First FiveFirst Five

Describe the differences Describe the differences between:between:1.1. digestion and absorptiondigestion and absorption2.2. physical/mechanical digestion physical/mechanical digestion

and chemical digestionand chemical digestion3.3. ingestion and egestioningestion and egestion

AnnouncementsAnnouncements

Turn in the worksheets that were assigned Turn in the worksheets that were assigned last week:last week:Photosynthesis & RespirationPhotosynthesis & RespirationHuman Digestive SystemHuman Digestive System

Quiz on Monday (3/31) or Tuedsay (4/1): Quiz on Monday (3/31) or Tuedsay (4/1): Digestive system, Respiration & Digestive system, Respiration & PhotosynthesisPhotosynthesis

Finish all Coursework by Friday at 4:45 p.m.Finish all Coursework by Friday at 4:45 p.m.Work times: Mon, Wed, Thurs during LRL; Work times: Mon, Wed, Thurs during LRL;

Mon – Thurs after school until 5:30 p.m.Mon – Thurs after school until 5:30 p.m.

Human DigestionHuman Digestion

Nutrition Nutrition

Definition:Definition:

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

Types of NutrientsTypes of Nutrients MicronutrientsMicronutrients- vitamins, minerals, & - vitamins, minerals, &

waterwater

MacronutrientsMacronutrients- proteins, lipids, - proteins, lipids, carbohydratescarbohydrates

Four Parts of Nutrition Four Parts of Nutrition

1.1.IngestionIngestion

2.2.DigestionDigestion

3.3.AbsorptionAbsorption

4.4.EgestionEgestion

Four Parts of Nutrition Four Parts of Nutrition

1.1.IngestionIngestiontaking substances into the body taking substances into the body through the mouththrough the mouth

2.2. DigestionDigestion

3.3. AbsorptionAbsorption

4.4. EgestionEgestion

Four Parts of Nutrition Four Parts of Nutrition

1.1. IngestionIngestion

2.2.DigestionDigestionbreak-down of large, insoluble food break-down of large, insoluble food molecules into small, water-soluble molecules into small, water-soluble molecules using mechanical and molecules using mechanical and chemical processeschemical processes

3.3. AbsorptionAbsorption

4.4. EgestionEgestion

Four Parts of Nutrition Four Parts of Nutrition

1.1. IngestionIngestion

2.2. DigestionDigestion

3.3.AbsorptionAbsorptionmovement of digested food movement of digested food molecules through the wall of the molecules through the wall of the intestine into the bloodintestine into the blood

4.4. EgestionEgestion

Four Parts of Nutrition Four Parts of Nutrition

1.1. IngestionIngestion

2.2. DigestionDigestion

3.3. AbsorptionAbsorption

4.4.EgestionEgestionpassing out of food that has not passing out of food that has not been digested, as feces, through been digested, as feces, through the anusthe anus

Human digestive Human digestive systemsystem

Ingestion takes Ingestion takes place in the place in the

mouthmouthmechanical digestionmechanical digestionteeth break up foodteeth break up food

chemical digestionchemical digestionsalivasaliva

amylase: an enzyme that digests starchamylase: an enzyme that digests starchmucin: a protein present in mucus that mucin: a protein present in mucus that

protects soft lining of digestive system protects soft lining of digestive system and lubricates food for easier swallowingand lubricates food for easier swallowing

buffers: neutralize acid to prevent tooth buffers: neutralize acid to prevent tooth decaydecay

anti-bacterial chemicals: kill bacteria that anti-bacterial chemicals: kill bacteria that enter mouth with foodenter mouth with food

Food moves through Food moves through the Esophagus to the the Esophagus to the Stomach by PeristalsisStomach by Peristalsis

Peristalsis: a series Peristalsis: a series of involuntary wave-of involuntary wave-like muscle like muscle contractions which contractions which move food along the move food along the digestive tractdigestive tract

Esophagus

Stomach: Stomach: functionfunction

food storagefood storagecan stretch to fit ~2L food can stretch to fit ~2L food

disinfect fooddisinfect foodHCl [pH 2] kills bacteria HCl [pH 2] kills bacteria

chemical digestionchemical digestionpepsin: an enzyme that breaks down pepsin: an enzyme that breaks down proteinsproteins

Food is further broken down into a thin Food is further broken down into a thin liquid called liquid called chymechyme..

Which type of digestion is the Which type of digestion is the following? following?

1.1. Chewing a saltine? -Chewing a saltine? -

2. Saliva breaking the saltine down into molecules of 2. Saliva breaking the saltine down into molecules of glucose? -glucose? -

3. Your tongue breaking pieces of a hamburger 3. Your tongue breaking pieces of a hamburger apart? apart?

4. Pepsin (an enzyme) in your stomach breaking the 4. Pepsin (an enzyme) in your stomach breaking the hamburger into amino acids? hamburger into amino acids?

