Digestive and Urinary System
Grecia Lopez, Per. 1

Major functions of the digestive system

  • Taking in food
  • Breaking said food down into nutrients
  • Absorbing molecules into the blood stream
  • Getting rid of any in-digestive remains

Major functions of the urinary system

  • The main functions of the urinary system are to filter blood and create and release urine waste product
  • This allows for the regulation of acid base balance, excretion of metabolic wasted, toxins, drugs, etc.

Major organs of the digestive system

Alimentary Canal (Gastrointestinal or GI Tract or Gut)


  • Muscular tube that runs from the mouth to the anus
  • Digests food and absorbs fragments through lining in the blood stream
  • Formed of: Mucosa, Submucosa, Muscularis externa, and serosa

Major organs of the urinary systems

Digestive enzymes

Location of digestion and absorption of each macromolecule

Layers of the GI tract (including stomach)

Nephron anatomy and physiology

Disorders of the digestive and urinary systems

Accessory Organs

Mouth


  • Begins the process of digestion and swallowing
  • Is an oral buccal cavity

Pharnyx


  • Food passes from the mouth into the exopharynx and then into the laryngopharnyx
  • Allows passage of food, fluids, and air

Esophagus


  • Fat muscular tube that runs from the laryngopharynx to the stomach
  • Collapses when food isn't in propulsion
  • The gastrosphogeal (cardiac) sphincter surrounds the cardial orifice
    • Helps protect the acid from acid reflux
    • Keeps the orifice closed when not swallowing
  • Propulsion that starts with deglutition

Stomach


  • Temporary storage tank that starts the chemical break down of protein digestion
  • Converts bolus into chyme
  • When empty, it forms folds called the rugae
  • Its major parts: the cardial part, fundus, body, pylaric part leading to the pylaric canal, the pylorus, the pyloric valve (sphincter controlling stomach emptying), and the greater and lesser curvature

Small Intestine


  • Its main functions are digestion and absorption
  • 2-4 m long from the pyloric sphincter to the ileoccecal valve, point at where its joins the large intestine
  • Subdivisions: Duodenum, Jejunum, Ileum
  • Has villi (finger like projections of mucosa) that have capillaries called lacteal for absorption
  • Has microvilli, cytoplasmic extensions o musocal cell that create a brush border for final carb and protein digestion

Large Intestine


  • Has 3 unique features: Teniae Coli, Haustra, and Epiploic appendages
  • Subdivisions: Cecum, appendix (masses of lymphoid tissue that storehouses bacteria), colon, rectum (3 valves), and anal canal (2 sphincters)
  • Major Functions: Propulsion of feces to anus and defecation (feces toward rectum) and absorption of vitamins, water, and electrolytes

Anus


  • Where stool comes out of the body

Digestive Glands


  • Produce secretions to break down food stuff

Salivary Glands


  • Makes saliva which cleanses the mouth, dissolves food, moistens food, and begins the breakdown of starch with enzyme amylase

Gallbladder


  • Stores the bile
  • Functions to store and concentrate bile by absorbing water and ions

Tongue

  • Assists in swallowing
  • Moves food during mastication

Teeth


  • Lie in the sockets of gum covered margins of the mandible and maxilla
  • Allow for mastication: chewing
  • Classified based on shape:
    • Incisors: Chisel shaped for cutting
    • Canines: Fang like teeth that tear or pierce
    • Premolars (bicuspids): Brood crowns with rounded cusps to grind
    • Molars: Brood crowns, round cusps; best grinders
  • Each tooth has 2 regions: Crown (exposed part above the gum) and Root (portion embedded in jawbone)

Liver


  • Production of bile (fat emulfifier)
  • Has 4 lobes: right, left, caudate, and quadrate
  • Has bile ducts

Pancreas


  • Supplies most of the enzymes needed to digest chyme and neutralize stomach acids
  • Produces pancreatic juices: A watery, alkaline solution (PH8) to neutralize chyme
  • Releases insulin and glucagon as its endocrine function

Digestive Processes

  1. Ingestion (eating)
  2. Propulsion (swallowing and peristalsis)
  3. Mechanical Breakdown (includes chewing, mixing food + saliva, churning food, and segmentation)
  4. Digestion (enzymes break down food into building blocks)
  5. Absorption (passage of digestive fragments from the lumen of the GI tract into the blood or lymph)
  6. Defecation (elimination of in-digestive substances via anus in the form of feces)

