Through which of the following medium does the blood enter the kidney?

Correct option is A

The correct answer is (a) renal artery

Explanation:

• Blood enters the kidney through the renal artery, which branches directly from the abdominal aorta.

• The renal artery carries oxygenated, nutrient-rich blood that also contains nitrogenous waste products (like urea) to be filtered.

• Once inside the kidney, the renal artery divides into smaller interlobar arteries, then arcuate arteries, and finally into afferent arterioles.

• These arterioles lead to the glomerulus, a network of capillaries where the actual filtration of blood occurs.

• According to NCERT Class 11 Biology, nearly $1100-1200$ ml of blood is filtered by the kidneys per minute, which is roughly $1/5^{th}$ of the blood pumped by each ventricle of the heart.

Information Booster:

• After filtration and reabsorption, the "clean" blood exits the kidney via the renal vein, which then drains into the inferior vena cava.

• The renal artery is essential not just for waste removal, but also for maintaining the kidney's own oxygen supply to power active transport mechanisms.

Additional Knowledge:

external iliac artery (Option b)

• This is a major artery in the pelvic region that provides the main blood supply to the legs.

• It becomes the femoral artery after it passes under the inguinal ligament.

axillary artery (Option c)

• This is a large blood vessel located in the armpit region.

• It conveys oxygenated blood to the lateral aspect of the thorax, the axilla, and the upper limb.

interatrial (ulnar) artery (Option d)

• The ulnar artery is a main blood vessel of the forearm and wrist.

• It supplies blood to the medial part of the forearm and the palm of the hand.