Structure and function of blood vessels Flashcards
Name 3 types of blood vessels
Arteries, Veins, Capillaries
What are capillaries for
exchange of nutrients/waste products between tissue cells and blood stream
As the arteries move away from the heart they branch into what
smaller tubes called arterioles
arterioles then branch to produce what
capillaries
As capillaries move away from tissue they converge to form what
large tubes known as venules
Venules merge to form what
Veins
Which is large, arteries and veins or capillaries
Arteries and veins
Arteries and Veins consist of how many basic layers known as what
3 layers known as tunica
What is the inner layer of the artery and vein called
Tunica intima
What does the tunica intima layer in the artery/vein consist of
single layer of endothelium resting on thin layer of connective tissue (basement membrane)
The tunica media (middle layer) contains what
concentric layers of smooth muscle
What is the outermost layer of the artery and vein called
tunica externa/tunica adventita
The tunica externa is made up of what
connective tissue which connects to the surrounding structures
The tunica media is thicker in what, arteries or veins? What is it bounded by
Arteries. Bounded by internal and external elastic laminas
Why do arteries have a thicker tunica media
Subject to internal pressures every time the heart contracts and blood is pushed out of the heart.
The internal and external elastin fibres in arteries help how
Help arteries to maintain their diameter following contraction and aid in maintaining blood pressure
What is the pulse a result of
expansion and recoil of the elastic arteries of the cardiac cycle
Veins contain 3 things
Valves, thicker outer fibrous layer, small amounts of elastin
The valves in the veins aid what
flow of bloodfrom the body (against gravity) back to the heary
Capillaries only have one layer, what layer is this
Tunica Intima
The transfer of material into and out of the capillaries is achieved through what 2 methods
Direct diffusion and vesicular transport
Another name for vesiuclar transpport
pinocytosis
Thinning of the endothelial cells in capillaries, produces what
membranes known as fenestrations or pores
Thinning of endothelial cells in capillaries assists what
diffusion of smaller molecules between tissue cells and blood stream
All epithelial cells are joined by what
tight intercellular junctions
endothelial cells in the capillary have tight intercellular junctions but are
incomplete
The incomplete junctions in endothelial cells allow for what
passing of larger molecules
Less permeable materials may be what and transported across the endothelial cells
Endocytosed (engulfed within plasma membrane)
Less permeable materials may be transported across the endothelial cells within what container
membrane bound containers known as vesicles
What is a form of endocytosis
Pinocytosis
What then happens once the vesicle reaches the tissue side of the endothelial cells
vesicle fuses with the plasma membrane and empties content into extracellular spaces > exocytosis