Cardiovascular diseases

Normal anatomy - arteries vs veins

Arteries are muscular-walled, high-pressure vessels that carry blood away from the heart; veins have thinner walls, larger lumens, and valves, and carry low-pressure blood back to the heart

Arterial wall layers

Tunica intima (inner endothelial lining; damage starts arteriosclerosis/atherosclerosis); tunica media (smooth muscle; alpha fibers constrict, beta fibers dilate, calcium constricts); tunica externa/adventitia (outer covering)

Hormones secreted by the endothelium

Nitric oxide (dilation), endothelin (constriction), VEGF (angiogenesis), C-type natriuretic peptide (diuresis), prostacyclin (inhibits clotting), thromboxane A2 (activates clotting)

Baroreceptors

Sense stretch of the vessel wall and signal the medulla and pons; BP too high activates PNS (lowers HR and contractility); BP too low activates SNS (raises HR, contractility, vasoconstriction)

RAAS system

Low renal perfusion causes JG cells to release renin; renin converts angiotensinogen (from liver) to angiotensin I; ACE in the lungs converts it to angiotensin II, which vasoconstricts and triggers aldosterone from the adrenal cortex; aldosterone retains sodium and water, raising BP

Liver's role in blood cholesterol

Makes cholesterol (HMG-CoA reductase, blocked by statins) and stores it; LDL receptors pull cholesterol from blood (more receptors = lower levels); converts cholesterol to bile acids excreted in feces

Signs of hyperlipidemia

Xanthoma (cholesterol under skin), xanthelasma (around eyes), arcus senilis (yellow-white ring around cornea); should prompt family history and CVD risk review

Peripheral artery disease - assessment

Intermittent claudication, diminished or absent pulses, coolness, paresthesia, pallor, sensation checked distal to proximal; diagnose with ankle-brachial index, lipid profile, duplex ultrasound, MRA, angiography, CT

Effect of glucose on arteries

High glucose injures endothelium through glycosylation, forming AGEs; AGEs cause inflammation and plaque and increase endothelin (vasoconstriction); links diabetes to CAD

Hypertension - criteria

Two or more readings with SBP over 130 or DBP over 80; "silent killer"

Hypertension - why it occurs

Primary (95%): unknown cause; secondary (5%): underlying disease such as Cushing's; risk factors include age, male sex, African American ethnicity, obesity, diabetes, smoking, high sodium, low potassium, stress, alcohol, high renin

Hypertension - key assessments

Fundoscopic exam (retinal vessels), chest (PMI shift), bruits, peripheral pulses/temperature/sensation, 12-lead ECG (LVH), urinalysis (protein = kidney damage), blood labs

Hypertension - complications

LVH (raises MI risk), aneurysm, cerebral hemorrhage, hypertensive retinopathy, renal disease (glomerular damage)

5 steps in atherosclerosis development

1) Endothelial injury; 2) WBCs attracted and adhere; 3) WBCs become macrophages, fill with LDL, become foam cells; 4) Cytokines attract fibroblasts, forming fatty streaks that become plaques; 5) Plaques calcify and get a fibrous platelet cap

Diagnostic techniques for atherosclerosis

Lipid profile, endothelial function tests (intracoronary Doppler, brachial artery ultrasound), hs-CRP, homocysteine, calcium CT scan, cardiac angiography, intravascular ultrasound

Peripheral artery disease - signs and symptoms

Intermittent claudication (pain with exertion relieved by rest, from lactic acid buildup) is the primary sign; nonpalpable lower-extremity pulses; most common at femoral artery above the knee; symptoms at over 70% occlusion; critical limb ischemia risks amputation

Aneurysm - abdominal aorta (AAA)

Most common location; may cause abdominal or back pain, nausea and vomiting, or a pulsatile mass in thin patients; risk is rupture; do NOT deep palpate

Aneurysm - cerebral arteries

"Berry" aneurysms; usually silent; rupture causes subarachnoid hemorrhage with a "thunderclap"/worst headache of life

Aneurysm - risk factors for rupture

Atherosclerosis, smoking, hypertension Aortic dissection - what it is :: A tear in the aortic lining that lets blood flow between the tunica intima and media; potentially lethal

Aortic dissection - how it presents

Sudden onset, "ripping" or "tearing" sound, pallor, tachycardia, variable BP, bounding pulse, wide pulse pressure, diastolic murmur, possible cardiac tamponade

Immunity and infectious disease

Infection happens when a pathogen overcomes defenses; innate immunity is immediate and nonspecific; adaptive immunity (B and T cells) is specific and builds memory

Basic concepts of infection

Chain of infection: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host How normal flora and the microbiome protect us :: Compete with pathogens for nutrients and space, make antimicrobial substances, maintain protective pH, train the immune system; antibiotics can disrupt them (C. diff, yeast infections)

Bacteria vs viruses

Bacteria are living cells that reproduce on their own and are treated with antibiotics; viruses are genetic material in a protein coat that need a host cell to replicate and don't respond to antibiotics

Normal body defenses

First line: skin, mucous membranes, cilia, tears and saliva, stomach acid, normal flora; second line: inflammation, fever, phagocytes, NK cells, complement; third line: adaptive immunity (antibodies, T cells, memory cells)