Blood Vessel Histo - Downing Flashcards
Describe continuous, fenestrated, and sinusoidal capillaries:
Continuous - no pores or fenestrations Fenestrated - pores covered by thin diaphragms found in clusters Sinusoidal - much wider in diameter, contain many large defects in walls
Where are continuous, fenestrated, and sinusoidal capillaries found?
Continuous - muscle, nervous and connective tissue Fenestrated - pancreas, intestines, and endocrine glands Sinusoidal - bone marrow, liver, spleen, lymphoid
What payers of the blood vessel wall are continuous with the: Endocardium: Myocardium: Epicardium:
Endocardium: Tunica intima Myocardium: Tunica media Epicardium: Tunica Adventitia
What is the function of metarterioles?
Smooth muscles can act as sphincters by controling blood entering into capillary bed by encircling the braches the enter into the capillary. Metarterioles use this system to shunt blood around when needed
Quickly summarize the specialized sensory structures in arteries:
Carotid baroreceptors: in walls of internal carotids, innervated by glossopharyngeal nerve, used to adjust BP
Carotid Body Chemoreceptors: Located at common carotid bifurcation, monitor chemical changes, supplies by glossopharyngeal and vagus nerves
Aortic bodies: chemoreceptors located on arotic arch, work like carotid bodies
What joinds together capillary endothelial cells?
Fascia occludentes
Function of pericytes?
Sometimes form gap junctions, probably can contract o regulate capillary blood flow.
They can actually turn into smooth muscle or endothelial cells… weird
What is the function behind arteriovenous anastamoses?
Plays a role in thermoregulation.
–Three segments:
•Arterial segment (structure similar to that of an artery)
•Intermediate segment: richly innervated with adrenergic and cholinergic nerve fibers
•Venous segment (structure similar to that of a vein)
–If shunt is open, blood largely bypasses capillary bed
–If shunt is closed, blood enters capillary bed
Selectins play an important role in diapedesis. What is that role?
L-selectins on leukocytes.
P and E -selectins on endothelial cells.
Selectins caue leukocytes to loosely bind and roll across endothelial cells to slow them down
(after this, integrins lock down the leukocytes more tightly)
What kinds of vessels have cuboidal rather than squamous epithelium?
high endothelial venules
–Allow for migration of specific types of leukocytes through the endothelial wall into the lymphoid parenchyma
Which layer of the vessel is not well-developed in the large veins like the Venae Cavae, renal, jugular, iliac, and azygous?
The tunica media!
What are varicose veins?
Common locations?
- Abnormally enlarged and tortuous veins due to loss of muscle tone; wall degeneration; valvular incompetence
- Usually affect superficial veins in legs of older individuals
- Other common locations: lower esophagus (esophageal varices); terminus of anal canal (hemorrhoids)
What vessel layer makes up the venous valves?
folds of the intima!
