Anatomy and Function of the Urinary System

Organs Involved:
- Kidneys: Two bean-shaped organs located in the lower back.
- Ureters: Tubes that carry urine from the kidneys to the bladder.
- Urinary Bladder: A muscular sac that stores urine until excretion.
- Urethra: A tube that carries urine from the bladder to the outside of the body.
Kidney Structure:
- Cortex: Outer layer containing nephrons.
- Medulla: Inner region consisting of renal pyramids.
- Renal Pelvis: Funnel-shaped structure that collects urine.

Filtration: Removes waste products and excess substances from the blood.
Regulation:
- Maintains electrolyte balance (sodium, potassium, calcium).
- Regulates blood pressure through the renin-angiotensin system.
- Controls blood pH by excreting hydrogen ions and reabsorbing bicarbonate.
Hormone Production:
- Erythropoietin: Stimulates red blood cell production.
- Calcitriol: Active form of vitamin D, regulates calcium metabolism.

Definition: Infection in any part of the urinary system, most commonly the bladder and urethra.
Causes:
- Bacterial invasion, usually by E. coli.
- Risk factors include female anatomy, sexual activity, and certain medical conditions.
Symptoms:
- Increased frequency and urgency to urinate.
- Pain or burning sensation during urination.
- Cloudy or strong-smelling urine, possible blood in urine.
Treatment: Antibiotics and increased fluid intake.

Types:
- Acute Renal Failure: Sudden loss of kidney function, often reversible.
- Chronic Renal Failure: Gradual loss of kidney function over time, often irreversible.
Causes:
- Acute: Dehydration, infections, medications, obstruction.
- Chronic: Diabetes, hypertension, glomerulonephritis.
Symptoms:
- Fatigue, swelling (edema), changes in urination, nausea, confusion.
Management: Dialysis, kidney transplant, lifestyle changes, and managing underlying conditions.

Processes:
- Filtration: Blood is filtered in the glomerulus, producing filtrate.
- Reabsorption: Essential substances (water, glucose, ions) are reabsorbed back into blood in tubules.
- Secretion: Additional wastes and excess ions are secreted into the tubules.
Final Product: Urine, which consists of water, urea, creatinine, electrolytes, and other waste products.
Volume and Composition:
- Average daily urine volume: 800-2000 mL.
- Composition varies based on hydration, diet, and health status.

Organs:
- Kidneys: Two kidney-shaped organs in the lower back responsible for filtering blood.
- Ureters: Tubes that transport urine from the kidneys to the urinary bladder.
- Urinary Bladder: A flexible muscular sac that stores urine until it is expelled.
- Urethra: The duct through which urine is discharged from the bladder.
Kidney Structure:
- Cortex: The outer layer where nephrons, the functional units of the kidney, are located.
- Medulla: The inner section characterized by renal pyramids that aid in urine concentration.
- Renal Pelvis: A funnel-shaped structure that collects urine produced in the kidneys for transport to the bladder.

Filtration: Vital for cleansing blood by eliminating waste and excess substances.
Regulatory Functions:
- Maintains balance of electrolytes like sodium, potassium, and calcium in the bloodstream.
- Regulates blood pressure through the renin-angiotensin system, influencing fluid balance.
- Controls blood pH by excreting hydrogen ions, reabsorbing bicarbonate as needed.
Hormones Produced:
- Erythropoietin: Promotes red blood cell formation in response to low oxygen levels.
- Calcitriol: The active form of vitamin D, crucial in regulating calcium and phosphate homeostasis.

Definition: Infections that impact any region of the urinary system, primarily affecting the bladder and urethra.
Causes:
- Commonly due to bacterial invasion, especially from E. coli.
- Risk factors include female anatomy, sexual practices, and certain underlying medical conditions.
Symptoms:
- Frequent and urgent need to urinate.
- Dysuria: pain or burning sensation during urination.
- Urine may appear cloudy, have a strong odor, or contain blood.
Treatment: Typically involves antibiotics and increased hydration to flush out the bacteria.

Types:
- Acute Renal Failure: Sudden decline in kidney function, potentially reversible with prompt treatment.
- Chronic Renal Failure: Progressive decline in kidney function over time, often leading to permanent damage.
Causes:
- Acute: Causes can include dehydration, infections, adverse effects from medications, or blockage in urine flow.
- Chronic: Commonly linked to diabetes, hypertension, and progressive kidney diseases like glomerulonephritis.
Symptoms:
- Include fatigue, swelling due to fluid retention (edema), alterations in urination patterns, nausea, and confusion.
Management: Approaches include dialysis, kidney transplantation, lifestyle modifications, and addressing underlying health issues.

Processes:
- Filtration: Occurs in the glomerulus, where blood is filtered to produce a substance called filtrate.
- Reabsorption: Essential substances such as water, glucose, and ions are reabsorbed back into the bloodstream from the renal tubules.
- Secretion: Additional wastes and extra ions are secreted into the renal tubules to be eliminated.
Final Product: Urine, consisting of water, urea, creatinine, various electrolytes, and other waste materials.
Volume and Composition:
- Average daily urine output ranges between 800 mL to 2000 mL.
- Urine composition can change based on hydration levels, dietary choices, and overall health conditions.