New CVS

Question 1

What are examples of cardiac glycosides ?

Answer 1

digitalis

ouxbain

Question 2

What are cardiac glycosides ?

Answer 2

they try to increase the output force of the heart
by reducing HR
supression of the Na/K ATPase

Question 3

What are cardiac glycosides used for ?

Answer 3

treatment in congestive heart failure

increase the amount of time spent in diastole

Question 4

What is the direct mode of the Na/Ca exchanger ?

Answer 4

direct mode allows Na in and removes Ca

Question 5

What is the indirect mode of Na/Ca exchanger ?

Answer 5

calcium enters and Na is removed

Question 6

What happens in hyponatraemia ?

Answer 6

reduced Na extracellular concentration 
hyposmotic conditions 
cardiomyocytes swell 
extrusion of intracellular solutes- Na/Cl and K 
reversed mode of the Na/Ca exchanger
positive iono/chrono and dromo

Question 7

What happens in hyponatraemia to circualtion ?

Answer 7

hyposmotic conditions 
cardiomyocytes swell 
reduced blood volume
polycythaemia and increased blood density 
hypotension 
leads to incrrased HR and contractility

Question 8

What happens in hypernatraemia ?

Answer 8

increased extracellular Na
Cardiomyocytes shrink
direct mode of exchanger
negative iono.chromo and dromo

Question 9

What happens in hyperkalaemia ?

Answer 9

increased extracellular K
Reduced driving force for K
Depolarisation
Negative iono/chromo/dromo

Question 10

What happens in hypokalaemia ?

Answer 10

reduced extracellular K
increased driving force for K
Hyperpolarisation
positice iono/chrono and dromo effects

Question 11

What happens in hypercalcaemia ?

Answer 11

Increased extracellular Ca
depolarisation
postive iono/dromo and chromo

Question 12

What happens in hypocalcaemia ?

Answer 12

reduced extracellular Ca
hyperpolarisation
negative iono/chromo and dromo effects

Question 13

What does the CVS system consist of ?

Answer 13

blood
vessels
heart

Question 14

What are the channels responsible for action potentials in smooth muscle cells

Answer 14

L-type Ca channels

Question 15

What do gap junctions in cardiomyocytes allow for ?

Answer 15

communication between cells without contact in the ECF

Question 16

Describe the mechanism of smooth muscle contraction ?

Answer 16

Na enters through voltage gated sodium channels
calcium enters through L-type calcium channels
calcium induced calcium release from SERCA via RyR receptors
calcium-calmodualin complex stimulates MLCK

Question 17

What are the haematocrit values for men ?

Answer 17

42-52%

Question 18

What are the haematocrit value for women ?

Answer 18

37-47%

Question 19

What is the rate of pulses in the SAN ?

Answer 19

70-100 bpm

Question 20

What is the role of the SAN ?

Answer 20

impulse spreads from the SAN across the atria

Question 21

What is bachmanns bundle ?

Answer 21

specialised pathway band that conducts impulse directly from right to let atrium

Question 22

What is the rate of the AVN ?

Answer 22

40-60

Question 23

What is the role of the AVN ?

Answer 23

delays impusle from the SAN by 100-120 ms to let blood fully eject from the atria to the ventricles

Question 24

What is the instrinsic rate of the Bundle of his ?

Answer 24

20-40

Question 25

What is the role of the bundle of His ?

Answer 25

transmits impulses from the AVN to the ventricles

branches into right and left

Question 26

What is the intrinsic rate of purkinje fibres ?

Answer 26

15-30

Question 27

What is the role of the purkinje fibres ?

Answer 27

distribute impulse to the myocardial cells in the ventricles
excitataion begins at the apex