Cardiovascular System

Question 1

Myocardium

Answer 1

Cardiac muscle

Question 2

Myogenic

Answer 2

Heart contracts without neural stimulus

Question 3

Step 1 of conduction system

Answer 3

SA node initiates cardiac impulse in posterior wall of right atrium

Question 4

Step 2 of conduction system

Answer 4

AV node collects and delays impulse to allow atrial systole to finish in lower part of right atrium

Question 5

Step 3 of conduction system

Answer 5

Bundle of His passes impulse down septum so that ventricular systole can start from the bottom to push blood up

Question 6

Step 4 of conduction system

Answer 6

Bundle branches carry impulse to the base of the ventricle and up the walls

Question 7

Step 5 of the conduction system

Answer 7

Purkinje fibres distribute impulse through walls of ventricles to cause contraction

Question 8

3 stages of the cardiac cycle

Answer 8

Atrial systole
Ventricular systole
Diastole

Question 9

Atrial systole

Answer 9

Atria contract and blood is pushed through the AV valves which then close

Question 10

Ventricular systole

Answer 10

Ventricles contract from the bottom up to push blood through the semilunar valves

Question 11

Diastole

Answer 11

Relaxation and refilling phase, slight passive blood flow into ventricles due to pressure

Question 12

Untrained resting HR

Answer 12

75

Question 13

Untrained exercise HR

Answer 13

220-age

Question 14

Untrained resting SV

Answer 14

70ml

Question 15

Untrained exercise SV

Answer 15

120ml

Question 16

Untrained resting Q

Answer 16

5l

Question 17

Untrained exercise Q

Answer 17

20l

Question 18

Trained resting HR

Answer 18

50

Question 19

Trained exercise HR

Answer 19

220-age

Question 20

Trained resting SV

Answer 20

100ml

Question 21

Trained exercise SV

Answer 21

200ml

Question 22

Trained resting Q

Answer 22

5l

Question 23

Trained exercise Q

Answer 23

40l

Question 24

5 Mechanisms of venous return

Answer 24

Pocket valves
Smooth muscle
Gravity
Muscle pump
Respiratory pump

Question 25

Pocket valves as a mechanism for venous return

Answer 25

Prevent backflow and direct blood towards the heart

Question 26

Smooth muscle as a mechanism for venous return

Answer 26

Involuntary muscle in middle layer of veins that maintains venomotor tone - increases pressure and pushes blood towards heart

Question 27

Gravity as mechanism for venous return

Answer 27

Blood flow from upper body is aided by gravity

Question 28

Muscle pump as a mechanism for venous return

Answer 28

Skeletal muscles squeeze veins when they contract - forcing blood towards heart

Question 29

Respiratory pump as a mechanism for venous return

Answer 29

Inhalation puts pressure on veins below lungs, pushing blood towards heart

Question 30

ANS

Answer 30

Autonomic nervous system (involuntary)

Question 31

Control mechanisms of heart rate

Answer 31

Neural control Intrinsic control Hormonal control

Question 32

CCC

Answer 32

Cardiac control centre, located in medulla oblongata

Question 33

Three receptors for CCC

Answer 33

Chemoreceptors Proprioreceptors Baroreceptors

Question 34

Chemoreceptors purpose

Answer 34

Detect chemical changes (lactic acid & CO2)

Question 35

Proprioreceptors purpose

Answer 35

Detect motor activity

Question 36

Baroreceptors purpose

Answer 36

Detect changes in blood pressure/lung inflation

Question 37

Intrinsic control for heart rate

Answer 37

Temperature changes Starling's Law

Question 38

Temperature changes as heart rate control

Answer 38

Increase in temperature means faster nerve impulses and reduced viscosity of blood

Question 39

Starling's Law

Answer 39

Venous return directly impacts stroke volume as ventricles stretch which increases ventricular contractility and more force of contraction

Question 40

Sympathetic nervous system with heart control

Answer 40

CCC stimulates accelerator nerve through the sympathetic nervous system to increase firing rate of SA node

Question 41

Parasympathetic nervous system with heart rate control

Answer 41

CCC stimulates vagus nerve using parasympathetic nervous system to decrease firing rate of SA node

Question 42

Hormonal control of heart rate

Answer 42

Adrenaline is released which increases firing rate of SA node and force of contraction Anticipatory rise when adrenaline released before activity starts

Question 43

Features of arteries

Answer 43

Layer of smooth muscle allows vasodilation and vasoconstriction Elastic tissue layer cushions and smooths blood flow

Question 44

Features of arterioles

Answer 44

Layer of smooth muscle allows vasodilation and constriction Pre-capillary sphincters to control blood flow to capillary bed

Question 45

Capillary features

Answer 45

Arranged in a mesh structure in capillary bed Wide surface area maximises gas exchange Walls one cell think for faster diffusion

Question 46

Veins features

Answer 46

Small layer of smooth muscle for venomotor tone Pocket valves to prevent backflow of blood

Question 47

Venules features

Answer 47

Small layer of smooth muscle for venomotor tone

Question 48

VCC

Answer 48

Vasomotor control centre, located in medulla oblongata

Question 49

Vascular shunt mechanism

Answer 49

Redistribution of blood during exercise, controlled by VCC

Question 50

Control mechanisms for VCC

Answer 50

Chemoreceptors and baroreceptors

Question 51

Sympathetic stimulation with VSM

Answer 51

Increases to cause vasoconstriction Decreases to cause vasodilation