Blood Vessels and Atherosclerosis Flashcards Preview

Cardiovascular System > Blood Vessels and Atherosclerosis > Flashcards

Flashcards in Blood Vessels and Atherosclerosis Deck (43):
1

What are the basic components of the vessel wall?

  • Endothelium
  • Intima
  • Internal Elastic Lamina
  • Media
  • External elastic lamina
  • Adventitia

2

What are the three types of arteries?

Large or elastic

Medium sized or muscular

Small arteries (<2mm) and arterioles (20-100microns)

3

What are examples of the large or elastic arteries?

Aorta and major branches; pulmonary artery

4

What are two examples of medium-size or muscular arteries?

Coronary arteries; renal arteries

5

In large arteries, elastic fibers alternate between _____ ______ _____ in media

smooth muscle cells

6

In muscular arteries media is primarily ______ _____ ____

Where are elastic fibers in muscular arteries?

Smooth muscle cells

Elastic fibers are limited to internal and external elastic lamina

7

For small arteries/arterioles What makes up the media? What is the purpose of the media?

Essentially all smoth muscle cells

Smooth muscle cell contraction adjust blood pressure and flow

8

Which arterioles have no elastica?

Terminal arterioles

9

What is the average diameter of a capillary?

Are there smooth muscles in capillaries?

7-8 microns in diameter

Partially surrounded by smooth muscle-like cells = pericytes

10

Where do leukocytes commonly emigrate in inflammation?

Venules

11

How much blood volume is contained in veins?

2/3 blood volume

12

What vessels drain interstitial fluid into blood and are a pathway for dissemination of disease?

lymphatics

13

How to endothelial cells respond to injury?

Stimulation - rapid reversible response independent of new protein synthesis (response to histamine)

Activation - Elaboration of gene products with biologic activity requires hours/days to develop

14

What happens in endothelial cell activation?

  • Increased expression of procoagulants, adhesion molecules, and proinflammatory factors
  • Altered expression of chemokines, cytokines and growth factors

15

How do vascular smooth muscles contribute to vascular repair?

Migrate to intima and proliferate (also occurs in pathologic processes like athersclerosis)

16

What is synthesyzed by Vascular smooth muscle cells?

  • Collagen
  • Elastin
  • Proteoglycans

17

What are the two basic pathologies of vascular disease?

  1. Narrowing or obstruction (thrombosis)
  2. Weakening of vessel wall (aneurysm and rupture)

18

What are three steps in intimal thickening?

  1. Recruitment of smooth muscle cells or smooth muscle precursor cells to the intima
  2. Smooth muscle cell mitosis
  3. Elaboration of extracellular matrix

A image thumb
19

Why does smooth muscle move to the intima and why is this potentially harmful?

This is a stereotyped response to vascular injury of ANY KIND

Intimal smooth muscle cells cannot contract and healing response may narrow or occlude the vessel

20

What is the difference between arteriosclerosis, atherosclerosis and arteriolosclerosis

  • Arteriosclerosis - hardening of the arteries (generic term
    • Atherosclerosis - elastic arteries and large/medium muscular arteries
    • Arteriolosclerosis - small arteries and arterioles

21

What is Monckeberg arteriosclerosis?

Calcific deposits in media of medium sized muscular arteries

A image thumb
22

What is atherosclerosis

A progressive disease of elastic arteries and large to medium-sized muscular arteries

23

What are the two basic types of damage in atherosclerosis?

Aneurysm formation - leading to rupture and hemorrhage

Stenosis - by atheroma leading to ischemia/thrombosis

24

In atherosclerosis what clinical syndromes are associated with the elastic arteries?

Aorta:

Carotid:

Iliac:

Aorta: aneurysm with rupture

Carotid: Occlusion causing stroke (possibly associated with thrombosis)

Iliac: Occlusion causing gangrene (possibly associated with thrombosis)

25

Clinical syndromes associated with athersclerosis in large/medium sized muscular arteries?

Coronary arteries:

Popliteal arteries:

Renal artery:

Mesenteric arteries:

Coronary arteries: occlusion causing MI

Popliteal arteries: occlusion causing gangrene

Renal artery: narrowing/occlusion causing secondary hypertension

Mesenteric arteries: narrowing/occlusion causing bowel infarction

26

What is atherosclerosis progression during the "pre clinical phase"?

