cardiovascular system

Question 1

atrial diastole

Answer 1

•atria relax and expand drawing blood into the atria.
•pressure in atria opens the AV valves

Question 2

ventricular diastole

Answer 2

•ventricles relax and expand drawing blood into the ventricles.
•semi-lunar valves closed to prevent blood from leaving the heart.

Question 3

atrial systole

Answer 3

•atria contract forcing blood into ventricles.

Question 4

ventricular systole

Answer 4

ventricles contract forcing the AV valves to shut and semi lunar valves to open pumping blood into the pulmonary artery and aorta.

Question 5

the conduction system

Answer 5

1.atria fills with blood, av valves close, atrial pressure rises above ventricular pressure, blood starts to pass into ventricles.
2.SA nose fires electrical impulse across atria, atria contracts, av valves forced open, blood is pumped into ventricles.
3.impulse is received by the AV node, delayed for a moment to allow atrial systole to complete.
4. AV node sends impulse down the right and left bundle of His to the bottom of the heart and the Purkinge fibres.
5. ventricles contract from the bottom upwards, so valves forced open, blood is pumped out of ventricles into PA and A.

Question 6

artery

Answer 6

•carry’s blood away from the heart.
•elastic walls to cope with high pressures.
•have rings of muscle to allow for vasoconstriction and dilation.

Question 7

capillary

Answer 7

•tiny, thin walled blood vessels.
•1 cell thick - for gaseous exchange.
•join ateries and veins.

Question 8

veins

Answer 8

• carry blood back to the heart.
•veins have thinner walls because pressure is lower.
•veins have valves to stop back flow.

Question 9

plasma

Answer 9

component of blood that holds the blood cells and whole blood in suspension. 55% of total blood volume

Question 10

platlets

Answer 10

reacts to extreme am bleeding by clotting.

Question 11

red blood cells

Answer 11

made in bone marrow, contain haemoglobin which carries oxygen and carbon dioxide.

Question 12

white blood cells

Answer 12

made in bone marrow, cells of the immune system to fight against the disease.

Question 13

heart rate and amounts

Answer 13

•the number of times the heart beats per minute.
•average = 70bpm
•endurance= 50bpm

Question 14

stroke volume and amounts

Answer 14

amount of blood ejected from the left ventricle per beat.
at rest = 70ml
endurance athletes = 100ml

Question 15

cardiac output and amounts

Answer 15

amount of blood ejected from the left ventricles per minute.
at rest & endurance athletes = 5l/min

Question 16

vasodilation

Answer 16

the widening of the lumen of a blood vessel to increase the volume of blood delivered to active areas

Question 17

vasoconstriction

Answer 17

the narrowing or the internal diameter (lumen) of the blood vessel to restrict the volume of blood.

Question 18

vascular shunting

Answer 18

•increased intensity of exercise is detected by receptors
•the receptors relay the message to the vasomotor control centre. the vcc send a message via the sympathies nervous system to decrease stimulation to the arteriole and pre-capillary sphincters at the muscles.
•Vasodilation happens and blood rushes through. the opposite (increased stimulation & vasoconstriction) at the organs.

Question 19

why is vascular shunting important

Answer 19

•increases the amount of oxygen delivered to the working muscles, allowing them to work aerobically quicker and for longer.
•allows waste products to be removed from the body more efficiently, reducing lactic acid.

Question 20

neutral factors affecting HR

Answer 20

•chemo, baro and proprioceptors send information is to the VCC which in turn increases stimulation of the SA node via the sympathetic nervous system.

Question 21

hormonal factors affecting HR

Answer 21

•adrenaline released prior to exercise stimulates the SNS which increases stimulation of SA node, which in turn increases HR.
•adrenaline also increases force of cardiac contractions, increasing SV and Q.

Question 22

increase temperatures affect on HR

Answer 22

causes increased speed of nerve transmission, which increases stimulation of SA node, increasing HR

Question 23

increased venous returns affect on HR

Answer 23

increase volume of blood returning, stretches the wall of the heart which increases stimulation of SA node, increasing HR.

Question 24

venous return

Answer 24

the return of blood to the heart during the cardiac cycle.

Question 25

2 problems that delay venous return

Answer 25

•blood pressure in the veins is very low. •most of the blood distributed lower than the heart and therefore has to fidget against gravity to make its way back to the heart.

Question 26

pocket valves

Answer 26

valves in veins stop the back flow of blood. this means once the blood reaches a certain point it cannot return, if not could result in blood pooling.

Question 27

skeletal muscle pump

Answer 27

when the muscles in the lower leg contract, they squeeze the surrounding veins and force the blood back to the heart.

Question 28

smooth muscle

Answer 28

veins are lined with smooth muscle that can venoconstrict and force the blood back towards the heart.

Question 29

respiratory pump

Answer 29

the pressure of thoracic cavity is increased and forces blood back to the heart. this happens more the higher our breathing rate is.

Question 30

gravity

Answer 30

blood from above the heart returns via gravity.

Question 31

Extrinsic factors regulating HR during exercise

Answer 31

- neutral factors - hormonal factors

Question 32

Intrinsic facts affecting HR during exercise

Answer 32

- increase temperature - increased venous return

Question 33

Stroke volume at sub-maximal

Answer 33

- at the start of exercise sv increases because venous return increases - during sub-maximal exercise sv then plateaus as HR plateaus

Question 34

Stroke volume at maximal

Answer 34

- at maximal intensities HR continues to increase which doesn’t leave enough time for ventricles to fill - less blood in ventricles, therefore less ejected per beat -results in a decrease in sv. This is known as vascular drift

Question 35

Cardiac output at submaximal

Answer 35

- cardiac output increases because hr and sv are both increasing - Q= HRxSV

Question 36

Cardiac output at maximum intensity

Answer 36

- cardiac output plateaus - HR continues to rise, but SV falls due to cardiovascular drift

Question 37

Cardiac output equation

Answer 37

Stroke volume x heart rate = cardiac output SV x HR = Q

Question 38

the cardiac cycle

Answer 38

- the sequence of events that occurs when the heart beats - there are two stages diastole (relaxes) and systole (contracts) - circulates blood around pulmonary and systematic circuits of the body

Question 39

functions of blood

Answer 39

- transport nutrients such as o2 and glucose - protect and fight disease - maintain homeostasis

Question 40

HR at submaximal

Answer 40

- steady increases then plateaus at around 120bpm - steady recovery

Question 41

HR at maximal

Answer 41

- increases to maximal HR (220-age) - recovery is a sharp decrease (EPOC) then steadily decreases

Question 42

starlings law of the heart

Answer 42

- SV depends on venous return - the volume of blood returning to the heart - during exercise VR increases, so blood is returning to the heart - this causes the walls of the heart chambers to stretch: stretch 1 = atria (more blood enters so they stretch this stimulates the SA nose causing it to increase firing rate) stretch 2 = ventricles (more blood enters so walls stretch causing a more forceful contraction of ventricular walls)