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    Digestive System
    Excretory System

7th Grade Biology
               The Nutrients

But First… Nutrients
                           The Nutrients

   Fuels
   Building Blocks
   Used for Movement, Growth and Repair
                                The Nutrients

    6 Types
      Carbohydrates (Sugars and Starches)
      Proteins (made from amino acids)
      Fats
      Vitamins
      Minerals (from the Earth)
      Water
            The Nutrients

            The Nutrients

                     The Nutrients


 Nutrients enter
 the body where
 the digestive and
 systems interact.
The Digestive System

  In Humans and other Mammals, the Digestive
   System consists of the mouth, teeth, saliva
   glands, esophagus, stomach, small and large
   intestines, aided by the liver, gallbladder and
   pancreas. This system converts food into
   energy and breaks down the non-nutritive
   components into waste to be excreted.
The Digestive System

              The Digestive System
               also interacts with the
               Nervous System.
                                The digestive System


 • Food comes in this way and digestion
   starts here!
                                       The digestive System


 • Food comes in this way and digestion starts here!
                                 The digestive System


   There should be about 32 teeth in the adult
   Teeth help you chop your food, breaking it
    down and increasing the surface area.
                            The digestive System
Saliva Glands

  When you do eat, the saliva breaks down
   the chemicals in the food a bit and helps
   make the food mushy and easy to swallow.
  Saliva contains enzymes.
                                  The digestive System

  You produce about 1.5 liters of saliva per day
                      The digestive System


          Your tongue helps out, pushing
           the food around while you chew
           with your teeth. It mixes in
           saliva. When you're ready to
           swallow, the tongue pushes a
           tiny bit of mushed-up food
           called a bolus toward the back
           of your throat and into the
           opening of your esophagus, the
           second part of the digestive
              The digestive System

            The digestive System

              The passageway
               to the stomach
               is about 10
               inches long (25

              Food moves
               down the
               esophagus with
               a wave like
               motion called
                         The digestive System


          Peristalsis is the rhythmic
           contraction of smooth
           muscles to propel contents
           through the digestive tract.
          The word is derived from New
           Latin and comes from the
           Greek peristaltikos, peristaltic,
           from peristellein, "to wrap
           around," and stellein, "to
          The digestive System

                               The digestive System

 The stomach is lined
  with a protective mucus
  to protect it from itself!

 The stomach contains
  gastric juices that aid in
  the breaking down of

 The stomach also
  churns food to help mix
  in the acids break it
          The digestive System

          The digestive System

          The digestive System

      The digestive System

But not these
kinds of Juices
                             The digestive System

Gastric Juices

  The stomach contains
   both digestive enzymes
   and acids that work
   together and aid in the
   breaking down of food.

  Acid (HCL)

  Enzymes
                               The digestive System

 Chyme is the semifluid
 mass of partly digested
 food expelled by the
 stomach into the
 duodenum. In other words,
 chyme is partially-digested
                                    The digestive System

Small Intestine

  The small intestine breaks down the food
   mixture even more so your body can absorb
   all the vitamins, minerals, proteins,
   carbohydrates, and fats. The pepperoni on
   your pizza is full of proteins - and a little fat -
   and the small intestine can help extract them -
   with a little help from three friends: the
   pancreas, liver, and gallbladder.
                  The digestive System

Small Intestine
                           The digestive System

Small Intestine

 The S.I. is made of 3 main parts

 1.Duodenum 26 cm (9.84 in)

 2.Jejunum 2.5 m (8.2 ft)

 3.ileum 3.5 m (11.5 ft)
                                   The digestive System

Duodenum          (First segment of the small intestine)

  The duodenum is a hollow jointed tube
   about 25-30 cm long connecting the
   stomach to the jejunum. It is the first and
   shortest part of the small intestine and it is
   where most chemical digestion takes
  The name duodenum is from the Latin
   duodenum digitorum, twelve fingers'
                                        The digestive System


 •The liver is the largest organ inside the body weighing
 approximately 1500 grams, or 3-4 pounds.

 •Despite its large size it is hidden beneath your rib cage
 on the right hand side of your body.

 • Normally the liver remains hidden and is your silent
 partner. Perhaps this is why its function is so mysterious
 and unknown to many.

 •Liver function is very complex
                                          The digestive System

 •The liver both stores and releases glucose, an essential
 sugar and source of energy required to maintain body
 functions. This is particularly important during periods of
 fasting, for example during sleep when the liver releases
 glucose which is vital for brain metabolism.

 •The liver is the primary source for the synthesis of
 proteins, particularly for proteins circulating in the blood,
 such as albumin and many of the clotting factors
 necessary to prevent bleeding into tissues.

