Exam 3 - lecture 20 Cardiovascular Histology Flashcards
1
Q
WHat are the three tunics of the heart wall?
A
Endocardium
Myocardium
Epicardium
2
Q
What are elastic arteries ?
A
- Conducting arteries
- stretch during systole and recoil during diastole
- tunica media consists of laters of elastic fibers organized into laminae
- 40 layers in newborn to 70 layers in orlder adult
- connective tissue is interspersed between the elastic laminae
- includes
- aorta
- pulmonary trunk
- large branches of aorta
3
Q
What is the role of prostacyclin in preventon of blood clot formation and the role of nitric oxide and endothelin in modulating smooth muscle activity ?
A
- Prostracyclin is a vasodilator
- NItric oxide dilates blood vessel and endothelin constricts blood vessel where there is blood vessel damage
4
Q
A
5
Q
What is the endocardium?
A
Innermost layer, liining the atria and ventricles
- componets include
- endothelium and subendothelial conenctive tissue
- continous with tunica intima of the blood vessels
- subendocardium is laycated between endocariuma nd myocardium
- contains nerves and purkinje fibers (subendocardial fibers) [they are muscle not nerves)
6
Q
WHat are purkinje fibers?
A
Large specialized cardiac Muscle cells
Carry imusles to ordinary cardiomyocytes
7
Q
What is the myocardium?
A
consists of cardiac muscle cells
8
Q
What is the epicardium?
A
- External surface covered by simple squamous epithelium (mesothelium)
- Overlies fibroelastic connective tissue containing adipose cells, nerves, and coronary vessels
9
Q
What are the vascular tunics?
A
- Tunica intima
- Endothelium and basal lamina
- found in all arteries and arterioles
- enfothelial cells produce von wille factor ViII
- Subendothelial connective tissue
- found in all elastic and muscular arteries and some arterioles
- internal elastic membrane
- incomplete in elastic arteries ut thick and complete in muscular arteries
- Endothelium and basal lamina
- Tunica media
- made up of collagen and elastic fibers
- TUnica adventitia
- outermost layer
- lacking in arterioles
- Consists of loose areolar tissue
- consists irregular fibroelastic tissue with adipocytes
- has small vessels (vasa vasorum) and nerves (nervi vasorum)
- outermost layer
10
Q
What are muscular arteries?
A
- Distrubuting arteries
- tunica media consists of smooth muscle that resonds to autonomic stimulation and hormones
- thickness of smooth muscle layer decreases as diameter becomes smaller
- gradual transistion from elastic artery to muscular artery
- Include:
- all named arteries of body exept elastic arteries
11
Q
What are arterioles?
A
- Small arteries
- Tunica media consists of one to three laters of smoooth muscle cells
- mean arterial pressure depends on proper tone of smooth muscles in arterioles (peripheal resistance arterioles)
- thickness of smooth muscle layer decreases as diameter becomes smaller
- Give rise to meta-arterioles which have a discontinuous layer of smooth muscle tissue
12
Q
What are pericytes
A
- UNdifferentiated mesenchymal cells
- may be contractile
- may serve as stem cells into fibroblasts
13
Q
WHat are continous, fenestrated, and discontinous capillaries and where are they found?
A
- Continous
- found in muscle, brain, thymus, lung,
- has a continous basal lamina and cytoplasm
- Fenestrated
- has many fenestrae with or w/o a thin diaphragm, basal lamina is continous
- Intestinal villi, choroid plexus, cillilary processes of the eyes, glomerular capillaries of kidney
- Discontinous (sinusoid)
- Basal lamina is discontinous, blood cells can pass through the vessel
- spleen and liver
14
Q
What are veins
A
- Comparison with arteries
- Larger lumen
- thinner wall
- valves are present in many veins
- Larger veins have a layer of longitudinal smooth muscle in the inner aspect of tunica adventitia
15
Q
What are lymphatics?
A
- single layer of endothelial cells
- basal amina may be absent
- anchoring filaments
- valves in larger lymphatics
16
Q
vascular tunics
A
17
Q
vascular tunics
A
18
Q
vascular tunics
A
19
Q
A
