Transcript Chap 22 – Digestive System

Begin reading Chap 22. Review
Lecture notes & all practice activities.
Chap 22 –
Digestive System
Learning Objectives
1.
2.
3.
4.
5.
6.
Describe peristalsis.
Identify the structures & explain the functions of each organ in the GI tract as
well as accessory digestive organs.
Be able to explain some of the hormones that act in the process of digestion,
their site of production, and target organs.
Explain chemical digestion of carbohydrates, proteins, lipids, and nucleic
acids.
Compare & contrast absorption with malabsorption regarding nutrients.
Be familiar with numerous intestinal disorders discussed in class.
Where It All Begins
When you were younger, did you ever hear
something similar to this?
“Now, chew your food carefully BEFORE you
swallow…”
(What do you think the reasoning was behind
that statement?)
Swallowing video: http://video.google.com/videoplay?docid=4375530805602416900
Food Moves Down the Esophagus
into the Stomach via Peristalsis
Peristalsis = __________________________?
*NOTE: Peristalsis is so strong that once food or liquid is
swallowed, it will reach your stomach even if you stand on
your head!
Digestion Begins in the Mouth
• __________ – chewing (_________) &
tooth action breaks apart food
• _________ – saliva in mouth begins
digesting ____; forms soft bolus (food ball)
Research Item – Take a minute to check it out!
What is Saliva composed of? Read the 2 paragraphs entitled
the Composition of Saliva”, page782. Note your findings to
share with the class.
Getting to Know
Your GI Organs
Instructions: Match the
functions with the
intestinal organ.
Write only the letter
of the answer.
Reference, pg 810.
Functions
Answer
Choices
(Organs)
1. Releases bi-carbonate rich juices that
help to neutralize acidic chyme
a. mouth
2. Stores bile and releases it to assist
small intestine as needed for lipid
digestion
b. esophagus
3. Mechanical digestion & propulsion;
peristalsis waves mix food with
gastric juice
c. stomach
4. Primary site for most absorption of
nutrients; slow digestion takes
place here
d. liver
5. Saliva & mechanical action begins
digestive process
e. gallbladder
6. Food tube that carries bolus from
mouth to stomach; first sit of
peristalsis
f. pancreas
7. Removes most of the remaining
water/ liquid from digesting food
g. small
intestine
8. Produces bile
h. large
intestine
GI Tract & Primary Organs, pg. 773
•
Label your
practice
diagram
(except for
the 3
“crossed
out”
structures).
PREDICT
• To be presented in class
Stomach
• To keep from digesting
itself, the stomach has
a ______ _______
with:
– A thick coat of
bicarbonate-rich mucus
on the stomach wall
– Gastric glands that
have cells
impermeable to HCL
• Damaged epithelial
cells are _______
replaced
Gastric pits
Gastric pits in the mucosa
of the stomach secrete
HCL; lined with chief cells
that secrete pepsinogen
(Protein digesting enzyme)
Problem: Tummy Trouble
A patient is complaining of gnawing upper
abdominal pain that appears 1-3 hours after
eating. The patient mentions that they seem to
feel temporarily better after eating again. (NOTE:
This has been ongoing for at least 4-6 months)
What might be the problem? What is the
possible cause?
What Does the Stomach Do?
• The stomach:
http://video.google.com/videoplay?docid=334990149
8863881080&q=stomach+view+on+endoscope&total
=9&start=0&num=10&so=0&type=search&plindex=0
– Holds ingested food like a _____ _______ (610 inches in length)
– Degrades this food both _________ (mixing &
churning) and __________
– Delivers chyme to the small intestine
– Begins ______ digestion with ________
– Secretes intrinsic factor required for
absorption of vitamin B12
– Sends liquids onward to the small intestine;
will retain solids until they are broken apart
Stomach 101
•
Label your practice diagram – ONLY structures circled in red.
I Can’t Believe I Ate The Whole Thing
• Stomach usually empties __ hours after
eating
• A meal high in fat may take up to __ hours
• ___ _______ meal empties quickest
(which is why you feel hungry again)
Review
1. Saliva begins digesting ________ in the
mouth?
2. Chief cells in the stomach mucosa secrete
________________ which act on _______?
3. Anatomical curve taking food ‘downward’
away from the stomach and into the small
intestine?
Small Intestine & Associated Structures
• Body’s most major digestive organ
- accomplishes virtually all ___________ of liquids & nutrients
- as chyme enters the duodenum:
Carbohydrates and proteins are only partially digested
No _____ digestion has taken place
- has an extensive surface area that is made even more vast by _____
& ________________
Villi & Microvilli continued…
Label your diagram (pg. 800) with the following: villi,
microvilli, lacteal, intestinal crypt, duodenal glands
Associated Organs
Small intestine completes digestion with
the help of __ other organs