Cardiac Function

Question 1

Ejection fraction =

Answer 1

Sv / Edv

Question 2

At rest ejection fraction

Answer 2

70%

Question 3

Factors affecting cardiac output

Answer 3

Hr and stroke volume

Question 4

Factors affecting stroke volume

Answer 4

Pre load and after load

Question 5

Factors affecting preload

Answer 5

Venous return
Ventricular plasticity
Ventricular size

Question 6

Factors affecting venous return

Answer 6

Pumps

Blood volume

Question 7

Factors affecting after load

Answer 7

Contractility

Systemic vascular resistance

Question 8

Factors affecting contractility

Answer 8

Myocardial mass
Length tension relationship
SNS
Adrenaline

Question 9

Factors affecting HR

Answer 9

PNS
Sns
Adrenaline

Question 10

Pns vs Sns

Answer 10

Pns = lower hr
Sns = increased hr and strength

Question 11

Denervated heart rate

Answer 11

100

Question 12

Normal hr

Answer 12

72 dominated by Pns

Question 13

Pns potential

Answer 13

Decrease to 0

Question 14

Sns potential

Answer 14

Increase by 300%

Question 15

Pns nerve

Answer 15

Venus nerve

Question 16

Sns nerve

Answer 16

Cardiac nerves

Question 17

Ventricular size

Answer 17

The bigger the lv the bigger the sv

Question 18

Ventricular plastisticity

Answer 18

Healthy myocardium stretches

Helps frank staling mechanism

Question 19

Limiting factor of plastisticity

Answer 19

Pericardium

Question 20

Frank staling mechanism

Answer 20

Increased stretching of myocardial walls will increase strength

Question 21

Cardiac muscle length tension relationship

Answer 21

Similar properties to skeletal muscle

Normally operates well below optimum length

Question 22

Ventricular volume on the lt relationship

Answer 22

Increased volume stretches the ventricular muscle towards optimum

Stretching the ventricles increases the pressure they can generate

Question 23

At rest where does the heart operate in rages to lt relationship

Answer 23

On the toe therefore increased filling immediately leads to increased q

Question 24

Blood volume in adults

Answer 24

5l

Question 25

Blood redistribution

Answer 25

At rest 20% to muscle | In exercise 85% to muscle

Question 26

Blood volume at rest

Answer 26

Excess blood 2/3 resides in veins

Question 27

Blood volume in exercise

Answer 27

Insufficient volume blood is shunted away from non workin muscle

Question 28

Vasodilator a

Answer 28

``` Nitric oxide increased Bradykinin increase Prostaglandins increase Increased potassium Increased co2 Increased lactate Decreased local po2 ```

Question 29

Vasoconstriction.

Answer 29

Increased Sns activity releases NE | ACTS on alpha receptors in smooth muscle to cause constriction

Question 30

Venous return pumps

Answer 30

Ventricular Ventricular rotation Respiratory Muscular

Question 31

Ventricular pump

Answer 31

High pressure durning contraction | Low pressure durning relaxation creates a vacuum sucking bloody towards heart

Question 32

Ventricular rotation

Answer 32

Wrings blood out in systole | Twists and recoils to suck blood in diastole

Question 33

Respiratory

Answer 33

Pressure Increases in thorax during expiration = blood towards heart Pressure low during inspiration creates vacuum drawing blood towards heart

Question 34

After load and cardiac performance

Answer 34

``` Factors which impede ejection fraction Volume of blood in arterial circulation Pressure in aorta Compliance of aorta Size of pulmonary / aorta lumen Inertial component of ejecting blood column ```

Question 35

After load and cardiac performance 2

Answer 35

Stroke volume down Preload increased Reduced velocity Increased myocardial O2 consumption

Question 36

Stroke volume = ?

Answer 36

Preload - after load