Phys Test #2

Front 1

How are cadiac muscle fibers similar to skeletal muscle fibers?

Back 1

-Striated appearance (myofibrils composed of actin & myosin)
-do not regenerate via mitosis (absence of satellite cells)
-undergoes hypertrophy in response to increased workload

Front 2

How are Cardiac Cells different from Skeletal Cells?

Back 2

-Intercalated discs
-Cardiac muscle is syncytial
-Cannot be tetanized (due to duration of action potential and length of refractory period)

Front 3

The intercalated discs allow for

Back 3

syncytial contraction

Front 4

What are intercalated discs?

Back 4

Specialized end-to-end junctions bt individual cardiac muscle fibers where cell membranes ahere to each other. Since the lateral portions are in contact it allows for a low-resistance pathway and allows ions to diffuse freely permitting the flow of info bt cells so that action potentials may be conducted fiber to fiber.

Front 5

Types of action potentials in cardiac cells?

Back 5

-fast response action potentials
-slow response action potentials
-slow response action potentials from pacemaker cells

Front 6

Sinus Tachycardia
-how fast bmp?
-where it originates
-can cause
-can elict
-disease-induced

Back 6

-rate >100 bpm
-originates in SA node
-fever
-heart failure
-thryrotoxicosis (extreme hyperthryoidism)

Front 7

Sinus brachycardia
-rate and rhythm
-originates

Back 7

- <60 bpm, regular rhythm
-originates in SA node

Front 8

Sick Sinus Syndrome (SSS)

Back 8

sinus brachycardia with irregular rhythm

Front 9

Atrioventricular (AV) nodal block can be

Back 9

1st degree
2nd degree
-Wenckebach
-Mobitz
3rd degree
Bundle Branch Block

Front 10

AV nodal block, 1st degree(incomplete heart block)

Back 10

prolong PR interval, PR prolongation consistent in ALL cycles

Front 11

AV nodal block, 2 degree (some atrial depolarizations pass through but not all)
-Wenckebach

Back 11

progressive lengthening of the PR interval with each beat until a impulse cannot be conducted, the last P wave stands alone, and the cycle repeats

Front 12

AV nodal block 2nd degree
-Mobitz

Back 12

produces a series of cycles consisting of one normal cycle (P wave associated QRS) preceeded by a series of P waves that fail to conduct through the AV node, EKG shows normal, expected P waves with no corresponding QRS waves
-each repeating series of dropped ventricular beats has a consistent P:QRS ration resulting in some type of regular rhythm

Front 13

AV nodal, 3rd degree(complete AV block)

Back 13

-complete block of all paths below the His bundle
-only automaticity foci in verntricles may escape
-ventricular rate 20-40 with large wide (PVC-like) QRS: ventricular focus

Front 14

Stokes-Adam syndrome

Back 14

complete heart block that comes and goes (paroxysmall) resulting in syncope

Front 15

Mechanism of Stokes-Adam syndrome

Back 15

AV block occurs, ventricles stop beating for 5-30 sec, due to overdrive suppression of the SA nodal pacemaker
-Purkinje pacemaker site beyond the block begins at ab 15-40 bmp (ventricular escape); however, there is a delay of up to 30sec before ventricular escape occurs, during this time no blood flows to the brain and after 5 sec you faint

Front 16

What would you treat Stokes-Adam Syndrome with?

Back 16

A pacemaker

Front 17

Atrial Escape Beat

Back 17

retrograde depolarization may occur producing an inverted P' wave before or after the QRS complex

Front 18

Ventricular Escape Beat

Back 18

Inverted T wave

Front 19

Atrial Escape rhythm

Back 19

if the atrial focus is low in the atrium, P' waves may be inverted in some leads due to retrograde depolarization

Front 20

Junctional Escape Rhythm Happens due to three things:

Back 20

1) Sinus Arrest and Failure of atrial automaticity foci to establish packemaking
2) Complete conduction block of the proximal end of the AV node
3) the junctional focus is not overdrive suppressed nad becomes the dominant packemaker