Urinary, Digestive, and Reproductive Systems

Urinary System

• Main Organs:
  • Kidneys
  • Ureters
  • Urinary bladder
  • Urethra
• Main Functions of Kidneys:
  1. Filter waste products from blood:
     • Main waste products: Urea, uric acid, and creatinine
  2. Maintain water balance and blood consistency.
  3. Metabolize and excrete medication and toxins.
  4. Secrete hormones: erythropoietin and renin.
  5. Activates Vitamin D.
• Kidney Location and Hilum:
  • Located retroperitoneal in the superior lateral region of the posterior abdominal wall.
  • Right kidney is lower due to the liver.
  • Hilum: Vertical cleft where vessels, ureters, and nerves enter/exit.
• Kidney Cross-Section Areas:
  • Cortex
  • Renal medulla
  • Renal pelvis
• Renal Pyramids:
  • Cone-shaped masses in the renal medulla.
• Renal Calices:
  • "Filled space" containing renal vessels, nerves, fat, and urine-carrying tubes.
  • Renal pelvis: Expanded superior part of the ureter.
  • Major calices: Branching extensions of the renal pelvis.
  • Minor calices: Cup-shaped tubes enclosing papillae of the pyramids, collecting urine.
• Urine Flow:
  • Calices collect urine from papillae, empty into the renal pelvis, then into the ureter, which transports it to the bladder.
• Branches of the Renal Artery:
  1. Renal arteries
  2. Segmental arteries
  3. Interlobar arteries
  4. Arcuate arteries
  5. Cortical radiate (interlobular) arteries
     • Afferent arterioles
     • Glomeruli
     • Efferent glomerular arteriole
     • Peritubular capillaries and vasa recta
• Veins of the Kidney:
  1. Cortical radiate vein
  2. Arcuate vein
  3. Interlobar vein
     • Renal vein
     • IVC (Inferior Vena Cava)
• Nephron Parts:
  1. Renal tubule
  2. Renal corpuscle
• Renal Corpuscle Components:
  1. Glomerulus:
     • Tuft of capillaries.
     • Supplied by afferent arteriole, drained by efferent arteriole.
     • Fenestrated capillaries.
  2. Glomerular (Bowman’s) capsule:
     • Parietal layer: Simple squamous epithelium.
     • Visceral layer: Podocytes.
• Podocytes:
  • Branching epithelial cells in the visceral layer.
  • Foot processes (pedicels) interdigitate around glomerular capillaries.
• Renal Tubule Components:
  • Proximal convoluted tubule
  • Nephron loop (Loop of Henle):
    • Ascending limb
    • Descending limb
  • Distal convoluted tubule
• Urine Production Stages:
  1. Filtration: Blood filtrate leaves kidney capillaries.
  2. Reabsorption: Nutrients, water, and essential ions reclaimed.
  3. Secretion: Active removal of undesirable molecules.
• Filtration Membrane Components:
  1. Fenestrated endothelium of the capillary.
  2. Filtration slits between podocyte foot processes.
  3. Basement membrane.
• Male Urethra Parts:
  1. Prostatic urethra: Passes through the prostate gland.
  2. Intermediate part of urethra: Passes through the urogenital diaphragm.
  3. Spongy (penile) urethra: Passes through the length of the penis.
• UTI (Urinary Tract Infection):
  • More common in women due to shorter urethra.

Digestive System (Chapter 23)

