Lecture 7 - Thrombosis Anatomy/Microanatomy

Arteries

• large lumen

• minimal resistance

• thick vessel walls

• smooth muscle/elastic fibers

Arterioles

• narrow lumen

• respond to SNS and PSNS innervation

What are the three layers to a vessel?

• tunica intima - endothelium

• tunica media - smooth muscle

• tunica adventitia - connective tissue

Continuous capillaries

uninterrupted endothelium and basement membrane

exchange small molecules and gasses

ex. brain, lung, muscle, bone

Fenestrated capillaries

discontinuous endothelium and continuous basement membrane

exchange slightly larger products

repel negatively charged products

ex. renal glomeruli, intestinal villi, endocrine glands, choroid plexuses, ciliary processes

Discontinuous capillaries

discontinuous endothelium and basement membrane

maximum passage of molecules

ex. liver, spleen, bone marrow, lymph nodes

How does blood return to the heart?

• 1-way valves

• cardiac suction

• skeletal muscle contraction

How much of the bodies blood is in the veins at any given time?

65%

compared to the 5% found in capillaries

Lymphatic vessels

• blind ended beginning

• large interendothelial gaps

• 1-way valves

• skeletal muscle contraction dependent movement

What are the functions of the endothelium?

• fluid distribution

• inflammation

• immunity

• angiogenesis

• hemostasis

Rete Mirabile

specialized vascular networks formed by arterial blood vessels through the center of large venous sinuses

functions as countercurrent exchangers

Which is cooler, venous blood or arterial blood?

venous blood, b/c it is coming from the extremities

Interstitium

the space between parenchymal and stromal cells and micro circulation

Interstitium Functions

• provide pathways used by microvasculature

• modulate systematic physiologic properties

• general fluid pool/reservoir providing cushioning for organs, water/ion reserves

• structural framework for cell survival

Extracellular matrix

the structural, adhesive, and absorptive components within the interstitium

What is the extracellular matric composed of?

• Type 1 collagen

• glycoproteins

• glycosaminoglycans

• proteoglycans

Type 1 collagen

structural framework

glycoproteins

attachment site for the structural proteins and adhesion site for transmigrating leukocytes

glycosaminoglycan

absorptive disaccharide complexes

proteoglycans

hydrophilic, can bind large amounts of water and molecules