11. Blood Vessle Structure/function And Response To Injury

Question 1

Arteries

Answer 1

Large or elastic arteries: aorta and pulmonary artery
Medium sized (muscular) - smaller branches of aorta
Muscular arteries made off smooth muscle cells

Question 2

Capillaries

Answer 2

Have only endothelial cell lining but no media,

Main site of gas exchange

Question 3

Veins

Answer 3

Blood reservoir
Larger lumen
Valves to prevent backflow

Question 4

Cellular composition of blood vessels

Answer 4

Endothelial cells
Smooth muscle cells
Connective tissue

Question 5

3 layers of blood vessels

Answer 5

Tunica intima (innermost layer) - single layer of endothelial cells, connective tissue

Tunica Media (middle layer) - smooth muscle cells, highest amount of elastic fibers

Tunica adventitia (outermost layer) - CT, nerve fibers, vasa Vasorum (for nourishment)

Question 6

Vascular smooth muscle cells functions

Answer 6

Involved in both normal vascular repair and pathological processes

Migrate and proliferate
Release cytokines and growth factors
Synthesize and remodel ECM - CT
Cause vasoconstriction/dilation

Contract and relax to control blood resistance and blood pressure by vasoconstriction/dilation

Question 7

Endothelial cell properties

Answer 7

Complex signaling patterns - receiving signals from cells tissues and blood flow

Structural properties - continuous/discontinuous, fenestrated (kidney glomerulus filtration)

Temporal variations - properties change from one moment to next depending on physiological need

Question 8

Activated endothelial cells

Answer 8

Activate in response to injury

Increase expression of:

Adhesion molecules: Cause adhesion of neutrophils
Release pro-inflammatory cytokines
Pro-coagulants: Promote coagulation

Question 9

NO production due to vascular wall injury

Answer 9

Blood flow induced

Agonists: histamine, norepinephrine, serotonin and acetylcholine

Causes vasodilation in intact endothelium (Physiological)
Causes vasoconstriction in disturbed or lost endothelium (pathophysiology)

Question 10

Leukocyte adhesion in response to vascular wall injury

Answer 10

Leukocyte adhesion to endothelium (diapedsis)

Inductive endothelium cell-specific antigen that binds to monocytes

Question 11

Changes in endothelial function in response to vascular wall injury

Answer 11

1. endothelial cell activation
2. NO production
3. Leukocyte adhesion

Question 12

Stereotypical response to vascular injury

Answer 12

EC loss or dysfunction

Smooth muscle cell growth

ECM synthesis and thickening of vascular wall

Question 13

Neointima

Answer 13

Intimal thickening

Injured endothelium and underlying vessel wall heals by stimulating smooth muscle cell growth an ECM production

1. Recruitment of SMC or SMC precursor cell to intima
2. SMC mitosis
3. Elaboration of ECM

Question 14

Nitric Oxide

Answer 14

Released by endothelial cells

Causes vasodilation = increase synthesis of NO

Decrease oxidation of LDL cholesterol - plaque complement

Decrease multiplication of SMC of artery wall

Decrease release of superoxide radicals

Histamine, norepinephrine, serotonin, acetylcholine

Question 15

Basal endothelial cell states

Answer 15

Anti-coagulation
No inflammatory cytokines
No leukocyte adhesion

Question 16

Stenosis

Answer 16

Narrowing

Causing partial or complete obstruction of vessel

Question 17

Aneurysm

Answer 17

Weakening of vessel walls causing dilation or rupture

Question 18

Vaso vasorum

Answer 18

Actually nourish all of the cell layers - bringing on O2 removing CO2

When there is a huge gap they cannot nourish the media - weakening of blood vessel wall and blood vessel will bulge out

Weakening called aneurism

Major consequence of damage to endothelium