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Lab The Digestive System Anatomy and Processes of the

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Lab The Digestive System Anatomy and Processes of the Powered By Docstoc
					                                                                                        Adapted from Akkaraju,
                                                                                                Liachovitzky &
                                                                                           McDaniel, 2009-10
Lab 9 – The Digestive System: Anatomy and Processes of the Digestive System

Objectives Checklist. After completion of this lab, you should be able to:
     locate each of the organs of the                        be able to trace the pathway of food
      digestive system on models and                           through the digestive tract and
      textbook figures and their anatomical                    indicate what processes occur along
      relationships to one another                             the way
     describe the processes happening                        identify the location, composition
      along the alimentary canal                               and function of the four major
                                                               histological layers found throughout
     distinguish between the digestive
                                                               the digestive tract (mucosa,
      tract and its accessory organs and
                                                               submucosa, muscularis, serosa)
      know the major functions of each
                                                              explain the purpose of membrane
     identify the products of each
                                                               adaptations such as villi and
      accessory gland and where each
                                                               microvilli
      delivers its product(s) to the
      digestive tract                                         distinguish between longitudinal,
                                                               circular, and oblique muscles
   
I. Pre-Lab Activities. These activities are to be completed before coming to lab.

A. Processes of the Digestive System
1. Define the following processes happening of the digestive system:

Process                     Definition/Description
Ingestion

Mechanical Digestion

Chemical Digestion

Motility: Peristalsis

Motility: Segmentation

Secretion

Absorption

Reabsorption (and
Compaction)
Defecation




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B. Anatomy of the Digestive System
1. Organs of the Alimentary Canal and Accessory Glands: Label the
   following diagram with the terms in the box.

Oral cavity        Rectum
(mouth)            Anus
Salivary glands    Liver
Pharynx            Stomach
Larynx             Gallbladder
Esophagus          Liver
Stomach            Diaphragm
Small intestine
Colon

2. Oral Cavity: Label the following diagrams with the terms in the
   boxes


Parotid gland                                         Incisors=I
Submandibular                                         Canines=C
gland                                                 Premolars=P
Sublingual gland                                      Molars=M
Sublingual duct                                       Palatin
orifices                                              tonsils
Submandibular
duct orifices




                                                           Crown
Esophagus                                                  Enamel
Trachea                                                    Dentin
Glottis                                                    Root
Oral Cavity                                                Root
Tongue                                                     canal
Oropharynx                                                 Gingiva
Laryngopharynx




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3. Stomach: Label the following diagram with the terms in the box
Cardiac sphincter       Rugae of mucosa
Cardiac region          Circular layer of the
Fundic region           muscularis externa
Body region             Oblique layer of the
Pyloric region          muscularis externa
Pyloric sphincter       Longitudinal layer of the
Duodenum                muscularis externa




4. Small Intestine and Large Intestine: Label the following
   diagram with the terms in the box


                                 Cecum
                                 Appendix
                                 Ascending colon
Duodenum                         Transverse colon
Jejunum                          Descending colon
Ileum                            Sigmoid colon
Ileocecal                        Haustra
sphincter
                                 Taenia coli
Pyloric Sphincter
                                 Rectum
Mesentery
                                 Anal canal
Appendix
                                 Internal anal sphincter
                                 External anal sphincter
                                 Anus




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C. The Histology of the Digestive Tract: Label the following diagrams using the terms in the box


                                            Mucosa (Mucous
                                            Membrane)
                                            Submucosa
                                            Muscularis
                                            externa
                                            Serosa
                                            Cross Section of
                                            the Esophagus
                                            Cross Section of
                                            the Stomach




   D. Watch a Digestive System Anatomy Preview by clicking here. Use the videos on the right hand
   side of the screen (or copy and paste
   http://www.youtube.com/user/aandpatbcc#p/c/62097452804965B5)


II. Lab Activities. These activities are to be completed during lab.

   A. Anatomy and Processes of the Digestive System
1. Find each of the organs that you labeled in the Pre-Lab Activity B on the models in the lab.
   Remember, you will be tested using models!
2. Circle the organs in the text box that are considered accessory organs (food does not pass
   through them, but they make product(s) which are delivered to the tract to help with digestion
   or absorption).