Tongue


  • Functions to grip, reposition, and mix food during chewing
  • Forms bolus (food + saliva)
  • Allows for swallowing, speech, and taste

Amylase


  • Breaks down starch into smaller molecules
  • Made in the mouth and pancreas

Digestive Processes in the stomach


'1. Break down the food

  1. Holding area for food
  2. Deliver chyme into the small intestine
  3. Denatures proteins by HCl
  4. Pepsin carries out enzymatic digestion of proteins
  5. Lipid-soluble alcohols and aspirin are absorbed into the blood
  6. Only stomach function essential to life is secretion of intrinsic factor for vitamin B12 absorption

Bile


  • Yellow-green, alkaline solution that contains bile salts and bilirubin
  • Bacteria break down in intestine stercoblin that gives brown color of feces

Proteases


  • Break down proteins into amino acids
  • Made in the pancreas

Lipases


  • Break down lipid fats into fatty acids and glycerol
  • Made in the pancreas

Nucleases


  • Break down nucleotides into nucleic acids
  1. Submucosa
  • Areolar CT that contains the vessels, follicles, and nerves
  • Surrounds the GI Tract as it had elastic tissue that help organs retain shape
  1. Muscularis Externa
  • Muscle layer responsible for segmentation and peristalsis
  • Circular layer thickens to form sphincters
  1. Mucosa
  • Tunic layer that lines the lumen
  • Functions to secrete mucus, digest enzymes, and hormones
  • Absorbs end products of digestion and protects against disease
  1. Serosa
  • Outermost layer made of visceral peritoneum

Stomach


  • The wall contains 4 tunics: muscularis and mucosa modified
  • Muscularis externa has circular and longitudinal smooth muscle layers, as well an extra 3rd layer called the oblique (diagnol) layer
  • Mucosa layer is modified to secrete alkaline mucus ...dotted with gastric glands which produce gastric juice
  • Mesentries keep everything in place!!

Digestive Processes in the Small Intestine


  • Chyme from the stomach contains partially digested carbs, proteins, and undigested fats
  • After a meal segmentation occurs which mixes and moves contents to the ileocecal valve
    • Parasympathetic increases motility; sympathetic decreases it
  • Between meals is that peristalsis occurs, initiated by a rise in the hormone motillin in the later intestinal phase
    • Meal reminants, bacteria, and debris are moved toward the large intestine
  • The Illeocecal sphincter relaxes and admits chyme into the large intestine:
    • Gastroileal reflex enhances the force of segmentation in the iluem
    • Gastrin increases motiility in Ileum
  • Ileocecal valve flaps close when the cyme exerts backward pressure
    • Prevents regurgitation into the ileum

Colon


  • Is formed of most retro peritoneal
    • Ascending Colon: Right side of abdominal cavity to the right kidney (has the right colic flexure)
    • Transverse Colon: Travels across the abdominal cavity (had the left colic flexure)
    • Descending Colon: Travels down the left side of the abdominal cavity
    • Sigmoid Colon: S-Shaped portion that travels through the pelvis

Bacterial Flora


  • Consists of 1000+ different types of bacteria
  • Its metabolic functions include fermentation, vitamin synthesis, gut bacteria, and health.
  • Gut bacteria can influence weight, susceptibility to various disease, and our moods.

Carbs


  • Digestion starts in the mouth but really takes place in the small intestine
  • This is done by the pancreatic amylase and the salivary amylase
  • Absorbed into the blood via the small intestine

Proteins


  • Digestion begins in the mouth, continues in the stomach, until it reaches the small intestine
  • This is done by pepsin in the presence of HCI, pancreatic enzymes, and brush border enzymes
  • The amino acids are absorbed in the small intestine by the microvilli

Lipids


  • Digestion begins in the mouth, then the stomach, until it reached the small intestine
  • Is done so by the lingual lipase, gastric lipase, emulsification, and pancreatic lipases
  • Fatty acids and glycerol are then absorbed by the small intestine

Nucleic Acids


  • Digestion begins in the small inestine
  • This is done thanks to brush border enzymes, pancreatic ribonuclease enzymes, and deoxyribonuclease enzymes
  • Absoprtion takes place in the intestinal mucosa of the small inestine

