ATS-13_Digestive system presentation_JM.pptx

GASTROINTESTINAL SYSTEM (DIGESTIVE SYSTEM)

Anatomy Overview

  • Major Parts of the Digestive System:

    • Mouth (Buccal Cavity)

    • Pharynx

    • Esophagus

    • Stomach

    • Small Intestine:

      • Duodenum

      • Jejunum

      • Ileum

    • Large Intestine:

      • Ascending Colon

      • Transverse Colon

      • Descending Colon

      • Sigmoid Colon

      • Rectum

      • Anus

    • Accessory Organs:

      • Pancreas

      • Liver

      • Gallbladder

Abdominal Quadrants

  • Divided into Four Quadrants:

    • RUQ: Right Upper Quadrant

    • LUQ: Left Upper Quadrant

    • RLQ: Right Lower Quadrant

    • LLQ: Left Lower Quadrant

    • Peri-Umbilical Region

    • Suprapubic Region

Abdominal Regions

  • Regions within the Abdomen:

    • Right Hypochondriac (RH)

    • Left Hypochondriac (LH)

    • Right Lumbar (RL)

    • Left Lumbar (LL)

    • Right Iliac (RI)

    • Left Iliac (LI)

Mouth

  • Function of the Mouth:

    • Known as the buccal cavity.

    • The digestive process begins here with mastication (grinding and chewing food).

  • Anatomy Features:

    • Teeth Structure:

      • Incisors: 8 total (4 upper, 4 lower)

      • Canines: 4 total (2 upper, 2 lower)

      • Premolars: 8 total (4 upper, 4 lower)

      • Molars: 12 total (6 upper, 6 lower)

    • Tongue, Hard Palate, Soft Palate

    • Salivary Glands:

      • Secrete saliva containing salivary amylase (initiates carbohydrate digestion).

      • Lysozyme destroys bacteria.

    • Bolus Formation: Food mixed with saliva.

Esophagus

  • Structure: A muscular tube approximately 10 to 12 inches long.

  • Function: Carries food from mouth to stomach.

  • Deglutition: Process of swallowing.

  • Peristalsis: Rhythmic, wavelike motion that moves food forward in the alimentary canal.

Stomach

  • Structure: Hollow, muscular, J-shaped organ; holds food for 2 to 4 hours.

  • Key Features:

    • Cardiac Sphincter: Prevents backward flow of food into the esophagus.

    • Rugae: Folds that allow the stomach to expand.

  • Functions:

    • Maceration: Mixing waves churn food into chyme.

    • Absorbs some substances, such as water and alcohol, but not food molecules.

  • Digestive Juices:

    • Produced by stomach glands; breaks down food.

      • Pepsin: Begins protein digestion.

      • Lipase: Breaks down fats.

      • Hydrochloric Acid (HCl): Kills bacteria, aids iron absorption, activates pepsin.

      • Intrinsic Factor: Required for Vitamin B12 absorption.

      • Mucus: Protects the stomach lining from acidity.

  • Pyloric Sphincter: Regulates passage of chyme into the small intestine.

Small Intestine

  • Structure: Approx. 20 feet long and 1 inch in diameter.

  • Sections:

    • Duodenum: 1st 12-14 inches; receives bile and pancreatic juice.

    • Jejunum: Approx. 8 feet long; middle section.

    • Ileum: Final 12 feet; connects to the large intestine via the ileocecal valve.

  • Absorption: Most nutrients absorbed into the bloodstream.

  • Villi: Fingerlike projections containing capillaries and lacteals for nutrient absorption.

Large Intestine

  • Length & Diameter: Approx. 5 feet long and 2 inches in diameter.

  • Main Functions:

    1. Absorption of water and remaining nutrients.

    2. Storage of indigestible materials before elimination.

    3. Production of B-complex vitamins and Vitamin K by E.coli.

    4. Transportation of wastes outside the body.

  • Sections:

    • Cecum

    • Colon (Ascending, Transverse, Descending, Sigmoid)

    • Rectum

    • Anus

  • Peristalsis: Moves chyme along the large intestine. Water and nutrients are absorbed; gas production leads to flatulence.