week 5

Question 1

ionotropy

Answer 1

contractility

Question 2

preload

Answer 2

ventricular filling

Question 3

PQRST

Answer 3

P wave- atria depolarization

QRS- ventricle depolarization

T- ventricle repolarize

Question 4

ACXVY

Answer 4

A- atria contract
C- tricuspid buldge
X- atria relax
V- passive filling of atria
Y- empty Atria into ventricles and open AV valves

Question 5

highest pressure

Answer 5

aorta 120/80= BP

Question 6

EDV
ESV
SV stroke volume

Answer 6

End diastolic volume (EDV) – the volume in the ventricle at the end of diastole
* End systolic volume (ESV) – the volume in the ventricle at the end of systole

the volume ejected with each heartbeat ▪ SV = EDV – ESV

Question 7

cardiac output
ejection fraction

Answer 7

Cardiac output is the volume ejected by each systole X heart rate
▪ CO = SV X HR

• Ejection fraction is the proportion of EDV that is ejected
  each beat
  ▪ EF = SV/EDV = (EDV – ESV)/EDV

Question 8

stroke volume effected by

Answer 8

preload
contractility/ ionotropy
afterloada

Question 9

afterload

Answer 9

The pressure that the heart must overcome to eject blood into the great arteries.
* Factorsthatincreaseafterload–aorticstenosis,elevatedblood pressure

Question 10

increase afterload ____ stroke volume and ejection fraction

Answer 10

decreases

Question 11

if ionotropy decreases then stroke volume

Answer 11

decreases

Question 12

PRELOAD OF ONE VENTRICLE DEPENDS ON THE CARDIAC OUTPUT OF THE OTHER.

Answer 12

!

Question 13

SERCA (Sarcoplasmic/Endoplasmic Reticulum Calcium ATPase)

Answer 13

reuptake calcium after contraction

Question 14

syncytium

Answer 14

cardiac myocytes are interconnected via branches and intercalated disks (gap junctions and desmosomes)

Question 15

4 types of action potential in the heart

Answer 15

atrial
ventricular
purkinje
automatic(via pacemaker SA and AV nodes)

Question 16

phase of action potential

Answer 16

▪ Phase 4 – resting membrane potential (RMP)
K+ leaky open

▪ Phase 0 – the rapid depolarization phase (upstroke)
Na+ influx

▪ Phase 1 & 2 – prolonged depolarization/plateau phase
K+ efflux then L type Ca2+ have influx

▪ Phase 3 - repolarization
close ca and open vgc K+

Question 17

calcium spark

Answer 17

one ca2+ VGC opens and then lets ca2+ out from neighbouring ryandoine receptor

Question 18

SERCA regulated by

Answer 18

phospholamban

Question 19

automatic cells

Answer 19

depolarize spontaneously

phase for “resting” is not stable because of funny current- left over Na+ and K+

Question 20

automatic cell APs

Answer 20

phase 0- depolarize from l type Ca2+

no phase 1 or 2

phase 3 depolarize; K+ efflux

phase 4- leaky resting membrane; funny current

Question 21

chronotrphy

Answer 21

heart rate

Question 22

pacmaker

Answer 22

SA- 60-100bpm

Question 23

bundle of his (AV bundle)

Answer 23

carry AP along septum of the heart

then purkinje bring to apex and base of heart for ventricles

Question 24

Bachman’s bundle

Answer 24

so left and right atrium contract at same time

Question 25

• P Wave: Atrial depolarization initiated by the SA node.
• PR Interval: Delay at the AV node allowing for ventricular filling.
• QRS Complex: Rapid depolarization of the ventricles via the conduction pathway (Bundle of His and Purkinje fibers).
• ST Segment: Ventricles in a depolarized state before repolarization.
• T Wave: Ventricular repolarization returning the heart to its resting state.
• QT Interval: Total time for ventricular depolarization and repolarization.