The Digestive System Ch. 14

Functions: mechanical and chemical breakdown of food *absorption of nutrients Consists of alimentary canal (mouth, pharynx, esophagus, stomach, sm. intestine, large intestine, anal canal) and accessory organs

Accessory Organs Liver Gallbladder Pancreas Appendix

Layers of the Canal Lining 1. Mucosa - protects tissues and carries absorption 2. Submucosa - glands, blood vessels, nerves 3. Muscular Layer - smooth muscle tissue, circular & longitudinal fibers, pushes food (PERISTALSIS) 4. Serosa (serous layer) - visceral perioneum, outer covering of the tube, lubricates surfaces (serous fluid)

Wall of the Alimentary Canal

Mixing Movements Contractions mix food with digestive juices Peristalsis - pushes food down the tube

Anatomy of the Mouth

Anatomy of a Tooth

Teeth (32) Incisors - cutting Cuspid (canine) – one point, Tearing Bicuspids – two points, tearing Molars - grinding

Tooth Decay

ROOT CANAL

Salivary Glands Parotid - ear, cheek Submandibular - below jaw Sublingual - under tongue

Pharynx (throat) nasopharynx oropharynx laryngopharynx

Esophagus esophageal hiatus is where it penetrates the diaphragm cardiac sphincter at entrance to stomach

STOMACH MUSCLES: Longitudinal, Circular, Oblique

Stomach Regions ● Cardiac sphincter ● Fundus ● Body ● Pyloric sphincter

Stomach Lining Gastric Juices contain acids that break down food - secreted by gastric glands PEPSIN - most important digestive enzyme for breaking down food Mucus prevents stomach from digesting itself

Chyme - paste, after food has been broken down, released then into the duodenum via the pyloric sphincter valve Rugae - folds within stomach Gastric Pits contain glands to make juices

Small Intestine Starts at the pyloric sphincter 1. Duodenum 2. Jejunum 3. Ileum *Mesentery Membrane holds it together, contains blood vessels

The main function of the small intestine is to secrete chemicals that break down food and carry the nutrients away in the blood stream. In one word: ABSORPTION

Greater Omentum a "curtain-like" membrane that covers the intestines, stores fat and lays like a drape

Greater Omentum

Intestinal villi - increase surface area to absorb nutrients, connect to vessels

Large Intestine Cecum Appendix Colon (4 parts) Cecum Ascending Transverse Descending Sigmoid Rectum Anus

Function of Large Intestine Secretes mucus, reabsorbs water, contains bacteria to aid in digestion (intestinal flora) Mass Movements (defecation) - removes undigested food The main job is WATER REABSORPTION...

Types 1–2 indicate constipation, with 3 and 4 being the ideal stools (especially the latter), as they are easy to defecate while not containing any excess liquid, and 5, 6 and 7 tending towards diarrhoea. constipation defecate diarrhoea Source: wiki

stomach cecum appendix ascending colon transverse colon descending colon sigmoid colon rectum

Disorders of the Digestive System GERD Gastroesophageal reflux disease

Dysentery or Diarrhea

Crampy abdominal pain Fatigue Loss of appetite Pain with passing stool (tenesmus); bloody stool Persistent, watery diarrhea Weight loss Constipation

IBS - Irritable Bowel Syndrome The muscles in the bowel wall may contract too forcefully or too weakly, too slowly or rapidly at certain times.

STOMACH ULCERS

Lactose Intolerance Inability to digest milk, can cause stomach upset

Hernia intestines poke through abdominal muscles

When people with celiac disease eat foods or use products containing gluten, their immune system responds by damaging or destroying villi Without healthy villi, a person becomes malnourished, no matter how much food one eats.

Gastric Bypass Surgery

Colon Cancer Colonoscopy is a screening technique to detect cancer. See Katie Couric's ColonoscopyKatie Couric's Colonoscopy

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