Renal System

Organs involved: renal artery, renal vein, vena cava, urethra, sphincter, dorsal aorta, kidneys, ureters, bladder.

Kidneys: Each kidney, about the size of a fist, is supplied by a renal artery and contains roughly a million nephrons to filter blood. Around 150-180 litres pass through daily, producing about 1.5 litres of urine.

Calyx/Calyses: The kidneys are encased by a renal capsule and cortex. Urine formed in the cortex flows through minor to major calyx.

Renal Pelvis: Funnels urine into the ureter, with movement aided by peristalsis.

Ureter and Urethra: The ureter transports urine from the kidney to the bladder; the urethra carries it outside the body.

Osmoregulation: Drinking excess water increases blood volume, prompting the pituitary gland to reduce ADH production. Thus, less water is reabsorbed in the nephron, increasing urine volume until balance restores.

Fluid Balance Homeostasis: To maintain water balance, fluid intake must match output. Water is vital as most bodily reactions occur in its presence. Intake sources include food and drink; outputs include urine, feces, sweat, expired air, crying, and vomiting. Indicators for needing more water include thirst and darker urine, with skin elasticity also serving as a gauge.