Urinary Anatomy and Physiology Study Guide PDF

Study Guide: Urinary Anatomy and Physiology Module 8 Overview Functions of the Urinary System: o Maintains homeostasis o Acid-base balance o Water balance o Electrolyte balance o Toxin removal o Blood pressure control o Eryth...

Study Guide: Urinary Anatomy and Physiology Module 8 Overview Functions of the Urinary System: o Maintains homeostasis o Acid-base balance o Water balance o Electrolyte balance o Toxin removal o Blood pressure control o Erythropoietin production o Vitamin D production Organs of the Urinary System Kidneys Ureters Bladder Urethra Kidneys Gross Anatomy: o Location: Retroperitoneal (behind the peritoneal cavity), costal region, asymmetrical (right kidney is lower) o Supportive Tissues: § Renal fascia: Dense fibrous connective tissue anchoring the kidney to the wall § Perirenal fat capsule: Fatty cushion insulating the kidneys § Fibrous capsule: Dense irregular connective tissue preventing infection spread o Layers: § Renal cortex: Striated outermost layer § Renal medulla: Innermost layer § Renal pyramids: Broad base faces the cortex § Renal columns: Separate renal pyramids § Renal papilla: Tops of the pyramids § Renal sinus: Empty space o Internal Anatomy: § Minor calyx: Collects urine from pyramidal papillae § Major calyx: Collects urine from minor calyces § Renal pelvis: Collects urine from major calyx § Urine flow: Renal pyramid → minor calyx → major calyx → renal pelvis → ureter Microanatomy: o Nephron: Functional unit of the kidney § Types: § Cortical  § Juxtamedullary § Components: § Renal corpuscle § Glomerular capsule (Bowman’s capsule) § Glomerulus § Renal tubules o Renal Corpuscle: § Filtration § Glomerular capsule: Cup-shaped, hollow structure surrounding the glomerulus § Layers: Parietal (simple squamous epithelium) and visceral (branching epithelium with podocytes) § Filtration membrane: Fenestrated endothelium, basement membrane, pedicles of podocytes with filtration slits o Renal Tubules: § Proximal convoluted tubules (PCT): Cuboidal cells with dense microvilli, functions in reabsorption and secretion § Loop of Henle: U-shaped structure with descending and ascending limbs § Distal convoluted tubules (DCT): Functions more in secretion than reabsorption, drains into collecting ducts o Juxtaglomerular Complex: § Macula densa: Chemoreceptors sensing NaCl content of filtrate § Granular cells (JG cells): Mechanoreceptors sensing blood pressure, release renin Functions of the Nephron: o Filtration: Movement of fluid from the glomerular capsule to capsular space o Reabsorption: Movement of filtrate from renal tubule to bloodstream o Secretion: Movement of fluid from the bloodstream into renal tubules Ureters Function: Transport urine from kidneys to the bladder Structure: o Mucosa: Transitional epithelium o Muscularis: 2-3 layers of smooth muscle o Adventitia: Outer fibrous connective tissue Urinary Bladder Function: Temporary storage of urine Location: o Males: Anterior to the rectum o Females: Anterior to vagina and uterus Structure: o Trigone: Smooth triangular area outlined by openings for ureters and urethra o Histology: § Mucosa: Transitional epithelial mucosa  § Submucosa: Connective tissue § Muscularis: Three layers of smooth muscle (detrusor muscle) § Adventitia: Outermost layer Sphincters: o Internal urethral sphincter: Involuntary smooth muscle at bladder-urethra junction o External urethral sphincter: Voluntary skeletal muscle surrounding the urethra Urethra Function: Drains urinary bladder Micturition: Expelling urine activated when the bladder fills to ~300 ml Female Urethra: o Length: 3-4 cm o Location: Tightly bound to anterior vaginal wall o External urethral orifice: Anterior to vaginal opening Male Urethra: o Carries semen and