Transcript Lab 11 – Digestion System Part III

Lab 11 – Digestion System
Part III
Dr. Kim Wilson
Lab Manual Reference
Reference in lab manual – pages 597 –
604 (introductory material only)
 Figure 39A.1 (page 599) – Flowchart of
digestion and absorption of foodstuffs.

Chemical Digestion

Enzymes – large protein molecules
produced by body cells
Act as biological catalysts
 Increase the rate of chemical reactions
without becoming part of the reaction

Hydrolases – digestive enzymes
 Substrates – molecules on which
enzymes act

Mechanisms of Food Propulsion and
Mixing
Deglutition (swallowing)
 2 phases:


1. Buccal (mouth)


Voluntarily controlled, initiated with tongue
2. Pharyngeal-esophageal

Involuntary, delivers contents to stomach
Segmentation and Peristalsis

Peristaltic movements – major means of
propelling food through digestive viscera


Waves of contraction followed by waves of
relaxation
Segmental movements – local constrictions of
the organ wall that occur rhythmically

Function to mix food with digestive juices and to
increase the rate of absorption by moving different
portions of the chymeover regions of the intestinal
wall.
PART 1: CHEMICAL
DIGESTION - SMALL INTESTINE
INSTRUCTIONS:
 1. Complete the sheet titled, "Student
Guide - Digestion Biokit: Intestinal
Digestion A & B". Record the results in
the spaces indicated and include in your
lab report.
 2. Answer related questions on the
Questions Sheet.

PART 2: ABSORPTION IN THE
SMALL INTESTINE
1. Complete the sheet titled, "Student
Guide - Digestion Biokit: Absorption in
the Small Intestine". Record the results
in the spaces indicated and include in
your lab report.
 2. Answer related questions on the
Questions Sheet.

PART 3: THE ACTION OF BILE
INTRODUCTION:
 Bile is an emulsifying agent since it's
necessary to break fats into small
droplets before they can be digested.
Fat emulsification by bile allows water to
mix with small fat droplets, a necessary
step in chemical digestion.

INSTRUCTIONS
1. Place an equal amount of water and
oil in a test tube.
 Record the results on the Results Sheet.
 2. Add a small amount of liquid
dishwashing soap to the mixture and
shake the test tube. Record the results
on the Results Sheet.
 3. Answer related questions on the
Questions Sheet.
