Digestive System Notes
• Quiz Friday!
4 main functions:
• 1. Ingestion—food material taken into mouth
• 2. Digestion—food is broken down, mechanically
and chemically, as it travels through the
gastrointestinal tract.
Digestive enzymes aid the breakdown of complex
nutrients.
• Proteins → amino acids
• Sugars → glucose
• Fats → fatty acids or triglycerides
3. Absorption
4. Elimination
*The body eliminates
• Digested food passes
into the bloodstream solid waste materials that
through lining cells of cannot be absorbed into
bloodstream.
the small intestine.
• Nutrients travel to all
cells of the body.
*The large intestine
concentrates feces.
• Cells burn nutrients to
release the energy
*The wastes pass out of
stored in food.
the body through the
anus.
Small Intestine
Villi in the lining of the small intestine help absorb
nutrients into the bloodstream.
Epiglottis- Flap leading to two tubes.
The esophagus & Trachea
Diagram on
Quiz- No
word bank.
The Digestive Tract
Parts of the Stomach
Food travels through the digestive tract by peristalsis
(wave like movements)
Stomach Continued
What is the function of
a sphincter?
Opens to allow for food
to travel through when
peristalsis passes by.
Parts of the small intestine: Extends from Ilium to
anus
Function: Major digestive
organ. Usable food is
prepared for journey into
cells of the body.
Length? 6-13 feet long
3 parts: D-J-I
Duodenum (10 inches)
Junum (8 feet)
Ileum (12 feet)- joins
the large intestines
Large Intestines (AKA colon)
• Function: Receives fluid waste from digestion
and stores until it can be released form the
body.
• Size? Larger in width then small intestines,
but shorter in length (5 feet)
• Made up of? Ascending, Transverse &
Descending, Sigmoid colon and Anus.
• Subdivisions of L.I.? Cecum, appendix, colon,
rectum and anal canal.
Large Intestines Continued
Function of
appendix? No
real function, not
needed!
Function Pancreas? Converts food into fuel &
helps assist in regulating blood sugar.
Function of Gall Bladder? Store & concentrates
bile (help in breakdown of fats & food)
Functions of the Liver…
Besides producing bile, the
liver also…
• Helps maintain normal blood
glucose levels
• Manufactures blood proteins
necessary for clotting
• Releases bilirubin, a pigment
in bile
• Removes toxins and poisons
from the blood
Food Pathway through the GI Tract
Food enters
through the
oral cavity and
exits through
the anus
Abnormal Conditions
• Hernia – protrusion of an organ or
part through the muscle normally
containing it
Abnormal Conditions Continued
• Anal fistula – abnormal tube-like passageway
near the anus
• Colonic polyposis – polyps (out pouching)
protrude from the mucous membrane of the
colon
• Diverticulosis – abnormal side pockets
(outpouchings) in the intestinal wall
Abnormal Conditions Continued
• Dysentery – painful, inflamed intestines
• Hemorrhoids – swollen, twisted, varicose
veins in the rectal region
• Cirrhosis – chronic degenerative disease of
the liver
• Viral hepatitis – inflammation of the liver
caused by a virus
• Cholelithiasis – gallstones in the gallbladder