• Organs:
  • Main organs: Mouth, pharynx, esophagus, stomach, small intestine, large intestine.
  • Accessory organs: Teeth, tongue, gallbladder, salivary glands, liver, pancreas (connected by ducts).
• Digestive System Functions:
  1. Ingestion: Occurs in the mouth.
  2. Propulsion (Peristalsis): Movement of food.
  3. Digestion:
     • Mechanical digestion: Prepares food for chemical digestion (chewing, churning).
     • Chemical digestion: Complex molecules broken down by enzymes.
  4. Absorption: Transport of digested nutrients to blood and lymph.
  5. Defecation: Elimination of indigestible substances as feces.
• Peritoneum:
  • Serous membrane.
    • Visceral peritoneum: Surrounds digestive organs.
    • Parietal peritoneum: Lines the body wall.
  • Peritoneal cavity: Potential space.
  • Mesentery:
    • Double layer of peritoneum.
    • Holds organs in place.
    • Sites of fat storage.
    • Route for vessels and nerves.
• Peristalsis vs. Segmentation:
  • Peristalsis: Waves of contraction and relaxation.
  • Segmentation: Rhythmic local constrictions, mixing food and increasing absorption efficiency.
• Alimentary Canal Wall Layers:
  1. Mucosa:
     • Epithelium (absorbing and secreting mucus).
     • Lamina propria.
     • Muscularis mucosae: Local movements of the mucosa.
  2. Submucosa:
     • Contains blood vessels, lymphatic vessels, nerve fibers.
  3. Muscularis externa:
     • Circular layer: Squeezes gut tube.
     • Longitudinal layer: Shortens gut tube.
  4. Serosa:
     • Same as visceral peritoneum.
     • Simple squamous epithelium.
• Oral Cavity Borders:
  • Lips anteriorly.
  • Cheeks laterally.
  • Palate superiorly:
    • Hard palate, soft palate, uvula.
  • Tongue inferiorly.
  • Fauces of oropharynx posteriorly.
• Tongue Functions:
  • Sense of taste.
  • Food manipulation during chewing.
  • Mixing food with saliva to form a bolus.
  • Swallowing: Pushing bolus into the pharynx.
  • Lingual frenulum secures tongue to floor of mouth.
• Teeth:
  • Deciduous teeth: 20 (first appear at 6 months).
  • Permanent teeth: 32 (erupt by adolescence).
  • Dental formula: 2I, 1C, 2P, 3M (x4 = 32).
    • 2 Incisors
    • 1 Canine
    • 2 Premolars
    • 3 Molars
• Tooth Parts and Layers:
  • Parts:
    • Crown: Exposed surface.
    • Neck: At the gum line.
    • Root: In tooth socket.
  • Layers:
    • Enamel: Outer layer, hardest tissue in body.
    • Dentin: Underlies enamel.
    • Pulp cavity: Center of tooth.
• Major Salivary Glands:
  • Parotid glands: Parotid duct parallel to zygomatic arch.
  • Submandibular glands: Along medial surface of mandible.
  • Sublingual glands: Under tongue.
• Saliva:
  • Complex mixture of water, ions, mucus, and enzymes.
  • Moistens mouth, dissolves food, wets food, and binds food into a bolus.
• Cardiac Sphincter:
  • Closes off the lumen, preventing regurgitation of stomach juices into the esophagus.
• Stomach Parts:
  • Cardiac region
  • Cardiac sphincter
  • Fundus
  • Body
  • Pyloric part:
    • Pyloric antrum
    • Pyloric canal
    • Pyloric sphincter (valve for stomach and duodenum)
  • Rugae of mucosa (mucosal folds)
  • Greater curvature
  • Lesser curvature
• Stomach Function:
  • Storage tank; food churned into chyme.
  • Food remains in stomach for about 4 hours.
• Muscularis Externa in Stomach:
  1. Longitudinal layer
  2. Circular layer
  3. Oblique layer
• Small Intestine Parts:
  1. Duodenum:
     • C-shaped loop; most chemical digestion occurs.
     • Receives enzymes and bile.
     • Main pancreatic duct and common bile duct enter.
     • Sphincters control entry of bile and pancreatic juices.
  2. Jejunum:
     • Most nutrient absorption takes place.
  3. Ileum:
     • Absorbs most vitamins and minerals.
• Small Intestine Functions:
  • Longest part of the alimentary canal.
  • Site of enzymatic digestion and absorption.
• Modifications for Absorption in Small Intestine:
  • Circular folds: Transverse ridges of mucosa and submucosa.
  • Villi: Fingerlike projections of the mucosa; covered with simple columnar epithelium.
  • Microvilli: Further increase surface area for absorption.
• Large Intestine Parts:
  1. Cecum
  2. Ascending colon
  3. Transverse colon
  4. Descending colon
  5. Sigmoid colon
  6. Rectum
  7. Anal canal
     • External anal sphincter
• Special Features of the Large Intestine:
  • Teniae coli: Thickening of longitudinal muscularis externa.
  • Haustra: Puckering created by teniae coli.
  • Epiploic appendages: Fat-filled pouches of visceral peritoneum.
  • Right colic (hepatic) flexure: Between ascending and transverse colon.
  • Left colic (splenic) flexure: Under spleen.
  • Ileocecal valve: Prevents backflow.
• Large Intestine Functions:
  • Absorb water and electrolytes.
  • Small amount of digestion by bacteria.
  • Mass peristaltic movements force feces toward the rectum.
• Liver Parts:
  • Located in RUQ under diaphragm, extends to LUQ.
  • Liver capsule: Connective tissue sheet.
    • Falciform ligament: Separates right and left lobes.
    • Round ligament: Separates left lobe from quadrate lobe.
    • Ligamentum venosum: Separates caudate lobe from left lobe.
• Porta Hepatis Elements:
  1. Hepatic portal vein: Brings blood toward the liver.
  2. Hepatic artery proper
  3. Common hepatic duct (bile duct): Brings bile out of liver.
     • Cystic duct takes bile to gallbladder; bile duct takes bile to duodenum.
• Liver Functions (Digestive System):
  • Bile production.
• Bile Storage and Secretion:
  • Stored in the gallbladder.
  • Secreted to duodenum via ducts.
• Pancreas Functions:
  • Endocrine function: Produces insulin and glucagon.
  • Exocrine function: Acinar cells secrete enzymes to digest food in the small intestine.
  • Main pancreatic duct joins bile duct to form the hepatopancreatic ampulla, emptying into duodenum.
• Peptic Ulcer Cause:
  • Helicobacter pylori.

