Urinary System PDF

Also known as the Renal System Consists of organs that produce, store, and excrete urine. Renal processes or renal functions: 1.Filtration (glomerulus) Occurs in the glomerulus of the kidney. Blood is filtered to remove waste products, excess substances, and water, forming a filtrate that enter...

Also known as the Renal System Consists of organs that produce, store, and excrete urine. Renal processes or renal functions: 1.Filtration (glomerulus) Occurs in the glomerulus of the kidney. Blood is filtered to remove waste products, excess substances, and water, forming a filtrate that enters the renal tubules. 2. Reabsorption filtrate passes through the renal tubules, where essential substances like water, glucose, and ions are reabsorbed back into the bloodstream to maintain balance. The major sites of reabsorption in the urinary system are: 1. Proximal Convoluted Tubule (PCT): The majority of reabsorption happens here. About 65-70% of the filtered water, sodium, potassium, glucose, and amino acids are reabsorbed into the surrounding capillaries (peritubular capillaries). 2. Loop of Henle: Descending limb, water is reabsorbed due to osmotic pressure; filtrate is more concentrated. Ascending limb, sodium, chloride, and other ions are actively reabsorbed but impermeable to water, making the filtrate more dilute. 3. Distal Convoluted Tubule (DCT): Additional reabsorption of sodium and chloride occurs; hormones like aldosterone regulate it. Water is also reabsorbed under ADH. 4. Collecting Duct: Final adjustments in water and electrolyte balance; ADH increases water reabsorption, concentrating the urine. 3. Secretion Additional waste products, excess ions (K, H) & other metabolic wastes(urea, creatinine), and other substances are secreted into the filtrate from the blood. The major sites of secretion are: 1. Proximal Convoluted Tubule (PCT): Secretion of organic acids, drugs, toxins, and (H+) to regulate pH balance. 2. Distal Convoluted Tubule (DCT): Secretion of K+ and H+ under the influence of hormones like aldosterone to help regulate electrolyte balance and pH. 3. Collecting Duct: Additional secretion of K+ and H+ may occur to fine-tune electrolyte balance and acid-base homeostasis. 4. Excretion The remaining waste, excess water, and other substances form urine, which is then excreted from the body through the urethra. Major Organs 1. Kidneys The main major bean-shaped organs (2) of the urinary system. Vital functions: 1.Filtration of blood 2.Excretion of waste products 3.Regulation of Electrolytes 4.Maintain Fluid Balance 5.Maintain Acid-Base Balance 6.Regulate Blood Pressure 7.Production of Erythropoietin 8.Activate Vitamin D Main parts of the Urinary System Internal Anatomy of the Kidney: 1. Renal Artery - Carries Oxygen blood with waste products from body to kidney for filtration 2. Renal vein - Carries filtered deoxygenated blood from the kidney back to the heart Not part of Nephron but part of renal artery and renal vein: a. Afferent Arteriole: i.Carries blood into the glomerulus of the nephron. ii.Has a larger diameter than the efferent arteriole, creates higher pressure in the glomerulus, facilitating the filtration of blood. b. Efferent Arteriole: i.Carries filtered blood away from the glomerulus. ii.Has a smaller diameter compared to the afferent arteriole, maintains high pressure in the glomerulus for efficient filtration. 3. Renal capsule - A tough, protective outer layer that encases the kidney 4. Renal Cortex - Outer portion - blood filtration occurs; Contains glomeruli and parts of nephrons. 5. Renal Medulla - Main function is for the concentration of the urine and reabsorption - Inner region containing the renal pyramids and parts of nephrons (the loops of Henle and collecting ducts), which help in the concentration of urine. The nephron consists of the following parts: a. Renal Corpuscle - Includes a.Glomerulus (filters blood) b.Bowman’s capsule (collects filtrate). b. Proximal Convoluted Tubule (PCT) The bulk of reabsorption. Reabsorbs 65%-75% of filtered water, electrolytes (sodium, Potassium), glucose, amino acids, bicarbonate back into the blood stream  Secretes certain waste products (hydrogen ions, ammonia, some drugs) into the tubular fluid to be excreted c. Loop of Henle - extends from PCT deep into the medulla then back to cortex. i. Descending Permeable to water but not solute; Concentrates urine by reabsorbing water ii. Ascending Permeable to water but actively transport ions d. Distal Convoluted Tubule (DCT) Selective reabsorption of Na & Ca; fine-tunes the level of Potassium & Hydrogen ions There is already an influence of Aldosterone. 