Human Circulatory System – Core Concepts

Ten question-and-answer flashcards covering the fundamental points about heart anatomy, blood flow pathways, and systemic versus pulmonary circulation.

What is the primary function of the heart and what are its four main chambers?

The heart acts as a muscular pump that propels blood throughout the body to deliver oxygen and nutrients while removing wastes. It has four chambers: right atrium, right ventricle, left atrium, and left ventricle.

Trace the path of deoxygenated blood through pulmonary circulation starting at the right ventricle.

Right ventricle → pulmonary valve → pulmonary trunk → right and left pulmonary arteries → smaller arterioles → pulmonary capillaries surrounding the alveoli (where gas exchange occurs and blood becomes oxygenated) → pulmonary venules → pulmonary veins → left atrium.

What role does the aorta play in systemic circulation?

The aorta is the largest artery in the body; it receives oxygen-rich blood from the left ventricle and distributes it to every systemic artery, supplying all body tissues except the lungs.

Why don’t red blood cells consume the oxygen they carry?

Mature red blood cells lack mitochondria and a nucleus, so they cannot perform aerobic respiration and therefore do not use up the oxygen they transport.

How does the heart muscle itself receive an oxygenated blood supply?

The myocardium is nourished by the coronary arteries, which branch directly from the base of the aorta and wrap around the heart to deliver oxygen-rich blood to cardiac tissue.

Distinguish between arteries and veins with respect to blood flow relative to the heart.

Arteries carry blood away from the heart (regardless of oxygen content), whereas veins return blood back to the heart.

What color convention is typically used to represent oxygenated versus deoxygenated blood in diagrams?

Oxygenated blood is shown in red, while deoxygenated blood is depicted in blue.

How do the lungs receive their own oxygenated blood, and what is unique about pulmonary capillary blood flow?

Lung tissue is supplied by bronchial arteries originating from the systemic aorta. Uniquely, blood in pulmonary capillaries transitions from deoxygenated to oxygenated as it passes around alveoli, and these capillaries operate under lower pressure than systemic ones.

Name the two major veins that return deoxygenated systemic blood to the heart.

The superior vena cava and the inferior vena cava.

What is the significance of the right and left ventricles in the two main circulatory circuits?

The right ventricle pumps deoxygenated blood into the pulmonary circuit for oxygenation, while the left ventricle pumps oxygenated blood into the systemic circuit; the left ventricle has thicker walls to generate higher pressure for systemic distribution.