PUBH 1145 Lecture Notes - Lecture 6: Tricuspid Valve, Coronary Artery Disease, Mitral Valve
22 Oct 2020
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6 – Diseases & Disorders of the Cardiovascular System
Cardiovascular System
- Consists of heart and blood vessels
- Transports oxygen, nutrients, and waste products among tissues
Heart
- Hollow, muscular organ that serves as the pump for circulation
o Myocardium – muscle
o Endocardium – internal lining
o Pericardium – outer membrane
- 4 chambers : 2 atria and 2 ventricles
o Atria collect blood and pass to ventricles
o Ventricles contract to disperse blood
- Valves prevent backflow of blood
o Mitral valve – between left atrium and ventricle is bicuspid
o Tricuspid valve – between right atrium and ventricle
o Aortic valve – between left ventricle and aorta
o Pulmonary valve – between right ventricle and pulmonary artery
Heart Function
- Diastole – filling stage
- Systole – pumping stage
- Coronary arteries provide blood flow to myocardium
- Electrical conduction powers systole
o Sino-atrial node acts as pacemaker
o Atrial-ventricular node slows signal
- Signal passes through right and left bundle branches and terminate in the
Purkinje fibers, eliciting ventricular contraction
- Innervated by vagus nerve
Blood Flow
- Left ventricle through aorta and to the body
- Right ventricle flows through the pulmonary artery for oxygenation in the lungs
- Arteries carry oxygenated blood to tissues
- Nutrient / oxygen / waste exchange occurs in capillaries
- Veins return blood to the heart
Vasculature
- Artery walls are muscular and thick, lined with endothelium
- Capillaries are the width of a red blood cell (RBC)
- Vein walls are thinner with wider lumen
o Valves prevent blood pooling from gravity
Diagnostics
- Auscultation : listening
o Normal S1 / S2, murmurs, rubs, extra sounds
- Electrocardiogram : tracing of electrical conduction
- Echocardiogram : ultrasound of the heart
o Can see abnormalities of motion
- Cardiac catheterization
o Catheter inserted that allows dye to pass into cardiac arteries
o Can determine blockages
- Swan-Ganz catheter
o Placed in pulmonary artery through right heart to assess cardiac function
Lipids & Cholesterol
- LDL : low density lipoprotein
o Can form plaques
o ‘Bad’ cholesterol
- HDL : high density lipoprotein
o Carries other cholesterols to liver for elimination
- Triglycerides : fat in the body
- Hyperlipidemia / Hypercholesteremia : abnormally high levels of cholesterol in blood
o Treated with diet, exercise, statins
Diseases of the Arteries
- Arteriosclerosis
o Artery calcifies and loses elasticity
o Increased blood pressure
- Atherosclerosis
o Thickening and narrowing of artery, often caused from hyperlipidemia
o Thickened plaques cause disturbances in blood flow, sometimes resulting in clot formation
(thrombosis)
o Treated with diet, exercise, blood thinning agents (ASA, Plavix)
▪ Surgery can remove or bypass plaque, catherization can displace plaque
- Aneurysm : weaking of the artery walls
o Risk factors : male, HTN, genetic predisposition
o Treatment : reduce blood pressure
▪ Surgical correction is necessary in some cases
o Aortic is most common
▪ Seen on imaging
o Cerebral aneurysms are found on imagining incidentally, or after they rupture
Hypertension
- Essential : no underlying cause
- Secondary : 2 /2 other identified disease
- Treatments
o Exercise, weight loss
o Beta-blockers : relax smooth musculature, slows heart rate
o ACE inhibitors : inhibits angiotensin converting enzyme
o ARBs : block angiotensin II receptors
Document Summary
6 diseases & disorders of the cardiovascular system. Transports oxygen, nutrients, and waste products among tissues. Hollow, muscular organ that serves as the pump for circulation: myocardium muscle, endocardium internal lining, pericardium outer membrane. 4 chambers : 2 atria and 2 ventricles: atria collect blood and pass to ventricles, ventricles contract to disperse blood. Coronary arteries provide blood flow to myocardium. Electrical conduction powers systole: sino-atrial node acts as pacemaker, atrial-ventricular node slows signal. Signal passes through right and left bundle branches and terminate in the. Left ventricle through aorta and to the body. Right ventricle flows through the pulmonary artery for oxygenation in the lungs. Nutrient / oxygen / waste exchange occurs in capillaries. Artery walls are muscular and thick, lined with endothelium. Capillaries are the width of a red blood cell (rbc) Vein walls are thinner with wider lumen: valves prevent blood pooling from gravity. Auscultation : listening: normal s1 / s2, murmurs, rubs, extra sounds.
