INTERNATIONAL HEALTH AGENCIES BY ANUSHRI SRIVASTAV.pptx
Sample PPT for presentation-25.pptx
1. Name of the School - SMAS
Department of cardiovascular technology
Course Code: BCVT3007. Course name-Electrocardiography
Topic - conduction system and action
potential
Presented by -fatima zehra (21smas1040048)
Nikita chandel
Ravi kumar singh
Shradha
Presented to -Dr. Saurav gurjar
2. Name of the School
Course Code: BCCT5004 Course Name:Cardiac care technician I
Student Name: Program Name:
Topic: conduction system of heart
The heart conduction system is the network of nodes, cells and signals that controls your
heartbeat. Each time your heart beats, electrical signals travel through your heart. These
signals cause different parts of your heart to expand and contract. The expansion and
contraction control blood flow through your heart and body.
3. • It consists of
• Sinoatrial node
• Atrioventricular node
• Atrioventricular bundle (bundle of His)
• Purkinje fibres
Elements of cardiac system
4. • SA NODE(sino atrial node)
• The sinoatrial (SA) node is a collection of specialised cells
(pacemaker cells
• It Is located in the upper wall of the right atrium at the junction
where the superior vena cava enters.
• SA node is a pacemaker of heart because it conduct the
nerve impulses
• AV NODE(atrio ventricular)
• Located within the atrioventricular septum,
• It also consist of cardiac muscle
5. • BUNDLE oF HIS
• It has specialised cardiac muscle
• It descends down the membranous part of the interventricular septum,
before dividing into two main bundles:
• Right bundle branch – conducts the impulse to the Purkinje fibres of the
right ventricle
• Left bundle branch – conducts the impulse to the Purkinje fibres of the left
ventricle.
6. Purkinjie Fibers
• The Purkinje fibres (sub-endocardial plexus of conduction cells)
are a network of specialised cells.
• These cells are located in the subendocardial surface of the
ventricular walls
• These fibers are specialized myocardial fibers that conduct an electrical
stimulus
References
8. Name of the School: SMAS
Course Code: BCVT3007 Course Name: Electrocardiography
Student Name: Ravi Kumar singh Program
NameB.Sc CVT
Topic-normal cell of heart and
properties of myocardium
9. • In the resting state, the myocyte membrane bears a negative
charge on the inner side.
When stimulated by an electrical impulse, the charge is altered by an
influx of calcium ions across the cell membrane.
This results in coupling of actin and myosin filaments and muscle
contraction. The spread of electrical impulse through the myocardium
is known as depolarization
Depolarization
10. Repolarization
Once the muscle contraction is completed, there is
efflux of potassium ions, in order to restore the
resting state of the cell membrane.
This results in uncoupling of actin and myosin
filaments and muscle relaxation.
The return of the myocardium to its resting
electrical state is known as repolarization
11. Rectification
The sodium-potassium pump
system moves sodium and potassium
ions against large concentration
gradients. It moves two potassium ions
into the cell where potassium levels are
high, and pumps three sodium ions out of
the cell and into the extracellular fluid.
12. Excitability: is the ability of a cardiac cell to generate an action
potential at its membrane in response to depolarization and to
transmit an impulse a long the membrane.
Rhythmicity: is the ability of a tissue to produce its own impulses
regularly. It is also called autorhythmicity or self-excitation.
Property of rhythmicity is present in all the tissues of heart.
Properties of myocardium
13. Properties of myocardium
• CONDUCTIVITY:
Human heart has a specialized conductive system,
through which impulses from SA node are transmitted
to all other parts of the heart
Contractility :
describes the relative ability of the heart to eject a stroke volume (SV)
at a given prevailing afterload (arterial pressure) and preload (end-
diastolic volume; EDV).
15. School of medical and allied sciences
Course Code: BCVT Course Name: Cardiovascular technology
Student Name:Nikita Chandel Program
DEPOLARISATION OF
MYOCARDIAL CELL
16. • The normal sequence and synchronous contraction of the atria and
ventricles require the rapid activation of groups of cardiac cells.
• An activation mechanism must enable
rapid changes in heart rate and also
respond to the changes in autonomic
tone.The propagating cardiac action
potential fulfils these roles.
DEPOLARISATION OF MYOCARDIAL CELL
17.
18. PHASES OF MYOCARDIAL CELL
• It illustrates the 5 phases of the normal action potential:
• Phase 4, or the resting potential, is stable at ≈−90 mV in normal working
myocardial cells.
• Phase 0 is the phase of Initial depolarization. The membrane potential
shifts into positive voltage range. This phase is central to rapid propagation
of the cardiac impulse.
• Phase 1 is a phase of Initial repolarization. This phase sets the potential for
the next phase of the action potential.
• Phase 2, a plateau phase, is the longest phase. It is unique among excitable
cells and marks the phase of calcium entry into the cell.
• Phase 3 is the phase of rapid repolarization that restores the membrane
potential to its resting value.1
19. Name of the School - SMAS
Department of cardiovascular technology
Course Code: BCVT3007. Course name-Electrocardiography
Student Name: fatima zehra Program Name: B.Sc CVT
20. • Electrical potential in SA node is different from that of other cardiac
muscle fibre. In SA node each impulse triggers the next impulse. It is
mainly due to the unstable resting membrane potential.
• Resting membrane potential in SA node cells exists only for a very
short duration and it has a negativity of -55 to -60mV. It is different
from the negativity of -85 to -95mV in other myocardial cells.
21. Action potential in pace maker has three phases :
PHASE 4 - Pacemaker potential
PHASE 0 - Rapid depolarization
PHASE 3. Rapid repolarization
22.
23. • This phase is called pacemaker potential or spontaneous
depolarization or pacemaker current. During this phase the
spontaneous depolarization starts very slowly and reaches the
threshold level of -40mV very slowly.
• * For this the Na ion leaks into the pacemaker fibers and causes
slow depolarization. Then, the Ca channel starts opening.
• At the beginning, there is a slow influx of calcium ions causing
further depolarization.
• * This , the initial part of pacemaker potential is due to slow influx of
sodium ions and later part is due to the slow influx of calcium ions
Phase 4
24. Pacemaker potential triggers the rapid depolarization.
Depolarization reaches the voltage of +5mV
*When the negativity is decreased to -40 mV, which is the
threshold level, the action potential starts with rapid
depolarization. The depolarization occurs because
influx of more calcium ions. Unlike in other tissues ,the
depolarization in SA node is mainly due
calcium ions, rather than sodium ions.
Phase 0
25. • Rapid depolarization is followed by rapid repolarization Repoiarization
reaches a voltage of - 55 to -60 mV resulting in hyperpolarization and
ends in resting membrane potential .Once again, the cycle is
repeated with spontaneous depolarization.
• It is due to the influx of potassium ion from pacemaker fibres
Potassium channels remain open for a longer time, causing efflux of
more potassium ions
Phase 3
26. • Pacemaker current always referred to as funny carrent because of its
unusual properties .
• It is initiated by opening of channels through which there is inward
movement of sodium ions. It triggers action potential
Funny current
