Digestive system

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					Digestive system

    Part One
• Turn to page 1b
• Click on next slide
• Color diagram and study for quiz tomorrow
• Turn back to page 1
• Complete notes using the slides that follow
I. The purpose of
 the digestive
 system is to
 provide the body
with NUTRIENTS,
WATER, and
ELECTROLYTES
 (minerals)
 needed for good
 health.
II. There are four steps in this process:
     A. INGESTION getting food into the
body.


  Label these parts
  on page 4a
B. DIGESTION physically and
chemically breaking down food
C. ABSORPTION
 moving digested particles into a
 transport system so it can reach
the body cells.
D.ELIMINATIONcompacting
and moving undigestible
material out of the body.
III. The digestive system includes:
      A. The ALIMENTARY canal a
      hollow tube consisting
      of the following organs:
        1. ORAL cavity and pharynx
           (mouth and throat)
         2. ESOPHAGUS
         3. STOMACH
         4. Intestine
       ( SMALL and LARGE)

      5. Anus
B. Various glands and storage cavities outside
the tube that produce ENZYMES and other
chemicals that aid the digestive processes.
      These juices are sent into the alimentary
     canal by way of DUCTS.
      These glands include:
           1. Salivary glands
             ( found in the CHEEKS
             and under the TONGUE)
2. Gastric glands
(found in the lining of the STOMACH)
3. The Liver ( the LARGESTorgan in the body , both a
gland and a METABOLIC control center)
4. The gall bladder
( a HOLLOW sac found near the LIVER)




 Label these
 Structures on page 14
5. The pancreas
 ( found under the stomach near
the DUODENUM)
6. Many small glands producing MUCUS
for lubrication
• HOMEWORK -
• Use TEXTBOOK to complete page 1a
• Information is found in chapter 22.
• Turn to page 3 in booklet and complete
  using the following slides.
I. Several things happen inside the ORAL
cavity (mouth)
   A. Gross anatomy of the Mouth
      1. The cavity is
lined with MUCUS
membranes
      2. The roof has a
hard and soft PALATE.
      3. The space between
the lips, cheeks and teeth
is the VESTIBULE
4. The fingerlike projection extending
 downward from soft palate is called the
 UVULA.
( function = prevent CHOKING)
5. The tongue is a large MUSCLE covered
with taste buds called PAPILLAE and
attached to floor of the mouth by a
FRENULUM
6. There are four types of teeth:
     a.) INCISORS (8) used for cutting
     b.) CANINES (4) used for tearing and
           ripping
     c.) PREMOLARS (8)
         used for grinding
          and crushing
     d.) MOLARS(12)
         used for grinding
         and crushing
Color and label page 4b
     Color and label
     Page 4b
7. Two areas of LYMPHATIC tissue called
tonsils exist at the back of the PHARYNX
and base of the TONGUE.
8. Three sets of SALIVARY glands empty
into the mouth.
      a.) PAROTIDS
 (located near the ears ,secretion comes
    inbetween molars)
b.) SUBMANDIBULAR ( located
under jaw, secretion comes in under
tongue)
c.) SUBLINGUAL ( located under
tongue, secretion comes in under
tongue)
B. Physiology in the mouth:
( several mechanical and
chemical changes occur)
1. Mechanical changes:
    a.) Food is kept between teeth
by CHEEK MUSCLES and
TONGUE. Here the food is CUT
and GROUND.
(MASTICATED)
b.) Food is formed into a BOLUS and
lubricated for swallowing
c.) Food is swallowed. Action is:
     i. voluntary in the MOUTH
     ii. involuntary in the PHARYNX and ESOPHOGUS
2. Chemical changes:
   a.) salivary glands produce SALIVA
   b.) food is DISSOLVED in water
       so it can be tasted.
   c.) Antibacterial agents from saliva      H2O


  DISINFECT food                   disinfectant    amylas
                                                   e



  d.) Starches are
 changed to SUGAR
 by the enzyme
 AMYLASE found
in saliva
II. When food passes through the pharynx:
      A. Two layers of skeletal muscles
ALTERNATELY contract setting up waves
     called PERISTALSIS.
B. Vapors from food pass up to NASAL cavity.
C. The involuntary contraction of the appropriate
muscles moves the EPIGLOTIS so the TRACHEA
is blocked off and food cannot enter it.
III. When food passes along the 10 inch
tube called the esophagus:
      A. PERISTALSIS
continues
and aided by
 the force of
GRAVITY
 food moves to
the stomach.
B. Muscles in the esophagus are
SMOOTH muscle                          Smooth
                                       Muscles
C. A sphincter called                  relax


the CARDIAC                           Cardiac
                                      Sphincter opens

valve controls the passage Smooth
                           Muscles

 of food                   contract


into the stomach.
• Complete page 4 for homework
• Study page 1B for quiz

				
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