Digestive System

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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. churn/mix foodb. digestion of proteins starts herec. Gastric juice is acidic (HCl) and

contains pepsin (enzyme to digest proteins)

d. Gastrin (hormone) stimulates to release of gastric juice

e. vomiting-reverse peristalsisf. 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 Intestinea. 20 – 30 feet long b. parts of sm. Intestine are:c. duodenum – listed aboved. jejunum – has folds of skin

called the brush border membrane.

e. ileum – selective absorption of some nutrients. What remains is liquid stool

f. Final digestion occurs hereg. food is absorbed in simplest

forms – amino acids, fatty acids, glycerole.

h. 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 waterg. 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.mcgraw-hill.com/sites/0072495855/student_view0/chapter26/animation__organs_of_digestion.html

Digestive Processes

I. Ingestion

a. Takes food in – mouth

II. Peristalsisa. Muscular contractions along digestive

tract-esophagus small and large intestine

III. Absorption

a. Taking of digested food into blood stream

b. Occurs in Sm. Intestine

IV. Storage

a. Animal “starch” stored as glycogen in liver

V. Elimination

a. Solid waste eliminated from large intestine

VI. Mechanical Digestion

a. Physically chewing-mouth

b. Churning action-stomach

VII. Chemical Digestion

a. Uses enzymes

b. Starts carbohydrate breakdown in mouth

c. Starts protein breakdown in stomach

d. Carbohydrates, proteins, and fats are fully digested in Sm. Intestine

Types of Food

Food Type % Diet Purpose Digestive End Product

Fats <30% 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 Gastric acid in stomach Contains HCl

Bile 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 enzymethat digests fat.

Bile is a solutionthat emulsifies fats.

Together, they speedup the breakdownof fats in the digestivesystem.

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 Made Here Acts Purpose

Amylase Mouth & Mouth & breaks polysacs to

Pancreas Sm. Intestine disacs (digests carbs)

Pepsin Gastric glands Stomach Starts digestion

of stomach

Rennin Stomach Stomach Coagulates (thickens)

protein in milk

Lipase Pancreas 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:

Use diagrams of Macromolecules to fill in the chart below. Use circled numbers to indicate locations of hydrolysis

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Hydrolysis

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