Human Circulatory System

Blood is bright red in its oxygenated form (i.e., leaving the lungs), when hemoglobin is bound to oxygen to form oxyhemoglobin i.e. inside arteries.

The afferent arteriole, which is a branch of the renal artery, enters the Bowman's capsule and divides into a network of capillaries known as the glomerulus.

The renal vein carries filtered, clean blood away from the kidneys and back toward the heart.

The efferent arteriole carries blood away from the glomerulus after filtration has occurred. Note that the term 'efferent renal artery' is technically imprecise, as it is an arteriole, but it is the intended answer.

The vasa recta are specialized capillary networks that surround the loop of Henle and collect reabsorbed water and solutes from the interstitial fluid, returning them to the general circulation.

Veins operate under lower pressure than arteries. Valves ensure that blood flows in one direction toward the heart and prevent it from pooling or flowing backward due to gravity.

The right auricle (atrium) receives deoxygenated blood from the body through the superior and inferior vena cava.

Oxygenated blood returns from the lungs to the left atrium of the heart via the pulmonary veins.

The pulmonary artery is unique because it is the only artery that carries deoxygenated blood from the heart to the lungs for oxygenation.

Capillaries have very thin walls that allow for the efficient diffusion of oxygen, nutrients, and waste products between the blood and surrounding tissues.

The superior vena cava drains deoxygenated blood from the upper body (head, neck, arms), while the inferior vena cava drains blood from the lower body.

Capillaries are microscopic blood vessels that connect arteries and veins, facilitating material exchange. Xylem and phloem are plant tissues, and the spleen is an organ.

Valves in the heart act as one-way doors that prevent blood from flowing backward into the previous chamber after it has been pumped forward.

Arteries carry blood away from the heart under high pressure, so they do not require valves. Veins, heart chambers, and lymphatic vessels all utilize valves to maintain unidirectional flow.

The aorta is the main artery that carries oxygenated blood from the left ventricle of the heart to the rest of the body.