Digestive System
This presentation is the property of its rightful owner.
Sponsored Links
1 / 48

Digestive System Function: to obtain nutrients PowerPoint PPT Presentation


  • 86 Views
  • Uploaded on
  • Presentation posted in: General

Digestive System Function: to obtain nutrients. Digestive System Function: obtaining nutrients. Activities of Digestion system: Ingestion – taking food or liquid into the mouth (eating or drinking). Movements Peristaltic and Segmentation Digestion Mechanical mastication

Download Presentation

Digestive System Function: to obtain nutrients

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


Digestive System

Function:

to obtain nutrients


Digestive System

Function: obtaining nutrients

  • Activities of Digestion system:

    • Ingestion – taking food or liquid into the mouth (eating or drinking).

    • Movements

      • Peristaltic and Segmentation

    • Digestion

      • Mechanical

        • mastication

        • churning

      • Chemical

        • Enzymes and acids

    • Absorption – movement of substances into the body (across epithelium).

    • Elimination – involves compaction to eliminate waste from body


The Digestive System


Layers of Gastrointestinal Tract

  • Four layers:

    • Know layers and their composition

  • Tunic mucosa

    • Epithelial

    • Propria

    • Muscularis mucosae

  • Tunic submucosa

  • Tunica muscularis externa

  • Tunica serosa-visceral peritoneum


Tunic Mucosa

  • Lines digestive tract

  • Moistened by glandular secretions

  • Simple or stratified depending on area of tract

  • Pleated for expansion (Surface Area)


1. Tunic Mucosa

  • A Mucous membrane

    • 1) Epithelium

    • 2) Lamina propria

    • 3) Muscularis mucosae

2. Tunic Submucosa

  • Areolar Connective Tissue

  • Innervation

  • May have glands


Muscularis Mucosa

  • Smooth muscle layer capable of plasticity

    • Ability to tolerate stretching

  • Visceral smooth muscle


3. Tunica Muscularis Externa

  • Smooth muscle layers

  • 1) Inner Circular Layer

  • 2) Outer Longitudinal Layer

4. Tunica Serosa (or Adventitia*)

Serous membrane – visceral peritoneum

  • * Name depends on location:

  • Inside peritoneal cavity = serosa

  • Outside peritoneal cavity = adventitia


Histology of the G.I. Tract


Serous Membranes

  • The Peritoneum: Two layers

    • Visceral peritoneum (a.k.a serosa)

    • Parietal peritoneum

      • Lines inner surfaces of body wall

  • Mesenteries: Fused double sheets of peritoneal membrane – to suspend portions of digestive tract:

    • Greater omentum

    • Lesser omentum

    • Mesentery proper

    • Transversemesocolon

    • Sigmoid mesocolon


  • Retroperitoneal Structures – these are attached to posterior abdominal wall

    • Ascending colon

    • Descending colon

    • Duodenum

    • Pancreas


Salivary glands

  • Parotid

  • Sublingual

  • Submandibular

    • Slightly different secretions

    • Release enzymes - amylase

    • Lubrication oral cavity


Fig

25.6


Fig

25.7

Only example of gomphosis joint

Incisors -clipping/cutting

Canines-tearing/slashing

Premolars- mashing/grinding

Molarsmashing/grinding


Teeth

Regions:

Crown

Neck

Root

Layers:

Enamel

Dentin

Pulp Cavity with Pulp

Cementum

Apical foramen

Root canal

Periodontal membrane


Voluntary control

Pharynx and Esophagus

Deglutition

Swallowing

Epiglottis closes over larynx


Tunica muscularis has three layers of muscle

Fig

25.11

Tunica mucosa has folds, rugae when empty


Histology of Gastric glands

Chief - Pepsinogen; Parietal - HCl; Neck/Mucous Cells

  • Secretin and cholecystokinin

    • Inhibit gastric secretion


Small Intestine

Duodenum

Jejunum

Ileum

Increase Surface Area for Absorption

Plicae Circulares

Intestinal villi

Microvilli

  • Lacteal (terminal lymphatic)

  • for lipid absorption

  • Intestinal glands

    • Goblet cells

    • Stem cells


Diagrammatic view highlighting the distinguishing features of each region of the small intestine.


  • Duodenum:

  • Duodenal (Brunner’s) glands produce:

    • secretin

    • CCK

    • Alkaline mucus


Ilieum: lymphatic aggregations (Peyer’s patches)


Secretin


CCK


  • Large intestine

  • Functions of large intestine

    • Reabsorb water and compact feces

    • Absorb vitamins

    • Store fecal matter

  • Cecum

    • Ileocecal valve

    • Collects material from small intestine

    • Vermiform appendix

  • Colon - ascending, transverse, descending and sigmoid

  • Rectum


Histology of Large Intestine

Large Intestine:

Lack of villi

Abundance of goblet cells

Mucous-secreting intestinal glands

Muscularis reduced to Taenia coli

Fatty appendices


Rectum and Anal canal


Other digestive organs

Horizontal section through the upper abdomen showing the position of the liver relative to other visceral organs.


Liver


Bile Ducts


Diagrammatic view of lobular organization.


Pancreas


EtOH on Liver


Pancreas


Pancreas

Exocrine: acini

Endocrine:

Pancreatic islets

Isles of Langerhans


  • Login