Cardio

Question 1

Tachycardia?

Answer 1

Rapid heart rate >100bpm

Question 2

What is an ECG?

Answer 2

Graphic record of electrical activity that reaches body surface.

Represents overall spread of electrical activity throughout heart during depolarisation and repolarisation

Question 3

Cardiac muscle refractory period?

Answer 3

250msec

Question 4

Function of fibrous skeleton

Answer 4

Structural

Guides and insulates electrical conduction down specialised muscle cell

Cause electrical waves to pause between atria and ventricles

Question 5

Bradycardia?

Answer 5

Slow heart rate <60bpm

Question 6

Stroke volume ?

Answer 6

Volume of blood pumped out of each ventricle per beat

Question 7

Ventricle pressure loop stages

Answer 7

A ventricular filling
B isovolumetric contraction
C ventricular ejection
D isovolumetric relaxation

Question 8

What is EDV?

Answer 8

Maximal volume of blood on ventricles achieved at end of filling
Before contraction

Question 9

What is ESV?

Answer 9

Minimal volume of blood in ventricle at the end of ejection

After contraction

Question 10

Preload ?

Answer 10

Initial stretching of the cardiac myocytes prior to contraction
Related to muscle sarcomere length

Question 11

Venous return ?

Answer 11

Volume of blood that return to heart

Question 12

Central venous pressure CVP?

Answer 12

Pressure of large veins in thoracic cavity

• inferior vena cava
• superior vena cava

Question 13

Factors that increase ventricular filling preload

Answer 13

Increase central venous pressure 
Increase aortic pressure
Increase atrial contractility 
Increase ventricular compliance 
Decrease heart rate

Question 14

Afterload?

Answer 14

Pressure required to open aortic valves

Resistance that vented is of heart has to overcome to eject the blood from ventricle chamber during systole

Question 15

Frank-Starling mechanism

Answer 15

Ability of heart to change its force of contraction and stroke volume in response to changes in venous return.

Increasing venous return increase EDV increases stroke volume (heart contracts more) to maintain ESV

Question 16

Why premature depolarisations abnormally shaped?

Answer 16

Impulses generated by ectopic site are not conducted through normal pathways.

Question 17

Foetal and adult haematocrit

Answer 17

14-18 g/dL
Adult 11.5-15.5 g/dL

Hb content

Question 18

Haematocrit ?

Answer 18

Ratio of volume of red blood cells to total volume of blood

Question 19

What is a capillary bed?

Answer 19

network of capillaries that supplies an organ