Blood Vessels Flashcards
What is the overall structure of an artery in comparison to veins?
They have much thicker walls because they transport blood away from the heart which is under high pressure.
Where can you find arteries?
Elastic: aorta (heart)
Muscular: branch off into kidney, liver
What is the order of vessels within the circulatory system?
Arteries (exit heart)
Arterioles (smallest artery)
Capillaries (smallest vessel)
Venules (Smallest Vein)
Veins (return to heart)
What do you call the hollow passageway of a vessel?
Lumen
What are the three distinct layers of arteries and veins?
-Tunica Intima
-Tunica Media
-Tunica Externa
What are the three distinct layers of arteries and veins?
-Tunica Intima
-Tunica Media
-Tunica Externa
What is the tunica intima?
Epithelial and connective tissue
-specialized simple squamous epithelium = endothelium
What is tunica media?
smooth muscle and connective tissue (elastic fibers)
- Thickest layer in arteries
- circular sheets
What is tunica externa?
- sheath of connective tissue composed primarily of collagenous fibers
- (Veins = smooth muscle layer)
- Larger in veins
What are the three kinds of capillaries?
- Continuous
- Fenestrated
- Sinusoid
What are continuous capillaries?
- complete endothelial layer with tight junctions between cells
What is the function of continuous capillaries?
- Impermeable and allows for water and ions
- all vascularized tissue have them.
- Rich in transport vesicles (endocytosis, exocytosis) (not in the brain)
What are fenestrated capillaries?
- Pores and tight junctions in endothelial lining.
What is the function of fenestrated capillaries?
- Permeable to larger molecules
- nutrient absorption
- Blood filtration
What are sinusoid capillaries?
-Flattened
- intercellular gaps
- incomplete basement membrane
- intercellular clefs
- fenestrations (pores)
