HUMAN ANATOMY

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HUMAN ANATOMY PHYSIOLOGY
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Human Digestive System
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Warm-Up - journal

1. Write down in correct sequence all the organs (at
   least 5) through which their food passes as it
   travels along the digestive tract.
2. Then try to list any glands or organs that are
   found along the digestive tract, but through
   which food does not pass.

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(No Transcript)
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Following the Digestive Trail
Accessory Organs
Tongue Epiglottis Pharynx (throat) Salivary glands

• Mouth
• Esophagus
• Stomach
• Small Intestine
• Large Intestine

Accessory Organs
Pancreas Liver Gall Bladder
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The Need for Digestion

• Major Functions
• 1. Ingestion - taking in food
• 2. Digestion-ability to process food in the body
  into a form that can be absorbed and used or
  excreted.
• 3. Absorption -pulling nutrients out of the food,
  occurs in the small intestine
• 4. Defecation or Excretion -removal of undigested
  food

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Overview Food processing occurs in four stages
Smallmolecules
Piecesof food
Nutrientmoleculesenter body cells
Chemical breakdown(enzymatic hydrolysis)
Mechanicalbreakdown
Undigestedmaterial
Food
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3
4
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INGESTION
DIGESTION
ELIMINATION
ABSORPTION
Figure 21.2
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A. Purpose

• Provides energy to stay alive
• Process of breaking food particles down into
  molecules small enough to be absorbed by cells
• To help build cells, tissues and organs
• ATP energy for synthesis

B. Why?
mitochondria
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C. Types of digestion

• MECHANICAL
• Changes the physical form of food (physical
  changes)
• Mouth- teeth chew (masticate) crush food
• stomach muscles (rugae) grinds churns
• 2. CHEMICAL
• Changes the chemical composition of food into a
  new substance with the aid of digestive enzymes (
  chemical changes).

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Review Nutrition

• Food broken down to usable nutrients and absorbed
  into the bloodstream.
• They are used by the body for metabolism,
  building and repair
• Nutrients include carbohydrates, proteins,
  lipids, vitamins, minerals and water.
• Carbohydrates
• Broken down into monosaccharides
• Bodys main source of energy.
• Proteins
• Broken down to amino acids
• Supply the raw materials for growth and repair.
• Lipids
• Broken down to 3 fatty acids and glycerol
• They are used to make steroid hormones, cell
  membranes
• Store energy

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Nutrient End product (building blocks) Transport
Carbohydrate Simple sugars (glucose fructose) Diffusion (w/out energy high to low)
Proteins Amino Acids Diffusion
Lipids (Fats) 3 Fatty Acids 1 glycerol Diffusion Active transport (with energy, low to high)
Draw/label this
IN Nutrients O2
To the cells
Artery
OUT CO2
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D. Gastro Intestinal Tract

• How is the digestive system similar to a vacuole
  in a one celled organism?
• One celled organism (ameoba, parameciu, euglena)-
  it is intracellular (vacuoles release digestive
  enzymes)
• Humans- it is Extracellular (outside the cells
  then absorbed into the bloodstream)

Reference RB pg 13 table 1-1
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Review Which type of digestion (mechanical or
chemical)?

1. Chewing a saltine?
2. Saliva breaking the saltine down into molecules
   of glucose?
3. Your tongue breaking pieces of a hamburger
   apart?
4. Pepsin (an enzyme) in your stomach breaking the
   hamburger into amino acids?

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Digestion System video clip click on image
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Following the Digestive Trail a one way tube
Accessory Organs
Tongue Epiglottis Pharynx (throat) Salivary glands

• Mouth
• Esophagus
• Stomach
• Small Intestine
• Large Intestine

Accessory Organs
Pancreas Liver Gall Bladder
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Mouth
Following the Trail 1

• Mechanical digestion begins here -
  chewing/crushing food
• Salivary glands secrete saliva, which moistens
  and lubricates food for swallowing.
• Saliva contains amylases (enzymes), which start
  the chemical breakdown of carbohydrates (starch).

