1-Blood Vessels Flashcards
the ratio of sick to well in a community. diseasaed or pathologic
morbid/morbidity
death and death rate
mort/mortality
what mechanism do vascular abnormalities cause disease
- narrowing or blockiing of vessel
- weakening of the wall
what is atherosclerosis
progressive narrowing
what is thrombosis
precipitous or sudden narrowing of vessel
where are intraparenchymal arteries found
within tissues of organs
how large are arterioles
20-100 um
how large are capillaries
7-8 um diameter
why do capillaries have a thin wall
permits passage of nutrients and oxygen from blood to tissue
what are fenestrated capillaries? where found?
- window like openings
- found in glomeruli, liver (called sinudoids), and endocrine organs (called sinusoids)
what are venules
capillary veins with thin walls designed to permit the reentry of fluids from tissues to blood circulation
-also the site for exit of WBC into tissues
veins or arteries have higher lumen
veins
how much of the bodies blodd is contained in the veins
2/3
what is the direct extension of interstitial tissue space that serves as sites for the drainage of interstitial fluids that have not cycled back into the blood circulation
lymphatics
what type of artery contract and dilate in order to accomadate and regulate blood flow
muscular (medium) arteries
main functions of arteries
carry blood from heart and regulate blood pressure
name some large arteries (elastic) in the body
- aorta
- subclavian
- CCA
- iliac
- pulmonary
name some medium sized (muscular arteries)
branches of aorta
what are distributing arteries
medium or muscular arteries
where are small arteries found
mostly within substance of tissues and organs
how large are small arteries
< 2mm
what is the tunica media made of
smooth muscle
what is the tunica adventia made of
fibrous connectice tissue
what is the tunica intima made of
endothelium
how does the tunica media acquire oxygen and nutrients
vasa vasorum–small arterioles arising from outside the vessel perforate the external elastic membrane and send oxygen to the outer 2/3 of tunica media
what layer is the vasa vasorum found in the vessel
tunica adventitia
where are the nerve fibers of the blood vessels found
tunica adventitia and tunica media
what layer of elastic arteries are elastic fibers found mostly
tunica media
the resistance of a blood vessel to fluid flow in an arteriole is inversely proportional to the 4th power of the diameter. what does this mean?
halving the diameter of an arteriole, increases the resistance 16-fold
what blood vessel is the principle point of physiologic resistance to blood flow
arterioles
what vessels are affected most by atherosclerosis
large elastic and medium muscular arteries
what vessels does hypertension affect most
small arteries and arterioles
what type of cells line capillaries
endothelial cells
capillaries are supported on the outside by______and the _____________ is absent
- thin basement membrane
- tunica media
how many cells thick are capillaries
one
where would i find capillaries with a continuous endothelial layer
muscle, heart, lung, skin, nervous system
where would i find capillaries in which the endothelium is fenstrated
endocrine glands, renal glomeruli, vessels of GI tract
where would i find capillaries with little or no basement membrane
liver, spleen, bone marrow
specialized mesenchymal cells that line the inside surface of blood vessels
endothelial cells
what are endocardial cells
endothelial cells lineing inside heart chambers and heart valves
what is the basic shape of endothelial cells
- polygonal
- elongated cells
- pinocytotic vesicles
- form junctional complexes
what are weibal-palade bodies
storage organelle found in endothelial cells that store von Willebrand Facto (vWF)
what does vWF do
helps repair damaged endothelial cells
how are endothelial cells identified immunohistochemically
- with factor VIII related antigen
- CD31
what are the 8 fxns of endothelial cells
1-structural 2-barrier 3-anticoagulant 4-vascular tone 5-inflammatory 6-immunologic 7-cell growth regulation 8-metabolic
what anticogaulants do endothelial cells secrete
- heparin like molecules
- plasminogen activator
- prostacyclin
- thrombomodulin
what procoagulents do endothelial cells secrete
- plasminigen activator inhibitor
- thromboplastin
- vWF (factor VIII)
what vasoactive substances do endothelial cells secrete
- constrictors–ACE, endothelin
- dilators–NO, prostacyclin
what inflammation and immunity substances do endothelial cells secrete
- inflammation–IL1, IL6, IL8
- adhesion–P/E selectin, ICAM1
- MHC
what growth stims and inhibitors do endothelial cells secrete
- stims–platelet derived GF (PDGF), colony stimulating factor (CSF), fibroblast growth F (FGF)
- inhibitors–heparin, TGF-beta
what is secreted from endothelial cells during angiogenesis
vascular endothelial growth factor (VEGF)
what is secreted from endothelial cells during EC matrix production
collagen, proteoglycans
what is the difference in between resting and sctivated endothelial cells
- morphologically–nothing
- functionally–appearance of surface receptors and adhesion molecules, and altered secretory programs
what is endothelial stimulation
endothelial response to abnormal stimuli is rapid (minutes)
what is endothelial activation
alterations in gene expression and protein synthesis. requires hours or days
what are some functions of smooth muscle cells
- constrict or dilate
- synthesize EC matrix malecules
- secretes cytokines and GF
- repair vascular injury AND PATHOLOGIC PROCESSES SUCH AS ATHEROSCLEROSIS
what do vascular smooth muscles look like
spindle shaped with single elongated nuclei (resemble fibroblasts)
what mediates the contractile fxn of smooth muscle cells
cytoplasmic filaments that contain actin and myosin
which substances stimulate the proliferation of smooth muscle cells in injured blood vessels
- Platelet-Derived GF (PDGF)–derived from platelets, endothelial cells and macrophages
- Basic Fibroblast GF (BFGF)
- IL1
which substancesinhibit the proliferation of smooth muscle cells in injured blood vessels
- TGF beta (transforming GF)
- IFN gamma (interferon)
- NO/EDRF (endothelial derived relaxing factor)
- Heparen sulphates
how does vascular injury stimulate smooth muscle cell growth
by disrupting the physiological balance b/w inhibition and stimulation
how is damage to the enodthelial vascular wall repaired
1-smooth muscle cells migrate from tunica media to tunica intima
2-area is filled with platelets and macrophages
-release of PDGF and BFGF to stimulate smooth muscle cells to grow onto site of injury
-formation of neointima
what happens when smooth muscle cells migrate from the media to intima? do they beahve the same?
-No, they DO NOT behave the same
-lose capacity to contract
gain capacity to divide
increase synthesis of EC matrix molecules
intimal smooth muscle cells may return to a nonproliferative state when…
1-overlying endothelial layer is reestablished to nonpreoliferative state
2-chronic stimulation stops
what would happen if the regrowth of endothelial cells does not occur
the inrimal thickening may continue and even enlarge. (similar to keloid scars)
what would be the result of excess and continuing proliferation by smooth muscle cells
thickening and enlargement of tunica intima
what is denudation
rmoval of epithelium from an underlying surface
