cardiovascular and respiratory system

Question 1

define pulmonary circuit

Answer 1

circuit that carries deoxygenated blood to lungs and oxygenated blood back to the heart

Question 2

define systemic circuit

Answer 2

circuit that carries oxygenated blood to the body and deoxygenated back to heart

Question 3

conduction system:

1 = sino-atrial node

Answer 3

SA node generates electrical impulse causes atria walls to contract, pacemaker

Question 4

2 = atrio-ventricular node

Answer 4

AV node collects impulse and delays for 0.1 seconds so atria can finish contracting

Question 5

3 = bundle of his

Answer 5

in the septum, splits impulse in 2 to distribute to each ventricle

Question 6

4 = bundle branches

Answer 6

carry impulse to base of each ventricle

Question 7

5 = purkyne fibres

Answer 7

distribute impulse through ventricle walls, causing contraction

Question 8

cardiac cycle:

1 = diastole

Answer 8

• atria and ventricles relax and atria fills with blood
• pressure increases and AV valves open
• blood enters ventricles
• SL valves closed to prevent blood leaving

Question 9

2 = atrial systole

Answer 9

-atria contracts, forcing remaining blood into ventricles

Question 10

3 = ventricle systole

Answer 10

-ventricles contract which increases pressure and so AV valves close to prevent backflow into atria

Question 11

define heart rate, give trained and untrained values and an explanation for the change

Answer 11

• number of times heart beats per minute
• untrained = 72bpm
• trained = 50bpm
• lowers because of cardiac hypertrophy - muscle more effiecient, stronger, greater volume of blood ejected per beat

Question 12

define stroke volume, give trained and untrained values and an explanation for the change

Answer 12

• volume of blood ejected from the left ventricle per beat
• untrained = 70ml
• trained = 100ml
• increased venous = which increases volume of blood available in ventricles for contracting
• incrreased ventricular elasticity = ^stretch & greater force of contraction

Question 13

define cardiac output, give trained and untrained values and equation

Answer 13

• volume of blood ejected from left ventricle per beat
• untrained = 5L
• trained = 5L
• Q = HR x SV

Question 14

HR response to exercise - 3 control methods

Answer 14

neural control (chemo, proprio, baro)
intrinsic control (temperature, venous return)
hormonal control (adrenaline/noradrenaline - sympathetic release of adrenaline

Question 15

HR response and effect of exercise

Answer 15

info sent to CCC in medulla oblongata
sympathetic nervous system ^ stimulation of SA node via accelerator nerve = ^ HR & greater force of ventricular contraction

Question 16

what is starlings law

Answer 16

• relationship between SV and end diastolic volume

- states that SV ^ in response to an ^ volume of blood in the ventricles

Question 17

what is blood pooling

Answer 17

accumulation of blood in veins due to lack of venous return

Question 18

what are the 5 venous return mechanisms and summarise each

Answer 18

1. pocket valves = prevent backflow
2. layer of smooth muscle = venoconstricts to aid movement
3. gravity = helps return blood from above heart
4. muscle pump = muscles contract, squeezing veins
5. respiratory pump = causes pressure differences, squeezing blood back to heart