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					Organic Compounds & Digestion                Thurs 9/9/10

 • macromolecules & monomers
    •finish up last outline
 • Vertebrate digestive system
    • structure and function
    • accessory organs
 • Mechanism of Digestion & Absorption of macromolecules
 • Macronutrients & Micronutrients
    • role of macronutrients
    • role of vitamins & minerals
Animal Nutrition & Digestion

•   Nutrient –



• Absorption




•5   categories of organic nutrients
      •
      •
•   Inorganic nutrients
      •
 Essential Nutrients:
Certain  compounds cannot be synthesized from any ingested
or stored precursor molecule

4   groups
     (1) Essential amino acids
         •
         •
         • Carnivores and omnivores
         • Most plants do not contain



     (2) Essential fatty acids
          • Certain polyunsaturated


         • Unsaturated fatty acids
         • Strict carnivores obtain
Essential Nutrients:

Certain  compounds cannot be synthesized from any ingested
or stored precursor molecule

4   groups
     (1) Minerals
         •
         • Many required in only
         • Some minerals


     (2) Vitamins
         • Important organic nutrients
         •Fat-soluble vitamins
         •Water-soluble vitamins
         •Not all
 Essential Nutrients:

 Animalsmay
 Polymers must be
Principles of digestion and absorption


•Digestion




•Products   of digestion



•
Digestion of macromolecules:

 Mouth / Oral Cavity:
 • all animals
 • jaw w/ teeth
     •
 • saliva
     –
     –
     –
     – Initiate digestion of
Pharynx & esophagus
• pathway only
• swallowing


    • tongue


    • go down
    • epiglottis


• action
•
•
Stomach: mechanical and chemical digestion            fig 14.5



• flow from esophagus

• saclike organ evolved


• partially
• regulates rate

• glands secrete
                                   •
    – hydrochloric acid

    – pepsinogen –                 • food
                                   • control into and out of
                                   stomach
Small intestine
 • Nearly all digestion of food, and absorption of food and water
 occur

 • Hydrolytic enzymes found on

 •Products of digestion
 absorbed



 •



                                                        fig 14.6
Small intestine: final chemical digestion & absorption
Absorption of nutrients:

• maximized surface area =


• capillary network absorbs


• fatty acids and monoglycerides


• Lacteal (lymphatic vessel) –




                                                         fig 14.6
Accessory organs:
                                  fig 14.7
• pancreas
    •


• liver
    • de-toxification of blood,



• gall bladder
    •
    •
Large Intestine:
• much shorter than
                                    fig 14.8


• primary function


• houses good bacteria
   •


   • produce vitamins    cecum -

       •
       •                 appendix

   • breaks
Digestion of
macromolecules:
Mechanisms of digestion and absorption   fig 14.1


• Carbohydrates
   –In typical omnivore,

   –Mouth –

   –S.I. –

   – Small intestine




see Table 14.1
Mechanisms of digestion and absorption   fig 14.1


• Proteins
    – stomach
    – pancreas


       •


    – small intestine


    – transported into




 see Table 14.1
Mechanisms of digestion and absorption   fig 14.1

• Fat
   – digestion entirely in


   –
   – phospholipids and bile salts

   –bile salts form


        –




see Table 14.1
    Role of Macronutrients:

Food intake drives
metabolism:

•


•


• carbohydrates


• proteins & lipids
 Role of Macronutrients:

Metabolism:

• the chemical pathways
that


• cellular respiration
provides ATP
   •


• breakdown products
provide
Role of Macronutrients:

Lipids:

•


• cells


• nerve cell


• other lipids in the cell
membranes
    •
Cholesterol
• HDL –high density
lipoprotein
   •
   •


• LDL –low density lipoprotein
   •
                                 • Dietary Cholesterol not
   •                             necessarily related to


                                 • Dietary Fat
             Role of Macronutrients:
Carbohydrates:
   •
   •
   •
Proteins:
   •
   •
   •
Nucleic Acids:
   •
   •
              Micronutrients: Vitamins
• Do not require digestion
• Absorbed in complete form
• Vitamins:
   •
   •
 •Water-soluble vitamins
 typically not stored and will
 be flushed out of system
       •
       •


       •
Micronutrients: Vitamins

• Fat-soluble vitamins follow pathway for fat absorption
   •
   •

• frequently act like
hormones
    •


• example: Vitamin D
facilitates the uptake of
calcium
    •
Micronutrients: Minerals
                              see Table 14.8
• Examples:
   • potassium, calcium,
   sodium, chloride, iron

• carry out many functions:
    • calcium


   • iron –


   • may act as co-factors
Nutrition:

• Best diet is a
balanced diet
• review “MyPyramid”
on page 266
• know the basic
recommendations




              figure
              14.13