Objective One: Describe the Structure and Function of the Urinary System

Urinary system

Two kidneys, two ureters, urinary bladder, and one urethra.

Primary function of the urinary system

Maintains homeostasis by regulating body-fluid volume and composition and eliminating waste.

Kidney functions

Filter blood; remove metabolic wastes; regulate fluids, electrolytes, and acid-base balance; produce urine; help regulate blood pressure through sodium/water balance and RAAS.

Renal capsule

Thin protective covering surrounding each kidney; helps protect it from injury and infection.

Renal cortex

Outer kidney region containing renal corpuscles, glomeruli, and portions of renal tubules; site where blood filtration begins.

Renal medulla

Inner kidney region containing renal pyramids, portions of nephrons, and collecting ducts involved in concentrating urine.

Renal calyces

Cup-shaped structures that collect urine from the renal pyramids and drain it into the renal pelvis.

Renal pelvis

Funnel-shaped cavity that collects urine before it enters the ureter.

Ureters

Two muscular tubes that transport urine from kidneys to bladder by peristalsis.

Urinary bladder

Hollow muscular organ that temporarily stores urine until urination.

Urethra

Final urinary-system tube that carries urine from the bladder outside the body.

What structures make up the urinary system?

Two kidneys, two ureters, one urinary bladder, and one urethra.

What is the urinary system's primary responsibility?

Maintain homeostasis by regulating body-fluid volume and composition, especially blood, and eliminating waste.

What are the major functions of the kidneys?

Filter blood, remove wastes, regulate fluid/electrolytes and acid-base balance, produce urine, and help regulate blood pressure.

What are the renal cortex and medulla?

Cortex: outer region where filtration begins; medulla: inner region containing pyramids and collecting ducts that help concentrate urine.

Trace urine flow from collecting ducts to outside the body.

Collecting ducts → calyces → renal pelvis → ureters → bladder → urethra → outside.

How do ureters move urine to the bladder?

Their muscular walls contract through peristaltic movements.

What happens during urination?

The bladder muscle contracts and urinary sphincters relax, allowing urine to pass through the urethra.