Heart Histology Flashcards
What are the characteristics of cardiac muscle cells in cross sections?
- Oval nucleus
- 1 centrally located nucleus
- Cross striations
What are the 3 layers of the heart?
Endocardium
myocardium
Epicardium
What is also known as the epicardium?
Viceral pericardium
What is the endocardium?
Inner lining of the heart and valves
- continuous with tunica intima of blood vessels
What are the 3 components of the endocardium?
Inner- Simple squamous endothelium and sunendothelial CT
Middle- CT and Smooth muscle
Outer- Subendocardial CT
Which layer and component is the conduction system located?
Endocardium Outer component (Subendocardial CT)
On histological view the endocardium and myocardium look like/
Smooth
Large oval nuclei that are centrally located
What is the endomysium?
CT that ensheaths each fiber
What is characteristic of the myocardium?
Arranged in complex spirals that contains vessels and of blood and lymphatics
What are the function of Endocrine secretions of the heart and where do they arise?
ANF- Atrial natriuretic factor
BNF- Brain Natriuretic factor
- both control urinary excretion of NA to regulate BP
Can you see intercalated discs on longitudinal sections?
no
What make up the intercalated discs?
- Desmosomes (fascia maculae)
- Gap junctions
- Fascia adherens
What is characteristic of the epicardium compared to other layers of the heart?
Adipose tissue
- able to distinguish between this and endocardium
- may also see nerve fibers arts, veins and loose CT
What makes up the outer mesothelial layer?
Simple squamous epithelium
Outer most layer of the epicardium
What is cardiac tampenade and what is its cause?
Excess fluid in the pericardial cavity
- pericarditis or myocardial rupture
- compresses heart and prevents blood from filling
Where is the location of the SA node?
Located at the junction of the superior vena cava of right atrium
- has own arterial and ANS supply
Where is the location of the AV node?
near opening of Coronary sinus
- Also have its own arterial and ANS supply
What supplies the papillary muscles of the heart?
Purkinje fibers
What cause the increased size and lack of staining of purkinje fibers?
Glycogen stores
What are some purposes of the cardiac skeleton?
- Support
2. Insulator the prevents the flow of the electrical impulses between the atria and ventricles
