Cardiovascular System

Question 1

What is health?

Answer 1

a state of complete physical, mental and social wellbeing

Question 2

What is fitness?

Answer 2

the ability to cope with the demands of the environment

Question 3

How is heart disease caused?

Answer 3

build up of fatty deposits- atherosclerosis
arteries cannot deliver oxygen - smaller lumen
causes pain - angina
exercise can stop this

Question 4

How are strokes caused?

Answer 4

occurs when blood supply to brain is cut off
ischaemic - blood clot stops blood supply
haemorrhagic- weakened blood vessel in brain bursts
exercise can reduce risk

Question 5

What is cholesteral?

Answer 5

LDL- bad cholesterol linked with heart disease (transport chol to tissues and causes build up)
HDL- good cholesterol linked with reducing risk (transport chol to liver to be broken down)
exercise increases HDL and lowers LDL

Question 6

What do baroreceptors do?

Answer 6

detect changes in blood pressure- increased blood pressure- sends message to cardiac control centre then to parasympathetic NS to lower heart rate

Question 7

What do proprioceptors do?

Answer 7

detect an increase in muscle movement and send message to cardiac control centre then to the sympathetic NS to increase heart rate

Question 8

What do chemoreceptors do?

Answer 8

detect chemical changes- when C02 and lactic acid levels go up send message to cardiac control centre then to sympathetic NS to increase HR

Question 9

What does myogenic mean?

Answer 9

the heart generates its own impulses

Question 10

How does an impulse travel through the heart for it to contract?

Answer 10

SA node generates the heartbeat
Atrial Systole
AV node- delayed
Bundle of HIS
Purkinje Fibres
Ventricular Systole - contraction

Question 11

How are factors affecting heart rate detected?

Answer 11

the receptors send a message to the medulla (cardiac control centre) in the brain which sends a message to the parasympathetic or sympathetic NS to in/decrease heart rate

Question 12

What is the hormonal control mechanism?

Answer 12

the release of adrenalin which stimulates the SAN which increases cardiac output
this is known as anticipatory rise

Question 13

What are the neural control mechanisms?

Answer 13

the sympathetic (adrenalin) and parasympathetic (vagus nerve) nervous system in increasing and decreasing the heart rate
chemoreceptors
baroreceptors
proprioceptors

Question 14

What is stroke volume?

Answer 14

volume of blood pumped out of the heart in each contraction

Question 15

Trained vs untrained person

Answer 15

trained person will have a higher stroke volume

untrained person will be a lot lower

Question 16

What can affect the stroke volume of a person?

Answer 16

venous return- more blood returning = higher sv

elasticity of cardiac fibres- more elastic means a larger contraction can occur

Question 17

How can exercise affect the heart?

Answer 17

bradycardia- lower resting heart rate (greater HR range)
hypertrophy- thickening of muscle wall so more blood can be pumped out
a trained athlete will have a greater HR range

Question 18

What is the equation for cardiac output?

Answer 18

cardiac output = stroke volume x heart rate

Question 19

How can a trained and untrained person have the same cardiac output?

Answer 19

different sized hearts/hypertrophy –trained bigger
different stroke volumes – trained bigger;
different heart rates – untrained higher;
=product of sv x hr will be the same
at maximal exercise if they are the same age- trained will be higher

Question 20

What does Starling’s Law say?

Answer 20

during exercise: increased venous return
greater diastolic filling
cardiac muscles stretch
bigger force of contraction
bigger ejection fraction

Question 21

What is ejection fraction?

Answer 21

% of blood pumped out by left ventricle per beat

Question 22

What is cardiovascular drift?

Answer 22

the progressive decrease in stroke volume and blood pressure while heart rate is rising

Question 23

How does cardiovascular drift occur?

Answer 23

occurs during steady state exercise lasting 60 mins in warm environments
fluid is lost as sweat so blood volume decreases
venous return decreases
decreases stroke volume (starlings law)

Question 24

What is venous return?

Answer 24

the return of blood to the vena cava - 70% of blood is left in the veins at rest so this can be returned to the heart when needed
the suction pressure of the heart draws up blood

Question 25

What are the venous return mechansims?

Answer 25

skeletal muscle pump- skeletal muscles compress veins and push blood back to the heart
respiratory muscle pump- respiratory muscles push blood back to the heart
pocket valves- allow blood to flow towards heart and prevent backflow
gravity

Question 26

Why is venous return important?

Answer 26

prevent blood pooling after exercise

ensures muscles are receiving enough oxygen

Question 27

Why is the redistribution of blood important?

Answer 27

increase o2 supply to working muscles
removes waste products from muscles
directs more blood to heart

Question 28

How are blood pressure and flow controlled?

Answer 28

by the vasomotor centre in the medulla

chemoreceptors stimulate vasomotor centre to redistribute blood vasodilation and vasocontstriction

Question 29

What are pre capillary sphincters?

Answer 29

tiny rings of muscle located at the openings of capillaries that aid blood redistribution
dilate during vasodilation
constrict during vasoconstriction

Question 30

What is the oxyhaemoglobin dissociation curve?

Answer 30

the s shaped curve showing how haemoglobin transports and releases oxygen

Question 31

What is the Bohr Shift?

Answer 31

the shift of the curve to the right which happens during exercise at a lower blood pH
the muscles require more oxygen so it is given up more readily by haemoglobin

Question 32

What factors affect are responsible for the dissociation ?

Answer 32

increase in temperature
increased pCO2
lower blood pH- more acidic

Question 33

What is A-VO2 difference?

Answer 33

difference between the oxygen content of the blood (arterial) arriving at the muscles and the blood (venous) leaving the muscles

Question 34

How does A-VO2 dif change during exercise?

Answer 34

A-VO2 difference is increased as the muscles require more oxygen
this affects gaseous exchange as the alveoli take up more oxygen and remove more carbon dioxide

Question 35

What are the different blood vessels?

Answer 35

arteries- carry oxygenated blood away from the heart at high pressure with thick walls
veins- carry deoxygenated blood to the heart at low pressure with thinner muscle layers
capillaries- narrow blood vessels wide enough to allow one rbc through

Question 36

What is myoglbin?

Answer 36

muscle haemoglobin- iron containing pigment found in slow twitch muscle fibres that has a higher affinity for oxygen

Question 37

How is blood redistributed?

Answer 37

the vascular shunt mechanism is the redistribution of cardiac output during exercise
trained individuals have a higher maximum cardiac output so they will be able to transport more blood (and O2) to working muscles
blood to muscles increases
blood to kidneys and brain stays same
blood to intestines decreases