Food is energy source and source of building blocks - PowerPoint PPT Presentation

1 / 11
About This Presentation
Title:

Food is energy source and source of building blocks

Description:

Anything that burns needs oxygen. That's why we have to breathe intake of oxygen. What do calories ... Chemical digestion amylase in saliva begins digestion ... – PowerPoint PPT presentation

Number of Views:23
Avg rating:3.0/5.0
Slides: 12
Provided by: bott7
Category:

less

Transcript and Presenter's Notes

Title: Food is energy source and source of building blocks


1
  • Food is energy source and source of building
    blocks
  • Body changes chemical energy stored in food into
  • Mechanical energy
  • Heat energy
  • Chemical energy
  • How?
  • By burning it
  • Anything that burns needs oxygen
  • Thats why we have to breathe intake of oxygen
  • What do calories have to do with this process?
  • They are the unit for energy and indicate how
    much energy we can get from digesting a
    particular food

2
Organs of Digestive Tract
  • Mouth
  • Pharynx
  • Esophagus
  • Stomach
  • Small Intestine
  • Large Intestine
  • Rectum
  • Anus
  • Accessory glands and organs
  • Salivary glands
  • Pancreas
  • Liver

3
(No Transcript)
4
(No Transcript)
5
(No Transcript)
6
Function of Digestion
  • Digestion is necessary so that molecules are
    small enough to pass through cell membranes
  • Converts large, insoluble polymers into small,
    soluble monomers.

7
Types of Digestion
  • Mechanical- makes smaller pieces of food by
    chewing and peristalsis. Increases surface area
    for enzyme activity
  • Chemical- breaks chemical bonds to form new
    molecules e.g. starch into glucose

8
  • Mouth
  • Mechanical digestion- increase surface area for
    enzymes activity
  • Chemical digestion amylase in saliva begins
    digestion
  • of starch (complex carbohydrate) into glucose
  • Pharynx
  • Junction of esophagus and trachea
  • Epiglottis temporarily closes of airway as food
    is swallowed
  • Esophagus
  • Ringed by muscles which contract peristalsis
  • Food is pushed down toward stomach

9
  • Stomach
  • Gastric juices (HCl, pepsin) are secreted by
    glands in stomach lining digesting proteins
  • Mechanical digestion turns bolus into an acidic
    liquid called chyme
  • Stomach muscles contract and eventually force
    chyme into small intestine

10
  • Small Intestine
  • Long (6m) and narrow (2.5cm) tube first section
    is duodenum
  • In duodenum chyme gets mixed with digestive
    juices
  • Bile produced in liver stored in gallbladder,
    emulsifies fat
  • Pancreatic juices neutralize acidic chyme,
    contain enzymes that digest proteins,
    carbohydrates and lipids
  • Villi in the small intestine are specialized for
    absorbing nutrients into circulatory and
    lymphatic system

11
  • Large Intestine (colon or bowel)
  • Here bacteria produce vitamin K and several B
    vitamins
  • Water is absorbed from undigestable food making
    it more solid water is recirculated
  • Feces are stored in rectum until excreted
Write a Comment
User Comments (0)
About PowerShow.com