Exam 2: Cardiovascular Diseases Flashcards
Causes of Hypertension:
Essential Hypertension
Sustained pressure increase (systolic over 140 and/or diastolic over 90)
Complex Multigenic disorder
Stress, obesity, smoking, inactivity, heavy salt consumption, genes whose products affect sodium reabsorption
Causes of Hypertension:
Secondary Hypertension
Renal Dysfunction
Endocrine Dysfunction
Cardiovascular Dysfunction
Neurologic Dysfunction
Parts of the body that participate in regulating blood volume
Hypertension
Hypertension
Regulation of Blood pressure through hormones, renal function, and heart function
Hypertension
Hyaline Arteriosclerosis
Protein deposits
Narrow lumen of vessels
Associated with benign hypertension
Leak of plasma proteins pas damaged endothelial cells
Glassy eosinophilic membrane
Hypertension
Hyperplastic Arteriosclerosis
Onion-skinning
smooth muscle and basemnt membrane overgrowing in response to the pressure increase
Associated with severe hypertension
PAS staining for basement membrane
Atherosclerosis
Characteristics of Atherosclerosis
Type of arteriosclerosis
Characterized by formation of atheromas
* atherosclerotic plaques
* lesion in tunia intima
* projecs into the lumen
Core is lipids w/ fibrous cap
Atherosclerosis
Pathogenesis of Atherosclerosis
- Endothelial cell dysfunction
- Formation of the atherosclerosis plaque
- T cells-macrophage interaction
- Fracture of the plaque and thrombosis
Pathogenesis of Atherosclerosis
- Endothelial Injury
Plaques initiate at sites where endothelium is intact
Results from endothelial dysfunction
Pathogenesis of Atherosclerosis
Most important contributors to Pathogenesis of Atherosclerosis step 1 are
Hemodynamic disturbancs
Hypercholesterolemia
Pathogensis: Atherosclerosis
Lipids are transported by…
apopproteins ( bind lipids)
Pathogensis: Atherosclerosis
Common abnormalities in Hypercholesterolemia
Sustained
Increased LDL levels
Decreased HDL levels
Presence of abnormal lipoproteins
Pathogensis: Atherosclerosis
Chronic Hyperlipidemia
Damage the intima by LDL accumulation
Atheroma begins to form as macrophages attempt to remove LDL
Directly affects endothelial functions
Pathogensis: Atherosclerosis
What causes oxidation of LDLs?
excess ROS
Pathogensis: Atherosclerosis
What happens to oxidized LDLs? What do they do?
- Directly damage endothelial cells by attachment
- Ingested by macrophages through specific receptor
- Accumulate in phagocytes which then appear foamy
- Stimulate cytokine, growth factor, and chemokine secretion to initiate immune response (monocyte recruitment)
- Macrophages release ROS (injures tissue and depletes NO)
Pathogensis: Atherosclerosis
How does the fibrous cap of the atherosclerosis plaque form?
Cytokines released durign inflammatory reaction induce smooth muscle cell proliferation (which migrate to the endothelium) and ECM production to form fibrous cap
Pathogensis: Atherosclerosis
How are T cells involved in the Pathogensis of Atherosclerosis?
- Dysfunctional endothelial cells express adhesion molecues
- Bound leukocytes migrate into intima due to chemokines from macrophages
- T lymphocytes induce chronic inflammation and release inflammatory cytokines
Pathogensis: Atherosclerosis
What causes thrombus formation?
- Damaged endothelium provides focal point for platelet binding and activation
- Accumulation of platelets produces blood clot with contribution from inflammatory mediators
- Clot breaks free
The tunica intima consists of:
Endothelium (simple squamous epithelium)
Supporting CT
Atherosclerosis
Atherosclerosis Progression
Normal Artery → Fatty streak → Fibrofatty Plaque → Advanced/Vulnerable Plaque →Aneurysm and Rupture/Occulusion by Thrombus/Critical Stenosis
Fatty streak can be bypassed and go straight to fibrofatty plaque (atheroma)
Atherosclerosis
What are the consequences of Atherosclerosis?
Obstruct blood flow
Rupture of plaque - thrombsis
Weaken underlying tunica media (aneurysm formation)
Coronary Artery Disease → MI
Myocardial Infarction is responsible for _ of deaths in US
1/4
Atherosclerosis
What are the clinical complications of atherosclerosis?
Occlusion results in infarct
* Myocardial Infarction
* Cerebral Infarction
* Peripheral vascular disease
Rupture results in hemorrhage
* Formation of thrombus
* Aortic aneurysm
Location of atherosclerotic plaque is crucial
Atherosclerosis
Thrombsis can produce…
distal occlusions and additional plaques
What is the path of blood flow through the heart?
- Blood from body
- Thru superior/inferior vena cava into right atrium
- Thru tricuspid valve into right ventricle
- Thru pulmonary arteries into the lungs
- Return from the lungs by pulmonary veins
- Thru left atrium
- Thru mitral valve into left ventricle
- Thru aortic valve into aorta and to the body
Myocardial Infarction
Ischemic Heart Disease
Group of diseases most commonly causes by atherosclerosis of cornary arteries
Myocardial Infarction
What is Ischemic Heart Diseases caused by?
Myocardial ischemia
* Lower perfusion than needed → Dcreased blood flow, Increased need
Myocardial Infarction
Lack of blood flow caused by ischemic heart disease affects:
Energy production
Nutrient availability
Waste Removal
Myocardial Infarction
Myocardial Infarction
type of Ischemic Heart Disease
Necrotic damage to the myocardium
Heart Attack
Myocardial Infarction
Can Severe Myocardial Infarction be stopped once it has started?
Can you prevent the damage?
Small window of time before cells die and damage is irreversible
Depends on ATP levels and accumulation of dangerous metabolites
Myocardial Infarction
Myocardial Infarction Pathology
24 hours: Coagulative Necrosis
3-4 days: Neutrophil infiltrate
7-10 days: Necrotic tissue being removed by macrophages
>2 weeks: Loose CT and vascularization (granulation tissue)
>Compensation: Scar tissue is healed - infarct
Myocardial Infarction
What is the effect of Reperfusion?
It impacts myocardiocyte function and surival
Myocardial Infarction
How does reperfusion work?
Temporary occlusion → flow is restored → reperfusion injury → salvage
* Flow restored
* Burst of ROS following resumption of oxygen-based energy production
* Some cells can cope and will recover → other will still undergo necrotis death
Myocardial Infarction
What is reperfusion injury?
Cells continue to dying for a period of time even though blood flow was restored
Myocardial Infarction: Reperfusion
What is Salvage in terms of reperfusion?
Degree to which you manage to stop myocardial infarction
i.e. 60% might be salvaged vs. losing 80-90%
Myocardial Infarction
How can timing of MI be assess clinically?
By measuring the protein release of necrotic cardiomyocytes
Increased levels of Troponin I, CK-MB, and Myoglobin
Cardiac Hypertrophy
What causes hypertrophy?
Increased workload
* increased blood pressure
* increased volume to move
* damage to the wall
Myocardiocytes become enlarged and add sarcomeres
MI
Cardiac Hypertrophy
What are the consequences of cardiac hypertrophy?
- Increased heart size and mass
- Increases protein synthesis
- induction of immediate-early genes
- Inductiton of fetal gene program
- abnormal proteins
- fibrosis
- inadqueate vasculature
Cardiac Hypertrophy
Cardiac Dysfunction is characterized by…
Heart failure
Arrhythimas
Neurohumoral stimulation
Conduction Disorders
Bradycardia
< 60 bpm
Conduction Disorders
Tachycardia
> 100 bpm