Cardiac Histology Flashcards
Layers of heart wall
Epicardium, myocardium, Endocardium
Epicardium; Very thick, mesothelial cells
Myocardium: The thickest, principal cardiac muscle layer
Endocardium: several layers, a very deep subendocardial layers that house purkinjee fibers
Heart valves made of what?
CT with overlying endocardium
Define systemic circulation
From Heart to arteries, to capillaries, to venules, veins, and back to heart.
Out and Back
What is a portal system
A vein or arteriole which provides transportation between two capillary beds.
Name the two portal systems
Hepatic, hypothalmic-hypophyseal
Walls of arteries and veins consist of three layers called
Tunics
What are the three layers of arteries and veins
Tunica Intima, Tunica Media, Tunica Adventitia
The tunica adventitia consists of what
Its own set of vessels known as vasa vasorum
What are nervi vasworum?
A network of autonomic nerves that control vessel diameter. They are responsible for the contraction and relaxation of smooth muscles in the tunica media
Contraction leads to an increase in vascular resistance which leads to an increase in
Blood pressure
Endothelial cells are the innermost layer of what?
Tunica intima
Smooth muscle cells in vessels are located where?
Tunica Media
Three categories of arteries
Large, medium, small duh
Large arteries are also called
Elastic arteries….ex: aorta
During diastole, the elastic recoil of large arteries assists in the management of blood pressure.
true
Medium artery also known as muscular artery
true
What are arterioles
Small arteries
How many layers of smooth muscle in arteriolar tunic media
1-5
How many layers of smooth muscle in medium artery?
more than 5
Three types of capillaries
continuous, fenestrated, and discontinuous
Capillaries consist of:
One layer endothelium and one basal lamina
Where are continuous capillaries found?
muscle, lung, CNS
Fenestrated capillaries are where?
Glands
Discontinuous capillaries also called?
Sinusoids
Found where?
Liver, Spleen, Bone marrow
Discontinuous capillaries are irregular in shape, have gaps between endothelial cells.
True
three categories of veins
venules, small medium veins, large veins
Histamine and serotonin work predominantly where?
Postcapillary venules
Muscular venules are located where
Distal to postcapillary venules
What is the major difference between a medium sized artery and a medium sized vein?
Medium sized artery has a much wider tunica media. Makes sense, more muscle
Large vein and artery comparison
Wall thickness of vein is considerably less than artery but the luminal space of the vein may be larger
Think or arterioles and venules being at different ends of capillary beds
true
AV Shunt
Arteriole/venule shunt
Lymphatic vessels
Fluid from tissue to blood
Lymphatic vessels end up as two large trunks which are
Right Lymphatic duct and thoracic duct
Purkinjee fibers are located where?
Endocardium
Whats one way to tell a large artery from a medium artery if you dont know what muscle or elastic fiber looks like?
The size of the tunica media compared to the tunica adventitia. In the Medium artery, they are both relatively the same size. In the Large artery though, the media is a good deal thicker than the adventitia.
