Cardiovascular Histology Flashcards
What are the three layers of the heart wall in all chambers?
epicardium
myocardium
endocardium
What is the epicardium?
It is the visceral layer of the pericardium
What is the myocardium?
the principle cardiac muscle layer of the heart
What is the endocardium? What does it contain?
most internal layer of the heart wall containing Purjinke fibers and nuclei
What are the layers/contents of the epicardium?
a layer of mesothelial cells
autonomic nerve tissue
loose CT
adipose tissue
the sarcoplasm of cardiac muscle in the middle myocardium usually contains what?
lipofuscin pigment
What are the contents of the endocardium?
1) endothelium and its supporting CT
2) a middle myoelastic layer of smooth muscle fibers and CT
3) deep layer of CT called the subendocardial layer
4) Purjinke fibers,
In what part of the heart does the endothelium contain a thick layer of Purjinke fibers?
ventricles
Which are larger, Purjinke fibers or cardiac muscle fibers?
Purjinke fibers (their nuclei are also larger)
The nucleus of Purjinke fibers are rich in what substance?
glycogen
A vein or arteriole situated in between two capillary beds is called what?
a portal system (e.g. the hepatic portal system)
walls of arteries and veins consist of ___ layers called ____
3; tunics
What are the names of the tunics of vein and arteries from innermost to outermost?
1) tunica intima
2) tunica media
3) tunica adventitia
What does the tunica intima consist of?
innermost layer
consists of:
1) endothelium and a basement basement of the endothelium and
2) a sub endothelial layer with CT and internal elastic lamina
What does the tunica media consist of?
middle layer
consists of:
1) circularly arranged layers of smooth muscle cells
2) elastic and collagen fibers
3) sometimes an external elastic membrane
What does the tunica adventitia consist of?
outermost CT layer
has external elastic lamina adjacent to tunica media, and has vasa vasorum and nervi vasorum (aka nervi vascularis)
What is a vasa vasorum?
a system of vessels found in large arteries and veins that provide blood supply to tunica adventitia and media
Tunica intima and part of tunica media are supplied by the vessel
What is the role of nervi vascularis?
they are a network of autonomic nerves that control vessel diameter
How do nervi vascularis control vessel diameter?
they cause contraction and relaxation of the smooth muscle in the T. media layer of the vessel
How can the tunica intima cause vasodilation?
the endothelium cells of the layer release endothelial derived relaxing factor
What are the roles of endothelial cells in vessels (5 things)?
- Play an important role in blood homeostasis
- Maintain selective permeability barrier
- Maintain nonthrombogenic barrier between blood platelets and sub endothelial tissue
- Modulate blood flow and vascular resistance
- Modification of lipoproteins by oxidation
What are the roles of smooth muscle cells in vessels (2 things)?
1) contraction/relaxation modulated BP
2) synthesize elastic fibers, reticular fibers, and proteoglycans
What are the three types of vessels?
1) large (elastic)
2) median (muscular)
3) small arteries (arterioles)
What is the only elastic artery?
the aorta