The preferable option for the fill in the blanks will be - D.
D. Juxtamedullary; vasa recta
Explanation:
The <u>juxtamedullary</u> nephrons have LOHs that span deeply into the medulla. The <u>vasa recta</u> are the capillary bed that drains these extended LOHs.
LOH = loop of Henle
We know that the longitudinal section of the kidney has two regions - 1. an outer dark cortex and 2. inner light medulla.
The juxtamedullary nephron is the structural and functional unit of the kidney with a long loop of Henle. Juxtamedullary nephrons have a long loop of Henle extending deep into the renal medulla.
The vasa recta capillaries are long, hairpin-shaped blood vessels that run parallel to the loops of Henle. The hairpin turns slow the rate of blood flow, which helps maintain the osmotic gradient required for water reabsorption.
The circulatory system, also called the cardiovascular system transports oxygen-rich blood from the heart to the lungs. The heart then circulates oxygenated blood throughout the body via arteries. The veins return oxygen-depleted blood to the heart, restarting the circulation process.