Accessory OrgansAccessory Organs

PancreasPancreas

LiverLiver

Gall BladderGall Bladder

Pancreas Pancreas

An organ which secretes both digestive enzymes An organ which secretes both digestive enzymes (exocrine) and hormones (endocrine)(exocrine) and hormones (endocrine)

Pancreatic juice contains enzymes which digest Pancreatic juice contains enzymes which digest all major nutrient types. all major nutrient types.

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

Pancreatic JuicePancreatic Juice

Digestive enzymesDigestive enzymesamylaseamylase

breaks down starchbreaks down starchtrypsintrypsin

breaks down proteins to polypeptidesbreaks down proteins to polypeptideslipaselipase

breaks down fats to fatty acids and breaks down fats to fatty acids and glycerolglycerol

Buffers Buffers neutralize acid from stomachneutralize acid from stomach

Liver Liver

converts excess glucose converts excess glucose (monosaccharide) to glycogen (monosaccharide) to glycogen (polysaccharide) for storage(polysaccharide) for storage

converts excess proteins and amino converts excess proteins and amino acids to other substances, such as acids to other substances, such as fats, for storagefats, for storage

produces bile for use in digestionproduces bile for use in digestion

Gall bladder Gall bladder Stores bile until needed in the Stores bile until needed in the

duodenum (small intestine)duodenum (small intestine)

Moves bile through the Moves bile through the bile ductbile duct

BileBileBile is a bitter, greenish-yellow Bile is a bitter, greenish-yellow

alkaline fluidalkaline fluidstored in the gallbladder between stored in the gallbladder between

mealsmealsdischarged into the duodenum(small discharged into the duodenum(small

intestine) upon eatingintestine) upon eatingaids the process of digestionaids the process of digestion

Bile emulsifies lipidsBile emulsifies lipidsphysically breaks apart large drops physically breaks apart large drops

of fat into small drops of fatof fat into small drops of fat

Small intestineSmall intestine

Functions:Functions:

chemical digestionchemical digestion

absorption of nutrients absorption of nutrients through liningthrough lining

small intestine has huge surface small intestine has huge surface area = 300 marea = 300 m2 2 (~size of tennis (~size of tennis court) court)

Small intestineSmall intestine

Structure: Structure: 3 sections3 sections1.1. duodenumduodenum = mostly = mostly

digestiondigestion2.2. jejunumjejunum = absorption of = absorption of

nutrients & waternutrients & water3.3. ileumileum = absorption of = absorption of

nutrients & waternutrients & water

Duodenum Duodenum

1st section of small intestine1st section of small intestine

acidic food from stomach mixes acidic food from stomach mixes with digestive juices from:with digestive juices from:

pancreaspancreasliverlivergall bladdergall bladder

the final stages of digestion are the final stages of digestion are completed in the duodenumcompleted in the duodenum

Absorption by Small Absorption by Small IntestinesIntestines

Absorption:Absorption:

movement of digested food movement of digested food molecules through the wall of the molecules through the wall of the intestine into the bloodintestine into the blood

Absorption by the Small Absorption by the Small IntestineIntestine

Digested nutrient molecules are small enough to Digested nutrient molecules are small enough to pass through the wall of the small intestine into pass through the wall of the small intestine into the blood.the blood.

Water, mineral salts, and vitamins are also Water, mineral salts, and vitamins are also absorbed in the small intestineabsorbed in the small intestine

VilliVilli finger-like projections in the wall of the small finger-like projections in the wall of the small

intestineintestine increase the surface area of the small intestinesincrease the surface area of the small intestines greater surface area provides better absorption of greater surface area provides better absorption of

materialsmaterials

Absorption by Small Absorption by Small IntestinesIntestines

Villi: finger-like projections that Villi: finger-like projections that increase surface area for absorptionincrease surface area for absorption

VILLIVILLI

Large Large Intestine/ColonIntestine/Colon

Functions:Functions:reabsorption of reabsorption of

waterwatermovement of movement of

undigested solid undigested solid materials (fibers)materials (fibers)

Structure:Structure:shorter and wider shorter and wider

than the small than the small intestineintestine

Rectum Rectum

Last section of colon Last section of colon (large intestine)(large intestine)

Eliminates fecesEliminates fecesundigested undigested

materialsmaterialsmainly cellulose mainly cellulose

from plantsfrom plantsroughage or roughage or

fiber fiber

pancreasproduces enzymes to digest proteins & starch

stomachkills germs break up fooddigest proteinsstore food

mouthbreak up fooddigest starchkill germsmoisten food

liverproduces bile

- stored in gall bladderbreak up fats

small intestinefinishes digestionabsorption of

nutrientscontains villi

large intestinefinishes digestionabsorption of

nutrientscontains villi

Digestive System Digestive System ClassworkClasswork

1) Go through the digestive system animation to visualize how the digestive system works.http://kitses.com/animation/swfs/digestion.swf

2) 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/buildabodydigestivesystem/

3) Answer the follow-up questions on the handout.

Finish as homework