All thatin spit!
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Esophagus
Following the Trail 2

• Muscular tube (aka food tube)
• As we swallow, we push food along the tube until
  the food reaches our stomach. This process of
  pushing down the food uses muscular wave-like
  contractions is called peristalsis
• Peristaltic contractions transport food to the
  stomach and allow a person to swallow even if
  he/she are upside down.
• Click Here for animation

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Stomach
Following the Trail 3

• Food (bolus) mixes with acidic gastric juices
  (HCl) and an enzyme called pepsin to form chyme.
• The chemical digestion of proteins begins in the
  stomach.
• Mechanical digestion continues-stomach grinds
  churns the bolus

But the stomach is made out of protein! What
stops the stomach from digesting itself?
mucus secreted by stomach cells protects stomach
lining
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Small intestine
Following the Trail 4
FYI- the small intestine has 3 parts

• Secretes digestive enzymes to begin breaking down
  fats
• Continues and completes ALL chemical digestion of
  carbs, proteins and fats
• Absorbs nutrients into the blood stream
• S.I. lined with fingerlike projections, called
  villi, which, in turn, are covered by microvilli
  which increase surface area
• The villi contain capillaries and lymphatic
  vessels for the absorption of nutrients
• Nutrients move into blood stream by what process
  (Think H to L!)? DIFFUSION!!!!!!!!!

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A Closer look at the villi microvilli of the
small instestine

• Absorption through increases surface area for
  absorption

Cross-Section of small intestine
Microvilli
Villi
SMALL INTESTINES6 meters long,but can
stretchto cover a tennis court
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Following the Trail 4 cont.the accessory
(helper) organs

• Food DOES NOT pass through these organs
• These organs secrete substances to aid in
  digestion

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Pancreas Found under the stomach
Following the Trail 4 cont.

• Secretes enzymes (lipase, amylase, protease) into
  the small intestine
• Secretes a base into S.I. to neutralize stomach
  acid WHY??
• So digestive enzymes arent denatured and can
  work!
• Makes hormones insulin glucagon to balance
  blood sugar levels to maintain homeostasis

pancreas
smallintestine
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Balancing Blood Sugar levels
Homeostasis
insulin
body cells takeup sugar from blood
liver storessugar
reducesappetite
blood sugar level
liver releasessugar
triggershunger
Feedback
glucagon
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Liver
Following the Trail 4 cont.

• Produces secretes bile to emulsify (breaks up)
  fats
• stores bile releases to the small intestine

Gall Bladder
FYI - bile contains colors from old red blood
cells collected in liver iron in RBC rusts
makes feces brown
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Large intestines (colon)
Following the Trail 5

• NO digestion occurs here
• WATER and vitamin K gets reabsorbed from
  undigested chyme
• Lined with bacteria (E. coli)
• Holds undigested or unabsorbed food wastes
  (feces)
• mainly cellulose from plants called roughage or
  fiber- keeps everything moving cleans out
  intestines
• Masses of bacteria
• Final stop for undigested materialeliminate feces

Rectum
So dont forget to wash your hands!
Anus
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E. Digestive Homeostasis Disorders
Body Invaders Digestive Problems Video
Discovery Health

• 1. Stomach
• 1) Mucus that prevents stomach from digesting
  itself
• a) Peptic ulcer occurs when layer of mucus fails
  (open sores)
• b) Gastric juices reach wall of stomach and begin
  to break down (painful)
• 2) Treatment
• Before Antacid would reduce amount of acid in
  stomach but would return
• Recently Ulcer is an infection by acid resistant
  bacteria Helicobacter pylori
• Treatment antibiotics

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• 2. Appendix
• No function may have once been used to digest
  plants (vestigal organ)
• Appendicitis inflammation of the appendix
  caused by E. Coli bacteria

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3. Large Intestine

• Constipation- too much water reabsorbed from the
  feces
• Diarrhea-too little water reabsorbed from the of
  feces prolonged diarrhea can cause dehydration
  of body tissues.

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4. Colon Cancer

• One of the most common types of cancers in North
  America
• Colon section before the rectum on lg.
  Intestine
• Cause
• Diet low in fiber causes feces to move too slow
  through colon
• Hereditary predisposition

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5. Gallstones

• small hard stones made of cholesterol that
  collect in the gallbladder.
• Due to a high saturated fat diet
• hereditary

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Digestive System Fill-In
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Digestive System Fill-In Answers