Cardiac Flashcards
Where is the endocardium located?
Closest to the chambers of the heart
Where is the epicardium located?
Closest to body (outside)
Which cells secrete fluid from the epicardium?
Mesothelial cells
What components are found in the endocardium?
Loose CT with smooth muscle
Purkinje fibers
What components are found in the epicardium?
Coronary vessels
Nerves
Fat
Mesothelial cells
What are the 4 key features of epithelium?
- Ectodermal origin
- Lines surfaces to protect, secrete, and absorb
- contains keratin
- can be multi layered
What are the 4 key features of endothelium?
- mesodermal origin
- single layer
- contain vimentins
- important roles in filtration and high diffusion areas
What are the 2 key features of mesothelium?
- Mesodermal origin
- single cell protective covering organs
The heart has ____ regions and _____ layers
2(atrium and ventricle),3(end,myo,epi)
What is notable about the myocardium of the ventricle in comparison to that of the atrium?
It is much thicker in the ventricle
Which 2 conduction system components are modified cardiac muscle that can both conduct and contract?
Sinoatrial and atrioventricular nodes.
*Bundle of his, purkinje fibers and both bundle branches are modified cardiac muscle that only conduct
How can you identify purkinje fibers on a slide?
- Larger than normal contractile fibers
- lack intercalated discs
- stain lighter due to high glycogen
What makes the heart an endocrine organ?
Release of atrial natriuretic peptide (ANP) by atrial myocytes
When is ANP released and what does it do?
In response to high blood pressure.
It acts to lower blood pressure
What happens to cells in hypertrophy?
They get bigger
What happens to cells in hyperplasia?
They increase in number
What are the 3 layers of a general blood vessel?
Tunica intima
Tunica media
Tunica adventitia
What is the notable difference in the 3 layers of a muscular artery vs. an associated vein?
The tunica media is much thicker in arteries (muscular)
What separates the tunica media from the tunica intima?
Dense elastic membrane called internal elastic lamina
What separates the adventitia from the media?
Dense elastic membrane called the external elastic lamina
What do the elastic properties of the aorta and other large arteries allow them to do?
Smooth out pressure pulses cause by ventricle contraction
What is characteristic of the tunica media in elastic arteries such as the aorta?
Elastic fibers
What is characteristic of tunic media of muscular arteries?
Highly layered to allow smooth muscle contraction and regulate blood pressure
What are arterioles?
1 or 2 layers of smooth muscle regulating blood flow to capillaries
Where are precapillary sphincters found?
Metarterioles
What does NO do to vessels?
Cause vasodilation
What do endothelins do to vessels?
Cause vasoconstriction
What are the 3 types of capillaries?
Continuous (tight junctions)
Fenestrated (little windows)
Sinusoids (larger openings)
What cells help form the blood brain barrier by wrapping around capillaries?
Pericytes/periendothelial cells
What do many lower extremity veins contain to prevent back flow?
Semilunar valves
What are the three layers of the heart?
Epicardium
Myocardium
Endocardium
