Ch 20 Flashcards
What are 3 layers of vessel wall?
Tunica Interna
Tunica Media
Tunica Externa
What is the composition of Tunica Interna?
Composed of endothelium.
This layer is in contact with the blood
What is endothelium?
Simple squamous epithelium
What are some functions of Tunica Interna?
- Selectively permeable barrier
- Secretes chemicals that stimulate dilation or constriction
- Repels blood cells and platelets so they wouldn’t stick to the wall
- Produce cell-adhesion molecules that induce leukocytes to stick to the surface when vessel is inflamed.
What is Tunica Media made of?
Smooth muscle (amount varies), collagen, and elastic tissue.
What are some functions of Tunica Media?
- Strengthens the vessels and prevents rupture
2. Regulates the diameter by vasoconstriction and vasodilation.
Which layer is the thickest layer?
Tunica Media
What is Tunica Externa made of?
Loose connective tissue
What are the functions of Tunica Externa?
- Anchors the vessel to tissues
2. Provides passage for small nerves and lymphatic vessels
What is Vasa Vasorum?
It is small vessels that supplies blood to outer wall of larger vessels
Arteries are sometimes called what?
Resistance Vessels
What are 3 categories of arteries (biggest to smallest)?
Conducting
Distributing
Resistance
What is Conducting Artery made of?
Internal elastic lamina
What is the function of Conducting Artery?
Reduce effects of BP surges.
What happens to Conducting Artery during systole?
It expands
What happens to Conducting Artery during diastole?
It recoils
What is Distributing Arteries made of?
Smooth muscle
What is the function of Distributing Arteries?
Distributes blood to specific organs
It can adjust flow based on demand
What is Resistance Arteries made of?
Smooth muscles, little elastic tissues.
What is Arterioles?
Smallest arteries that lead into capillary bed
What are functions of Resistance Arteries?
It’s primary control of blood flow.
Most responsible for Peripheral Resistance
Significantly effects BP
