Cardiavascular Histology Flashcards
Cardiac tunics
Endocardium
Myocardium
Epicardium
Endocardium
- Innermost layer, lining the atria and the ventricles
- components: endothelium, subendothelial CT
- Continuous with the tunica of the blood vessels entering and leaving the heart
- Subendocardium is layer located between the endocardium and the myocardium
- contains nerves and purkinje fibers (subendocardial fibers)
A layer located between the endocardium and the myocardium
Subendocardium
The subendocardium contains
nerves and purkinje fibers (subendocardial fibers)
Purkinje fibers
- Large, specialized cardiac muscle cells
- Carry impulses to ordinary cardiomyocytes
Myocardium
Consists of cardiac muscle cells
Epicardium
- External surface is covered by simple squamous epithelium (mesothelium)
- Mesothelium overlies fibroelastic CT containing adipose cells, nerves, and coronary vessels
The epicardium’s external surface is covered by
simple squamous epithelium (mesothelium)
What is mesothelium
-The simple squamous epithelium covering the external surface of the epicardium
The cardiac Skeleton
- Dense collagenous CT
- Myocardial fibers originate and insert into the cardiac skeleton
Wall of all blood vessels except the capillaries are characterized by
three layers (tunics)
Components of the tunica intima
- Endothelium and its basal lamina
- found in all arteries and arterioles
- endothelial cells produce von Willebrand’s factor VIII
- Subendothelial CT
- found in all elastic and muscular arteries and some arterioles
- Internal elastic membrane
- incomplete in elastic arteries but thick and complete in muscular arteries
The tunica media is mad up of
- circular smooth muscle tissue and fibroblasts
- contains collagen and elastic fibers
Tunica media contains
collagen and elastic fibers
The tunica Adventitia
- outermost layer
- lacking in arterioles
- consists of loose areolar tissue
- contains irregular fibroelastic tissue with adipocytes
- has small vessels (vasa vasorum) and nerves (nervi vasorum)
The tunica adventitia is not present in
Arterioles
The tunica adventitia consists of
loose areolar tissue
Tunica adventitia contains
irregular fibroelastic tissue with adipocytes
What is the vasa vasorum and neri vasorum
-small vessels and nerves that are present in the tunica adventitia
What are the conducting arteries
the more elastic arteries
What are the distributing arteries
The more muscular arteries
Pressure ____ as arteries leave the heart and become progressively smaller
drops