Urinary System Overview and Functions

Urinary System Overview

• Kidneys filter blood, sending urine to the bladder.
• In females, the kidneys are positioned near the ovaries.
• Kidneys are located in the upper part of the posterior abdominal wall, on either side of the vertebral column.
• The right kidney is positioned at the level of T12 to L3, while the left is at the level of T11 to L2.
• The left kidney is slightly higher than the right.

Urinary System Functions

• Blood filtration: Removes waste products.
• Electrolyte balance maintenance: Regulates electrolytes.
• Acid-base balance maintenance: Maintains proper pH.
• Blood volume regulation: Adjusts blood volume.
• Blood pressure regulation: Maintains appropriate blood pressure through hormonal regulation.
• Erythropoietin production: Stimulates red blood cell production.
• Vitamin D activation: Activates vitamin D.

Urinary System Structure and Location

• The urinary system includes two kidneys, two ureters, a urinary bladder, and a urethra.
• The kidneys are located posterior to the abdominal wall and are close to the transverse (T) vertebra and lumbar (L) vertebra.
• The hilum renale is a fissure on the kidney's medial surface where structures enter and exit the kidney.
• The hilum is approximately at the level of the L1 vertebra.
• The hilum opens into a region called the sinus renalis.
• The sinus renalis contains the calices minor and major.
• The renal pelvis is the funnel-shaped structure within the sinus renalis.

Urine Formation Stages

• Filtration: Fluid from the blood passes into the glomerular capsule.
• Reabsorption: Essential substances are taken back into the blood.
• Secretion: Wastes are added to the fluid.
• Excretion: Urine is produced.

Ureters

• Tubes that carry urine from kidneys to the bladder.
• They are about 25-30 cm long.
• They pass through the linea terminalis to enter the pelvic minor before reaching the bladder.

Bladder

• A reservoir for urine.
• Located posterior to the symphysis pubis in the pelvis.
• In females, the bladder is anterior to the uterus. In males, it is anterior to the rectum.
• The normal capacity is approximately 220 mL, but it can hold up to 500 mL of urine.
• When full, it extends to the level of the umbilicus.

Urethra

• In males, it is about 20 cm long, and in females, it's about 3-5 cm.
• The urethra has internal and external sphincters that control urination.

This quiz covers essential aspects of the urinary system, including the structure and functions of the kidneys, ureters, bladder, and urethra. It also highlights the regulatory roles the urinary system plays in maintaining bodily homeostasis such as blood volume and pressure. Test your knowledge on the crucial functions of this vital organ system.