Morphofunctional Features Of Cardiac Conduction System. Compare Morphology _20251016_110744_0000.pdf

Cardio

1. Palak Yadav
1 B

2. Introduction to the Cardiac
Conduction System

Thecardiac conduction systemis
responsible for initiating and
coordinating the heart's rhythmic
contractions.
It comprises specialized
cardiomyocytes that generate
electrical impulses and propagate
them throughout the heart.
Understanding its morphofunctional
features is essential for diagnosing
and managing arrhythmias and
conduction disorders.

3. Overview of Cardiac Conduction Pathways
The main components include the sinoatrial
(SA) node, atrioventricular (AV) node,
bundle of His, bundle branches, and
Purkinje fibers. These structures are
composed of modified cardiomyocytes with
specialized conduction properties. The
conduction pathway ensures synchronized
atrial and ventricular contractions for
effective cardiac output.

4. Morphology of Pacemaker Cells in the SA Node
SA node cells are smaller than typical
cardiomyocytes and have fewer myofibrils.
They possess a centrally located nucleus
and a high density of specific ion channels
facilitating automaticity.
These cells display a less organized
contractile apparatus compared to working
cardiomyocytes.

5. Functional Features of SA Node Cells
The primary function of SA node cells is
spontaneous depolarization due to unstable
resting potentials.
They generate rhythmic action potentials
that set the pace of the heartbeat.
Their unique ion channel composition allows
rapid depolarization and automaticity.

6. Morphology of Atrial and Ventricular Cardiomyocytes
Typical cardiomyocytes are elongated,
striated, and contain a large number of
myofibrils. They have centrally located
nuclei and intercalated discs for
synchronized contraction. Atrial and
ventricular cells differ slightly in size and
shape but share many structural features.

7. Functional Features of Working Cardiomyocytes
These cells are responsible for force
generation and mechanical contraction of
the heart.
They exhibit a stable resting membrane
potential and rapid depolarization during
contraction.
Their contractile function is supported by
organized sarcomeres and extensive T-
tubules.

8. Morphology of the AV Node Cells
AV node cells are smaller and less
organized than working cardiomyocytes.
They have fewer myofibrils and a higher
nuclear-to-cytoplasm ratio.
These cells are specialized for slow
conduction and delay of impulses.

9. Functional Features of AV Node Cells
The AV node ensures a delay in impulse
conduction, allowing ventricular filling.
They exhibit slow conduction velocity due to
fewer gap junctions and different ion
channel expression.
These cells help coordinate atrial and
ventricular contractions effectively.

10. Morphology of the Bundle of His and Bundle Branches
Cells in the bundle of His and branches are
specialized for rapid conduction.
They are larger, with fewer myofibrils, and
have a high density of conduction fibers.
Their structure facilitates quick transmission
of impulses from the AV node to the
ventricles.

11. Morphology of Purkinje Fibers
Purkinje fibers are large, pale-staining cells
with abundant glycogen and fewer
myofibrils. They have extensive intercalated
discs that support synchronized impulse
propagation. Their unique morphology
allows rapid conduction to coordinate
ventricular contraction.

12. Comparison of Cardiomyocyte Types
Pacemaker cells are small, with less
developed contractile apparatus, specialized
for automaticity.
Working cardiomyocytes are elongated,
striated, and designed for contraction and
force generation.
Conduction system cells (e.g., Purkinje
fibers) are large, pale, and specialized for
rapid impulse transmission.

13. Functional Implications of Morphological Differences
Morphological variations enable different cell
types to perform their specific conduction or
contractile roles efficiently.
Small pacemaker cells facilitate automatic
rhythm generation, while large Purkinje
fibers ensure quick impulse spread.
The structural specialization supports the
precise timing and coordination of cardiac
contractions.

14. Pathological Considerations
Structural abnormalities in conduction
system cells can lead to arrhythmias or
conduction blockages.
Hypertrophy or fibrosis may alter the
morphology and conduction properties of
these cells.
Understanding normal morphology aids in
diagnosing conduction system diseases via
histological and imaging techniques.

15. Summary of Morphofunctional Features
The cardiac conduction system showcases
diverse morphological adaptations tailored
for electrical conduction.
Each cell type's unique structure underpins
its specific functional role within the heart's
conduction network.
The integrated morphofunctional design
ensures efficient, synchronized cardiac
activity essential for life.