Physiology Test 2: Cardiac System Overview

Front 1

Basic distribution of water in the body

Back 1

67% intracellular
27%intersitial(extravascular edema)
6% plasma(intravascular)

Front 2

What is the importance of interstitial fluid?

Back 2

1. Cells get their nutrition from here.
2.Cells release their products here.
3. Plasma must regulate interstitial composition

Front 3

Factors necessary for controlling the composition of interstitial fluid

Back 3

1. Must have adequate blood flow
2. Incoming blood needs control to achieve what is desired for interstitial fluid

Front 4

Water movement in the blood and cells occurs by what mechanisms?

Back 4

1. Between the interstitial fluid and plasma water moves by osmosis and pressure gradient, not ions.
2. Between the intracellular and interstitial fluids water moves due to ion concentration. This is important to consider when rehydrating patients

Front 5

What are the components of vessles?

Back 5

1. Arteries
2. Capillaries
3. Veins
4. Lymphatics

Front 6

Blood components

Back 6

1. Water, RBCs, WBCs, platelets, and dissolved elements

Front 7

What do platelets do?

Back 7

They protect and preserve the integrity of the cardivascular system.

Front 8

Basic pressure of the heart pump is caused by what?

Back 8

1. The left side causes high pressure for pushing blood through systemic circulation(100-120Torr)
2. The right side causes a weaker pressure for pushing blood through the lungs(12-16Torr)

Front 9

How does the heart lower pressure in the systemic circulation?

Back 9

It lowers resistance by having its ciruit in parellel not series. So if one area gets backed up more capillaries can dialate in other areas and lower overall resistance.

Front 10

What part of the body is resistant to diversion of pressure?

Back 10

The liver is a series circuit that makes it more susceptible to pressure build up. This means that edema can happen easily here.

Front 11

Average high/low pressure of veins and arteries?

Back 11

Average pressure in arteries is high while average pressure in veins is low. Veins are higher volume and more compliant.

Front 12

What is the normal minute flow of the heart?

Back 12

Normally the blood flows out at about 5-6L/min

Front 13

What is the proportion of blood flow to the tissues regulated by?

Back 13

1. It is regulated by necessity of tissue function. Highly metabolic tissues will get more blood flow to them.

Front 14

What is teh preload?

Back 14

The amount of blood that gets loaded into the ventricles

Front 15

What is the afterload?

Back 15

The amount of blood that the heart spits out and works against.

Front 16

What is the blood proportion and resistance in the arterial side of the body?

Back 16

The proportion of blood is small at about 30% yet it has the highest resistance. The majority of that resistance is produced by the arterioles.

Front 17

What is the purpose of the venous portion of the body?

Back 17

It is to return blood to the heart and is therefore the capacitance portion. The veins have very little ton, smooth muscle and are easily distended. They contain 70%of the blood volume

Front 18

What is meant by vasomotor tone?

Back 18

It is the relative tone of the arterioles. It can be increased by the sympathetic nervous system and decreased by the parasympathetic.

Front 19

How do pulmonary venous pressures relate to an MI.

Back 19

1. They increase with MI in the left ventricle
2. THey decrease with an MI in the right ventricle

Front 20

The five phases of the cardiac action potential?

Back 20

0. Rapid influx of Na depolarizes the cell. Resting potential here is -85mV
1. The intial notch drop is due to K(efflux)/Cl(influx) channels
2. The plateu phase is cause by a balance of Ca/K movement
3. The Ca channels close and K channels stay open allowing K out.
4. Resting diastole potential

Front 21

Pacemaker action potential

Back 21

Phase 4. Caused by an influx of Na that slowly depolarizes the cell(-60to-50mV)(funny current)
Phase 0. T and L Ca channels open and cause depolarization
Phase 3. K channels open and cause repolarization

Front 22

Absolute refractory period(ARP) in the heart action potential

Back 22

When no amount of stimulation will cause another contraction. Happens until the slow K channels open

Front 23

Relative refractory period in the heart action potential

Back 23

During repolarization if the signal is strong enough ther can be another reaction

Front 24

What do the sympathetic fibers in the heart accomplish and where are they?

Back 24

1. The are located primarily in teh heart muscle
2. The have a strong effect on the force of contraction
3. Intense stimulation can increase CO from 5-6L/min to 25-30 L/min

Front 25

What effect do the parasympathetic fibers of the heart have and where are they?

Back 25

1. The are located primarily on the SA and AV nodes
2. They come from the vagus nerve
3. They have a large effect on the heart rate and impulse conduction
4. Intense stimulation here can cause arrest

Front 26

What happens during atrial systole?

Back 26

Both the atria contract to empty the last little but of blood after passive fillage into the ventricles. The atrial kick.

Front 27

Why are atria necessary?

Back 27

Younger hearts don't need them by as you get older heaerts get more stiff and need the kick because the ventricles don't relax quite as much.

Front 28

What happens during isovolumic ventricular contraction?

Back 28

It is the point where all the valves are closed and the ventricles must create enough pressure to overcome arterial pressure and proceed.

Front 29

What happens during ventricular ejection?

Back 29

The contraction forces the valves to blow open and the blood ejects into systemic circulation.

Front 30

What happens during ventricular relaxation?

Back 30

Both sets of valves close again and the pressure drops in the ventricles. Venous pressure opens the mitral and tricuspid valves to refill the atria and ventricles.

Front 31

S1 and S2 happens when?

Back 31

S1 is closure of the mitral and tricuspid valves, S2 is closure of the Semilunar valves

Front 32

Dicrotic notch is what?

Back 32

The slight increase in aortic pressure due to opening and closing of the AV valves

Front 33

PV loop steps?

Back 33

1. Take the ventricular volume and plot it against the pressure.
2. The verticle lines are isovolumic contraction and relaxation
3. After ESV there is a small pressure increase and a large volume increase to EDV as the ventricles fill.
4. Then a short isolvolumic contraction occurs until the semilunar valves blow open.
5. Ejection occurs out of the ventricles which raises pressure to a peak and then decrease slightly until the semilunar valves shut.
5. The ventricles then relasx isovolumetrically to end systolic volume, the pressure drops low enough for the mitral and tricuspid valves to open