Histology block II cardiovascular

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At what end is blood pressure higher/hydrostatic pressure higher pushing blood out of vessel into tissues? At what end is osmotic pressure higher pushing blood into vessel from tissues?

Arterial end. Venous end.
What is a Venous portal system? Where can you find them? Where can you find Arteriole portal system?

They are in venules sandwhiched between capillaries. You can find them in between hypothalamus and pituartery gland as well as hepatic portal cells in liver. APS found in kidneys.
- A. Single Layer Endothelium
- B. Tunica Intima
- C. Internal Elastic Membrane
- D. Tunica Interna
- E. Tunica Adventitial
- Trick: Think darkly staining internal elastic membranes, fibers and collagen here (it's a special stain for elastic membrane)
- A. Internal Elastic Membrane (black)
- B. Elastic Fibers (light in cartoon, not shown in stain)
- C. smooth muscle cell
- D. External Elastic Membrane
- E. Elastic fibers (dark)
- F. Collagen Fibrils (lightly stained)
- A. Endothelial Cell (single layer)
- B. Internal Elastic Membrane
- C. Smooth muscle (with corkscrew nucleus)
- D. Tunica Media
- E. Nuclei (sometimes you see in cells)
- F. Collagen bundles (light)
- G. Elastic Fibers (white)
- H. Tunica Adventitia
- A. Endothelial Cells
- B. Tunica Intima
- C. Tunica Media
- D. Tunica Adventitial
- E. Blood Vessels (Vasa Vasorum)
A. Endothelial Cells
Name the fxn of Tunica Adventitial.
VASLIM
- VV (vasodilator & vasoconstrictor)
- AA (anticoagulant & antithrombogenic) * if damaged will clot
- S - Selectively permeable membrane barrier
- L- lipoprotein modifier (oxidize LDLs)
- I- immune regulator
- M- metabolic- growth factors
Tunica Intima contains the endothelium layer with Weibeld Palade Bodies. What are they?
- –rod-like inclusions in cytoplasm of arterial endothelium
- –Electron-dense structures that contain: •Von Willebrand factor and P- selectin.
What are VWF and P-selectin in Wielbel-Palade Bodies of Tunica Intima?

.•VWF allows platelet adhesion to site of endothelial injury•Antibody to VWF is used asselectinimmunohistochemical marker to ID endothelial-derived tumors•P-selectin is a cell adhesion molecule involved in neutrophil-endothelial cell recognition. (Like neutrophils and selectin as it borrows out of membrane)
- A. Wiebel Palade Bodies (rod like in TI)
- B.Microvilli
- C. Junctional Complex
- D. Adhesion Molecules
- E. Cell surface receptors
- F. Basal Lamina
Systole causes what 2 things to happen?

•Systole causes:–distension of elastic wall–and recoil of walls •helps maintain blood pressure during diastole
Subendothelium of TA has what components?

•In larger arteries this layer contains•elastic fibers•collagen fibers•macrophages•smooth muscle -makes this layer CONTRACTILE-Excretes extracellular ground substance
What are foam cells?

In TA, oxidised LDLs are in turn endocytosed by macrophages to form foam cells in atheromas (lump in blood vessel- cholesterol)
Damage to ENDOTHELIUM cells can cause what?

damage to endothelium can cause the release of prothrombogenic agents (clot in blood vessel) eg. von Willebrand factor or plasminogen-activator inhibitor
Tunica Media, comprised mostly of smooth muscle which 3 elements. What are these?

–Smooth muscle secretes•collagen•elastin •proteoglycansno fibroblasts present
What are precapillary sphincters?

smooth muscle at entrance to capillary bed in Arterioles. Contraction causes increased vascular resistance and reduction in blood flow to capillaries
What are Atherosclerotic lesions?

Lesions in arteries due to atheromas (lumps of fat). This can cause ischemia (hbp) and myocardio infarction (heart attack).
What is the structure of a capillary?

•single layer of endothelial cells and their basal lamina•Tube just large enough for red cell to pass•Margins of endothelial cells joined by tight junctions
You can find 2 type of specialized endothelium layer of Sinusoids hepatic (liver) cells. What are these and their functions?

•KUPFFER cells (macrophages)•ITO cells (vitamin A storage cells/ hepatic stellate cells)
Small blood vessels (arterioles and venules) are often found surrounded by what 2 things?
- 1. Connective tissue for blood exchange
- 2. Fibroblasts (to create clot factors if needed)