                           Pancreas    Small intestine   Laryngopharynx
                           Liver       Gall bladder      Oral cavity
                           Colon       Anus              Salivary glands
                           Stomach     Esophagus         Larynx
                           Rectum      Oropharynx        Appendix



3. For each of the following accessory organs, describe its products (enzymes or other
   secretions) and how the product gets into the digestive tract (part of the tract that it empties
   into).




                                                 92
  accessory                                    Products                           delivered to:
                                                                               (where in the GI tract it
    organ                                      (enzymes etc.)
                                                                                        goes)
   salivary
    glands



   pancreas




     liver


4. Use models to help you fill in the flow chart below showing all of the structures/organs that
   food passes through as it moves through the digestive tract. After you complete the flow
   chart, lightly shade the boxes where the pH is acidic. Next, write the name of the
   appropriate accessory organs in the spaces to the left and write the name(s) of the products
   that each produces above or below the arrow (see example).


                                                                               FOOD
                           salivary amylase,                    oral cavity
                           salivary lipase

     salivary gland




                                                                                       small
                                                                                     intestine




                                                                                large intestine




                                                                  anus
                                                                               FECES

                                                        93
5. Use the information you summarized in the Pre-Lab Activity A.1 table. and in the previous
   exercise, to fill in the table below. Find in the models (and in the dissected pig if available)
   all the organs you list in the table below.
Process                    List ALL -when applicable- the organs where this process happens
Ingestion

Mechanical Digestion

Chemical Digestion

Motility: Peristalsis

Motility: Segmentation

Secretion

Absorption

Reabsorption (and
Compaction)
Defecation



6. Describe mechanical digestion. Where does it occur? What structures are responsible for
   mechanical digestion?




7. Describe chemical digestion. What is responsible for chemical digestion?




8. Fill in the following table with a summary description of the major function(s) of each organ.

         mouth

       esophagus

        stomach

     small intestine




                                                 94
 large intestine (colon)

        rectum


9. Where does chemical digestion begin? Where in the digestive tract does the majority of
chemical digestion take place?


10. Where does absorption begin? Where in the digestive tract does the majority of absorption
take place?


11. What is the primary function of the large intestine? Why is this important?



12. Mucus is secreted everywhere along the digestive tract. What purpose does it serve? Why
do you think that the number of goblet cells (produce mucus) is so much higher in the large
intestine?




B. The Histology of the Digestive Tract
       1. The type of epithelium varies through the digestive tract. Fill in the table with the
          appropriate type of epithelium and the purpose that it serves.
            Epithelial Type         Where Found                           Purpose
                               oral cavity, upper
                               esophagus
                               anal canal
                               stomach
                               small and large
                               intestines

       2. While most of the digestive tract has two layers of muscle in the muscularis externa
          (longitudinal and circular), the stomach has a third oblique layer. Based on what you
          know about the role of the stomach in both mechanical and chemical digestion, why
          do you think the stomach has this third layer?




                                                95
       3. Which part of the digestive tract has villi? How are villi different from microvilli?
          What purpose does each one serve?



       4. Gather slides of the different organs of the digestive tract and identify each of the
          layers (mucosa, submucosa, muscularis, serosa) in each using low or medium
          magnification. After you identify the mucosa, change to high magnification and
          sketch what you see. Use your book to help you identify structures (villi, glands,
          crypts, etc.). To review these tissues, you can use an online histology tutorial (e.g.
          http://www.mhhe.com/biosci/ap/histology_mh/start_histology.html).
               Organ                Sketch                 Organ                 Sketch
                                                       small
                                                       intestine
            esophagus                                  slide # 32
            slide # 30                                 (composite of all
                                                       three regions)



                                                       large
            stomach
                                                       intestine
            slide # 31
                                                       slide # 33



   C. Viewing Station

Go to the laptops in the viewing station and watch the following short videos:

           1. Ingestion (See epiglottis in action at the beginning of the video!):
              http://www.youtube.com/watch?v=umnnA50IDIY

           2. Rugae of the stomach: http://www.youtube.com/watch?v=Ln09qihUi3g

           3. Peristalsis in Stomach: http://www.youtube.com/watch?v=YH3U_SLp9G0

           4. Peristalsis in Stomach: http://www.youtube.com/watch?v=pJCjDtfhsCI

           5. Peristalsis in Duodenum and Jejunum:
              http://www.youtube.com/watch?v=jn0QIlaDVYs

           6. Segmentation in Jejunum: http://www.youtube.com/watch?v=PfnKvErPwY4




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