urine o Three regions: § Prostatic urethra: Within prostate (2.5 cm) § Intermediate part (membranous urethra): Passes through urogenital diaphragm (2 cm) § Spongy urethra: Passes through penis (15 cm), opens via external urethral orifice Study Guide: Anatomy & Physiology II - Urinary System Module 8: Urinary Anatomy and Physiology Key Topics: 1. Anatomy of the Urinary System o Kidneys: Structure and function o Ureters: Transport of urine from kidneys to bladder o Bladder: Storage of urine o Urethra: Excretion of urine 2. Nephron Structure and Function o Glomerulus: Tuft of capillaries involved in filtration o Proximal Convoluted Tubule (PCT): Reabsorption of water, ions, and nutrients o Loop of Henle: Descends into the medulla, involved in concentrating urine o Distal Convoluted Tubule (DCT): Further reabsorption and secretion o Collecting Duct: Final concentration of urine 3. Urine Formation Processes o Filtration: Occurs in the glomerulus o Reabsorption: Mainly in PCT and Loop of Henle  o Secretion: Occurs in DCT 4. Glomerular Filtration Rate (GFR) o Definition: Amount of filtrate formed by all nephrons in both kidneys per minute (125 ml/min) o Factors Influencing GFR: § Net Filtration Pressure (NFP) § Total surface area for filtration § Permeability of the filtration membrane 5. Renal Clearance o Formula: Cx = (V x Ux) / Px § Cx: Plasma clearance of substance X § V: Urine flow rate (ml/min) § Ux: Concentration of X in urine § Px: Concentration of X in plasma o Comparison to GFR: Determines if a substance is reabsorbed or secreted 6. Urine Volume and Concentration o Dehydration: Leads to darker, more concentrated urine o Hydration: Maintains proper urine volume and concentration 7. Micturition (Urine Excretion) o Anatomy and Physiology: Bladder and urethra o Neural Control: Coordination of muscle contractions for urine release o Common Issues: Urinary incontinence, urinary retention Review Questions: 1. Which of the following structures is not part of a nephron? o A) Glomerulus o B) Proximal convoluted tubule o C) Loop of Henle o D) Aorta 2. Which of the following descends into the medulla? o A) Bowmans capsule o B) DCT o C) PCT o D) Loop of Henle 3. The tuft of capillaries in the renal corpuscle is called the _____. o A) Podocytes o B) Glomerulus o C) Calyx o D) Renal Pyramid Additional Resources: Nephron Review Animation: Watch the animation and answer questions on Nearpod for bonus points. o Nephron Animation Study Guide: Fluid and Electrolyte Homeostasis Fluid and Acid-Base Balance 1. Introduction to Body Fluids Main Component: Water Fluid Balance: Maintaining appropriate volume and concentration of intracellular and extracellular fluids Body Fluid Composition: o Intracellular Fluid (ICF): 40% of body weight o Extracellular Fluid (ECF): 20% of body weight (includes plasma and interstitial fluid) 2. Composition of Body Fluids Solvent: Water Solutes: o Nonelectrolytes: Do not dissociate in water (e.g., glucose, lipids) o Electrolytes: Dissociate in water, produce charged particles 3. Osmosis and Tonicity Osmosis: Movement of water across a selectively permeable membrane Tonicity: o Hypertonic: More solute, less water o Hypotonic: Less solute, more water o Isotonic: Equal solute, equal water 4. Water Movement Influenced by Two Gradients: o Hydrostatic Pressure Gradient: Pushing force exerted by fluid o Osmotic Pressure Gradient: Pulling force Osmolarity: Number of solute particles per liter of solution Fluid Movement: o Plasma and Interstitial Fluid: Across capillary walls, determined by Net Filtration Pressure (NFP) o Interstitial Fluid and ICF: Across cell membrane, water moves freely, solutes move through protein transporters 5. Regulation of Water Balance Water Intake: Governed by hypothalamic thirst center, stimulated