Human Digestive System - PowerPoint PPT Presentation

1 / 34
About This Presentation
Title:

Human Digestive System

Description:

Human Digestive System To be used with Digestive System Guided Notes Gaccione/Bakka Belleville High School – PowerPoint PPT presentation

Number of Views:104
Avg rating:3.0/5.0
Slides: 35
Provided by: Press152
Category:

less

Transcript and Presenter's Notes

Title: Human Digestive System


1
Human Digestive System
  • To be used with Digestive System Guided Notes
  • Gaccione/Bakka
  • Belleville High School

2
Nutrition
  • Nutrition process by which
  • organisms obtain and utilize
  • their food
  • Utilizing nutrition - 2 Parts
  • 1. ingestion- taking in of food
  • 2. digestion- mechanical and
  • chemical breakdown of food
  • so that it can be absorbed and
  • used by the body cells

3
Types of Feeders
  • Autotrophs- self feeders-make their own food.
    Example green plants
  • Heterotrophs- consumers.
  • Depend upon other
  • organisms for their food.
  • Example Giraffe

4
Types of Nutrients
  • Nutrients- substances in food that organisms can
    use
  • 2 types - micro macronutrients
  • Micronutrients - nutrients needed in small
    amounts by an organism 
  • examples
  • vitamins (used as coenzymes to help enzymes)
  • and minerals

5
Types of Nutrients
  • macronutrients-
  • nutrients needed in large amounts by an
    organism 
  • Large molecules like carbohydrates, fats,
  • and proteins that require digestion.

6
Carbohydrates
  • Used for
  • Energy or energy storage
  • Should constitute 50 of the energy for the body.
  • Found in fresh fruits and vegetables as well as
    whole grains, pasta rice.
  • Provide a source of nondigestible materials
    (roughage or fiber)
  • stimulates the muscles of the alimentary canal or
    food tube(esophagus, stomach intestines)

7
Fats
  • Used for
  • Energy storage
  • Protection
  • Insulation
  • Part of cell membranes
  • Fats contain more potential energy per each unit
    of their mass then any other major nutrient.

8
Proteins
  • Used for
  • Energy
  • Growth and repair
  • Cell membranes
  • Muscle
  • Blood (hemoglobin)
  • enzymes

9
Other Molecules
  • Water, vitamins, and minerals are small molecules
    that can be absorbed without digestion

10
Nutritional requirement
  • Calorie used to measure the energy in foods
  • Varies on different types of food
  • Nutritional requirements (amount of calories
    needed) vary with the human
  • 1.)  body weight
  • 2.)  age 
  • 3.)  activity level
  • 4.)  your sex - male or female
  • 5.)  natural body efficiency

11
Chemical Digestion
  • Hydrolysis the splitting of large, insoluble
    molecules into small, soluble molecules with the
    addition of water
  • Regulated by digestive enzymes
  • Maltose water ? simple sugars (glucose)
  • Starch water ? simple sugars
  • Proteins water ? amino acids
  • Lipids water  ? 3 fatty acids glycerol

12
Human Digestive Tract
  • Human digestive tract aka Alimentary Canal
  • consists of a continuous one way food tube
  • Gastrointestinal Tract (GI)
  • Upper GI -
  • mouth, esophagus stomach
  • Lower GI -
  • small large intestine anus
  • Peristalsis
  • -- constriction of the esophagus

13
Mouth and Teeth
  • Mouth ingests food
  • 1minute
  • Oral cavity contains the tongue, teeth, and
    salivary gland openings
  • Teeth mechanically breakdown food
  • increases the surface area of the food
  • improves enzyme action

14
Saliva and Tongue
  • Salivary glands
  • secretes digestive fluid - saliva
  • 2 Roles of Saliva
  • 1. Provides lubrication for the chewed food
  • 2. Contains the digestive enzyme amylase that
    begins the digestion of starch.
  • Secretion of saliva is stimulated automatically.
  • Tongue acts as a plunger to push food back
  • into the throat (pharynx)

15
Esophagus and Stomach
  • Esophagus 1 minute
  • 10 inch long muscular tube
  • its muscular walls move food from the mouth to
    the stomach by peristalsis
  • Stomach 2 to 4 hours
  • muscular J-shaped sac, size of your fist
  • Protein(pepsin) begins its digestion here
  • mixes the partially chewed food with gastric juice

