[LEC] THIRD SHIFTING

• What is the primary purpose of the digestive system?

  Acquire nutrients for anabolism and catabolism
• What are the main components of the digestive system?

  • Digestive Tract: Oral cavity to anus
  • Accessory Organs: Teeth, tongue, salivary glands, liver, pancreas, gallbladder
• What is ingestion in the digestive process?

  The act of consuming food into the oral cavity
• What processes are involved in mechanical digestion?

  • Chewing (mastication) in the oral cavity
  • Churning in the stomach
  • Segmentation in the small intestine
• What is the purpose of mechanical digestion?

  To physically break food into smaller pieces
• How does chemical digestion occur?

  It breaks complex molecules into smaller absorbable units
• What enzyme begins carbohydrate digestion in the oral cavity?

  Salivary amylase
• What is the action of salivary amylase?

  Begins breaking starch into disaccharides
• When does salivary amylase become inactive?

  When pH drops below 4.5 in the stomach
• What is the result of carbohydrate digestion in the small intestine?

  Monosaccharides are absorbed
• What enzyme breaks polysaccharides in the small intestine?

  Pancreatic alpha-amylase
• What enzymes are involved in carbohydrate digestion at the brush border?

  • Maltase: Converts maltose into glucose
  • Sucrase: Converts sucrose into glucose and fructose
  • Lactase: Converts lactose into glucose and galactose
• What enzyme begins lipid digestion in the oral cavity?

  Lingual lipase
• What is the action of bile salts in lipid digestion?

  Emulsify fats, increasing surface area
• What happens to monoglycerides and fatty acids in the small intestine?

  They form micelles for absorption
• What is the role of pepsin in protein digestion?

  Breaks proteins into smaller polypeptides
• What enzyme in the stomach continues lipid digestion?

  Lipase
• What pancreatic enzymes are involved in protein digestion in the small intestine?

  Trypsin, chymotrypsin, carboxypeptidase, elastase
• How are amino acids absorbed in the small intestine?

  Via facilitated diffusion and cotransport
• What enzymes break nucleic acids into nucleotides?

  Pancreatic nucleases
• How are nucleotides absorbed in the small intestine?

  Via active transport into intestinal capillaries
• What is the primary site for nutrient absorption?

  • Small Intestine
  • Absorbs carbohydrates, lipids, proteins, vitamins, water, and electrolytes
• What is the role of peristalsis in the digestive system?

  Moves food along the digestive tract
• What does HCl do in the stomach?

  Denatures proteins and activates pepsinogen
• What substances are secreted to aid digestion?

  Enzymes, acids, bile, and buffers
• What is the function of bile?

  Emulsifies fats for easier digestion
• What is the process of defecation?

  Elimination of indigestible substances as feces
• What are the main functions of the urinary system?

  1. Excretion of metabolic wastes
  2. Elimination of wastes from the body
  3. Homeostatic regulation (blood volume, ion balance, pH)
• What is the functional unit of the kidney?

  Nephron
• What occurs in the renal corpuscle?

  Blood filtration occurs here
• What is the glomerular filtration rate (GFR)?

  Rate kidneys filter blood, normal is 180 liters/day
• How is GFR regulated?

  By autoregulation and hormonal regulation
• What is the role of the kidneys?

  Produce urine and filter blood
• What is the function of the ureters?

  Carry urine from kidneys to the bladder
• What is the role of the urinary bladder?

  Stores urine temporarily
• What is the function of the urethra?

  Discharges urine from the bladder
• What are some symptoms of digestive disorders?

  Nausea, vomiting, abdominal pain, bloating
• What imaging tests are used to diagnose digestive disorders?

  • Endoscopy
  • Colonoscopy
  • Ultrasound
  • CT Scan/MRI
• What are common disorders of the digestive system?

  • GERD
  • Peptic ulcers
  • Celiac disease
  • IBS
  • IBD
  • Diverticulitis
  • Liver diseases
  • Pancreatitis
  • Gallstones
  • Colon cancer
• What laboratory tests are used for digestive disorders?

  • Blood tests
  • Stool tests
  • Breath tests