CLASS 20 - Central Perfusion, Atherogenesis and Intro to Ischemic Heart Disease (IHD) Flashcards
What is atherogenesis?
Changes in vessel walls leading to thickening + plaque formation
Describe the Response to Injury Theory of Atherogenesis in terms of where atherosclerotic plaques are formed.
States that atherosclerotic plaques tend to form wheveer arteries are most stressed (such as the bending + branching points).
What is the current injury of atherogenesis?
States that plaque formation involves an inflammatory event stimulated by a vessel wall injury.
What are the 2 types of stress that can cause injury to the intima of an artery ?
Mechanical + Oxidative
What are the 2 types of mechanical stress that can cause damage to the intima of an artery?
High blood pressure (can injure vessel wall)
Blood viscosity (thick blood from polycythemia and hyperglycemia)
What type of oxidative stress that causes damage to the intima of an artery?
High levels of ROS (reactive oxygen species such as superoxide) which damage cell structures
What are the 2 types of “emias” that are associated with increased production of ROS
Hyperlipidemia
Hyperglycemia
Describe the role of ROS in terms of their reactions with LDL (Low Density Lipids) and NO (nitric oxide). What effects do these reactions have on the artery wall?
- ROS oxidize LDL which damages artery walls
- ROS destroys NO which eliminates its protective effect of vasodilation
What is the relationship between phagocytes and superoxide (ROS) during the inflammatory response ?
During the inflammatory response, phagocytes produce superoxide (ROS).
What is the role of WBCs macrophages when the arterial wall is damaged as a result of oxidative stress?
When the arterial wall is damaged, the inflammatory response brings WBCs to the area. Macrophages are activated and consume oxidized LDL.
Eventually, these macrophages die and become lipid filled foam cells that form a bulge in the side of the artery wall (aka a plaque).
What is hyperlipidemia?
Why is this problematic?
Hyperlipidemia is a condition of having too mnay lipids in the blood.
This is problematic because high amounts of specific lipids can cause atherosclerosis.
What are the 3 types of serum lipids?
Cholesterol
Tyiglycerides
Phospholipids
What is atherosclerosis?
hardening, occlusion, or damage to the arteries which causes the blood vessels to become narrow or blocked
What is cholesterol?
Cholesterol is a small organic molecule that is used in cell membranes and to form steroid hormones
What is the role of triglycerides in the body?
What is the roles of tyiglycerides when the body is in a fasting state?
stored in the body as an important source of energy.
bind to VDL when the body is in a fasting state
Are phospholipids used as a clinical indicator for hyperlipidemia in the context of atherosclerotic disease?
No.
What is the role of phospholipids?
Used to form plasma membranes
What are lipoproteins?
How do they function?
What are the 3 types of Lipoproteins?
Lipoproteins are lipids surrounded by a “shell” of protein.
They function to transport lipids though the blood stream.
VLDL, HDL, and LDL
What is the most common type of lipid in the body and a major source of energy?
Triglycerides.
What are VLDLs?
What is their function?
What do they contain?
= very low density lypoproteins
carry cholesterol + other lipids away from the liver to body cells
VLDLs contain high level of triglycerides
What will happen to the artery if we have lots of VLDLs in the blood?
Artery narrows due to plaque formation, therefore increases the risk of CAD.
identify whether these lipoprotein levels should be high or low in the blood:
VLDL
LDL
HDL
low
low
high
What are LDLs?
What do they contain? What is their function?
What risk is associated with high levels of LDL?
= low density lipoproteins (aka “bad cholesterol”)
Contain a high amt of cholesterol and transport cholesterol from the liver to body cells.
High levels of LDL increase the risk of plaque formation, PAD, and heart disease.
What is the primary risk factor for atherosclerotic disease? Why?
Elevated LDL.
LDLs deposit cholesterol in vessel walls for storage.
What is HDL?
What is its function?
What is associated with high levels of HDLs?
= High Density Lipoprotein
Remove cholesterol from the body and transports it to the liver for disposal.
High HDLs in the blood may lower risk of developing heart disease.
What is the general goal for LDL levels in mmol / L?
< 2.5 mmol / L
What is the goal for Total Cholesterol values?
Less than 4.0.
What are the optimal triglyceride levels in mmol / L
1.7 mmol / L
What is angina?
Ischemic pain in the heart (“chest pain”)
What are the 3 components of cardiac / myocardial activity?
- heart rate
- contractility
- afterload
Describe the effect of the narrowing of the arteries due to arterial disease on the supply of blood/oxygen to the heart.
decreases it (duh)
What is the relationship between myocardial activity and oxygen demand?
activity increases, demand increases
What is the major cause of CAD?
Atherosclerosis.
What are the 2 major risk factors for atherosclerosis?
Hypertension - increased pressure can injure vessel wall and start inflammatory process
High cholesterol / Hyperlipidemia - provides material needed to develop the plawues along the insie of the vessel.
Identify the 3 developmental stages of atherosclerosis.
1) fatty streak
2) fibrous plaque
3) complicated lesion
Describe fatty streaks.
What drugs can we use to potentially reverse this process?
- earliest atherosclerotic lesions
- lipids accumulate and migrate into smooth muscle cells
- may be reversed by drugs that lower LDL (Statins, bile acid resins, nicotinic acid, cholesterol absorption inhibitors, orlistat)
Describe fibrous plaques.
Collagen covers the fatty streak to form a fibrous plaque.
Vessel lumen is narrowed.
Arterial wall thickens
Blood flow is reduced.