Biology 322 Human Anatomy I Digestive System. Functions:
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Transcript of Biology 322 Human Anatomy I Digestive System. Functions:
Organs
Two functional groups:
1. Alimentary Canal or Gastrointestinal tract Organs which ingest, propel, digest, absorb, & eliminate Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, anus
2. Accessory Digestive Organs Assist with digestion Teeth, tongue, salivary glands, liver, gall bladder, pancreas
Esophagus:
Propels food from pharynx to stomachPosterior to trachea & heart
: Nonkeratinized stratified squamous epithelium Many mucous-secreting cells Thin lamina propria Thin muscularis mucosa
: Thick layer of dense irregular CT
: Upper third = skeletal muscle Middle third = mixed Lower third = smooth muscle
Thin layer of connective tisssue
Small Intestine:
Mucosa Epithelium Lamina propria Muscularis mucosa
Submucosa
Muscularis Externa
Serosa or Adventitia
Small Intestine:
Mucosa specialized three ways to increase surface area for absorption
1. All layers of mucosa thrown into folds called
Small Intestine:
Mucosa specialized three ways to increase surface area for absorption
2. Epithelium and lamina propria form finger-like
Small Intestine:
Mucosa specialized three ways to increase surface area for absorption
3. Plasma membranes of epithelial cells form finger-like
Small Intestine:
Nutrients, ions, etc. are absorbed through these plasma membranes & passed through the cell to the deeper lamina propria, where they are absorbed into capillaries & lymphatic vessels.
Abdominal Accessory Organs:Abdominal Accessory Organs:
Liver,
Gall bladder,
Pancreas,
& associated ducts
Four lobesBlood supply:
Liver
Most superior organ in abdomenImmediately inferior to diaphragmPartially protected by ribsDevelops from embryonic intestineMass ~ 1.5 kg