Mariah Hernandez p.3
Digestive system

Major functions of the digestive system

Major organs of the digestive system

Digestive enzymes (including names and functions)

Location of digestion and absorption of each macromolecule

Layers of the GI tract (including stomach)

Disorders of the digestive system

Function: digestion and absorption of food for metabolism

Proteins (stomach and small intestine)

  • Proteins —> peptides—> amino acid
  • Pepsin —> protein —> peptide
  • Protease —> peptide —> amino acid

Carbohydrates (mouth and small intestine)

  • Polysaccharides —> disaccharides —> monosaccharides
  • Amylase —> poly —> di

Disaccaride —> monosaccaride

  • Maltase —> glucose
  • Lactase —> glucose and galactose
  • sucrase —> glucose and fructose

DNA/RNA (pancreas)

  • Nucleic acid —> nucleotides
  • Nuclease —> nucleotides

Lipids (small intestine)

  • Fats —> fatty acids
  • Lipase —> fatty acids and glycerol

chemically digested food moves from intestine into blood and lymph

contains villi and microvilli for absorption

Aborbs:

  • water
  • fats
  • carbohydrates
  • proteins
  • Vitamins
  • minerals

Alimentary Canal

  • long irregularly shaped tube open at both ends approx: 9m
  • mouth, pharynx, esophagus, stomach, small intestine, large intestine

Layers of the wall of Gi Tract

  • from the most inner layer or lining, to the exterior:
  • mucose
  • submucose
  • muscular layer
  • serosa

Mucosa:

  • Mucous membrand- produces mucus for reduction of friction and protections
  • Simple columnar in intestine for absorption and secretion
  • Nonkeratinized stratified squamous in mouth, esophagus, and anus protection against friction - Muscularis mucosae
  • Two thin layers of smooth muscle

Submucosa:

  • Areolar connective tissue containing major blood vessel
  • Many elastic fibers to retain shape
  • Submucosal plexus
  • Autonomic nerve supply
  • Glands and lymphatic tissue

Muscularis layer:

  • Muscle layer
  • Two layers of smooth muscles to allow peristalsis and segmentation
  • Inner circular layer: squeeze, decrease size of lumen; in some areas act sphincter or valves
  • Outer longitudinal layer: shortens intestine
  • Myenteric plexus

Serosa:

  • Outer covering of the GI tract
  • Serous membrane
  • Composed of thin layer of areolar connective tissue and simple squamous epithelium
  • Produce serous fluid for lubrication
  • attaches the digestive tract to the wall of the abdominopelvi cavity by forming folds called mesenteries

Alimentary canal or gastrointestinal tract (GI)

  • Mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus

Accessory digestive organs

  • Teeth, tongue, gallbladder, salivary glands, liver and pancreas

Salivary gland: (accessory organ)

  • secretes saliva, moistens and dissolves food particles, and begins carbohydrate digestions

Salivary Secretion:

  • contains serous cells= produce watery liquid w/ salivary amylase
  • receive parasympathetic stimulation that triggers the production of a large volume of saliva at the sight or smell of foos

Roof- formed by hard and soft palate
Floor- formed by tongue and it muscles

Mouth: opening for food and food enters the mouth

  • chews (mastication) and lubricates food with saliva
  • saliva contains enzymes that starts chemical digestion

Tongue:

  • a thick muscular organ covered by mucous membrane with taste buds
  • attached to the mouth by moving food in mouth

Cheecks and lips

  • checks form the lateral walls of the mouth involved in expressions and chewing
  • lips mobile structures that surround the mouth opening

Palate:

  • Palate is the roof of the oral cavity
  • Palatine tonsils associated w/ palate in the back of the mouth
  • lymphatic tissue mass= pharyngeal tonsils

Teeth:

  • Develop 2 sets
  • different teeth are used for different things; incisor, cuspids, bicuspids, and molars

function:

  • masticate food into smaller pieces
    -mechanical breakdown

Major Salivary Glands:

  • parotid gland (largest) secretes a clear watery fluid rich in amylase
  • submandibular gland secrete a viscous fluid
  • Sublingual glands (smallest) secretes a saliva that is thick and stringy

Pharynx and Esophagus

  • cavity behind the mouth
  • a muscular tube leading to the stomach

Esophagus: leads to the stomach

  • lower esophageal ( cardiac) sphincter prevents back flow

Structure of pharynx

  • connects nasal and oral cavities w/ the larynx and esophagus and is divided into the nasopharynx

Function: Passage way for food (and air) from mouth to esophagus

  • deglutition- swallowing
  • Epiglottis- closes so food goes into esophagus

Function:

  • connects pharynx to stomach
  • for food only
  • digestive function= propulsion
  • moves food by peristalisis
    Perstalsis- rhythmic wavelike contraction by muscular layers of wall

Gastroesophageal Reflux disease: heartburn happens and uncontrol able GERD can lead to bleeding in the esophagus

Chronic Diarrhea: uncontrollable urgency; can occur if body doesn’t absorb foods

Chronic Constipation: meaning having 3 bowel movements a week for only a couple weeks

Gall stone: blocks ducts and hepatic duct


proteins— stomach and small intestine
lipids — small intestine
DNA/RNA — pancreas
Carbhohydrates — smal intestine

enzymes - produced by border cells and break down proteins and carbs into their monomers

  • reduces peptides to amino acids
    Paptidases: reduces succors to glucose and frutose
    Sucrase: reduces frutous to luscious
    HCI- breaks down peptides board into proteins

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Hepatitis: inflammation of the liver

  • can be because of viruses

Gall Bladder: connects with the small intestine and is under the liver