DIGESTIVE DIGESTIVE SYSTEMSYSTEM

-This group of organs that break -This group of organs that break down food into smaller particles down food into smaller particles or moleculesor molecules

-This breakdown makes it -This breakdown makes it possible for the smaller digestive possible for the smaller digestive particles to pass through the particles to pass through the intestinal wall into the intestinal wall into the bloodstreambloodstream

DigestionDigestion??????

What What isis

The chemical breakdown of complex The chemical breakdown of complex biological molecules into their biological molecules into their component parts.component parts.

•Lipids to fatty acids Lipids to fatty acids •Proteins to individual amino acidsProteins to individual amino acids•Carbohydrates into simple sugarsCarbohydrates into simple sugars

DigestionDigestion

•Produces various chemicals to Produces various chemicals to break down the food.break down the food.•Filters out harmful Filters out harmful substances.substances.•Gets rid of solid wastes.Gets rid of solid wastes.

FunctioFunctionsns

TYPES TYPES OF OF

DIGESTIONDIGESTION

•Changes the chemical composition of Changes the chemical composition of food with the aid of digestive enzymesfood with the aid of digestive enzymes

CarbohydrateCarbohydrateProteinProteinLipidLipid

•Digestive enzymes are special proteins Digestive enzymes are special proteins that help break up large molecules of that help break up large molecules of food into very tiny molecules that can be food into very tiny molecules that can be absorbed and used by the cells in the absorbed and used by the cells in the form of nutrition.form of nutrition.

Chemical DigestionChemical Digestion

1. Liver• Largest gland in the body

• Aids in chemical digestion by producing bile.• Occupies much of the space in the upper

portion of the abdomen

2. Gall bladder• A small organ found on the surface of the liver

which stores the bile.

3. Pancreas• Large glandular organ lying just below the

stomachSecretes different enzymes and pour these into the

small intestines via the common bile duct

Chemical DigestionChemical Digestion

4. Intestinal Glands

Completes the digestion of food.

1. Peptidase – peptides to amino acids2. Sucrase – sucrose to glucose3. Maltase – Maltose to glucose and fructose4. Lactase – lactose to galactose and glucose

Enzymes secreted by Pancreas

Lipase – enzyme that digest fats or splits fat into soluble glycerol and fatty acids

Pancreatic amylase – acts like salivary amylase, splitting starch into a double sugar maltose

Trypsin and chymotrypsin – breaks proteins toamino acids.

Chemical DigestionChemical Digestion

Mechanical DigestionMechanical Digestion•Changes the physical form Changes the physical form

of foodof food>Chew >Chew >Tear>Tear>Grind>Grind>Mash>Mash>Mix>Mix

1.1.IngestionIngestion2.2.MovementMovement3.3.DigestionDigestion4.4.AbsorptionAbsorption5.5.Further Further digestiondigestion

Phases of Phases of DigestionDigestion

•A long A long muscular tube muscular tube with many with many sections and sections and areas.areas.

•Begins with the Begins with the mouth and ends mouth and ends with the anus.with the anus.

The Digestive The Digestive TractTract

Path of DigestionPath of Digestion

>Mouth>Mouth>Pharynx>Pharynx>Esophagus>Esophagus>Stomach>Stomach>Small Intestine>Small Intestine>Large Intestine>Large Intestine>Anus>Anus

- this is where food is mixed with the saliva secreted by several sets of salivary glands

- Saliva dissolves and softens food and acts as a lubricant, facilitating swallowing and passage through the next portions of the digestive tract.

MoutMouthh

Teeth - This is where food

is broken into smaller pieces by both biting and chewing.

Tongue- manipulates the

food during chewing and forms it into a mass called bolus, in preparation for swallowing.

-Pushes the bolus through a cavity called the pharynx and into esophagus.

MoutMouthh

- a long tube running through the throat and thorax and connecting to stomach in the upper portion of the abdominal cavity. -Food takes about 4 to 8 seconds as it passes through to the stomach.

Peristalsis – contraction movement of esophagus muscle

Sphincter – special ring of muscle found on the junction between esophagus and stomach, which when contracted closes the entrance to the stomach.

EsophagusEsophagus

>This is a large muscular sac, which functions as a storage organ, making discontinuous feeding possible.

Rugae –>folds of the stomach that increases its surface area. >churns the food, mixing it with the gastric juiceGastric Juice –> contains enzymes that break down proteinChyme ->soupy mixture that leaves the stomach and passes through the pyloric sphincter into the small intestines.

StomachStomach

StomachStomach

>This is where final digestion and absorption takes placeMeasures 23 ft long in an adult

Small IntestineSmall Intestine

>>Takes about 4 – 8 hrs to complete its journey.>Mucosa (inner wall) – secretes several enzymes that acts on the food.>Where the pancreatic enzymes are emptied into.>Digested nutrients are absorbed through intestinal walls.>Absorbed materials cross the mucosa into the blood then other parts of the body for storage or further chemical change.

Site of greatest amount of digestion and absorptionSite of greatest amount of digestion and absorptionSmall IntestineSmall Intestine

Duodenum – first section of the small intestines attached to the stomachJejunum – middle portion of the intestineIleum – very long coiled section lying lower in the abdominal cavityVilli – Finger-like projections in the inner wall of the small intestine that increases absorptive surface area.

Small IntestineSmall Intestine

- also known as colon- Reabsorbs much of

the water used in the digestive process and excretes certain salts, such as those of calcium and iron. Waste stays for 10 – 12 Waste stays for 10 – 12 hours.hours.

Caecum – this is a small and functionally unimportant for humanAppendix – finger-like process found at the tip of the caecumFeces – undigested food excreted into the colon and eliminated from the body. Rectum – Last portion of the large intestines that functions as a storage chamber for the feces until defecation

Large IntestinesLarge Intestines

AnusAnus >opening for the

elimination of feces.