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

2. Digestive Tract = ___________ Mouth Pharynx Esophagus Stomach
Small Intestine
Large Intestine
Anus
Accessory Organs
Teeth and salivary glands
Liver/gall bladder
Pancreas
Mesenteries
Mouth---bite, chew, swallow
Pharynx and esophagus----transport
Stomach----mechanical disruption; absorption of water & alcohol
Small intestine--chemical & mechanical digestion & absorption
Large intestine----absorb electrolytes & vitamins (B and K)
Rectum and anus---defecation

3. 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 ____________

5. 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

6. Vestibule: space between lips and gums (gingiva)/teeth
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

8. Oral Cavity Floor: Palate: Tonsils: 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

10. Primary teeth: deciduous – ‘baby teeth’ Adult 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

13. Tortora & Grabowski 9/e 2000 JWS
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
Tortora & Grabowski 9/e 2000 JWS

14. 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

15. The Esophagus Anatomy Functions Pierces the diaphragm at hiatus
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
The Esophagus

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

17. Greater Omentum- fatty apron: covers transverse colon and small intestine.

18. 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

19. Falciform Ligament
Lesser Omentum
Greater Omentum
Mesentary Proper
Mesocolon

20. 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?

21. 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

22. 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

23. What stimulates secretion of Gastrin?

24. Secretion of gastric juice – parasympathetic involvement – sensory stimuli

25. Special adaptations – functions Support
Small Intestine
Three parts
Digestive processes
Absorption of lipids 
Special adaptations – functions
Support

27. Absorption in Small Intestine

28. Bile salts act to emulsify Fatty acids + glycerol at villi
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

29. Where will the absorbed nutrients go?

30. 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

32. Lobes divided into lobules
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

34. 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

36. Large Intestine Regions Functions Cecum Colon – 4 regions Rectum
Veriform appendix
Colon – 4 regions
Rectum
Anal canal
Internal & external anal sphincters
Functions

37. 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.

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

40. Essential amino acids (8)
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

41. 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?

44. Carbohydrates – all are not the same
Glycemic Index: impact/rate of change in blood glucose levels after ingestion

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

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

47. The End.