ch 3 digestion absorption and transport n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
CH 3: Digestion, Absorption, and Transport PowerPoint Presentation
Download Presentation
CH 3: Digestion, Absorption, and Transport

Loading in 2 Seconds...

play fullscreen
1 / 43

CH 3: Digestion, Absorption, and Transport - PowerPoint PPT Presentation


  • 412 Views
  • Uploaded on

CH 3: Digestion, Absorption, and Transport. The GI Tract. Overview Digestive System. Functions: Digestion, Absorption, Elimination Digestion – process of breaking down foods to release nutrients Goal is to break nutrients into absorbable units 2 types of digestions: Mechanical

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'CH 3: Digestion, Absorption, and Transport' - ghada


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
overview digestive system
Overview Digestive System
  • Functions: Digestion, Absorption, Elimination
    • Digestion – process of breaking down foods to release nutrients
      • Goal is to break nutrients into absorbable units
    • 2 types of digestions:
      • Mechanical
      • Enzymatic (chemical)
overview digestive system1
Overview Digestive System
  • Absorption – movement of nutrients out of GI tract into blood or lymph
    • Water soluble nutrients 
    • Fat soluble nutrients 
  • Excretion – elimination of undigested foods (feces)
overview digestive system2
Overview Digestive System
  • Structure Gastrointestinal (GI) Tract
    • Continuous tube from mouth to anus
      • See board and page 27
digestive tract
Digestive Tract
  • Layers of GI tract organs
    • Serosa (outermost)
      • Interface between GI tract and lymph & blood
    • Muscle Layers
      • Longitudinal muscles
      • Circular muscles
    • Submucosal and Mucosal and layers (innermost)
      • Nerves, blood and lymph vessels
      • Cells of the mucosal layer produce secretions
mouth
Mouth
  • Structure – teeth, tongue, salivary glands
  • Secretions
    • Saliva
    • Salivary amylase …..
  • Digestion
    • Mechanical ….
    • Enzymatic/chemical ….
  • Swallow  tongue pushes food  pharynx  ……
esophagus
Esophagus
  • Structure – 12” tube
    • UES and LES
  • Function
    • Transports food from mouth to stomach
    • Peristalsis and gravity aid food movement
  • Secretions -- mucus
  • Digestion
    • Mechanical (limited)
    • Enzymatic/chemical – starch digestion continues
stomach
Stomach
  • Structure ….page 73
  • Secretions …..
  • Digestion ……
    • Mechanical
    • Enzymatic/chemical
slide14
Stomach
  • Structure – muscular sack that can expand
    • extra muscle layer to aid in the mechanical digestion of food (pg 73)
stomach related secretions
Stomach Related Secretions
  • Gastrin – hormone that stimulates stomach to release secretions
  • Hydrochloric Acid (HCl) -- unravels proteins, kills bacteria, activates pepsinogen
  • Pepsinogen – once activated, begins protein digestion
  • Mucus – secreted by goblet cells, protects stomach, moistens food
stomach digestion
Stomach - Digestion
  • Mechanical
    • Stomach muscles grind food into a paste called chyme
  • Enzymatic/chemical
    • Proteins uncoiled
    • Protein digestion to polypeptides begins
    • Starch digestion stops (why??)
small intestine si
Small Intestine (SI)
  • Function – The SI is where:
    • the majority of digestion to absorbable units occurs
      • Digestion of carbohydrates, fats, and proteins
      • Vitamins and minerals do not need digestion
    • Nutrients are absorbed into either capillaries or lacteals
small intestine
Small Intestine
  • Structure – see page 79
    • Length -- ~ 21’-22’ long when relaxed
    • Layers …..
    • Mucosal folds, villi, microvilli ….
    • Goblet cells and crypts – create secretions
    • Lacteals and capillaries ….
  • Sections
      • Duodenum
      • Jejunum
      • Ileum
small intestines
Small Intestines
  • Secretions of the SI
    • Mucus
      • Secreted by ____________ cells
    • Digestive enzymes that finish the digestion of carbs, fats, and proteins
      • Secreted from crypts
small intestine2
Small Intestine
  • Secretions of the SI, cont’d
    • Hormones
      • Secretin …
      • CCK ….
      • Gastric-inhibitory peptide …
small intestine3
Small Intestine

Hormone Summary

  • Secretin – produced when chyme enters SI
    • stimulates pancreatic secretions
  • *CCK – produced when fat enters SI
    • Stimulates _________to release ______
    • Slows GI motility (slows peristalsis)
    • *Cholecystokinin
  • Gastric–inhibitory peptide– produced when chyme enters SI
    • Slows stomach secretions
    • Slows GI motility
secretions into si
Secretions into SI
  • Pancreatic secretions:
    • Released in response to ________
    • Sodium bicarbonate
      • Neutralizes acidic chyme
    • Digestive enzymes that begin the digestion of carbs, fats, and proteins
secretions into si1
Secretions into SI
  • Liver and Gall Bladder
    • Liver makes bile
    • Gall bladder concentrates and stores bile
    • Bile is released into SI in response to the hormone _______
  • Function of bile:
small intestine4
Small Intestine
  • Digestion - Mechanical
    • Peristalsis pushes food through SI
    • Segmentation mixes chyme with digestive enzymes
      • Also breaks up food mass into smaller masses
    • Bile emulsifies fats
slide33
SI
  • Digestion – Chemical/Enzymatic
    • Pancreatic and SI enzymes digest carbs, fats, and proteins to absorbable units
      • Duodenum
      • Jejunum
      • Ileum
slide34
SI
  • Absorbed into capillaries (blood)
    • Digested carbohydrates and proteins
    • Minerals
      • Some require helper proteins/cells on walls of SI to be absorbed
    • Water soluble vitamins
  • Blood takes nutrients to the liver for processing after absorption (pg 81)
slide35
SI
  • Absorbed into lacteals (lymph)
    • Digested fats
    • Fat soluble vitamins
    • Cholesterol
  • Nutrients travel through lymph system to chest area where lymph and blood join
  • Nutrients enter blood and travel to liver
slide37

SI Review

What is the relationship between the structure of the SI and its function?

large intestine or colon
Large Intestine or Colon
  • Undigested foods (fiber) enter into colon
  • Unabsorbed nutrients pass into colon
    • E.g. calcium, iron, cholesterol trapped in fiber
colon
Colon
  • Structure
    • 5-6’ long
    • Wider diameter than SI
      • No villi or microvilli
    • Appendix is a little pouch near beginning of colon
    • Colon “wraps around” SI
    • Page 82
colon1
Colon
  • Secretions
    • Mucus
    • Bacteria living in colon
      • Digest small amounts of fiber and undigested nutrients
      • Often produce…...
colon2
Colon
  • Absorption
    • Water, salts, vitamins made by bacteria are absorbed into __________
  • Fiber attracts water
    • Too little fiber in diet 
    • Too much fiber in diet 
rectum
Rectum
  • Feces pass from colon into rectum
  • Rectum stores feces until excretion occurs