💓 Blood Pressure Regulation & Drug Class Selection Simulator

Baseline Blood Pressure Regulation

BP equals cardiac output times resistance, tuned by RAAS.

• Core eq.: BP = CO × SVR (hemodynamic identity)
• <120: Normal systolic target (mmHg, resting)
• ↓ Renal perfusion: RAAS trigger (juxtaglomerular cells)
• Na⁺/H₂O retention: Aldosterone effect (raises volume)

Cardiac output and vascular resistance

Short placeholder: CO and SVR multiply to set arterial pressure.

The RAAS cascade

Short placeholder: renin cleaves angiotensinogen, ACE makes AII.

Feedback and homeostasis

Short placeholder: baroreceptors and kidneys close the loop.

Placeholder key insight: RAAS is slow but powerful BP modulator.

Hypertension Develops

Elevated resistance or volume pushes BP above healthy target.

• ≥140/90: Stage 2 HTN threshold (mmHg, AHA/ACC)
• ~1.3 B: Global adults affected (placeholder estimate)
• ↑ Renin: Overactive RAAS (drives AII overshoot)
• Stroke, CKD, MI: Chronic risk (end-organ damage)

Rising vascular resistance

Short placeholder: chronic vasoconstriction narrows arterioles.

Volume overload

Short placeholder: excess sodium retention expands blood volume.

RAAS overactivation

Short placeholder: persistent renin drive sustains hypertension.

Placeholder key insight: severity varies mild to severe.

Drug Class Selection

Each drug class intercepts a different point in the pathway.

• RAAS cascade: ACEi/ARB target (blocks AII formation/action)
• Vascular smooth muscle: CCB target (direct vasodilation)
• Renal Na⁺ handling: Thiazide target (reduces blood volume)
• 3: Drug classes shown (first-line options)

ACE inhibitors and ARBs

Short placeholder: block angiotensin-converting enzyme or receptor.

Calcium channel blockers

Short placeholder: relax smooth muscle, widen arterioles directly.

Thiazide diuretics

Short placeholder: promote renal sodium and water excretion.

Placeholder key insight: mechanism guides class choice.

Drug class quick reference

Mechanism-Specific BP Lowering

The chosen drug visibly blocks its node; BP output falls.

• ↓ AII, ↓ SVR: ACEi/ARB effect (cascade interrupted)
• ↓ SVR directly: CCB effect (resistance dial narrows)
• ↓ Volume: Thiazide effect (reservoir drains)
• 8–12 mmHg: Typical SBP drop (monotherapy, placeholder)

Blockade visualized

Short placeholder: block icon appears at the targeted node.

Downstream consequence

Short placeholder: flow past the block point drops sharply.

Gauge response

Short placeholder: BP needle eases toward target zone.

Placeholder key insight: mechanism explains onset timing.

BP Returns Toward Target

Pressure normalizes; patient factors guide class selection.

• <130: Target SBP (mmHg, most adults)
• CCB/thiazide: Race-guided first-line (placeholder, Black patients)
• ACEi/ARB: Diabetes/CKD first-line (renal protection)
• CCB favored: Elderly consideration (placeholder guidance)

BP normalization

Short placeholder: gauge needle settles into green target zone.

Patient-factor guidance

Short placeholder: age, race, comorbidities steer drug choice.

Long-term management

Short placeholder: combination therapy often needed over time.

Placeholder key insight: individualized therapy improves outcomes.