Reproductive System (Chapter 25)

• Gonads:
  • Male: Testes produce sperm.
  • Female: Ovaries produce ovum (egg).
• Male Reproductive System Ducts:
  1. Epididymis
  2. Ductus (vas) deferens
  3. Ejaculatory ducts
  4. Urethra (for urine and semen)
• Male Reproductive System Glands:
  1. Seminal glands
  2. Prostate gland
  3. Bulbourethral glands
• Scrotum:
  • Skin and fascia surrounding the testes.
  • Maintains temperature 3 degrees cooler than body temperature optimal for spermatogenesis.
• Spermatogenic Cells:
  • Produce sperm through spermatogenesis.
• Interstitial Cells:
  • Produce testosterone.
• Epididymis:
  • Sperm maturation; gain the ability to produce and swim.
  • Comma-shaped organ arches over the posterior and lateral side of the testis.
• Ductus (Vas) Deferens:
  • Stores and transports sperm during ejaculation.
  • Runs from the tail of the epididymis, through the spermatic cord and inguinal canal, and enters the pelvic cavity.
• Spermatic Cord Components:
  • Testicular vessels and nerves
  • Ductus deferens
• Seminal Vesicles:
  • Lie on the posterior surface of the bladder.
  • Secrete 60% of semen volume.
• Prostate Gland:
  • Encircles the first part of the urethra, inferior to the bladder.
  • Secretes about 1/3 of semen volume.
  • Aid in protection and movement of sperm.
• Bulbourethral Glands:
  • Pea-sized glands inferior to the prostate within the urogenital diaphragm.
  • Produces mucus that neutralizes acidic urine in the urethra and lubricates the urethra.
• Penis Internal Structures:
  • Two corpora cavernosa: Make up most of the penis.
  • One corpus spongiosum: Surrounds the spongy urethra.
• Erection and Ejaculation:
  • Erection: Parasympathetic control.
  • Ejaculation: Sympathetic control.
• Ovaries Parts:
  • Medulla: Blood vessels and nerves.
  • Cortex: Houses follicles forming gametes.
• Oviducts Parts:
  • Infundibulum: Opening of uterine tube into the peritoneal cavity.
  • Ampulla: Widest part; site of fertilization.
  • Isthmus: Narrow portion; empties into the uterus.
• Uterus Location:
  • Hollow, thick-walled, muscular organ in the pelvic cavity.
  • Between the urinary bladder and rectum.
  • Receives, retains, and nourishes a fertilized ovum.
• Uterus Parts:
  • Fundus: Rounded region superior to the uterine tube entrance.
  • Body: Major portion of the uterus.
  • Isthmus: Narrow region between the body and cervix.
  • Cervix: Projects into the vagina.
    • Internal OS: Opening between the cervix and uterus.
    • External OS: Opening between the cervix and vagina.
    • Cervical canal: Cavity of cervix.
• Uterus Layers:
  1. Endometrium:
     • Functional layer: Shed during menstruation.
     • Basal layer: Contains stem cells for a new functional layer.
  2. Myometrium:
     • Interlacing bundles of smooth muscle.
     • Contract during childbirth.
  3. Perimetrium:
     • Serous layer; peritoneum.
• Female External Genitalia (Vulva):
  • Mons pubis: Fatty area overlying pubic symphysis.
  • Labia majora: Fatty skin running posteriorly from the mons pubis.
  • Labia minora: Thin folds within the labia majora.
  • Vestibule: Enclosed by labia minora; contains the urethra and vagina openings.
  • Clitoris: Erectile tissue.
  • Prepuce of clitoris: Surrounding clitoris.
  • Urethral orifice
  • Vaginal orifice
  • Hymen: Membrane partially covering the vagina opening.
• Ovarian Cycle Phases:
  1. Follicular phase: Follicle-stimulating.
  2. Ovulation:
     • Midway through the cycle (day 14).
     • LH surge signals ovulation.
  3. Luteal phase: After ovulation.
• Uterine Cycle Phases:
  1. Menstrual bleeding (5 days)
  2. Proliferative phase (days 6-14): Functional layer rebuilds.
  3. Secretory phase (days 15-28):
     • Glands are growing in the endometrium
• Menarche and Menopause:
  • Menarche: Starting of menstrual cycle in adolescence.
  • Menopause: Stopping of menstrual cycle.