What is the flow of blood, excluding the heart?
Where does gas & nutrient exchange occur?
The capillaries. Gas exchange can occur here because capillaries are only one endothelial layer thick, making them thin enough for gas exchange to occur.
What is a tunic?
A tunic, in laymen's terms, is a covering or a layer. A tunic is also used to describe the structure of arteries and veins.
Describe the three tunicas of the arteries and veins.
- Tunica interna (intima)
- -Contains lining of simple squamous epithelium (endothelium), basement membrane, and layer of elastic tissue (internal elastic lamina).
- -The endothelium lines the entire cardiovascular system.
- -Normally, endothelium is the only tissue that contacts blood.
- Tunica Media
- -Thickest Layer
- -Middle Layer
- -Consists of elastic fibers and smooth muscle that extend circularly around the lumen.
- Tunica Externa
- -Outermost layer
- -Composed mainly of elastic and collagen fibers.
- -In muscular arteries, an external elastic lamina composed of elastic tissue separates the tunica externa from the tunica media.
Which tunica layer contains endothelium (simple squamous epithelium)?
Tunica interna (intima)
Which tunica layer contains smooth muscle?
Which tunica layer is the thickest?
Which tunica layer is composed mainly of elastic and collagen fibers?