Yee haw Nursin’ cardiology cardiac action potential video note youtube 📝

YouTube is mai study materialllll slay 🫀👀👄

Positive ion

________ is balanced by the influx of another, and membrane potential remains relatively.

cardiac myocytes

In ________, there is also a plateau phase, which occurs when the efflux of one.

Electrical activities

________ of the heart, as a whole, can be recorded in the form of surface electrocardiogram, ECG or EKG.

ST segment

The ________ reflects the plateau phase of action potentials in ventricular myocytes.

P

________ wave represents the sum of depolarization in all atrial myocytes,

ECG

A(n) ________ is a composite recording of all the action potentials produced by the cells of the heart.

QRS complex

The ________ reflects ventricular depolarisation

repolarization phase

The ________ is due to a net efflux of positive ions.

AV node

The ________ passes the signals onto the AV bundle, then bundle branches, Purkinje fibers, and finally the ventricular myocytes.

the impulses start in the SA node

the primary pacemaker of the heart, then spread though the

The QRS complex reflects ventricular depolarization

Q wave corresponds to depolarization of the interventricular septum, R wave is produced by depolarization of the main mass of the ventricles, S wave represents the last phase of ventricular depolarization at the base of the heart

Action potential

_____ is the Brief reversal of electric polarity of cell membrane made by flow of ions in and out of the cell

Depolarisation

_______ is Net influx of positively charged ions. Membrane voltage increased and becomes less negative. Cells become less polarised.

Q

_______ wave corresponds to depolarization of the interventricular septum

S

wave represents the last phase of ventricular depolarization at the base of the heart.

produced by depolarization of the main mass of the ventricles,

R wave

Plateau phase

Efflux of one positive ion is balanced by another influx. Membrane potential is unchanged. Place where muscle contraction occours

ECG cardiac muscle cycle

* P wave represents the sum of depolarization in all atrial myocytes,
* The QRS complex reflects ventricular depolarization: Q wave corresponds to depolarization of the interventricular septum, R wave is produced by depolarization of the main mass of the ventricles, S wave represents the last phase of ventricular depolarization at the base of the heart. Atrial repolarization also occurs during this time but the signal is obscured by the large QRS complex.
* The ST segment reflects the plateau phase of action potentials in ventricular myocytes. This is when the ventricles contract and pump blood.
* T wave corresponds to ventricular repolarization that occurs immediately before ventricular relaxation. The peak of T wave reflects repolarization of epicardial cells, while the end of T wave corresponds

with repolarization of mid-myocardial cells.

Action potential heart muscle sequence

the impulses start in the SA node - the primary pacemaker of the heart, then spread though the

contractile myocytes of the atria to reach the

AV node. The AV node passes the signals onto the AV bundle, then bundle branches, Purkinje fibers, and finally the ventricular myocytes.

Myocytes from different layers of the heart wall:

the epicardium, mid-myocardium, and endocardium

exhibit different rates of repolarization, due to different ratios of ion channels. Electrical activities of the heart, as a whole, can be recorded in the form of surface electrocardiogram, ECG or EKG. An ECG is a composite recording of all the action potentials produced by the cells of the heart.

Pacemaker potential

Slows depolarisation to both opening of Na+ channels and closing of K channels. Never a flatline

Depolarisation

Pacemaker potential reaches threshold. Depolarisation is due to Cal influx through Cal channel

Depolarisation

Ca channel closing K channel opening, allow K to go in. Brings membrane potential back to its negative voltage