Download Digestive System

Digestive System
http://health.howstuffworks.com/
adam-200142.htm
Swenson
Salivary Glands
a. Secrete enzyme
amylase (breaks
down carbs)
b. cover food to
produce bolus
(Mucous lubricates
food)
Tongue
a. moves food side to
side to be chewed
and keeps between
teeth
b. moves bolus to
back of throat
c. closes off mouth
when swallowing
Trachea
A. Wind Pipe
B. Epiglottis – flap of skin that covers the
trachea so food does not enter the wind
pipe and cause you to choke.
Esophagus
a. Food to the stomach
by peristalsis
Liver
a. produces and
secretes bile which
emulsifies fats
b. detoxifies blood
c. stores glycogen
(animal form of
starch)
d. Reduces/neutralizes
acidse. bile breaks
up fats
Gall Bladder
a. Stores bile
Stomach
a.
b.
c.
d.
e.
f.
churn/mix food
digestion of proteins starts here
Gastric juice is acidic (HCl) and
contains pepsin (enzyme to digest
proteins)
Gastrin (hormone) stimulates to
release of gastric juice
vomiting-reverse peristalsis
pyloric sphincter controls opening
and end of stomach
Bile Duct
a. duct or tube from gall
bladder to small
intestine
Trachea
a. wind pipe
b. protected by epiglottis during swallowing
(covering)
Small Intestine
a.
b.
c.
d.
e.
f.
g.
h.
20 – 30 feet long
parts of sm. Intestine are:
duodenum – listed above
jejunum – has folds of skin
called the brush border
membrane.
ileum – selective absorption of
some nutrients. What remains is
liquid stool
Final digestion occurs here
food is absorbed in simplest
forms – amino acids, fatty acids,
glycerole.
Villi – small finger like projects
that contain vessels to absorb
food
Duodenum
a. Most of the digestion
begins here (proteins,
fats and carbs)
Pancreas
a. produces powerful
digestive enzymes
b. Produces and
secretes insulin –
important in
regulating blood
sugar levels
Pancreas Duct
a. A duct or tube from pancreas
to small intestine
Appendix
 Vestigial organ –
“dead end”
a. May at one time
have aided in
digestion of cellulose
but has no function
today
Large Intestine (colon)
a. Parts are: Cecum – large
entrance controlled by a
sphincter that protects the
small intestine from the
large intestines
concentrated bacteria,
b. Ascending colon –
upwards,
c. Transverse colon – across,
d. descending colon – down,
e. sigmoid colon – end
f. reabsorbs water
g. Some solid wastes are stored before they enter rectum
Rectum
 Rectum
a. Stores solid waste until full
 Anus
a. Controlled by sphincter muscle by
peristalsis.
Digestion animation review
http://highered.mcgrawhill.com/sites/0072495855/student_view0/
chapter26/animation__organs_of_digestio
n.html
Digestive Processes
I. Ingestion
a. Takes food in – mouth
II. Peristalsis
a. Muscular contractions along digestive
tract-esophagus  small and large
intestine
III.
a.
b.
IV.
a.
V.
a.
Absorption
Taking of digested food into blood stream
Occurs in Sm. Intestine
Storage
Animal “starch” stored as glycogen in liver
Elimination
Solid waste eliminated from large intestine
VI.
a.
b.
VII.
a.
b.
c.
d.
Mechanical Digestion
Physically chewing-mouth
Churning action-stomach
Chemical Digestion
Uses enzymes
Starts carbohydrate breakdown in
mouth
Starts protein breakdown in stomach
Carbohydrates, proteins, and fats are
fully digested in Sm. Intestine
Types of Food
Food Type
Fats
% Diet
<30%
Purpose
Digestive End Product
Store energy
Glycerol + 3
Absorb Vitamins
fatty acids
Protect organs
Carbohydrates 55% Energy source
monosaccharides
Absorption of food
glucose
Fiber
Proteins
>15%
Growth
Amino Acids
maintenance/repair
makes enzymes
What happens to the Digestive End
Product (listed above):
 Absorbed into blood and delivered to cells and
organs




For Fats  used or stored
For Carbohydrates used for energy or stored
For Proteins used to rebuild/enzymes
Remember organisms are very efficiently adapted to
providing the nutrients they need. The complex
process of changing one type of macromolecule into
another is very complex with any one able to change
into the other, through many steps and much energy
input.
To speed Digestion organisms use
chemicals and enzymes

Acids



Bile



Gastric acid in stomach
Contains HCl
Secreted by liver-stored in gall bladder
Emulsifies fats (dissolves-NOT digest)
Enzymes – each enzyme (made of protein) is
regulated, with a special “job”




Jobs include
Operate by “Lock and Key” approach
Some examples
Hydrolysis – (Breaking down polysaccharides to create
simple sugars)
Enzymes are:
1. Highly specific
2. Can speed up the
same chemical
reaction in either
direction.
3. NOT used up in
the reaction.
Lipase is an enzyme
that digests fat.
Bile is a solution
that emulsifies fats.
Together, they speed
up the breakdown
of fats in the digestive
system.
Enzymes in Plants
 Remember, Autotrophs make their own organic
nutrients (simple sugars). How do plants do
this?
 Enzymes speed the necessary chemical
reactions and give organisms the ability to
control how much, where, and when these
reactions occur Glucose is coupled together
into starch in the roots of plants for storage.
 The enzyme for this reaction is called: Sucrase
 The chemical reaction that occurs is a
Dehydration Synthesis, draw the structures of
two glucose molecules being joined to create a
disaccharide.
How do they work?
 Enzymes function by binding to one or more of
the reactants (substrate) in a reaction.
 The exact location on the enzyme where
substrate binding takes place is called the
active site of the enzyme.
 The shape of the active site just fits the shape of
the substrate, somewhat like a lock fits a key.
 In this way only the correct substrate binds to
the enzyme
http://www.efhealing.com/images/enzymes.jpg
Types of Enzymes
Enzyme
Amylase
Pepsin
Rennin
Lipase
Made Here
Acts
Mouth &
Mouth &
Pancreas
Sm. Intestine
Gastric glands
Stomach
of stomach
Stomach
Stomach
Pancreas
Purpose
breaks polysacs to
disacs (digests carbs)
Starts digestion
Coagulates (thickens)
protein in milk
Sm. Intestine Reduces fats to fatty
acids and glycerol
(building blocks of fats)
Enzymatic Digestion of food types
(Macromolecules)
Name the chemical process used by these
enzymes to help digest fats,
carbohydrates, and proteins:
Hydrolysis
 Use diagrams of Macromolecules to fill in
the chart below. Use circled numbers to
indicate locations of hydrolysis
 http://www.whfoods.com/genpage.php?tn
ame=faq&dbid=16#digestion
Digestive Problems:
Lactose Intolerence Inability to digest milk sugar (enzyme
lactase)
Appendicitis Bacteria gets in appendix and causes flu like
symptoms and eventually shooting pain in
right side. Surgically removed.
Tape worms
Parasite that stays in your intestines and
absorbs all the nutrients. Get it from
undercooked meat.
Diabetes
Cannot produce insulin in pancreas