Normal artery → Fatty streak → Fibrofatty plaque → Advanced/vulnerable plaque

27

How does an advanced vulnerable plaque advance in the evolution of atherosclerosis (3 outcomes)

  1. Aneurysm and rupture
  2. Occlusion by thrombis
  3. Critical stenosis

A image thumb
28

How does a fatty streak appear morphologically?

Multiple yellow, flat dots to streaks, usually in aorta and later in coronaries

A image thumb
29

Describe lipid incorporation:

  • Low-density lipoprotein (LDL) cholesterol is transported into the vessel wall
  • Endothelial cells and monocytes/macrophages: 
    • generate free radicalsoxidize LDL (oxLDL) ⇒ lipid peroxidation
  • oxLDL is taken up by macrophages via ‘scavenger’ receptors ⇒ activates macrophages ⇒ releases proinflammatory cytokines

30

Describe the morphology of a fibro-fatty plaque: 

Q image thumb

  • Raised yellow-white plaque in intima with soft yellow core and white fibrous cap
  • Often eccentric (involve only part of vessel circumference) & patchy; may coalesce & become diffuse

A image thumb
31

What can a fibro-fatty plaque impinge on?

lumen

32

What is the risk for advanced/vulnerable plaques?

  • Rupture ulceration, erosion, & hemmorhage
    • Lead to thrombosis, embolism
    • Progressive luminal narrowing (leading to critical stenosis)
  • Atheroembolism
  • Aneurysm formation
    • Wall weakening leading to aneurysm & rupture

33

Vunerable plaque vs. Stable plaque

  • Vunerable:
    • thin fibrous cap
    • large lipid core
    • inflammation
  • Stable:
    • thick fibrous cap
    • small lipid core
    • minimal inflammation

A image thumb
34

What is the morphology of complicated atheromatous lesions?

Caused by calcification within the atheromatous plaque

Surface defects:

  • ulceration
  • erosion
  • overlying thrombus

A image thumb
35

What is the consequence of hemorrhage into a plaque?

likely to cause further narrowing of vessel lumen

36

What happens if there is thrombosis (partial or complete) of the vessel lumen?

  • thrombus may be incorporated into the lesion, further narrowing it (if it is not already occluded!)
  • likely happens repeatedly

37

Factors contributing to thrombosis:

  1. shear stress
  2. high levels of LDL
  3. smoking (? through elevation of fibrinogen)

38

What causes aneurysm formation?  

What can an aneurysm  lead to?

  • Atrophy (due to pressure and or ischemia) of media, destruction of elastic fibers
  • Leads to thinned weakened wall prone to rupture

39

What is the hypothesis of atherosclerosis?

Hypothesis: chronic inflammatory response of arterial wall to endothelial injury

  • Components of process:
    • Endothelial injury
    • Hemodynamic disturbances
    • Lipid accumulation
    • Inflammation
    • Infection
    • Smooth muscle proliferation

40

Chronic endothelial injury/dysfunction ⇒ ...

What are some strongly suspected causes?

Chronic endothelial injury/dysfunction ⇒ ↑ permeability, enhanced leukocyte adhesion

  • Strongly suspected causes:
    • Hemodynamic disturbances: plaques occur in areas of disturbed flow patterns (at ostia and vessel branch points)
    • Hypercholesterolemia
    • Other possible contributors:
      1. Hypertension
      2. Cigarette smoke toxins
      3. Homocysteine
      4. Infectious agents

41

How does inflammation play a role in the pathogenesis of atherosclerosis?

  • Adhesion molecules (from endothelial cells) attract leukocytes
  • Monocyte adhesion, migration & transformation to macrophages
    • Initially protective response, but ultimately cause lesion progression
  • T lymphs: secretion of cytokines & fibrogenic mediators

42

How does infection play a role in atherosclerosis pathogenesis?

How do smooth muscle cells play a role?

  • Infection: Importance is unclear at present
    • Herpes virus
    • CMV
    • Chlamydia pneumoniae
  • Smooth muscle cells:
    • Proliferation and migration into intima with production of matrix proteins

43

How is chronic hyperlipidemia related to atherosclerosis?

Chronic hyperlipidemia:

  • Can directly impair endothelial cell function
  • Lipoproteins accumulate in intima