Download Digestive System Notes

Digestive System
Unit 9
How it Works
• Consists of one long tube from mouth to
anus and the accessory organs
– Those that aid in the process of digestion
– Ex: Salivary Glands, Liver, Pancreas, Gall
Bladder
• Peristalsis: Physical action of the smooth
muscles that move digestive materials
through the system
Functions To Know
1)
2)
3)
4)
5)
6)
7)
8)
Ingestion of Food
Physical break down of food
Chemical break down of food
Food Storage
Water absorption
Vitamin synthesis
Food Absorption
Elimination of waste (indigestible materials)
Major Organs and Functions
1. Oral Cavity: Where food enters
2. Pharynx: Space behind oral cavity that leads to
3 places: Nasal Cavity, Stomach, and Trachea
3. Tongue: Large muscle, propels food, taste bud
4. Salivary Glands: Secretes enzymes to begin
digestion of carbohydrates, moistens bolus
(food ball), makes saliva:
(mixture of mucus, water, enzymes, and
antibacterial compounds, slightly acidic)
Taste Bud Myth?
•
•
•
•
“New Research Suggest
Different Take On Map”
Columbia University
researchers say our taste bud
map is wrong!
Yes, we still taste the basics:
salty, bitter, sour, sweet and
savory
BUT, Each taste bud can
detect ALL 5 flavors
Brain interprets flavors with
info from sense of smell
Salivary Glands
• Make Saliva
• 3 Different Glands
• Pavlov’s Dogs?
5. Uvula: prevents materials from entering
nasal cavity with soft palate
6. Epiglottis: “lid” that covers the trachea
when swallowing
*Why do people
choke?
Lower Structures
7. Esophagus: Long muscular tube that leads to
the stomach, undergoes peristalsis
8. Stomach: Muscular chamber on the left side of
the body that uses HCl and enzymes to break
down food (phys. and chem.) Makes chyme
(liquid digestive product from food), folds
called “rugae” for expansion
9. Sphincters: Band of circular muscles that block
off areas of D.S. until product is ready to move
(Found from back of mouth all the way to anus)
Label the Stomach In Notes
Cardiac Sphincter
10. Small Intestine
•
17 ft. long organ that breakdown/absorb
all materials into bloodstream, 3 portions
a) Duodenum: 1st portion, receives fluid from
pancreas and gall bladder (10 in.)
b) Jejunum: 2nd portion, 6.5 ft in length
c) Ileum: 3rd portion, 10 ft, leads to large
intestine
-Inside lined with VILLI to absorb nutrients into
blood stream, increases surface area!
Villi Info
Primary surface of
nutrient absorption in
the gastrointestinal
tract and increase the
surface area.
They are packed with
enzymes that aid in the
breakdown of complex
nutrients into simpler
compounds that are
more easily absorbed.
11. Large Intestine
•
•
Named for its diameter (3 inches wide), 4.5 ft
in length
Absorbs left over water and Na+, eliminates
solid waste (feces)
d)
e)
f)
g)
h)
i)
j)
Cecum: 1st part, pouch like has bacteria
Ascending : Right side of body
Transverse: Goes across right to left
Descending: Passes down left side
Sigmoid : S- shaped in groin area
Rectum: Muscular Chamber that leads to anus, 3
sets of sphincters, holds feces
Anus: terminus of D.T., contains sphincters
*Add arrows
to diagram to
show the path
thru the L.I.
Cecum
Anus
To Poop or Not To Poop…
• As the rectal walls expand due to the materials filling it
from within, stretch receptors from the nervous system
located in the rectal walls stimulate the desire to defecate.
• If the urge is not acted upon, the material in the rectum
is often returned to the colon where more water is
absorbed.
• If defecation is delayed for a prolonged period,
constipation and hardened feces results - OUCH
Accessory Organs
12. Liver: Second largest organ in the body,
located in the upper right abdominal quadrant
Functions Include:
a. Production of Liver Bile (for fat digestion)
b. Detoxifies harmful chemicals
c. Storage of glycogen (form of glucose)
d. Release of glucose into blood
e. Protein synthesis of vital molecules
f. Production of hormones
(for blood pressure)
The Liver
More Accessory Organs
12. Pancreas: left side of body, secretes insulin and
digestive juices directly into duodenum (1st part
of small intestine)
13. Gallbladder: located in liver lobes, stores,
concentrates, and secretes bile for the
breakdown of fat
14. Appendix: No current function (except to be
infected) about the size of a pinky finger,
located off the cecum.
The Pancreas and Gall Bladder
Digestion Videos
• Oprah Video
• Digestion Process
Digestive Review/Activities
• What causes diarrhea?
• Silent but deadly??
• Does stress cause digestive problems?
Digestive System Complications
• Crohn’s Disease
• Irritable Bowel
Syndrome
• Celiac’s Disease
• Lactose Intolerance
• Hiatal Hernia
• Ulcers
• *Diabetes
Diabetes Type 1
Diabetes Type 2
Is Sugar Toxic?
• Dangers of Hidden Sugar
• Sugar vs. High Fructose Corn Syrup