cardiac function & dysfunction

Question 1

what does systole means

Answer 1

contract

Question 2

what does diastole mean?

Answer 2

relax

Question 3

when does the relaxation period occur?

Answer 3

after the T wave

Question 4

how does the relaxation period work?

Answer 4

ventricular pressure drops below atrial & AV valves open
ventricular filling occurs

Question 5

what happens after the P wave

Answer 5

atrial systole/contraction and ventricular diastole

Question 6

what happens QRS

Answer 6

ventricular systole and atria diastole

Question 7

how many heart sounds can be heard from one heart beat?

Answer 7

2 sounds from 4

Question 8

which out of the 4 sounds can you heat

Answer 8

sound 1/2

Question 9

what happens during sound 1

Answer 9

‘lub’
louder longer closure of AVvalves soon after ventricular systole

Question 10

what happens during sound 2

Answer 10

‘dub’
quieter shorter closure of semilunar valves at beginning of ventricular diastole

Question 11

what happens during sound 3

Answer 11

rapid ventricular filling

Question 12

what happens during sound 4

Answer 12

atrial contraction

Question 13

what is a heart murmur

Answer 13

abnormal sounds
rushing/ gurgling

Question 14

how do you measure cardiac output

Answer 14

CO= stroke volume (SV) x heart rate
(ml/min) (ml/beat) (beats/min)

Question 15

what happens during exercise

Answer 15

CO rises to supply working tissue with more O2 & nutrients

Question 16

what happens if stroke volume may fail

Answer 16

ventricular myocardium damaged or blood volume reduced by bleeding

Question 17

what happens during homeostatic mechanisms

Answer 17

act to maintain adequate CO by increasing heart rate & contractility

Question 18

autonomic regulation of heart rate

Answer 18

originates in the cardiovascular centre in the medulla oblongata

Question 19

input to CV centre

Answer 19

From higher brain centres (e.g., hypothalamus)
From sensory receptors
Proprioceptors
Chemoreceptors
Baroreceptors

Question 20

output to heart

Answer 20

Increased depolarisation in SA node: increases heart rate
Increased contractility of A & V: increases stroke volume
Decreased depolarisation in SA node: decreases heart rate

Question 21

what are 2 chemical regulations of heart rate

Answer 21

hormones and ions

Question 22

how do hormones regulate heart rate

Answer 22

released with exercise, stress & excitement
epinephrine & norepinephrine
increase both heart rate & contractility
thyroid hormones (do same as above)

Question 23

how does ions regulate heart rate

Answer 23

increase in K+ or Na+ decreases heart contraction & rate
high conc of Na+ blocks Ca2+ influx during cardiac AP, so contraction decreased
high conc K+ blocks generation of AP
increase Ca2+ speeds heart rate & strengthens heart

Question 24

what are 4 other factors that can regulate heart rate

Answer 24

age
gender
physical fitness
body temperture

Question 25

what is arrhythmia

Answer 25

Irregular heart rhythm due to defect in the conduction system of the heart
Causes:
drugs (caffeine, nicotine, alcohol etc.,)
anxiety
Hyperthyroidism
K+ deficiency
certain heart diseases.

Question 26

examples of arrhythmia

Answer 26

heart blockers
atrial flutter
atrial fibrillation
ventricular fibrillation