Urinary System Overview

Urinary System Overview

• The urinary system is responsible for filtering waste from the blood and eliminating it in urine.
• The system consists of the kidneys, ureters, bladder, and urethra.
• Kidneys are located in the posterior abdominal wall, on either side of the vertebral column.
• The right kidney is positioned at the level of T12 to L3, and the left kidney is at the level of T11 to L2. The left kidney is slightly higher than the right.
• The hilum renale is a fissure found on the medial surface of each kidney.
• Through the hilum renale, structures enter and exit the kidney. The hilum is located at approximately vertebral level L1.

Urinary System Components

• Kidneys: Filter blood, produce urine.
• Ureters: Drains urine from the kidneys to the bladder.
• Bladder: Stores urine. It's approximately 220-500 mL.
• Urethra: Transports urine from the bladder to the outside of the body.

Bladder Structure and Function

• The bladder is a reservoir for urine.
• The normal capacity of the bladder is approximately 220 mL.
• The bladder can hold up to 500 mL before needing to empty.
• The bladder is located posterior to the symphysis pubis in females. In males, it is anterior to the rectum.

Ureters

• The ureters are channels approximately 25–30 cm in length.
• They transport urine from the kidneys to the bladder.
• The ureters pass through the linea terminalis to enter the pelvis minor.

Urethra

• In males, the urethra is 20 cm long.
• In females, the urethra is 3–5 cm long.
• Internal and external sphincters control the release of urine.

Kidneys: Internal Structures

• The kidneys are composed of nephrons (functional units).
• Each kidney contains over one million nephrons.
• Nephrons filter blood and produce urine.

Stages of Urine Formation

• Filtration: Passage of plasma fluid from glomerulus to glomerular capsule.
• Reabsorption: Beneficial substances (water, glucose, and electrolytes) are transported back into the bloodstream.
• Excretion: Metabolic waste products are transferred from capillaries into the tubules, forming urine.

Blood Vessels of the Urinary System

• Renal artery: Branches from abdominal aorta, provides blood supply to the kidneys.
• Renal vein: Drains blood from the kidneys into the inferior vena cava.

Parts of the Urethra (males)

• Pars prostatica
• Pars membranacea
• Pars spongiosa

Structures of the Urinary System

• Glomerulus
• Bowman's capsule
• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule
• Collecting duct

Explore the essential aspects of the urinary system, including its components, functions, and anatomical details. This quiz covers the role of the kidneys, ureters, bladder, and urethra in waste elimination and urine production. Test your knowledge on the structure and function of this vital system.