by increased plasma osmolarity or drop in blood volume Water Output: Regulated by kidneys, primarily through ADH (Antidiuretic Hormone) o ADH: Increases water reabsorption, decreases osmolarity, increases volume of body fluids 6. Water Imbalances Dehydration: o Causes: Hemorrhage, burns, vomiting, diarrhea, sweating, water deprivation, diuretic abuse, endocrine disturbances  o Signs: Thirst, dry skin, weight loss, fever, mental confusion, hypernatremia o Treatment: Hypotonic saline Overhydration (Hypotonic Hydration): o Causes: Renal insugiciency, rapid water ingestion o Signs: Nausea, vomiting, cramps, cerebral edema, hyponatremia o Treatment: Hypertonic saline Electrolyte Homeostasis 1. Sodium (Na+) Role: Regulates ECF volume and osmolarity Intake and Output: o Intake: Food and drinks o Output: Urine, sweat, feces Ebects on ECF: o Primary Contributor: 280 mOsm of total 300 mOsm ECF solute concentration o Controls: ECF volume and water distribution o Changes in Na+ Levels: Agect ECF volume and blood pressure Regulation: o Aldosterone: Increases Na+ reabsorption o ANP (Atrial Natriuretic Peptide): Increases Na+ excretion 2. Potassium (K+) Role: Agects resting membrane potential (RMP) in neurons and muscle cells Ebects of K+ Concentration: o Increased ECF [K+]: Causes depolarization, reduced excitability o Hyperkalemia: RMP more positive, cells less functional o Decreased ECF [K+]: Causes hyperpolarization o Hypokalemia: RMP more negative, cells less responsive Regulation: Modulated by kidneys via aldosterone-dependent secretion in the distal convoluted tubule (DCT) Key Questions 1. Electrolyte Balance: Usually refers to salt balance in the body. 2. Percentage of ECF Constituted by Plasma: About 20%. Study Guide: Reproductive Anatomy and Physiology Male Reproductive Anatomy 1. Testes o Sperm-producing gonads within the scrotum. o Surrounded by two tunics: Tunica vaginalis (outer) and Tunica albuginea (inner). o Contains seminiferous tubules for sperm production. o Important cell types: § Sustentocytes/Sertoli cells: Support sperm formation. § Spermatogenic cells: Give rise to sperm.  § Interstitial endocrine cells (Leydig cells): Produce testosterone. 2. Accessory Organs o Scrotum: Sac of skin and superficial fascia, divided by a midline septum. o Epididymis: Site of sperm maturation and storage. o Vas deferens: Transports sperm from the epididymis to the urethra. o Spermatic cord: Encloses nerve fibers, blood vessels, and lymphatics. o Urethra: Conveys urine and semen; has three regions (prostatic, membranous, spongy). o Penis: Male copulatory organ with erectile tissues (corpus spongiosum and corpora cavernosa). o Glands: § Seminal glands: Secrete fructose and prostaglandins. § Prostate gland: Secretes enzymes and PSA. § Bulbourethral gland: Secretes alkaline mucous. Female Reproductive Anatomy 1. Ovaries o Paired structures flanking the uterus. o Surrounded by fibrous tunica albuginea. o Outer cortex houses forming gametes; inner medulla contains blood vessels and nerves. o Follicles: Tiny saclike structures containing immature eggs (oocytes). 2. Accessory Organs o Fallopian Tubes: Usual site of fertilization; regions include infundibulum, ampulla, and isthmus. o Uterus: Hollow, muscular organ with three layers (perimetrium, myometrium, endometrium). o Vagina: Functions as birth canal, passageway for menstrual flow, and organ of copulation. o Mammary Glands: Produce milk to nourish newborns. General Biology Concepts 1. Chromosomes and Sexual Reproduction o Humans have 23 pairs of chromosomes (46 total). o Ogspring receive 23 chromosomes from each parent (diploid = 2n). o Gametes (egg and sperm) are haploid (1n) with 23 chromosomes. 