🚪 Cardiovascular System Lesson

TPMA: the four heart valves, in order

Four one-way valves keep blood moving forward through the heart. TPMA gives you all four in the exact order blood passes through them.

Tricuspid

Pulmonary

Mitral

Aortic

📖 Full Breakdown

Four valves, right to left, each preventing backflow

Each valve sits at a chamber exit and closes the moment pressure reverses, keeping blood moving in one direction only.

Tricuspid valve

Right atrioventricular valve, between RA and RV. Has 3 leaflets (hence "tri"). Chordae tendineae anchor the leaflets to prevent them inverting under pressure.

Pulmonary valve

Semilunar valve between the right ventricle and the pulmonary trunk. Its 3 half-moon-shaped cusps snap shut once the ventricle relaxes, preventing blood from flowing back from the lungs.

Mitral valve

Left atrioventricular valve, between LA and LV. Has only 2 cusps (bicuspid) — this is the valve most commonly affected by rheumatic fever.

Aortic valve

Semilunar valve between the left ventricle and the aorta. Aortic stenosis (narrowing of this valve) is the most common valve disease in adults.

🩺 Clinical / Exam Application

An elderly patient presents with exertional chest pain, fainting spells, and a harsh systolic murmur. This classic triad points toward aortic stenosis — the aortic valve has narrowed and calcified over years, forcing the left ventricle to generate dangerously high pressure to push blood through the tiny remaining opening. Knowing TPMA in order tells you immediately which valve sits at the very end of the pathway, explaining why aortic disease affects the whole systemic circulation downstream.

⚠️ Exam Alert

The AV valves (tricuspid, mitral) separate atria from ventricles; the semilunar valves (pulmonary, aortic) separate ventricles from their great vessels. Exam questions often test which category a given valve belongs to, not just its name.

🚧 Common Trap

Students frequently mix up which AV valve has how many cusps. Anchor it by letter count: "TRIcuspid" literally has 3 cusps and sits on the right; mitral (2 cusps, bicuspid) sits on the left — if you remember tricuspid = 3 = right, mitral is automatically the other one.

✅ Quick Check

Name the two AV valves and the two semilunar valves separately, and state which side of the heart (right or left) each one sits on.

📝 Exam Prep

Common Exam Questions

❓ Which heart valve is located between the left atrium and left ventricle?

✅ The mitral (bicuspid) valve — between LA and LV. It has 2 cusps and is the most commonly affected valve in rheumatic fever.

❓ What is the difference between an AV valve and a semilunar valve?

✅ AV (atrioventricular) valves — tricuspid and mitral — sit between an atrium and its ventricle. Semilunar valves — pulmonary and aortic — sit between a ventricle and its outgoing great vessel (pulmonary trunk or aorta).