 •The liver makes bile that is used to aid in digestion.
        The digestive System

                           The digestive System


               The gallbladder is an organ
              that is located on the
              underside of the liver and on
              the right side of the abdomen.
              The function of the
              gallbladder is to store bile that
              is produced in the liver before
              the bile is secreted into the
              intestines. Bile secreted into
              the intestines helps the body
              digest fats.
              The digestive System

                                  The digestive System

Bile Duct

  Bile ducts are tubes that carry bile from the
  liver to the gallbladder for storage and to the
  small intestine to aid in digestion.
                          The digestive System


  Bile is a fluid
  produced by the liver
  that aids in the
  digestion process.
                     The digestive System

            The Pancreas is a gland
             organ in the Digestive
             System. It is both
             exocrine (secreting
             pancreatic juice
             containing digestive
             enzymes) and endocrine
             (producing several
             important hormones,
             including insulin,
             glucagon, and
                                    The digestive System

Jejunum        (Second segment of the small intestine)

  The jejunum is the central of the three
   divisions of the small intestine and lies
   between the duodenum and the ileum.
  In adult humans the jejunum is about 8ft long
  The pH in the jejunum is usually between 7
   and 8 (neutral or slightly alkaline).
  The jejunum and the ileum are suspended
   which gives the bowel great mobility within the
   abdomen. It also contains muscles to help
   move the food along.
                               The digestive System

Jejunum   (Second segment of the small intestine)
                               The digestive System

Jejunum   (Second segment of the small intestine)
                                       The digestive System

Ileum     (Third and last segment of the small intestine)

 The ileum is the final section of the small
  intestine. It is about 6 to 12 feet (2-4 m) long in
  humans, follows the duodenum and jejunum.
  The pH in the ileum is usually between 7 and 8
  (neutral or slightly alkaline).
 Its function is mainly to absorb vitamin B12 and
  bile salts and whatever products of digestion that
  were not absorbed by the jejunum
                              The digestive System

Large Intestine / Colon

  The large intestine, an organ which is
   now more commonly referred to by its
   Greek name, the colon, is the last part of
   the digestive system. Its function is to
   absorb the remaining water from
   indigestible food matter, store this
   unusable food matter (wastes) and then
   eliminate the wastes from the body.
                              The digestive System

Large Intestine / Colon

 The large intestine takes 12 to 25 hours to
  finish up the remaining processes of the
  digestive system.
 Food is not broken down any further in this
  stage of digestion.
 The large intestine absorbs vitamins that are
  created by the bacteria inhabiting the colon.
 It is also very important in compacting the
                       The digestive System

Large Intestine / Colon
   Ascending Colon
   Transverse Colon
   Descending Colon
   Sigmoid Colon
   Rectum
           The digestive System

The Excretory System
  The excretory system is the system that discharges
   wastes. It is responsible for the elimination of wastes
   produced by homeostasis. There are several parts of the
   body that are responsible for this process, such as the
   sweat glands, the liver, the lungs, and the kidney
  It removes wastes of the organism, balancing and
   regulating the chemical composition of its body fluids.
   The excretory system eliminates excretory products from
   the body, collects water and filters body fluids.
  Without the excretory system, the build-up of harmful
   wastes could damage the body, resulting in destructive,
   dangerous, and even fatal deadness.
                                      The Excretory System

The Excretory System
  Urinary system
     Kidneys
     Nephron
     Urine
  Rectum / (sometimes the L.I. is considered part too)
  Lung
     Exhales Carbon dioxide
  Skin
     Sweats
  Liver
     Makes Bile
  Spleen
     Removes old RBCs
                                       The Excretory System


 The rectum (from the Latin rectum intestinum, meaning
  straight intestine)
 The rectum is the final straight portion of the large
  intestine in some mammals, and the gut in others,
  terminating in the anus.
 The human rectum is about 12 cm long.
 The rectum acts as a temporary storage facility for feces.
  As the rectal walls expand due to the materials filling it
  from within, stretch receptors from the nervous system
  located in the rectal walls stimulate the desire to
  defecate. If the urge is not acted upon, the material in the
  rectum is often returned to the colon where more water is
                                  The Excretory System


  In anatomy, the anus (from Latin ānus "ring
   (circle)[1][2], anus") is the external opening of
   the rectum. Closure is controlled by sphincter
   muscles. Feces are expelled from the body
   through the anus during the act of defecation,
   which is the primary function of the anus. Most
   animals — from simple worms to elephants and
   humans — have a tubular gut, with a mouth at
   one end and an anus at the other.
       The Excretory System

           The Excretory System

        The Excretory System

                 The Excretory System

Urinary System
                                   The Excretory System


  The kidneys are complex organs that have
   numerous biological roles. Their primary role is to
   maintain the homeostatic balance of bodily fluids by
   filtering and secreting metabolites (such as urea)
   and minerals from the blood and excreting them,
   along with water, as urine.

  Because the kidneys are poised to sense plasma
   concentrations of compounds such as sodium,
   potassium, hydrogen ion, oxygen, and glucose, they
   are important regulators of blood pressure, glucose
   metabolism, and erythropoeisis.
                           The Excretory System


  The medical field that studies the
   kidneys and diseases of the kidney is
   called nephrology[1]. The prefix
   nephro- meaning kidney is from the
   Ancient Greek word nephros (νεφρός);
   the adjective renal meaning related to
   the kidney is from Latin rēnēs,
   meaning kidneys.
          The Excretory System

                           The Excretory System

   The Ureter is the
    tube that leads from
    the kidneys to the
                           The Excretory System


  The important part
   of the excretory
   system stores Urine
   until it is excreted.
                         The Excretory System

   The Urethra is the
    tube that leads
    from the bladder
    to the exit point
    for the urinary
          The Excretory System

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