5. Collecting Duct The final segment of the nephron extending into the medulla and renal pelvis. Water reabsorption under the influence of ADH Final urine composition: - adjust salt, urea levels before the fluid enters the renal pelvis 6. Renal Pyramids - Triangular structures in renal medulla with the loops of Henle & collecting ducts. - Main function is to continue the work of the renal medulla; funnel the formed urine from collecting ducts towards papillae, drain into minor and major calyses. From there into renal pelvis. 7. Renal Pelvis - Central cavity that collects urine from renal pyramids and drains it into the ureter. 8. Ureter - A tube that transports urine from the kidney to the bladder for storage. 9. Calyces (Minor and Major) - Cup-like structures that collect urine from renal pyramids and funnel it into the renal pelvis. 2. Ureters Muscular tubes that transport urine from the kidneys to the bladder through peristalsis 3. Bladder A hollow, expandable organ that stores urine until it’s ready to be excreted 4. Urethra A tube that carries urine from the bladder to the outside of the body during urination Support Organs 1. Liver Converts toxic substances into urea, which the kidneys excrete in urine. 2. Lungs Help maintain blood pH balance, indirectly supporting kidney function in regulating acid-base levels. 3. Skin (Sweat Glands) Regulates fluid and electrolyte balance through sweat, providing a secondary waste removal route. 4. Endocrine Glands a. Adrenal Glands - Release hormones like aldosterone to help control blood pressure and kidney water balance. b. Pituitary Gland - Release ADH to help the kidneys conserve water and maintain hydration. 5. Circulatory System Supplies blood for kidney filtration and maintains the blood pressure necessary for kidney function. Composition of Urine: Normal components of urine includes: 1. Water (95% of urine) 2. Urea 3. Creatinine 4. Uric acid 5. Electrolytes: Sodium (Na⁺) Potassium (K⁺) Chloride (Cl⁻) Calcium (Ca²⁺) Magnesium (Mg²⁺) Bicarbonate (HCO₃⁻) 6. Other dissolved ions 7. Small amounts of nitrogenous waste 8. Hormones and metabolites 9. Trace amounts of vitamins 10. Pigments Abnormal components in urine include: 1. Proteins – Indicate kidney damage. 2. Glucose – Suggests diabetes. 3. Ketones – Associated with diabetes or starvation. 4. Blood cells (RBCs/WBCs) – Indicate infection, injury, or disease. 5. Bacteria – Sign of a urinary tract infection (UTI). 6. Crystals – May indicate kidney stones. 7. Hemoglobin – Could suggest hemolysis or injury. 8. Myoglobin – Indicates muscle injury. Common Disorders 1. Urinary Tract Infection (UTI) - Infection in the urinary system, usually affecting the bladder (cystitis) or kidneys (pyelonephritis). Frequent Urination – A strong, persistent urge to urinate, often with little urine produced. Burning Sensation During Urination – Pain or discomfort when urinating, often described as a burning or stinging sensation. Cloudy or Bloody Urine – Urine may appear cloudy, dark, or have a reddish or pink tint due to the presence of blood.  Strong-Smelling Urine – A foul or strong odor from the urine, which can be an indication of infection. Pelvic Pain or Lower Abdominal Pain – Pain or pressure in the lower abdomen or pelvic area. Fatigue or Malaise – Feeling unusually tired or unwell. Fever and Chills – In cases of more severe infections or when the infection spreads to the kidneys (pyelonephritis), fever and chills may occur. Nausea and Vomiting – These symptoms may indicate that the infection has reached the kidneys. 2. Kidney Stones (Nephrolithiasis) Solid deposits of minerals and salts that form in the kidneys and can cause pain, blockage, or infection;The size of stone is the most determinant of treatment 1. Calcium Oxalate Stones Description: The most common type of kidney stones, formed when calcium combines with oxalate in the urine. Food Sources to Avoid or Limit: High-oxalate foods: Spinach, beets, nuts, chocolate, rhubarb, and tea. Calcium-rich foods: Although calcium itself is not a direct cause, it’s important to balance calcium intake as it binds to oxalate in the digestive tract, reducing oxalate absorption and stone formation. 2. Calcium Phosphate Stones Description: These form in alkaline (higher pH) urine, often associated with conditions like renal tubular acidosis or certain medications. Food Sources to Consider: Alkaline-promoting foods: Vegetables, legumes, dairy, and some fruits like melons. Acid-promoting foods (to balance urine pH if prone): Meat, poultry, fish, and grains in moderation. 3. Uric Acid Stones Description: Formed when urine is too acidic, often due to high levels of purines, which break down into uric acid. These stones are common in people with gout or those consuming a high-protein diet. Food Sources to Avoid or Limit: High-purine foods: Red meat, organ meats (liver, kidney), shellfish, and certain fish (sardines, anchovies). Alternative Sources: Plant-based proteins and hydration to dilute urine acidity. 