Urinary System Overview

Overview

The urinary system, also known as the renal system, is responsible for producing, storing, and eliminating urine from the body.

Functions

• Filter waste and excess fluids from the blood
• Regulate electrolyte levels
• Maintain acid-base balance
• Produce hormones that help regulate blood pressure
• Store and eliminate waste

Organs

• Kidneys: filter waste and excess fluids from the blood, regulate electrolyte levels, and maintain acid-base balance
  • Located in the upper back, one on each side of the spine
  • Each kidney contains approximately 1 million nephrons, the functional units of the kidney
• Ureters: tubes that connect the kidneys to the bladder
  • Muscular walls that propel urine through peristalsis
• Bladder: stores urine
  • Hollow, muscular organ that expands to hold urine
  • Inner lining of epithelial cells and smooth muscle
• Urethra: tube that carries urine from the bladder to the outside of the body
  • In males, the urethra also carries semen during ejaculation

Nephron Structure

• Renal corpuscle: glomerulus and Bowman's capsule
  • Glomerulus: cluster of capillaries that filter the blood
  • Bowman's capsule: double-layered epithelial structure that surrounds the glomerulus
• Proximal convoluted tubule: reabsorbs water, ions, and nutrients back into the blood
• Loop of Henle: reabsorbs more water and ions back into the blood
• Distal convoluted tubule: regulates electrolyte levels and pH
• Collecting duct: collects urine from multiple nephrons and transports it to the renal pelvis

Urine Formation

• Glomerular filtration: blood pressure forces water and solutes out of the glomerulus and into Bowman's capsule
• Tubular reabsorption: nutrients, water, and ions are reabsorbed back into the blood
• Tubular secretion: waste and excess substances are secreted into the urine

Urine Characteristics

• pH: slightly acidic to neutral (pH 6.0-7.0)
• Specific gravity: concentration of solutes in the urine (1.003-1.030)
• Volume: varies depending on hydration level and other factors (average 1-2 liters per day)

Urinary System Overview

• Responsible for producing, storing, and eliminating urine from the body

Functions

• Filters waste and excess fluids from the blood
• Regulates electrolyte levels
• Maintains acid-base balance
• Produces hormones that help regulate blood pressure
• Stores and eliminates waste

Organs

• Kidneys: filter waste and excess fluids, regulate electrolyte levels, and maintain acid-base balance
  • Located in the upper back, one on each side of the spine
  • Each kidney contains approximately 1 million nephrons, the functional units of the kidney
• Ureters: tubes that connect the kidneys to the bladder, with muscular walls that propel urine through peristalsis
• Bladder: stores urine, a hollow, muscular organ that expands to hold urine
  • Inner lining composed of epithelial cells and smooth muscle
• Urethra: tube that carries urine from the bladder to the outside of the body
  • In males, the urethra also carries semen during ejaculation

Nephron Structure

• Renal corpuscle: glomerulus and Bowman's capsule
  • Glomerulus: cluster of capillaries that filter the blood
  • Bowman's capsule: double-layered epithelial structure that surrounds the glomerulus
• Proximal convoluted tubule: reabsorbs water, ions, and nutrients back into the blood
• Loop of Henle: reabsorbs more water and ions back into the blood
• Distal convoluted tubule: regulates electrolyte levels and pH
• Collecting duct: collects urine from multiple nephrons and transports it to the renal pelvis

Urine Formation

• Glomerular filtration: blood pressure forces water and solutes out of the glomerulus and into Bowman's capsule
• Tubular reabsorption: nutrients, water, and ions are reabsorbed back into the blood
• Tubular secretion: waste and excess substances are secreted into the urine

Urine Characteristics

• pH: slightly acidic to neutral (pH 6.0-7.0)
• Specific gravity: concentration of solutes in the urine (1.003-1.030)
• Volume: varies depending on hydration level and other factors (average 1-2 liters per day)