19.3

Front 1

cardiocytes

Back 1

muscle cells of the heart
-short branched muscle cells will central nucleus.
cells are joined together by intercalated discs

Front 2

intercalated disks

Back 2

junctions that hold cardiocytes together
-has interdigitating folds- folds where the cardiocytes connect to increase surface area of cell contact
-fascia adherens- actin anchors to each cells PM, and then transmembran proteins connects the PMs. desmonosomes fill gaps between these
- disks also have gap junctions where ions can flow freely, allowing for elctrical impulses to pass from one cell to the next

allow for a single stimulation to cause contraction of all cells.

Front 3

initial heart beat

Back 3

starts in the sinoatrial node

Front 4

sinoatrial (SA) node

Back 4

patch of modified cardiocytes in the right atrium near the superior vena cava which initiate each heartbeat (pacemaker cells). Impulses from the SA node travel through all the atrial cardiocytes.

Front 5

atrioventricular (AV) node

Back 5

found near the tricuspid valve on the interatrial septum. Only point where electrical impulses from the SA node can reach the ventricles. The fibrous skeleton prevents any other impulse transmission.

Front 6

atrioventriucluar (AV) bundle

Back 6

pathway where signals leave the AV node.

Front 7

Purkinje fibers

Back 7

branch from the bundle branches at the apex to carry the electrical exitation upwards through both ventricles.

Front 8

**conduction pathway

Back 8

1. SA node
2. Atrial myocardium
3. AV node
4. AV bundle
5. L+R bundle branches
6. Purkinje fibers
7. ventricular myocardium

Front 9

systole

Back 9

contraction of heart
contraction of atrium of ventricles

Front 10

diastole

Back 10

relaxation of heart
artial or ventricular relaxation

Front 11

arrhythmia

Back 11

any abnormal cardiac rhythem