4. Struvite Stones Description: Usually associated with urinary tract infections (UTIs), these stones are composed of magnesium, ammonium, and phosphate. Dietary Focus: There’s less of a direct dietary link, as these are often due to infections. Good hydration and monitoring infections are key preventive measures. 5. Cystine Stones Description: Rare and formed due to a genetic disorder called cystinuria, which causes cystine (an amino acid) to leak into the urine and form stones. Dietary Management: High hydration: Increasing fluid intake to dilute the urine. Sodium restriction: Lower sodium intake helps reduce cystine in urine. General Preventive Dietary Tips Stay hydrated: Drinking plenty of water dilutes urine and reduces stone formation for all types. Moderate sodium: High sodium increases calcium in urine, raising the risk for calcium-based stones. Balance animal protein intake: High protein can increase calcium and uric acid in urine, so moderation is key. Include citrus fruits: Lemons and oranges contain citrate, which can help prevent stones by binding to calcium. 3. Chronic Kidney Disease (CKD) Gradual loss of kidney function over time, often due to conditions like diabetes or hypertension. Early Symptoms: Fatigue, loss of appetite, swelling (especially in feet/ankles), and changes in urination. Moderate to Severe Symptoms: High blood pressure, shortness of breath, persistent itching, muscle cramps, eye puffiness, and metallic taste. Advanced CKD: Severe fatigue, confusion, and unintentional weight loss. Can end to ESRD and need dialysis 4. Acute Kidney Disease Also known as Acute Kidney Injury (AKI), is a sudden decrease in kidney function that occurs within hours to days AKI is often due to a specific underlying cause, such as:  Decreased blood flow to the kidneys: Commonly from severe dehydration, heart failure, or blood loss. Direct kidney damage: From infections, toxins, certain medications (e.g., nonsteroidal anti-inflammatory drugs, some antibiotics), or traumatic injury. Urinary obstruction: Blockages like kidney stones, enlarged prostate, or tumors, which prevent urine from draining properly. Symptoms may vary but can include: Sudden decrease in urine output Swelling in legs, ankles, or around the eyes (fluid retention) Fatigue, confusion, or difficulty concentrating Nausea and vomiting Chest pain or pressure (due to fluid buildup around the heart) Shortness of breath 5. Bladder Cancer Cancer that begins in the cells of the bladder, often causing blood in the urine. Signs and Symptoms Blood in urine (hematuria): The most common symptom, usually painless and appearing intermittently. Frequent urination: A frequent need to urinate with little output. Painful urination: Discomfort or burning sensation during urination. Pelvic or back pain: May occur in advanced stages if cancer spreads. Risk Factors Smoking: A major risk factor, as chemicals from smoke are filtered into the urine. Chemical exposure: Long-term exposure to industrial chemicals, such as those used in dyes, rubber, or leather. Chronic bladder inflammation: From recurrent infections, stones, or prolonged catheter use. Age and gender: More common in older adults and men. 6. Incontinence Loss of bladder control, leading to unintentional leakage of urine. General Symptoms Urine leakage with physical movement or exertion Sudden, urgent need to urinate without warning Frequent urination or need to wake up at night to urinate  7. Polycystic Kidney Disease (PKD) A genetic disorder where cysts form in the kidneys, potentially leading to kidney failure. Common Signs and Symptoms High blood pressure: One of the earliest and most common symptoms, as cysts affect blood flow and hormone regulation in the kidneys. Back or side pain: Dull, aching pain due to kidney enlargement or cyst rupture. Abdominal fullness or enlargement: Enlarged kidneys may cause a feeling of fullness or visible swelling in the abdomen. Blood in urine (hematuria): Caused by cysts rupturing or by urinary tract infections. Frequent urinary tract infections (UTIs): Often occurring in the kidney cysts, causing pain, fever, and discomfort with urination. Kidney stones: More common in PKD patients, causing sudden pain, blood in the urine, and urinary blockage. Nephrotic syndrome is a kidney disorder characterized by damage to the glomeruli, the tiny blood vessels in the kidneys that filter waste and excess fluids from the blood. This damage allows proteins, especially albumin, to leak into the urine, leading to a specific set of symptoms and complications. Signs and Symptoms of Nephrotic Syndrome 1.Proteinuria: Excessive protein in the urine, making the urine appear foamy. 2.Hypoalbuminemia: Low levels of albumin in the blood due to protein loss in the urine. 3.Edema (swelling): Swelling in the legs, ankles, feet, and around the eyes due to fluid retention. 4.Hyperlipidemia: High levels of cholesterol and triglycerides in the blood as the body increases lipid production in response to low protein levels.