Unit 4 - Cardiovascular Disorders 1 Flashcards
What accounts for 80% of cardiac diseases?
Atherosclerosis
What are the three layers of an artery?
- Endothelium (inner!)
- Smooth muscle
- Collagen and elastic fibers (outer!)
Describe what happens during atherosclerosis.
- Lipids get into the vascular endothelium - due to injury
- WBCs try to clear them away
- WBC and vascular endothelium release growth factors that promote plaque formation
- Plaque blocks the artery
What 2 effects does plaque have on an artery?
- Decrease size of lumen
2. Decrease the elasticity of the artery
What is the difference between arteriosclerosis and atherosclerosis?
Arteriosclerosis = Ca+2 deposits in the wall of the artery WITHOUT plaque formation
What is the function of lipoproteins?
Enable the transportation of lipids in the blood
Why are HDLs good for the body?
They pick up excess lipids in circulation and send them to the liver
How much of total cholesterol should someone have in their system?
What can a patient do if they have too much cholesterol?
Exercise!
- increases HDLs
- lowers LDLs
- lowers total cholesterol
How much HDLs should a patient have?
> 1.5 mmol/L
Why is hypertension a risk factor for atherosclerosis?
Hypertension causes injury to the inner blood vessel wall - increases probability that lipids will enter blood vessel wall
How much will your risk of a cardiac event be lowered if you decrease cholesterol by 1 mmol/L?
50% reduction
What happens if the plaque ruptures in the artery?
Mini thrombi form
What do macrophages (WBCs) develop into after eating lipids?
Foam cells
Why could it be good if plaque has a thick cap?
Lower risk of rupture (forming a thrombus)
Why can heart attacks result from atherosclerosis?
If plaque ruptures, a clot forms. Could create a full occlusion if it blocks a small enough artery
What are the characteristics of stable plaque?
- THICK fibrous cap
- Partially block vessels
- Do not TEND to form clots or emboli
“Chronic Ischemic Syndrome”
What are the characteristics of unstable plaque?
- THIN fibrous caps
- Plaque can rupture and form a clot
- May completely block an artery
- Clot may break free and become and embolus
How can an aneurysm form due to atherosclerosis?
- Wall of artery weakens and stretches
bulges outwards
What are the clinical syndromes associated with coronary artery disease?
- Angina pectoris (chest pain)
- MI and unstable angina
- Chronic ischemic heart disease
- Sudden cardiac death
What are 2 clinical presentations that will occur with plaque?
- Asymptomatic
2. Angina pectoris
What are 2 clinical presentation that will occur with a non-occlusive thrombis
- Angina Pectoris
2. Congestive heart failure
What are 2 clincial presentations that will occur with an occlusive thrombus?
- Congestive heart failure
2. Myocardial infarct
Why can ischemia cause cardiac arrhythmias?
When oxygen is lacking, the Na+/K+ pumps don’t work as effectively because the pump needs ATP to function. ATP is formed in the presence of oxygen. When there is not enough oxygen, ATP is lacking, the pumps will fail! = Conduction deficits
What occurs if there is a mismatch between oxygen supply and demand?
Angina
What are 4 reasons for increased demand of oxygen?
- Increased afterload (anything that resists blood flow through the arteries)
- Increased contractility (when exercise occurs)
- Increased preload (increased stretch of the heart muscle)
- Increased heart rate
What are 3 reasons for decreased supply of oxygen?
- Decreased perfusion pressure (flow of blood to the heart vessel is decreased)
- Fixed stenosis (STABLE PLAQUE)
- Decreased oxygen content
How can you decreased demand of oxygen?
- Beta-blockers (slow down the heart)
- Vasodilators (decrease afterload)
- Rest
- Calcium channel blockers