2. Meiosis o Reduces chromosome number from 46 to 23 to form haploid gametes. o Involves two divisions: Meiosis I and Meiosis II. o Results in four haploid cells from one diploid cell. 3. Mitosis o Process of cell division for growth and repair. o Produces two identical diploid cells from one diploid cell. Male Reproductive Physiology 1. Hormonal Control o Testosterone stimulates spermatogenesis.  oRegulated by a multi-tiered negative feedback loop: § GnRH from hypothalamus. § FSH and LH from anterior pituitary. § LH stimulates testosterone production; FSH stimulates sustentacular cells. 2. Spermatogenesis o Formation of sperm in seminiferous tubules. o Steps: § Mitosis: Spermatogonia form primary spermatocytes. § Meiosis I: Primary spermatocytes form secondary spermatocytes. § Meiosis II: Secondary spermatocytes form spermatids. § Spermatids mature into spermatozoa. Female Reproductive Physiology 1. Oogenesis o Formation of oocytes. o Begins during fetal development; primary oocytes arrest at prophase I. o At puberty, hormonal changes trigger the ovarian cycle. o Each month, primary oocytes complete meiosis I to form secondary oocytes. 2. Ovarian Cycle o Follicular Phase (Days 0-14): Follicle growth and development. o Ovulation: Release of secondary oocyte. o Luteal Phase (Days 15-28): Corpus luteum formation and hormone secretion. 3. Hormonal Control o Fluctuating levels of GnRH, FSH, and LH regulate the ovarian cycle. o High levels of estrogen and progesterone play key roles. Study Guide: Fluid, Electrolyte, and Acid-Base Balance Module 9.0: Fluid and Acid-Base Balance Introduction: Main Component: Water Fluid Balance: Maintaining appropriate volume and concentration of intracellular and extracellular fluids Body Fluids Composition: o Total Body Weight: ~60% o Intracellular Fluid (ICF): 40% of body weight o Extracellular Fluid (ECF): 20% of body weight (includes plasma and interstitial fluid) Body Fluids: Solvent: Water Solutes: o Nonelectrolytes: Do not dissociate in water (e.g., glucose, lipids) o Electrolytes: Dissociate in water, produce charged particles Osmosis and Tonicity: Osmosis: Movement of water across a selectively permeable membrane Tonicity: o Hypertonic: More solute, less water o Hypotonic: Less solute, more water o Isotonic: Equal solute, equal water Water Movement: Influenced by Gradients: o Hydrostatic Pressure Gradient: Pushing force exerted by fluid o Osmotic Pressure Gradient: Pulling force Osmolarity: Number of solute particles per liter of solution Fluid Movement: o Plasma and Interstitial Fluid: Across capillary walls o Interstitial Fluid and ICF: Across cell membrane Water Balance: Intake and Output: ~2500 ml/day Regulation of Water Intake: Governed by hypothalamic thirst center Regulation of Water Output: Primarily by kidneys through ADH Water Imbalances: Dehydration: o Causes: Hemorrhage, burns, vomiting, diarrhea, sweating, water deprivation, diuretic abuse, endocrine disturbances o Signs: Cottony oral mucosa, thirst, dry flushed skin o Symptoms: Weight loss, fever, mental confusion, hypernatremia o Treatment: Hypotonic saline Overhydration (Hypotonic Hydration): o Causes: Renal insugiciency, rapid excess water ingestion o Signs: Metabolic disturbances, nausea, vomiting, cramping, cerebral edema, possible death o Symptoms: Hyponatremia o Treatment: Hypertonic saline Electrolyte Homeostasis Sodium (Na+): Role: Regulates ECF volume and osmolarity Intake and Output: o Intake: Food and drinks o Output: Urine, sweat, feces Contribution to ECF Osmolarity: 280 mOsm of total 300 mOsm Control of ECF Volume and Water Distribution: Water follows salt Na+ Load: Total Na+ content in the body o Regulation: Aldosterone (RAAS) and ANP o Aldosterone: Increases Na+ reabsorption o ANP: Inhibits RAAS and ADH, increases Na+ excretion Potassium (K+):  Role: Agects resting membrane potential (RMP) in neurons