Kidneys


  • The major excretory organ, as they maintain the bodies internal environment
  • Regulate total water volume and total solute concentration in the water
  • Can regulate blood pressure and RBC, activating vitamin D, and carrying out glucogenesis
  • Renal Cortex, Renal Medulla, and Renal Pelvis
  • Urine is produced from filtrate of the nephron

Ureters


  • Transport urine from the kidneys to the urinary bladder
  • As bladder pressure increases, distal ends of ureters close, preventing the back flow of urine

Urinary Bladder


  • Temporary storage reservoir for urine
  • Different in males and females
    • Males: Prostate inferior to bladder neck...therefore the urethra is longer
    • Females: Anterior to the vagina and uterus...therefore the urethra is shorter
  • Collapses when empty
  • Can hold twice of what it can when it is full if necessary but it can burst if overdistended

Urethra


  • Transports urine out the body

Urine Flow

  • Nephron in the kidneys → Ureters → Urinary Bladder → Urethra
  • Structural and functional units that form urine in the kidneys
  • Have two main parts: the renal corpuscle and the renal tubule
    • Renal Corpuscle consists of the glomerulus and the glomerular capsule (both allow for filtration)
    • Renal Tubule consists of a conovluted tubule, nephron loop, and distal convoluted tubule that returns substances that were filtered but are needed by the body back into the blood
  • Two types of collecting cells: Principal Cells and Intercarcelated Cells

Urine


  • Can be examined via urinalysis for disease
  • Chemical composition: 95% water and 5% solutes
  • Has nitrogenous waste: urea (from amino acid breakdown), uric acid, and creatinine
  • Clear, slightly aromatic when fresh, slighlty acidic (~PH6)

Cholecystitis


  • An inflammation of the gall bladder
  • Causes and Risks: Blockage of the gall duct by gallstones, being a female, and inflammation
  • Symptoms: Tender abdomen, vomiting, and bloating
  • Treatment: Medication, fasting, and cholecystectomy

Gastroesophageal Reflux Disease (GERD)


  • Chronic disease that occurs when the esophagus sphincter relaxes so the contents of the stomach move back to the esophagus
  • Causes and Risks: Frequent acid reflux, pregnancy, and diabetes
  • Symptoms: Heart burn, acid reflex, and sour taste
  • Treatment: Surgery, prescription medication, and over the counter medication

Inflammatory Bowl Disease


  • A chronic complex intestinal condition that causes inflammation in the digestive tract
  • Causes and Risks: Causes are unknown but may be due to genetics, the environment, or ones immunity
  • Symptoms: Abdominal pain, diarrhea, bowel obstruction
  • Treatment: Medication, diet adjustment, and fluid replacement

Peptic Ulcers


  • Sores that develop in the lining of the stomach or the duodenum
  • Causes and Risks: Excess acid production, stress, or imbalance in gastric juices
  • Symptoms: Heart burn, bloody stool, nausea
  • Treatments: Lifestyle changes, medication, and endoscopic surgery

Colon Diseases

Colorectal Cancer


  • Uncontrolled cell growth in the colon
  • Causes and Risks: Heredity, chemical exposure, and radiation
  • Symptoms: Change in bowel movement, pelvic pain, and bloody stool
  • Treatment: Chemotherapy, radiation, and medication

Diverticulitis


  • Pouches form on the wall of the colon
  • Causes and Risks: Age, infection, and diet
  • Symptoms: LLQ pain, bloating, gas, and constipation
  • Treatment: Medication, antibiotics, and surgery

Bladder Cancer


  • When cells of the bladder grow abnormally they can cause tumors in the bladder
  • Causes: Smoking, radiation, or exposure to chemicals
  • Symptoms: Pain in pass urine, back pain, and pain in the lower stomach
  • Treatments: A well balanced diet, exercise, and drinking lots of water

Urinary Tract Infection (UTI)


  • Abnormal growth of bacteria in the urinary tract
  • Causes and Risks: Pregnancy, being a female, and being sexually active
  • Symptoms: Burning with urination, frequent urination, and fever and chills
  • Treatment: Oral antibiotic pills, cranberry pills, and phenazopyridine

Kidney Stones


  • When the urine has high levels of minerals or salts, stones can be formed
  • Causes and Risks: Too much calcium, too much cysteine, UTIs
  • Symptoms: Sharp cramping pain in the back and side, intense urination, and a burning feeling
  • Treatment: Medication, surgery, or short wave lithotripsy (SWL)