Lecture 19 9/22/23 Flashcards
What structures fall into the blood vessel category?
-arteries
-veins
-capillaries
What are the three layers of a blood vessel wall?
-tunica intima
-tunica media
-tunica adventitia
What are the characteristics of the tunica intima?
-spindle-shaped endothelial cells
-in contact with lumen/blood
-internal elastic lamina/membrane
What are the characteristics of the tunica media?
-mostly smooth muscle
-thickness varies
-can have elastic fibers and/or external elastic lamina
What are the characteristics of the tunica adventitia?
-dense collagen surrounding vessel that transitions into loose
-blends with surrounding tissue
-anchors blood vessel
-may include vasa vasorum and nervi vasorum in larger vessels
-may contain adipose tissue
What are arteries?
high pressure vessels that take blood away from the heart
What are the characteristics of elastic arteries?
-include aorta and largest branches
-tunica media contains lots of elastin
-need to be able to stretch
What are the characteristics of muscular arteries?
-medium-sized
-muscular tunica media
-most common
-3 or more layers of smooth muscle in wall
What are the characteristics of arterioles?
-less than 3 layers of smooth muscle in wall
-small
-innervated by sympathetic NS
-regulate blood flow into capillaries via pre-capillary sphincter
-determine amount of blood that goes to each tissue
What are capillaries?
endothelium and basement membrane only
What are the characteristics of capillaries?
-where oxygen, nutrient, and carbon dioxide diffuse
-associated with nearly every cell
-RBCs are single file in lumen
-most numerous vessel
What are the three types of capillary?
-continuous
-fenestrated
-discontinuous
What are the characteristics of continuous capillaries?
-complete basement membranes
-tight junctions between cells
-allow for gas transport
What tissues have continuous capillaries?
-muscle
-brain
-lung
What are the characteristics of fenestrated capillaries?
-complete basement membrane
-holes in endothelial cells
-substantial transport of fluids, ions, hormones, and nutrients
What tissues have fenestrated capillaries?
-intestine
-glomeruli
-endocrine glands
What are the characteristics of discontinuous capillaries?
-incomplete basement membrane and endothelial cells
-allow for passage of large molecules and whole cells
What tissues have discontinuous capillaries?
-liver
-spleen
-lymph nodes
-bone marrow
-placenta
How does inflammation impact the passage of cells through capillaries?
during inflammation, cells can pass through any capillary as long as appropriate receptor binding occurs
What are veins?
low pressure vessels that take blood towards the heart
What are the characteristics of venules?
-thin walled
-lack tunica media
What are the characteristics of medium-sized veins?
-thin, muscular tunica media
-valves for one way flow
-irregularly shaped due to less smooth muscle
What are the characteristics of large veins?
-thin, muscular tunica media
-valves
Which large veins DO NOT have valves?
-hepatic portal vein
-vena cavae