and muscle cells Ebects of K+ Concentration Changes: o Increased ECF [K+]: Depolarization of RMP, reduced excitability o Hyperkalemia: RMP more positive, cells less functional o Decreased ECF [K+]: Hyperpolarization o Hypokalemia: RMP more negative, cells less responsive Regulation: Kidneys via aldosterone-dependent secretion in principal cells of the DCT Key Questions 1. About how much (percentage-wise) of extracellular fluid (ECF) is constituted by plasma? o Options: 5, 10, 20, 40 2. “Electrolyte balance” usually refers to _____ balance in the body. o Options: Protein, Salt, Acid, Base Study Guide: Fluid and Acid-Base Balance Module 9.0: Fluid and Acid-Base Balance Key Concepts: 1. Dissociation of Water, Acids, and Bases: o Water: Dissociates into hydroxide ions (OH-) and hydrogen ions (H+). o Acids: Dissociate in water to increase hydrogen ions (H+). Strong acids completely dissociate (e.g., HCl), while weak acids do not completely dissociate (e.g., H2CO3). o Bases: Dissociate in water to increase hydroxide ions (OH-) and decrease hydrogen ions (H+). Strong bases completely dissociate (e.g., NaOH), while weak bases do not completely dissociate (e.g., NH3). 2. pH Scale: o Measures the concentration of H+ in a solution. o Scale ranges from 0 to 14: § Acidic solutions: pH < 7 (more H+ than OH-) § Neutral solutions: pH = 7 (H+ = OH-) § Basic solutions: pH > 7 (more OH- than H+) o pH and [H+] are reciprocal: If [H+] increases, pH decreases and vice versa. 3. pH Homeostasis: o Normal blood pH: 7.35 to 7.45. o Imbalances: § Alkalosis: pH > 7.45 § Acidosis: pH < 7.35 o Ebects of pH Imbalance: § Neurons: Neuron excitability is correlated to pH. § Proteins: Denaturation. § Potassium Levels:  § Acidosis: Type A intercalated cells secrete H+ and reabsorb K+. § Alkalosis: Type B intercalated cells secrete K+ and reabsorb H+. 4. Sources of Excess H+: o Carbonic acid, diet, and metabolic activities. 5. Buber Systems: o Chemical Bubers: Resist changes in pH by binding or releasing H+. § Carbonic Acid/Bicarbonate Buber System: § CO2 + H2O ⇌ H2CO3 ⇌ HCO3- + H+ § When pH drops, bicarbonate ions bind H+ to form H2CO3. § When pH increases, H2CO3 dissociates. § Phosphate Buber System: Active in the urinary system. 6. Bubering Mechanisms: o Respiratory Bubering: § Acidosis: Increases ventilation to remove CO2. § Alkalosis: Decreases ventilation to retain CO2. o Renal Bubering: § Type A cells (active during acidosis): Secrete H+ and reabsorb HCO3-. § Type B cells (active during alkalosis): Reabsorb H+ and secrete HCO3-. 7. Acid/Base Imbalances: o Acidosis: § Respiratory Acidosis: § Cause: Hypoventilation. § Egect: Retention of CO2, increased H+. § Compensation: Chemical bugers, increased ventilation, renal compensation (Type A cells). § Metabolic Acidosis: § Cause: Addition of H+ or decrease of HCO3- (e.g., diet, intense exercise, diarrhea). § Compensation: Chemical bugers, increased ventilation, renal compensation (Type A cells). o Alkalosis: § Respiratory Alkalosis: § Cause: Hyperventilation. § Egect: Excessive loss of CO2, decreased H+. § Compensation: Chemical bugers, decreased ventilation, renal compensation (Type B cells). § Metabolic Alkalosis: § Cause: Loss of H+ or excess HCO3- (e.g., prolonged vomiting, overuse of antacids). § Compensation: Chemical bugers, decreased ventilation, renal compensation (Type B cells). Tips for Studying: Understand the basic concepts of acids, bases, and pH. Memorize the normal pH range for blood and the definitions of acidosis and alkalosis. Learn the causes and ebects of pH imbalances and how the body compensates for these imbalances. Familiarize yourself with the chemical buber systems and how they function to maintain pH homeostasis. Review the respiratory and renal mechanisms for bugering pH changes.