SFP: Heart Histology Flashcards
What is the difference between the visceral and parietal pericardium?
The visceral is in contact with the heart itself, and the parietal lines the inside of the sac.
What are the layers of the heart from superficial to deep?
Epicardium, myocardium, endocardium.
Describe the structure of the endocardium.
- It has an endothelium
- Subendothelial connective tissue layer containing smooth muscle and elastic fibers
- Subendocardial layer that contains connective tissue and merges with the myocardium.
Describe the structure of the epicardium.
- Mesothelium containing simple squamous epithelium and a basal lamina
- Supportive layer of loose connective tissue with blood vessels, fat, and nerves.
What is the function of fat in the epicardium?
It provides cushion.
What is the function of serous fluid?
It gives lubrication to allow the heart to move without friction.
What is the arrangement of cells in cardiac muscle?
Branching.
What are intercalated discs?
Regions of contact within interdigitating processes of cardiac muscle.
What will intercalated discs in transverse regions of the heart have?
Desmosomes and fascia adherens.
What will intercalated discs in longitudinal regions of heart muscle have?
Gap junctions to provide ionic continuity for a wave of contraction.
Describe the nucleus of cardiac muscle.
One nucleus that is centrally located.
Describe the contractile apparatus of cardiac muscle.
Composed of dyads containing a T tubule and 1 expanded terminal cistern of SR.
What is the arrangement of cells in the atria?
Overlapping networks (pectinate) impart a woven appearance
This structure allows for effective contraction of the atrial walls.
What is the arrangement of cells in the ventricles?
Complex cell layers that helically wrap around the ventricular cavity
This arrangement supports strong and coordinated contractions.
Are cardiac myocytes smaller in the atria or ventricles?
Atria
Atrial myocytes are generally smaller than ventricular myocytes.
What do atrial cardiac myocytes contain?
Granules containing Atrial Natriuretic Factor
This factor plays a role in regulating blood pressure and fluid balance.
Which has a more extensive T tubule system: atria or ventricles?
Ventricles
The extensive T tubule system in ventricles is important for rapid conduction of impulses.
Do atria or ventricles have more gap junctions?
Atria
More gap junctions facilitate rapid electrical conduction in the atria.
Which has more elastic fibers: atria or ventricles?
Atria
Atria contain pectinate muscles that increase elasticity.
Which conducts impulses faster: atria or ventricles?
Atria
Atria are designed to conduct impulses quickly to trigger contraction.