Histology Block 3 Flashcards
What kind of artery has an obvious internal elastic membrane?
Muscular arteries
What is present in the tunica media?
Smooth muscles and extracellular matrix
Where is elastic fibers, lamella, collagen fibers (type 3), and proteoglycans synthesized in blood vessels?
Tunica media
When present what does the external elastic lamina seperate?
The media and adventitia
What is present in the Tunica Intima of blood vessels?
Endothelium and basal lamina (basement membrane)
Which layer of blood vessles contains vasa vasorum and innervation?
Tunica Adventitia. Especially in veins
Does the amount of elastic tissue increase or decrease as blood vessels become smaller?
The elastic tissue decreases and the smooth muscle component becomes more prominent
Is the tunica intima thicker or thinner in elastic arteries than in muscular arteries?
Tunica intima is thick in elastic arteries than in muscular arteries
What do Weibel-palade bodies contain?
Factor VIII related antigen (von-willebrand factor) interleukin 8, P-selectin and endothelin
The elastic arteries have a thick tunica media. True or false?
True
Tunica adventitia contains blood vessels and nerves. True or false?
True
Mutations in elastic muscle fibers in elastic arteries can cause…
Aneurysm
Where is extracellular matrix synthesized in blood vessels?
Tunica Media
What is the unique feature of muscular arteries?
Internal elastic lamina
What happens when an artery or arteriole is damaged?
Its smooth muscle contracts, producing a vascular spasm of the vessel. This limits the blood flow and blood loss at the site of damage
Carotid body is sensitive to what?
There are two O’s in carOtid bOdy. So it is sensitive to Oxygen (O2), high carbon dioxide concentration and low pH of arterial blood.
Where are carotid bodies found?
At bifurcation of common carotid artery
Bifurcation: The place where two branches divide.
What is a carotid body?
The carotid body is a small cluster of chemoreceptor cells, and supporting sustentacular cells. The carotid body is located in the adventitia, in the bifurcation (fork) of the common carotid artery, which runs along both sides of the neck.
What is a carotid sinus?
The carotid sinus is a baroreceptor that senses changes in systemic blood pressure and is located in the adventitia of the carotid bulb of the internal carotid artery. Due to its location the carotid sinus is an intimately related but distinct organ from the carotid body.
What does the carotid sinus react to?
carotid SinuS has two S’s and so does preSSure. It reacts to changes in blood preSSure.
Where is the carotid sinus found?
The lower end of the internal carotid
How does the tunica intima change with age?
Tunica intima becomes thicker with age because smooth muscles migrate from the tunica media into the tunica intima. This decreases the lumen size. The vessels also become more rigid
How do the elastic arteries change with age?
Decrease in collagen and elastic fibers and they lay down more elastic lamellae with age
How do muscular arteries change with age?
There is an increase of muscle without the elastic fibers. In advance age loss of elastic tissue make vessels to elongated and become tortuous (twisted)
Aneurysm cause
When media is weakened by an embryonic defect. disease or lesion, the wall of the artery dilates and may rupture
What two conditions have an increased risk of aneurysm?
Type IV Ehlers-Danlos syndrome- because of collagen defects
Marfan syndrome- because of fibrillin defect. Specifically associated with aortic dissecting aneurysm
What is arteriosclerosis?
Thickening of the walls and loss of elasicity
What is atherosclerosis?
Fibrofatty plaques in intima
Arteriolosclerosis
Thickening of the walls of smaller arteries
Arteriosclerosis and arteriolosclerosis are different. True or false?
True.
Arteriosclerosis- thickening of walls and loss of elasticity
Arteriolosclerosis- thickening of the walls in smaller arteries
Formation of an Atherosclerotic Plaque:
- Something causes the endothelium to let in more LDL cholesterol than normal. The increase of LDL cholesterol increases the production of reactive oxygen species oxidizes LDL in the tunica intima of the artery.
- endothelial cell express cell adhesion molecules (CAMs) that initiate monocyte migration through the endothelium that differentiate into macrophages
- Macrophages phagocytize oxidized LDL slowly transforming themselves into foam cells. Increasing amounts foam cells thicken the walls which decreases the size of the lumen.
- Platelet derived growth factor (PDGF) and other growth factors released from endothelial cells stimulate the migration of the smooth muscle cells from the tunica media to the tunica intima
- In the tunica intima smooth muscle cells produce large amounts of extracellular matrix (proteoglycans, collagen) that increase the thickness of the tunica intima
Angioplasty
Widening narrowed or obstructed arteries
What is elevated in hyperlipidemia?
Cholesterol or triglycerides
Cholesterol is essential for the synthesis of what?
Plasma membranes, steroid hormones, and bile acids
Triglycerides play an essential role in what?
Transporting and storing fatty acids for energy