16
Inside the Stomach
  • Gastric juice
  • Contains the following
  • 1. Water solvent
  • 2. Mucus lubrication
  • 3. Hydrochloric acid (HCl) pH2 makes food
    acidic
  • Allows the enzyme pepsin to function
  • 4. Pepsin gastric protease
  • Begins the digestion of protein in the stomach
  • Acid Reflux Disease Pepcid AC

17
From the stomach to the SI
  • Pyloric sphincter muscular valve between the
    stomach and the small intestine
  • regulating the passage of the partially digested
    mass
  • Food is held 2-4 hours in the stomach.
  • Gastric bypass

18
Small Intestine - 12 hours
  • a 20-25 foot long twisted tube of small diameter
    (about 1 inch)
  • lined with enzyme secreting intestinal glands
    does most of the chemical digestion
  • chemical digestion of carbohydrates, fats(lipids)
    proteins are digested in SI
  • accessory structures, the liver, gall bladder and
    the pancreas, empty their secretions into the SI

19
Accessory Structures of SI
  • Liver largest body organ
  • digestive function is to make bile
  • also produces insulin that
  • breaks down glucose
  • Disorder Hepatitis -
  • inflammation of the liver
  • transmitted by food or blood

20
Accessory Structures of SI
  • Gall bladder small sac beneath the liver
    that stores bile
  • Bile emulsifies fats(lipids)
  • breaks down fats
  • into smaller particles.
  • Bile duct carries bile from
  • the gall bladder to the S.I.

21
Accessory Structures of SI
  • Pancreas located near the small intestine
  • pancreatic juice is carried to the SI by the
    pancreatic duct
  • Pancreatic juice secretes 3 enzymes that digests
  • carbs, fats proteins.

22
Liver, Gallbladder, and Pancreas not part of
the alimentary canal all secrete into the small
intestine
23
Digestion and Absorption of SI
  • Intestinal glands line the small intestine
  • secrete intestinal juice
  • Nearly all digestion occurs in the small
    intestine all digestion is completed in the SI.
  • intestinal juice contains enzymes to breakdown
    proteins, fats, and carbohydrates

24
Absorption in the SI
  • Absorption in the SI
  • Absorption occurs directly through the wall into
    blood vessels, without the need for special
    adaptations.
  • Villi microscopic fingerlike projections on the
    SI wall
  • increase the surface area for nutrient absorption
  • contain a capillary and a lymph vessel

25
Villi - a closer look
26
Absorption in the LI - 5 hours
  • Large Intestine
  • Averages 6 feet in length
  • 2.5 inches in diameter
  • Sometimes called the colon
  • No digestion in the LI
  • Appears as an inverted U surrounding the SI
  • Undigested food and water enter the large
    intestine where water is absorbed.
  •  
  • Appendix vestigial organ not needed in human
    digestion
  • at the beginning of the LI

27
Removal of Undigested Food
  • Strong peristaltic action forces feces out
    through the rectum and the anus.
  • Defecation the removal of feces

28
anus - epiglottis - large intestine - stomach -
small intestinemouth - pancreas - appendix -
esophagus - gallbladder - liver
mouth
epiglottis
esophagus
liver
stomach
gallbladder
pancreas
large intestine
small intestine
appendix
anus
29
Digestive Homeostasis Disorders
  • Ulcers open sores in the lining of the stomach
    or the small intestine. Mucus normally prevents
    ulcers.
  • associated with some kind of irritant or
    bacterial infection

30
Digestive Homeostasis Disorders
  • Appendicitis infection and inflammation of the
    appendix

31
Digestive Homeostasis Disorders
  • Gallstones small hard particles made of
    cholesterol which form and collect in the gall
    bladder
  • may block the bile duct causing pain and
    discomfort
  • treated by lasers or surgical removal of the gall
    bladder

32
Digestive Homeostasis Disorders
  • Constipation the feces are evacuated
    infrequently and with difficulty
  • Caused by sluggish peristalsis that allows excess
    water to be removed from the feces (fecal
    material hardens)
  • may result from insufficient roughage in the diet

33
Constipation, cont.
  • Treatment for Constipation

34
Digestive Homeostasis Disorders
  • Diarrhea opposite of constipation
  • - water is not absorbed by the body
  • caused by infections or stress
  • prolonged diarrhea severe dehydration
Write a Comment
User Comments (0)
About PowerShow.com