The Endothelial Cell Flashcards
(42 cards)
The exact location of the endothelium in the cardiovascular system
In the endocardium layer of the heart; it lines the entire circulatory system
What function does the endothelium play as a barrier between the blood and other structures of the circulatory system?
It is a thin barrier that allows blood to move more smoothly and therefore circulate more quickly through out the body
List the four primary types of tissue in the body
1) Epithelium 2) connective tissue 3) nervous tissue 4) muscle tissue
Describe why the endothelium has a selectively permeable membrane
It’s lipid structure permits lipid-soluble molecules such as O2, CO2, and anesthetics to cross between blood and tissue
What role does the glycocalyx play as part of the endothelium
A coating of biopolymers on the lumen surface, forms a semipermeable layer, reflects plasma proteins but permits the passage of smaller solutes and water.
List and describe the different functions of the endothelium (there are seven of them)
see individual cards for each function
Function 1 of the endothelium
Regulates blood-tissue exchange through a semipermeable membrane that retains plasma & blood cells inside the circulation, yet permit nutrient transfer into the tissues.
Function (1) of the endothelium
Regulates blood-tissue exchange through a semipermeable membrane that retains plasma & blood cells inside the circulation, yet permit nutrient transfer into the tissues.
Function (2) of the endothelium
Regulates vascular tone; secretes vasoconstrictor peptide and three vasodilator agents: nitric oxide, endothelium-derived hyper-polarizing factor, and prostacyclin
Function (3) of the endothelium
Surface enzymes modify vasoactive peptides in the blood stream, angiotensin-converting enzyme is a primary enzyme modifier of circulating vasoactive peptides.
Function (4) of the endothelium
Secretes both anti-thrombotic and pro-clotting factors. Nitric oxide & prostacyclin, but also inhibit platelet aggregation. Also secretes von Willebrand factor (a component of the clotting cascade).
Function (5) of the endothelium
Participates in the inflammatory defense against pathogens,
venular endothelium inserts adhesion molecules in an inflamed tissue in order to capture circulating leukocytes & promote their migration in the source of inflammation.
Function (6) of the endothelium
Initiates new blood vessel formation (angiogenesis).
Function (7) of the endothelium
Endothelial dysfunction contributes to atheroma (abnormal fatty deposit in an artery); this is the single biggest cause of morbidity and mortality.
Differentiate and summarize functions of the endothelium
- angiogenesis (growth of new blood vessels), serve as a barrier
- control development of heart muscle in embryo
- regulate function of myocardium
- inflammation, immune response, atherosclerosis
- endothelial dysfunction, atherosclerosis
- loss of healthy endothelial function associated w/ smoking, CAD, diabetes, hypercholesterolemia, high BP
What role does actin-myosin structure play as part of the endothelium?
actin-myosin cytoskeleton provides shape & structure: anchors surface molecules, anchors intracellular junction, resists the shearing effect of the blood stream.
What are intercellular clefts?
Provides a pathway for water and nutrient transfer; small lipids-insoluble solutes, glucose, amino acids, and drugs can cross the endothelial barrier here
What are gap junctions
arterial endothelium-transmit signal: homo-cellular - transmit ions, membrane potential, chemical messages between cells. Hetero-cellular conveys signals between endothelium & underlying vascular smooth muscle. Together, they cause ascending vasodilation along small arteries.
Describe Intercellular cleft
20 nm wide and occupy only 0.2 - 0.4% of the capillary surface. Provides pathway for water and small, lipid-insoluble solutes
Describe intercellular gap junction
proteins form holes between adjacent cells allowing ions and molecules to pass freely between cells
Describe the function of the glycocalyx
negatively charged barrier to macromolecules. “Sugar coat” located on the outer surface, semipermeable membrane allows small solutes but not plasma proteins or LDL to pass through.
Functions: a) aids in attachment of some cells (b) binds antigens and enzymes to cell surface (c) facilitates cell-cell recognition (d) protects cells from injury (e) assists T cells and antigen-presenting cells to align with each other
Describe why the basal lamina is an important part of the endothelium
prevents capillary rupture by blood pressure.
What are ion channels
channels that influence intracellular Ca2+ ion concentration & regulate functions: nitric oxide production & hyper-permeability of inflammation
Describe EDRF and its relationship to nitric oxide
Endothelium-Derived Relaxing Factor: nitric oxide. Acetylcholine stimulates the release of this vasodilator.
