Unformatted text preview: Chapter 24
Chapter
Digestion
a maintenance system Today we will lecture on
Today
How digestion
How
accomplished
accomplished
–
–
–
– Overview
Single cell
Tubes
Specializations How humans digest
– From mouth to bowel
– ?? Controlled Digestion
Defined as
Defined Digestion
Defined as
Defined
Digestive Systems “do”
– Ingestion
– Mechanical breakdown
– Chemical breakdown
– Absorption
– Elimination
Elimination animals
Cellular digestion systems Digestion in a sac
Digestion in a tube Cellular
Digestion Sponge
Sponge
Each cell is
its own digestive
factory – Intracellular
Intracellular
digestion
digestion
– Food vaculole
– Lysosomes
Lysosomes What Phylum ? Simplest Digestive System
Simplest
Cnidarians
– One opening sac
A gastrovascular cavity
Permits extracellular
digestion
digestion
Digestion occurs
outside the cell This system too slow for
This
active animals Digestion in a tube
Digestion
Permits frequent dining
Has specialized regions
An extracellular process
– Donut
Donut Tube digestion
supports an
active animal Donut Idea
Donut Specialized Digestion Systems
Specialized
Why specialized??????
1)
2) Specialized Digestion Systems
Specialized
Why specialized??????
1)
2)
FOR EXAMPLE
Cellulose & animal systems Ruminant animals ase – Cellul RUMEN OTHER SPECIALIZATIONS
OTHER
Tube length, Teeth, & Gizzards Intestine length
– Long/short why? crop why OTHER SPECIALIZATIONS
OTHER
Tube length, Teeth, & Gizzards Intestine length
– Long/short why? Carnivores
Herbivores
Omnivores Teeth
– Why teeth???? Birds & crops & gizzards
Birds crops
– Why????? gizzzard crop Human
Digestive
System
System Consists of
1. digestive tube
aka the alimentary canal
2. digestive organs/glands
e.g. gall bladder teeth
tongue 1 2 11 + 5
3 4 5
6 7 8 9 10 11 1 1.
2.
3.
4.
5.
6.
7.
8.
9. Mouth
Pharynx
Esophagus
Cardiac Sphincter
Stomach
Pyloric Sphincter
Small Intestine
Sphincter
Large Intestine
1. Colon = 9a
2. Rectum = 9b
10. Anus (sphincter) 2 A 3 4 B Liver
C Gall bladder
D Pancreas
E Appendix D 5 7 6 B A Salivary glands C 8 E 9a 9b 10 The brain and food
The Mouth
Salivary glands
Teeth
Tongue Mouth
Food enters
Mouth waters 3 pr salivary glands
Lube food
Why?
Fights bacteria via enzymes
Dissolves acids/sugars
Amylase Mouth
Teeth
Chew
Tongue
Taste
Swallow
Brain told food here.
Brain tells stomach to make HCl. TASTE
TASTE
Salty
Sour
Bitter
Sweet
Umani Pharynx
Pharynx
functions
1.
2. Esophagus peristalsis CARDIAC SPHINCTER
PREVENTS FOOD FROM RE-ENTERING ESOPHAGUS
SEPARATES ENVIRONMENTS Stomach
Stomach 1. Mechanically breaks down food
2. Stores food & slowly releases it
into the duodenum
3. Chemically breaks down food Stomach
Stomach
1. Mechanically breaks down food
2. Stores food & slowly releases it
into the duodenum
3. Chemically breaks down food
via HCl
Gastric
mucus
juice
Pepsinogen “acid” Chyme = ? pepsin = a protease
“never drink on an empty
never
stomach”
stomach”
“hunger pangs” Pyloric sphincter
Pyloric
Separates stomach from duodenum
Permits @ 1 teaspoon of “acid” chyme to
Permits
pass @ every 20 seconds
pass
=Time between stomach peristalic wave
=Time
contractions
contractions Ulcers
Ulcers Who is barry
marshall? 1984 Heliocobacter pylori A good year Heliocobacter
pylori Where are we in digestion?
Where What’s happening!!!!!!
What’s First problem
Acid chyme
Solved by panceatic juice NaHCO3 Amylase
Protease
Lipase Second problem
Fats
Solved byEmulsifies fats
liver bile Bile salts
Water
Cholesterol recap
recap
Digestion starts in mouth (amylase)
Stomach breaks down some proteins
Stomach
(pepsin)
(pepsin)
Pancreas provides enzymes to break
Pancreas
down fats, carbohydrates, and proteins
down
Liver bile emulsifies fats
NEW: ENZYMES EMBEDDED IN WALL
NEW:
OF SMALL INTESTINE
COMPLETE THE DIGESTIVE The small intestine is not only the
major site of digestion but it also is
the biggest player in ABSORPTION
95% Ilium
&
jejunum Absorption Large Intestine
Large
3 parts – Colon
– Rectum
– Appendix Does – Absorb water
– Produce vitamins
HOW? – Compacts and stores waste
– Eliminates
Eliminates Diarrhea & Constipation
Diarrhea Review Have a great break!!!!
Have amen
amen ...
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Full Document
- Fall '08
- Duwel
- Digestive System, Specialized Digestion Systems
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