Cardiovascular System From A& P Exam # 2

Front 1

Properties of Cardiac muscle
Microanatomy:

Back 1

cells are short, fat, branched, and interconnected at junctions called intercalated discs (contain both desmesomes and gap junctions)
~gap junctions allow ions to pass freely between cell( allows entire myocardium to behave as a unit)
~ cells contain sarcomeres, sarcoplasmic reticulum, many mitochondria, and a large amount of myoglobulin( allowing for a hogh aerobic capacity)

Front 2

Mechanisms of contraction/ characteristics:

Back 2

~contraction of the heart is an "ALL-OR-NONE"
~ stimulation of the heart is "Autorythmic"

Front 3

The heart contains 2 specialized types of cardiac muscle cells:

Back 3

~ contractile cells- 99% of cardiac muscle
~ Non-contractile Autorythmic or Pacemaker cells- 1% myocardail cells

Front 4

~ Autorythmic/ Pacemaker cells:Describe their Funtion:

Back 4

~ SLOW leakage of positive ion channels
~ Gradual increase in membrane potential
~ When threshold reached- AP
~ AP travels thruout conduction system
~ AP triggers contraction of myocardium

Front 5

Different parts of the heart's conduction system have their own?

Back 5

have their own " Autorythmicity" rate

Front 6

The heart has 4 valves, name them:

Back 6

~AV or Atioventricular v.
~ Tricuspid v.
~ Aortic Semilunar v.
~ Pulmonary v.
~ Bicuspid v.

Front 7

SA node ( Pacemaker) has an "autorythmicity" rate of ?

Back 7

= 70 beats/minute

Front 8

AV node (autorythmicity rate of):

Back 8

= 50 beats/minute

Front 9

AV Bundle/Bundle branches:

Back 9

= 35beats/minute

Front 10

Purkinje Fibers:

Back 10

= 30 beats/minute

Front 11

how many beats per minute is normal ?

Back 11

~ 70-80 beats/minute is the normal

Front 12

ECG: what is it ?

Back 12

~ an electrocariogram is a recording of the electrical changes that accompany the cardiac cycle. (Also called EKG)