Cardiovascular Diseases 4

Question 1

5 layers of the arterial wall?

Answer 1

1. Intima: endothelium + lil bit of CT
2. Internal Elastic Lamina (IEL): fenestrated for diffusion
3. Media: Vascular Smooth Muscle Cells (VSMCs)
4. External Elastic Lamina (EEL): elastin
5. Adventitia: loose CT + collagen

Question 2

3 features of ENDOTHELIAL cells and 4 functions?

Answer 2

1. Elongated cell containing pinocytotic vesicles
2. Form tight junctions with neighbouring cells
3. Line entire vasculature within the body
4. REGULATE IMMUNE + INFLAMMATORY REACTIONS
5. Modulate vascular tone (through VSMCs)
6. Modify LDLs + growth of VSMCs
7. Metabolises hormones e.g. histamine

Question 3

Atherogenesis ultimately stems from endothelial _____ and _____.

Answer 3

Activation, dysfunction

Question 4

What is 1 PHYSIOLOGICAL + 1 PATHOLOGICAL function of VSMCs?

What are the 2 types of VSMC?

Answer 4

Phys: maintain vascular tone
Path: aiding in vascular repair through formation of a neointima/fibrous cap

1. Contractile: normal, found in media, maintain vascular tone
2. Proliferative: moves to intima, can’t contract but can divide, wound healing

Question 5

How do monocytes get drawn to and then trapped in the wall?

Endothelium
LDL
Foam cells

Answer 5

1. Damaged endothelium (due to smoking, hypertension etc.) allows LDLs to pass through the wall
2. Monocytes are drawn to these LDLs and pass through the wall (becoming macrophages)
3. Eat (by producing toxic free radicals) these LDLs (becoming FOAM CELLS) till they die and become immobilised
4. More monocytes drawn in and vicious cycles continues. Ca2+ also enters —> thickening.

Question 6

What are 3 modifiable, 3 non-modifiable and 3 other risk factors for developing atherosclerosis?

*** = 5 most important

Answer 6

Modificable

• Smoking ***
• Hypertension ***
• Hyperlipidemia ** (HDL + Cholesterol) **

Non-Modificable

• Age (increases with age)
• Gender (more likely if male + post-menopause)
• Family history

Other

• Diabetes ***
• Infections
• Hyperhomocystinemia

Question 7

What are 3 consequences of atherosclerosis?

Answer 7

1. Aneurysm and rupture (due to wall weaking)
2. Occlusion by thombus (due to plaque rupture)
3. Critical stenosis (due to the plaque just continuing to grow until vessel is blocked)

Question 8

What are the 2 types of aneurysms?

Answer 8

TRUE: wall bulges, thinned but intact
FALSE: wall has ruptured, bulge though as a haematoma has formed on the outside and is held there by external extravascular tissue

Question 9

What is the definition of THROMBOSIS?

Answer 9

Thrombosis represents the INAPPROPRIATE activation of normal haemostatic processes, such as formation of a blood clot (thrombus), in UNINJURED vasculature or thrombotic occlusion of a vessel after relatively MINOR INJURY.

(Haemostasis = the appropriate, controlled formation of clot in response to an injury)

Question 10

What is the definition of EMBOLISM?

Answer 10

Any intravascular solid, liquid or gaseous mass carried by the blood to a site distant from its point of origin.
Emboli lodge in vessels too small to allow their passage, resulting in INFARCTION and NECROSIS of the distal tissue.

Question 11

99% of emboli are _______.

What are 3 other causes of emboli?

Answer 11

Thrombus (thromboembolus)

1. Bone or fat droplets (broken bone)
2. Gas bubbles (chest wall injury)
3. Atherosclerotic debris

Question 12

How is a narrowed or blocked blood vessel treated?

Answer 12

ANGIOPLASTY (balloon) followed by implantation of a STENT