First Five

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First Five

• Describe the differences between
• digestion and absorption
• physical/mechanical digestion and chemical
  digestion
• ingestion and egestion

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Announcements

• Turn in the worksheets that were assigned last
  week
• Photosynthesis Respiration
• Human Digestive System
• Quiz on Monday (3/31) or Tuedsay (4/1) Digestive
  system, Respiration Photosynthesis
• Finish all Coursework by Friday at 445 p.m.
• Work times Mon, Wed, Thurs during LRL
• Mon Thurs after school until 530 p.m.

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Human Digestion
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Nutrition

• Definition
• Taking in, absorbing and assimilating nutrients
  for energy, growth, and tissue repair

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Types of Nutrients

• Micronutrients- vitamins, minerals, water
• Macronutrients- proteins, lipids, carbohydrates

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Four Parts of Nutrition

1. Ingestion
2. Digestion
3. Absorption
4. Egestion

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Four Parts of Nutrition

• Ingestion
• taking substances into the body through the mouth
• Digestion
• Absorption
• Egestion

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Four Parts of Nutrition

• Ingestion
• Digestion
• break-down of large, insoluble food molecules
  into small, water-soluble molecules using
  mechanical and chemical processes
• Absorption
• Egestion

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Four Parts of Nutrition

• Ingestion
• Digestion
• Absorption
• movement of digested food molecules through the
  wall of the intestine into the blood
• Egestion

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Four Parts of Nutrition

• Ingestion
• Digestion
• Absorption
• Egestion
• passing out of food that has not been digested,
  as feces, through the anus

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Human digestive system
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Ingestion takes place in the mouth

• mechanical digestion
• teeth break up food
• chemical digestion
• saliva
• amylase an enzyme that digests starch
• mucin a protein present in mucus that protects
  soft lining of digestive system and lubricates
  food for easier swallowing
• buffers neutralize acid to prevent tooth decay
• anti-bacterial chemicals kill bacteria that
  enter mouth with food

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Esophagus

• Food moves through the Esophagus to the Stomach
  by Peristalsis
• Peristalsis a series of involuntary wave-like
  muscle contractions which move food along the
  digestive tract

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Stomach function

• food storage
• can stretch to fit 2L food
• disinfect food
• HCl pH 2 kills bacteria
• chemical digestion
• pepsin an enzyme that breaks down proteins
• Food is further broken down into a thin liquid
  called chyme.

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Which type of digestion is the following?
Mechanical

• 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?

Chemical
Mechanical
Chemical
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Accessory Organs

• Pancreas
• Liver
• Gall Bladder

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Pancreas

• An organ which secretes both digestive enzymes
  (exocrine) and hormones (endocrine)
• Pancreatic juice contains enzymes which digest
  all major nutrient types.

• Pancreatic juice moves through the pancreatic
  duct into the duodenum (small intestine).

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Pancreatic Juice

• Digestive enzymes
• amylase
• breaks down starch
• trypsin
• breaks down proteins to polypeptides
• lipase
• breaks down fats to fatty acids and glycerol
• Buffers
• neutralize acid from stomach

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Liver

• converts excess glucose (monosaccharide) to
  glycogen (polysaccharide) for storage
• converts excess proteins and amino acids to other
  substances, such as fats, for storage
• produces bile for use in digestion

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Gall bladder

• Stores bile until needed in the duodenum (small
  intestine)
• Moves bile through the bile duct

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Bile

• Bile is a bitter, greenish-yellow alkaline fluid
• stored in the gallbladder between meals
• discharged into the duodenum(small intestine)
  upon eating
• aids the process of digestion
• Bile emulsifies lipids
• physically breaks apart large drops of fat into
  small drops of fat

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(No Transcript)
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Small intestine

• Functions
• chemical digestion
• absorption of nutrients through lining
• small intestine has huge surface area 300 m2
  (size of tennis court)

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Small intestine

• Structure 3 sections
• duodenum mostly digestion
• jejunum absorption of nutrients water
• ileum absorption of nutrients water

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Duodenum

• 1st section of small intestine
• acidic food from stomach mixes with digestive
  juices from
• pancreas
• liver
• gall bladder
• the final stages of digestion are completed in
  the duodenum

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Absorption by Small Intestines

• Absorption
• movement of digested food molecules through the
  wall of the intestine into the blood

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Absorption by the Small Intestine

• Digested nutrient molecules are small enough to
  pass through the wall of the small intestine into
  the blood.
• Water, mineral salts, and vitamins are also
  absorbed in the small intestine
• Villi
• finger-like projections in the wall of the small
  intestine
• increase the surface area of the small intestines
• greater surface area provides better absorption
  of materials

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Absorption by Small Intestines

• Villi finger-like projections that increase
  surface area for absorption

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VILLI
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Large Intestine/Colon

• Functions
• reabsorption of water
• movement of undigested solid materials (fibers)
• Structure
• shorter and wider than the small intestine

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Rectum

• Last section of colon (large intestine)
• Eliminates feces
• undigested materials
• mainly cellulose from plants
• roughage or fiber

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mouth ?break up food ?digest starch ?kill
germs ?moisten food
stomach ?kills germs ?break up food ?digest
proteins ?store food
small intestine ?finishes digestion ?absorption
of nutrients ?contains villi
pancreas ?produces enzymes to digest proteins
starch
large intestine ?finishes digestion ?absorption
of nutrients ?contains villi
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Digestive System Classwork

• 1) Go through the digestive system animation to
  visualize how the digestive system
  works.http//kitses.com/animation/swfs/digestion.
  swf2) Complete Build-A-Body Digestive
  System.-- Build the digestive system-- Read
  through the Case Studies to answer the questions
  on the handout.http//www.brainpop.com/games/buil
  dabodydigestivesystem/3) Answer the follow-up
  questions on the handout.
• Finish as homework