Lec 20

Question 1

Systole

Answer 1

Contraction

Question 2

Diastole

Answer 2

Relaxing

Question 3

During diastole

Answer 3

Chambers are filing with blood

Question 4

Late diastole

Answer 4

Both chambers are relaxed
Ventricle fill passivley

Question 5

Atrial systole

Answer 5

Atrial contraction 15% of blood

Question 6

Isovolumic Ventricular Contraction

Answer 6

Pushes AV valves close
Not enough pressure to semilunar valve

Question 7

Ventricular ejection

Answer 7

Ventricular pressure rises
Semilunar valve open

Question 8

Isovolumic ventricular relaxation

Answer 8

Semilunar valve close
AV close (not enough pressure to open)

Question 9

S1

Answer 9

AV valve shut

Question 10

S2

Answer 10

Semilunar valve shut

Question 11

End-diastolic volume

Answer 11

Volume of blood in ventricle at the end of ventricular diastole

Question 12

End systolic volume

Answer 12

Volume blood in ventricle at end of ventricular ejection

Question 13

Stroke volume

Answer 13

EDV-ESV
What can pumped out of heart
Average resting SV= 70ml/beat

Question 14

Pressure/volume diagram of left ventricle

Answer 14

Volume =x-axis
Pressure = y-axis

Question 15

Pressure/volume diagram of left ventricle

Answer 15

1- passively feeling the ventricle (no pressure change)
2- Atria contracted (max vol reach 135)—pressure increase slightly
3- Isovolumic ventrical systole (high increase in pressure)—no vol change
4- Ventricular ejection (min vol reach65)
5- ventricular diastole/Isovolumic ventricular relaxation (high pressure decrease)— no vol change

Question 16

Cardiac output

Answer 16

Vol of blood pumped by one ventricle in a given period of time
HR * SV

Question 17

Average restingn CO

Answer 17

5L/min

Question 18

Autonomic innervation of heart

Answer 18

sympathetic
From: Thoracic and Lumbar
To: SA node/AV node/Ventricular myocardium

parasympatethic
From: medulla
To: SA node/AV node

Question 19

Autonomic effect on SA node

Answer 19

Modulation of heart rate (chronotropic effect)
—parasympathetic or sympathetic
same effect on AV node but SA node will overwrite it

Question 20

Autonomic effect on Ventricular myocyte

Answer 20

Modulation of contractility (Inotropic effect)
—only sympathetic
*by removing sympathetic, contractility reduces

Question 21

Chronotropic and inotropic

Answer 21

Are usually together

Question 22

Chronotropic effect

Answer 22

Sympathetic: NE on Betta1 receptor
Parasympathetic: ACh on M2 receptor

Question 23

Contraction force formula

Answer 23

HR * Stroke Volume

Question 24

Contraction force determined by

Answer 24

1- sarcomere length EDV
only true in cardiac not smooth
2- contractibility of muscle

Question 25

Frank-starling curve

Answer 25

Length-tension relationship Greater stretch= greater force to contract

Question 26

Increase EDV factors

Answer 26

1- increase venous retuurn 2- decrease HR — more filling time

Question 27

Sympathetic effect on ventricular contractility

Answer 27

Sympathetic increase Less time Higher HR Higher contractility Increase stroke volume

Question 28

SNS on myocyte contractibility

Answer 28

-Epinephrine and Norepinephrine -Bind to Betta1 receptors -Activate cAMP (GS) secondary messenger -Result in **phosphorylation of voltage gated Ca channels** **phospholamban**

Question 29

Phosphrylation of voltage gated ca channels

Answer 29

cAMP activate PKA Voltage Ca channels opening time increase Higher Ca entry from ECF More CA released/Ca store in SR **More forceful contraction**

Question 30

Phosphorylation of phospholamban

Answer 30

Higher Ca-ATPase on SR: 1.1- Ca store in Sr 1.2- Ca more release **more forceful contraction** 2.1- Ca removed from cytosol faster 2.2- Shorter Ca-troponin binding time **shorter duration of contraction**