Lect 17Digestive Gastrointestinal Tract Accessory Organs Intro to Anatomy , Physiology and Nutrition

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Lect 17DigestiveGastrointestinal
TractAccessory OrgansIntro to Anatomy ,
Physiology and Nutrition
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• Digestive Tract ___________
• Mouth
• Pharynx
• Esophagus
• Stomach
• Small Intestine
• Large Intestine
• Anus

• Accessory Organs
• Teeth and salivary glands
• Liver/gall bladder
• Pancreas
• Mesenteries

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• Alimentary Canal - Characteristic Cross Section
• __________ Passage down the middle
• Mucosa
• Submucosa
• What kind of tissue?
• What is found in this layer?
• Muscle layer
• Serosa ? Type of membrane ____________

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• Functions of the Digestive System
• The process of taking foods and liquid into the
  mouth
• Ingestion
• The release of water, acid, buffers, and enzymes
  by cells and accessory organs into the lumen.
• Secretion
• Alternating contraction and relaxation of smooth
  muscle.
• Peristalsis ? Mixing and propulsion
• Mechanical and chemical break down of organic
  material into small molecules.
• Digestion

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• Mouth
• Cheeks lateral walls
• buccinator muscles, bucal fat pads
• Non-keratinized stratified squamous epithelium
• Lips attach to gum labial frenulum (a midline
  fold)
• Vestibule space between lips and gums
  (gingiva)/teeth
• Oral cavity proper from gums and teeth to
  Fauces

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• Oral Cavity
• Floor
• Mylohyoid muscle
• Tongue
• frenulum
• Palate
• Hard Palate palantine bones part of maxilla
• Soft Palate Uvula close oral cavity?
  nasopharynx
• Tonsils
• Palatine either side of tongue
• Lingual near base of tongue at hyoid bone
• Pharyngeal adenoids posterior wall of pharynx

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• Teeth
• Fours types
• Incisors
• Canines
• Premolars
• Molars
• Primary teeth deciduous baby teeth
• Adult teeth
• dental formula number of teeth of each type in
  one half of each jaw reading from the front
  (incisors) to back (molars)
• Humans Adults 2123/2123

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Salivary Glands

• Parotid below your ear and over the masseter
• Submandibular is under lower edge of mandible
• Sublingual is deep to the tongue in floor of
  mouth
• All have ducts that empty into the oral cavity

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• Swallowing
• What prevents food from entering nasal cavity
• What temporarily seals oral cavity/pharynx?
• What closes opening to respiratory passage?
• Peristaltic wave pushes _______ down __________.

Pharynx 3 regions Nasopharynx
Oropharynx
Laryngopharynx
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The Esophagus

• Anatomy
• A collapsible 10 inch long muscular tube.
• Functions
• Secrete mucus and transport food from the pharynx
  to the stomach.
• Rhythmic waves of muscle contraction?
• (Peristalisis).
• Pierces the diaphragm at hiatus
• hiatal hernia or diaphragmatic hernia

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• Peritoneum
• visceral layer covers organs
• parietal layer lines the walls of body cavity
• Peritoneal cavity
• potential space containing a bit of serous fluid

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Greater Omentum- fatty apron covers transverse
colon and small intestine.
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• Falciform Ligament Suspends liver from anterior
  wall of abdomen/diaphragm
• Lesser Omentum suspends stomach and duodenum
  from liver
• Mesentary Proper Extends from dorsal wall of
  abdominal cavity, suspends small intestine
• Mesocolon binds transverse and sigmoid colon to
  dorsal abd. wall

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Falciform Ligament
Lesser Omentum
Greater Omentum
Mesentary Proper
Mesocolon
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• Which side is it on?
• Size when empty?
• Parts of stomach?
• Structure of its walls?
• Smooth muscle layers
• rugae
• Gastric pits
• What digestive processes occur here
• Associated mesenteries?
• Semifluid contents are known as?

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• Gastric Pits and Gastric Glands
• Gastric Pits shallow depressions of gastric
  mucosa
• Gastric Glands
• Open to gastric pits
• Endocrine and exocrine cells in walls
• Exocrine secretions ? gastric juice

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• Protects walls of stomach
• Acid environment activates pepsinogen
• Absoption o f B12 in small intestine
• Initiates protein breakdown
• Hormonal activity initiates smooth muscle action
  and secretion of gastric juice

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• What stimulates secretion of Gastrin?

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Secretion of gastric juice parasympathetic
involvement sensory stimuli
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• Small Intestine
• Three parts
• Digestive processes
• Absorption of lipids
• ?
• Special adaptations functions
• Support

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Absorption in Small Intestine
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• Absorption of Lipids
• Bile salts act to emulsify
• Fatty acids glycerol at villi
• Intermediate metabolic conversions ? chylomicrons
  protein encased structures enter blood stream
• Delivered to
• tissues as LDL
• Liver as HDL
• Bile salts ? feces

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Where will the absorbed nutrients go?
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• Pancreas- Endocrine/Exocrine
• Endocrine Islet tissues
• Exocrine acinar cells via pancreatic duct ? ??
  (where)
• Pancreatic juice
• Pancreatic amylase
• Trypsin
• Lipase etc.
• Releases bicarbonate ions neutralizes chyme
• Regulation via
• secretin from duodenal epithelial tissues
• Cholecystokinin

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• Liver
• Lobes divided into lobules
• Blood from portal vein ? sinusoids ? central
  canal
• Multiple functions
• Blood glucose ? glycogen ? blood glucose
• Lipid oxidation
• Formation of urea from NH2
• Deamination of aa
• Storage
• Production of bile

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• Bile and the Gall Bladder
• Bile
• Bile salts
• Others
• Emulsification of lipids
• Released as fatty substance enter lumen of
  duodenum
• Cholecystokinin (CCK) stimulates contrations of
  gall bladder

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• Large Intestine
• Regions
• Cecum
• Veriform appendix
• Colon 4 regions
• Rectum
• Anal canal
• Internal external anal sphincters
• Functions

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Symbiotic Bacteria Reside in the Colon

• Numbers- about 50 species.
• Fecal component- accounts for about 1/3 the total
  weight of feces.
• They are nourished by undigested foods.
• Their metabolic processes produce gas.
• Some produce vitamins B and K.
• They decompose pigmented molecules, which give
  feces its brown color.

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• Nutrition
• Macronutrients energy source
• Calorie measure of energy in foods
• Micronutrients required for vital biochemical
  processes
• Incl. vitamins minerals
• Hydrolysis initial step

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• Essential nutrients
• Essential fatty acids
• Required for synthesis of other forms in liver
• Linoleic acid
• Essential amino acids (8)
• See table 15.8
• Complete vs partially complete proteins

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• Issues with Fats and Cholesterol
• 4x amt of energy in carbs
• Does Cholesterol intake greatly impact risk of
  heart disease?
• What is the impact of intake of different kinds
  of fats on arthrosclerosis (linked to heart
  disease)?
• Trans fats?

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• Carbohydrates all are not the same
• Glycemic Index impact/rate of change in blood
  glucose levels after ingestion

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• Some examples of high vs. low glycemic index
  foods
• Impact of milling on glycemic index

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• Vitamins
• Fat soluble
• Water-soluble
• B complex
• C (ascorbic acid)

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The End.