Physiology and Anatomy (Cardiovascular System)

Question 1

Starling’s Law

Answer 1

1) Increased venous return leads to greater diastolic filling
2) Improves elasticity of cardiac muscle and strengthens contraction of the heart
3) Increases ejection fraction of the heart which increases stroke volume

Question 2

Cardiovascular Drift

Answer 2

Body warms and sweats during exercise which leads to water from plasma lost as sweat. Therefore it makes blood more viscous, lowering venous return which decreases stroke volume so your body increases heart rate to compensate.

Question 3

Chemoreceptors

Answer 3

Sensors in your blood vessels that detect concentration of CO2/lactic acid.

Question 4

Proprioceptors

Answer 4

In your tendons which detect movement.

Question 5

Baroreceptors

Answer 5

Receptors in the wall of the aorta and arteries that detect changes of blood pressure

Question 6

Sympathetic Nervous System

Answer 6

Increases heart rate and causes the redistribution of blood to the muscles.

Question 7

Parasympathetic Nervous System

Answer 7

Decreases heart rate and causes redistribution of blood to internal systems.

Question 8

How heart rate is increased

Answer 8

1) Receptors detect change
2) Impulse sent to the Medulla Oblongata (Cardiac Control Centre) via the peripheral nervous system and central nervous system
3) CCC decides action and relays to the SAN to control heart beat

Question 9

Role of Adrenaline

Answer 9

Before a competition there is a anticipatory rise due to adrenaline which prepares the body for exercise and strengthens ventricular systole

Question 10

Cardiac Conduction System

Answer 10

1) The SAN causes ATRIAL SYSTOLE
2) The impulse travels to AVN which repeats it with a delay
3) The impulse goes down the BUNDLE OF HIS and PURKINJE FIBRES down to the ventricles
4) This all leads to VENTRICULAR SYSTOLE

Question 11

Active mechanisms in venous return

Answer 11

1) Skeletal Muscle Pump: Change of shape during muscle contraction causes muscle to press onto veins, pushing blood back to the heart
2) Respiratory Pump: Change of pressure in chest cavity during inhalation and exhalation compresses on vein
3) Pocket Valves: Ensures blood flows in one direction and back to the heart

Question 12

Factors effecting blood flow

Answer 12

• Blood flow (cardiac output)
• Lumen size (vessel diameter)
• Viscosity
• Vessel length

Question 13

Effects of training on the heart

Answer 13

• Cardiac Hypertrophy
• Increased Contractility / Ejection Fraction
• Increased stroke volume
• Bradycardia
• Greater diastolic filling

Question 14

Effects of exercise on the vascular system

Answer 14

• Capable of creating more blood cells
• Increased capillarisation of muscles
• Increased ability to vasodilate and vasoconstrict
• Blood becomes less viscous
• Blood becomes more efficient at removing waste product (buffering)

Question 15

Myoglobin

Answer 15

Store of oxygen in your mitochondria

Question 16

Practical Pressure

Answer 16

High partial pressure means that it easier for oxygen to bind with haemoglobin (high affinity) while low partial pressure means it easier for oxygen to be released (low affinity)

Question 17

The Bohr Shift

Answer 17

Oxyhaemoglobin disassociation curve shifts to right as increased affinity of carbon dioxide during exercise lowers affinity of oxygen

Question 18

Vascular Shunt Mechanism

Answer 18

Blood is redirected to areas that need blood the most

Question 19

How is blood flow controlled?

Answer 19

1) Chemoreceptors detect change in CO2 levels in your blood
2) Impulse then sent to your vasomotor centre in your medulla oblongata
3) Chosen sympathetic response increases blood flow by vasodilating or constricting

Question 20

Pre-capillary Sphincters

Answer 20

Rings of muscle located at the opening of the capillary.
Contract = Vasoconstriction
Relax = Vasodilation

Question 21

Arterio-venous Oxygen Difference

Answer 21

Difference between the oxygen concentration of arterial blood arriving at the muscles and venous blood leaving.

• Low difference at rest and high difference at exercise