muscle tension
so the heart has the ability to change its force of contraction (& stroke volume) in response to changes in venous return

Question 6

the 3 fluid compartments of a cell

Answer 6

1) intracellular: inside the cell
2) interstitial: surrounds the cell
3) extracellular: located inside the capillary

Question 7

hydrostatic pressure

Answer 7

fluid within the blood exerts hydrostatic pressure, a force that attempts to push fluid out of the capillary pores and into the interstitial and intracellular space
water pushing power

Question 8

oncotic (osmotic) pressure

Answer 8

particles within the blood (like albumin, sodium, & glucose) exert osmotic pressure, a force that attempts to pull fluid from the interstitial & intracellular spaces into the capillary
water pulling pressure

Question 9

starling’s law of capillary forces

Answer 9

oncotic pressure forces and hydrostatic pressure forces oppose each other at every capillary membrane and attempt to balance each other out

Question 10

afterload

Answer 10

“resistance that must be overcome in order to eject blood from the chamber”
-left ventricular AL is primarily determined by aortic BP
-an increase in AL will lead to a decrease in SV unless the heart compensates
ex: a person w/ high BP will have high AL and be at risk for a lower SV

Question 11

contractility

Answer 11

“contractile force of the heart muscle cells”
-primarily determined by the amount of free Ca within the myocardial cell
-increased contractility increases SV by causing a greater % of the volume to be ejected

Question 12

Left ventricular failure: backward effects

Answer 12

creates a buildup of hydrostatic pressure in the left atrium, pulmonary veins & pulmonary capillaries
pulmonary edema
S/s: crackles (fine = mild, coarse = severe), cough, dyspnea, orthopnea & paroxysmal nocturnal dyspnae & pink frothy sputum (severe)

Question 13

Left ventricular failure: forward effects

Answer 13

decreased perfusion of the brain, kidneys & other organs
activates a neurohormonal response that includes stimulation of RAAS in response to the kidneys releasing renin, ADH & SNS -> this increase BV & BP through by RAAS, increases HR & vasocon by SNS & increases BV by ADH

Question 14

coronary arteries

Answer 14

branch off of the aorta and they feed the heart the oxygenated blood