Week 1

Question 1

How are cardiac muscle cells electrically coupled

Answer 1

Via gap junctions

Question 2

What muscle type is found in the middle layer of the aorta

Answer 2

Smooth muscle

Question 3

What does calcium do in a action potential

Answer 3

Removes the tropomyosin block

Question 4

The nerves and ganglia that transmit action potentials to smooth muscle and cardiac muscle are part of:

Answer 4

Efferent division
The parasympathetic nervous system
Peripheral nervous system
Autonomic nervous system

Question 5

Sequence of a reflex arc

Answer 5

Sensory receptor
Afferent (sensory neurone)
Interneurone
Efferent (motor) neurone
Effector organ

Question 6

Postganglionic sympathetic neurones release the transmitter:

Answer 6

Noradrenaline

Question 7

Function of CVS

Answer 7

Transport and exchange

Question 8

Arrangement of the CVS

Answer 8

Right atrium- pulmonary artery- lungs- pulmonary vein- left atrium- aorta- systemic circulation- right atrium

Question 9

Pulmonary artery and pulmonary vein

Answer 9

Artery away from heart but pulmonary artery is deoxygenated
Vein towards the heart but pulmonary vein is oxygenated

Question 10

The left and right sides of the heart are in series with eachother

Answer 10

Output of RV into pulmonary circulation= output of LV into systemic circulation

Question 11

Vascular beds

Answer 11

Parallel arrangement
All beds get blood with same level of oxygenation
Prevents changes in blood flow in one organ affecting flow in other organs

Question 12

Blood flow in the heart

Answer 12

In order for blood to flow through the systemic blood vessels at a rate that ensures metabolic demand can be met, considerable pressure has to be applied to the blood
Blood flow unidirectional due to one way valves
Systole= phase of contraction and ejection
Diastole= phase of relaxation and filling

Question 13

Cardiac output

Answer 13

Pumping activity of heart is expressed as the cardiac output CO
CO= volume of blood pumped/min = 5L/min
Determined by:
-stroke volume SV 70ml, volume ejected per contraction
-heart rate HR 70b/min
CO=SV * HR
Left CO= right CO

Question 14

Pulse pressure in the aorta

Answer 14

Pulse pressure= systolic pressure- diastolic pressure
Diastole= 60% of total cardiac cycle
Elastic recoil maintains pressure during diastole

Question 15

Mean ABP

Answer 15

Mean ABP= (SP-DP)/3 +DP
Eg 120-80/3 + 80= 93mmg

Question 16

Pressure throughout systemic vasculature

Answer 16

Greatest resistance is in arterioles
Because pressure falls as move through the system- there must be resistance to flow
Blood enters right side of the heart at minimal pressure

Question 17

What determines pressure in the arterial system

Answer 17

Resistance to blood flow
Blood volume in the arterial system

Pressure= flow * resistance
ABP= cardiac output * total peripheral resistance TPR

Question 18

Total peripheral resistance TPR

Answer 18

Or systemic vascular resistance SVR
Is the resistance to flow offered by all systemic vasculature excluding pulmonary circulation

Question 19

How do arterioles control blood flow to individuals organs

Answer 19

Vasoconstriction or vasodilation changes resistance therefore controls flow
Vasodilation increase flow
Vasoconstriction decreases flow
Resistance controlled by nerves, local factors, hormones

Question 20

Blood vessels

Answer 20

Veins: very low pressure, thin walls, under control ANS, accommodate large volumes, reservoirs
Arteries: high pressure, muscular walls, elastic, conduits
Small arteries, arterioles: modest pressure, muscular walls, under influence of local factors and ANS, control flow to tissues
Capillaries: low pressure, single endothelial cell wall, exchange
Venules: low pressure, conduits

Question 21

Venous return and cardiac output

Answer 21

Any imbalance between VR and CO (eg standing decrease VR), leads to a coordinated response so that ABP is maintained

Question 22

ABP is maintained by negative feedback control

Answer 22

ABP= CO * TPR
(SV * HR) * TPR

Low ABP -> ANS- cardiac stimulation, vascular constriction, kidneys- increase blood volume
Increase ABP