Blood Vessels Flashcards
What type of organ does a blood vessel qualify as?
tubular organ
What is the only exception regarding blood vessels qualifying as ‘tubular organs’?
typical names describing all layers are NOT used!
What does the blood vessel wall layer composition depend on?
the size of the vessel
What are the three principal layers the arterial wall?
tunica interna (intima)
tunica media
tunica externa
State all layers present in the arterial wall (from lumen to outside)
- endothelium
- tunica interna (intima)
- internal elastic membrane
- tunica media (+elastic fibers)
- external elastic membrane
- tunica externa
What is the name(s) of the vessel wall layer adjacent to the lumen? What is it comprised of?
Tunica Interna (Tunica Intima):
- endothelium (simple squamous epithelium)
- subendothelium (fibrous connective tissue)
- internal elastic membrane (elastic fibers)
What is endothelium?
simple squamous epithelium which lines blood vessels and lymphatics.
What is subendothelium?
fibrous connective tissue
What is the internal elastic membrane?
A condensation of elastic fibers in the deep region of the tunica interna of blood vessels.
State the names of the 3 principal arterial wall layers, and what they would be called in a typical tubular organ.
Tunica Interna (Intima) = Tunica Mucosa
Tunica Media = Tunica Muscularis
Tunica Externa = Tunica Adventitia
What is another name for “Tunica Interna”?
Tunica Intima
Why do blood vessels have specific wall names?
In order for its users to know that one is talking strictly about blood vessels (not any other tubular organ).
What helps resist the high arterial blood pressure?
The internal elastic membrane positioned in the tunica interna of arteries. (condensation of elastic fibers in the deep region of the tunica interna)
What is the function of the elastic membranes of arteries?
Elastic membranes guarantee elastic properties for the entire structure, resisting changes in shape, and ensuring that the structure returns to its original shape afetr stretching.
What is a significant difference in the composition of veins in comparison to arteries?
Veins lack: Elastic Membranes!
- no high pressure= no high resistance needed
- no condensation of elastic fibers
What is the composition of tunica media?
mixture of:
- smooth muscle (major)
- connective tissue (minor)
What is the location of tunica media?
between:
- tunica interna
- tunica externa
What is present in some vessels as an outer layer of tunica media? What is it? Name?
External Elastic Membrane:
- condensation of elastic fibers
What is the third, outermost layer, of blood vessels? What does this layer usually blend into?
Tunica Externa:
- tissue layer usually blends into the surroundng connective tissue
What is tunica externa composed of?
connective tissue proper: loose connective tissue
same as tunica adventitia
In what pattern are smooth muscle cells arranged in tunica media?
How does this compare to that of other tubular organs?
circular pattern
(all cells go in the circular pattern, there is no longitudinal layer!)
NOT TYPICAL IN TUBULAR ORGANS! usually: inner circular, outer longit.
What are the different types of arteries?
- elastic arteries
- muscular arteries
What is the major difference between elastic and muscular arteries?
TUNICA MEDIA!
State the specificity of tunica media and tunica interna of elastic arteries.
- high proportion of elastic membranes
very few in tunica interna, however still more than in muscular arteries
State the specificity of tunica media of muscular arteries.
- low proportion of elastic membranes
In what pattern is the elastic membrane of tunica media arranged in vessles?
circular pattern (sheets):
- same as muscle cells
State the composition of tunica media in elastic arteries.
mixture of:
- smooth muscle (minor)
- connective tissue (minor)
- elastic membrane (major)
elastic membranes take up most of teh proportions (little smooth muscle)
What is the function of the tunica externa of blood vessels?
connects blood vessels with other surrounding organs (usually muscles)
What structure may be present in the tunica externa of blood vessles?
vasa vasorum (blood vessel in a blood vessel)
What is the function of vasa vasorum?
guarantee energy and oxygen to the walls of large arteries (eg. aorta)
What is another name used to refer to elastic arteries?
large arteries
In short, state the structure of tunica media of elastic arteries.
Large amounts of elastic fibers scattered among smooth muscle cells.
In short, state the structure of tunica media of muscular arteries.
- smooth muscle
- internal elastic membrane
- lacks elastic fibers in the tunica media
What is another name used to refer to muscular arteries?
medium arteries