Blood vessels

Question 1

Structure of blood vessels

Answer 1

Tunica intima
tunica media
Tunica adventitia

Question 2

Tunica intima

Answer 2

Edothelium/basal lamina/subendothelial layer of loose connective tissue
Forms permeable/semipermeable barrier

Question 3

Tunica media

Answer 3

Variable amounts of 
-elastic fibers and lamellae
-reticular fibers
-proteoglycans
controls diameter and blood pressure and movement

Question 4

Tunica adventitia

Answer 4

Outermost layer
Fibrobalsts and longitudinally oriented type I collagen and elastic fibers
Larger blood vessels
-vasovasorum

Provides physical support
attaches vessels to tissue
carries vessels and nerves

Question 5

Elastic artery

Answer 5

Intima- endothelium, incon. IEL
Media- 40-70 elastic lamellae
Adventitia- thin

Question 6

Muscular artery

Answer 6

Intima- endothelium, thick IEL
Media- 6-39 SM layers +/- EEL
adventitia- thin

Question 7

Arteriole

Answer 7

intima- endothelium, +/- IEL
Media- 1-5 SM layers
Adventitia- loose CT

Question 8

Structural changes in arteries with age

Answer 8

Largest arteries grow until age 25
-intima and media involved
Media stiffens starting @ age 30
Atherosclerotic plaques in the intima
Calcification of the media of muscular arteries
Coronaries can be threatened by plaque by age 25

Question 9

Pathophysiological changes in arteries with age

Answer 9

Large elastic arteries show greater change compared to muscular arteries
Atherosclerotic Plaques
-form in intima
-noncellular lipid material accumulation in the sub endothelial layer

Question 10

Endothelial cells

Answer 10

have intermediate filaments that provide structural support
-desmin
-vimentin
Joined by occluding (tight) and gap junctions

Synthesizes
-Types I,III,IV and V collagen
Fibronectin
Laminin
Coagulants
Anticoagulants

Question 11

Pericytes

Answer 11

Satellite cells
-surround capillaries and some post-capillary venues
some capable of contraction- regulate blood flow
Stem cells for endothelial and smooth muscle cells after injury

Question 12

Veins vs arteries

Answer 12

More variation in size and structure
Larger caliber, more numerous
More vaso vasorum
More collagen and less elastic substance and smooth muscle
Thick adventitia
Valves in small and medium veins

Question 13

Portal system

Answer 13

Carry blood from one capillary to another

• Hepatic portal vein- btwn intestines and liver
• Hypophyseal portal veins of pituitary
• efferent arterioles of the renal cortex

Question 14

Arteriovenous anastomoses

Answer 14

Direct cross connections btwn arterioles and venues

-smooth muscle cells form a sphincter that regulates blood flow and allows a bypass of a capillary bed