The physiology of cardiac function L8

Question 1

what is special about cardiac muscle

Answer 1

intercalated discs

Question 2

functional muscle cells

Answer 2

myocyte

Question 3

what is a sarcomere between

Answer 3

2 Z lines

Question 4

what is a sarcomere made up of

Answer 4

overlapping contractile proteins myosin and actin

Question 5

what is the thin filament made up off

Answer 5

actin

Question 6

what is the thick filament made up off

Answer 6

myosin

Question 7

H zone=

Answer 7

just myosin

Question 8

I band=

Answer 8

just actin

Question 9

A band=

Answer 9

actin and myosin

Question 10

Myosin molecule structure=

Answer 10

long molecule, 2 heads containing ATPase, alpha helix chain with a hinge region

Question 11

what is needed for cross bridge formation

Answer 11

hydrolysis of ATP

Question 12

Troponin C=

Answer 12

binding site for Ca2+ ions

Question 13

Troponin I=

Answer 13

inhibits actin and myosin coupling

Question 14

Troponin T

Answer 14

attaches to tropomyosin

Question 15

3 parts of troponin complex

Answer 15

TnT
TnC
TnI

Question 16

what transmitter is released at SA and AV nodes during sympathetic stimulation

Answer 16

noradrenaline

Question 17

what does noradrenaline bind to at SA and AV nodes

Answer 17

B1 receptors

Question 18

what types of protein do B1 receptors trigger

Answer 18

G protein

Question 19

what is the overall result of sympathetic stimulation on the SA and AV nodes

Answer 19

Ca2+ channels open and increase speed and force of contraction

Question 20

relaxation is also called

Answer 20

lusitropy

Question 21

what does an increase in returning to resting level more quickly

Answer 21

allows contractile machinery to relax faster more time for ventricle filling

Question 22

what modulates Ca2+ binding to Tnc

Answer 22

PKA phosphoylation (increased dissociation)

Question 23

where does parasympathetic control come from

Answer 23

cardioinhibitory center cardioacceleratory

Question 24

what transmitter is used in parasympathetic control

Answer 24

acetyl choline

Question 25

What does acetyl choline bind to

Answer 25

muscarinic M2 cholinergic receptors

Question 26

what effect does acetyl choline have

Answer 26

hyperpolarising the cell decreasing muscle contraction

Question 27

inotropy=

Answer 27

contraction of myocardium

Question 28

lusitropy=

Answer 28

relaxation of myocardium

Question 29

chromotropy=

Answer 29

firing of sinoatrial nerve

Question 30

dromotropy=

Answer 30

conduction velocity of atrioventricular node

Question 31

cardiac output calculation

Answer 31

heart rate x stroke volume

Question 32

cardiac output=

Answer 32

volume of blood pumped from one ventricle each minute

Question 33

ejection fraction=

Answer 33

fraction of end diastolic volume (EDV) ejected out by each ventricle/ beat

Question 34

EDV=

Answer 34

end diastolic volume

Question 35

ESV=

Answer 35

end systolic volume

Question 36

stroke volume can be calculated by

Answer 36

EDV- ESV

Question 37

ejection fraction calculation

Answer 37

stroke volume/ EDV

Question 38

normal ejection fraction=

Answer 38

55%-75%

Question 39

2 types of action potential in the heart

Answer 39

fast response

slow response

Question 40

where is the fast response

Answer 40

cell to cell depolarisation in cardiac myocytes

Question 41

where is the slow response

Answer 41

SA and AV nodes

Question 42

what is the trigger for SA and AV nodes depolarisation

Answer 42

Calcium