Download - The Digestive System
Presented By: Sam Lund, Donovan Parker, Tom Srebernak
1. Extract nutrients from food
2. Transform nutrients into useful formsEx. Oreo= Glucose (sugar)
3. Absorb nutrients and distribute them where they are needed
Ingestion: Intake of nutrients
Digestion: Breakdown of large particles into smaller ones
Absorption: Uptake of nutrient molecules
Defecation: Elimination of undigested residues
1. Intake- Breaks up food- Moves food through the GI tract (Peristalsis)- Mixes with digestive enzymes
2. Secretion- Release of enzymes and hormones for
chemical digestion and regulation
3. Membrane Transport- Absorption of nutrients from the tissues by
the blood and lymph for transport
Mechanical: Physical breakdown of food
Chemical: Digestive enzymes hydrolyze food particles to break larger molecules into smaller ones
Some nutrients are absorbed without digestion Vitamins, minerals, cholesterol, water
Oral Cavity Pharynx Esophagus Stomach Small Intestine Large Intestine
6 meters in length
Functions: Chemical Digestion Nutrient Absorption Nutrient
Transportation
Digestion and absorption of food
Digestive enzymes secreted by the pancreas Enter the small
intestine via the pancreatic duct.
Duodenum (25 cm) Food mixes with bile
from the gallbladder. Jejunum (2.5m)
Absorbs nutrients into the bloodstream.
Ileum (3.6 m) Reabsorbs bile acids.
1.5 meters long Responsible for absorption of water from
the indigestible residue of food
Ascending Colon: Descending Colon:
Up the right side Down the left side
Cecum: Sac on Sigmoid Colon:
lower right side S-shaped
Ascending Colon-Removes water and other nutrients
Transverse Colon-Expulsion of waste materials, continues leaching out
Descending Colon-Absorbs water from fecal matter. Stores food particles that are to be emptied into the rectum.
Sigmoid Colon- Make and eliminate feces. Contains 60 varieties of bacteria
Rectum- Temporary storage for fecal matter before it’s eliminated from the body through the anal canal.
Functions: A. Ingestion:
Cheeks lips and tongue mobilize food
B. Digestion: Mechanical
Mastication Chemical
3 salivary glands Digests some starches and fat
Purpose: Pharyngeal constrictors force food down during swallowing
Divided into 3 parts: Epipharynx Mesopharynx Hypopharynx
Straight Muscular tube about 1 foot long
Purpose: Muscular contraction moves food towards stomach
Muscular sac on the left side of the peritoneal cavity
Functions: Food storage Mechanical
digestion Chemical
digestion
Saliva: Amylase: Breaks down starch Lipase: Breaks down fats when it enters the
stomach
Stomach: HCL: Activates enzymes, breaks up foods Pepsin: Digests proteins Renin: Digests milk
Starches bloodstream
Fats lymph vessels (lacteals)
Proteins bloodstream