TEAS® Science Study Guide
Cardiovascular System
The cardiovascular system transports oxygen, nutrients, hormones, and waste throughout the body.
Path of blood through the heart
Body → vena cava → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → lungs → pulmonary vein → left atrium → mitral valve → left ventricle → aortic valve → aorta → body
Memorize this. It is the single most-tested sequence in A&P.
The two circuits
- Pulmonary circulation — Right side of the heart sends oxygen-poor blood to the lungs.
- Systemic circulation — Left side of the heart sends oxygen-rich blood to the body.
The left ventricle has the thickest wall because it pumps blood the farthest.
Blood vessels
- Arteries — Carry blood away from the heart. Thick, muscular walls.
- Veins — Carry blood toward the heart. Thinner walls, with valves to prevent backflow.
- Capillaries — Tiny vessels where gas and nutrient exchange happens.
The exception TEAS loves: arteries usually carry oxygen-rich blood and veins usually carry oxygen-poor blood — but the pulmonary artery carries oxygen-poor blood, and the pulmonary veins carry oxygen-rich blood. Define arteries and veins by direction, not oxygen.
Blood components
- Red blood cells (erythrocytes) — Carry oxygen using hemoglobin, an iron-containing protein.
- White blood cells (leukocytes) — Fight infection.
- Platelets — Clotting.
- Plasma — The liquid portion; mostly water.
Terms to know
- Systole — Contraction phase; the heart pumps blood out. The top number in a blood pressure reading.
- Diastole — Relaxation phase; the heart fills. The bottom number.
- SA node — The heart’s natural pacemaker; sets the rhythm.
- Atria — Upper chambers, receive blood. Ventricles — Lower chambers, pump blood out.
What the TEAS asks most
- Which chamber pumps blood to the body? Left ventricle.
- Which vessel carries oxygen-poor blood away from the heart? Pulmonary artery.
- What does hemoglobin do? Carries oxygen.
- Which side of the heart handles oxygen-poor blood? Right.