Transcript Microscopic Anatomy of the GI Tract

BIOL 204 Lab For Week 12 Digestive System Anatomy
Microscopic Anatomy of the GI Tract
The GI tract consists of a tube that extends from the mouth to the anus. It
has four tissue layers (tunics):
Another, detailed view of GI tract tunics
There are structural modifications of the tunics in various
areas of the GI tract
Gross Anatomy of the GI Tract
The GI Tract: Mouth
The Esophagus
The Esophagus
Gastroesophageal Junction
Gastric pit
The Esophagus
The Stomach
Microscopic anatomy of the stomach.
B. The Liver
Gross View of the Liver
The Duodenum of the Small Intestine Receives the
Ducts of the Liver, Gall Bladder and Pancreas
Liver Microscopic Anatomy
Pancreas Gross Anatomy
Microscopic View of the Pancreas:
Islet Cells: endocrine; secrete insulin and glucagon
Acinar Cells: exocrine; secrete digestive enzymes
Small Intestine Gross Anatomy
Histology of the Small Intestine
(Duodenum)
Intestinal Villus
Portions of the Large Intestine
Extrinsic Salivary Glands
Types of Permanent Teeth
Each jaw has:
2 central incisors
2 lateral incisors
2 canines (eyeteeth)
4 premolars
6 molars
Internal Anatomy
of a Tooth
Mesenteries of the abdominal digestive organs.
1. Diaphragm
2. Liver – left lobe
3. Falciform Ligament
4. Liver right lobe
5. Stomach
6. Greater Omentum
7. Ascending Colon
8. Cecum
9. Small Intestine
10. Descending Colon
11. Sigmoid Colon
An Appendix, Unfixed
Gall Bladder on the Underside of
the Liver
Liver – Gross View
Serosal Surface
Human Duodenum, Unfixed
Cat Dissection
1. Parotid Gland
2. Sublingual
Gland
3. Submandibular
Gland
4. Esophagus
5. Tongue
6. Masseter
Muscle
7. Larynx
8. Trachea
Cat
Dissection
Abdomen
1.
2.
3.
4.
5.
6.
Diaphragm
Round Ligament
Falciform Ligament
Left Lateral Lobe of Liver
Left Medial Lobe of Liver
Quadrate Lobe of Liver
7.
8.
9.
10.
11.
Right Medial Lobe of Liver
Right Lateral Lobe of Liver
Gall Bladder
Spleen
Greater Omentum
Cat Abdomen – Greater Omentum Removed
1.
2.
3.
4.
5.
6.
7.
Cardiac Stomach
Fundic Stomach
Stomach Body
Pyloric Stomach
Lesser Omentum
Duodenum
Pancreas (Ventral)
8.
9.
10.
11.
12.
13.
14.
Ascending Colon
Ileum
Jejunum
Sigmoid Colon
Spleen
Gastrospleenic Ligament
Bladder
Small and Large
Intestine
Removed
1.
2.
3.
4.
5.
Small Intestine
THE Mesentary
Ileum
Cecum
Ascending Colon
6.
7.
8.
9.
10.
Transverse Colon
Descending Colon
Sigmoid Colon
Mesocolon
Greater Omentum
Gall Bladder and Lobes of the Liver
BIOL 204 Lab
Week 12
Digestive Enzymes
Digestive Enzymes:
are used in the lumen of the GI tract to break down complex
molecules into absorbable subunits
Enzymes are biological catalysts which increase the rate of a
chemical reaction without themselves becoming part of the product:
In this experiment we will observe the activity of three
different enzymes:
Amylase:
digests starch into disaccharides
Trypsin:
digests proteins into peptides
Lipase:
digests fats into glycerol and fatty acids
Variables tested ……
1. Incubation temperature:
How will enzyme activity compare when incubated at O o C and
37 o C?
2. Denaturization of Enzymes
How will enzyme activity be altered if the enzyme is denatured by
boiling?
Activity 1
Trypsin Activity
Trypsin an enzyme, secreted by pancreatic acinar cells,
that hydrolyzes proteins into small fragments (peptones,
peptides and proteoses)”
In this experiment, trypsin will act on an artificial
substrate to yield a yellow colored product:
Trypsin
BAPNA + H2O
1.
N-benzoyl-L-arginine + p-nitroaniline
(yellow)
Reaction rate will be compared at these different incubation
temperatures:
370 C and 0o C
What do you predict will happen?
2.
The rate of the reaction will be determined using boiled
trypsin. What do you predict will happen?
Activity 2
Amylase Activity
Amylase is a carbohydrate digesting enzyme, produced by
salivary glands and pancreatic acinar cells, that hydrolyzes
starch into maltose (disaccharides):
Amylase
Starch + H2O
maltose (disaccharides)
Indicators:
Starch: IKI (Lugol’s solution) -
turns “blue/black” in the
presence of starch
Benedict’s Solution:
turns green/orange/ red/brown
in the presence of reducing sugar
IKI Test For Starch in a
Spot Plate
Benedict’s Test for
reducing sugar in heat
test tubes
As in activity one, the reaction will be observed under
different conditions:
Boiled Enzyme (Amylase)
Incubation Temperature: 0oC and 37oC
Activity 3
Lipase Activity
Lipase is a hydrolytic enzyme, made primarily by pancreatic
acinar cells, that hydrolyzes neutral fats into fatty acids and
glycerol:
Lipase
Fat +
H2O
Fatty Acids + Glycerol
Fat Digestion:
Indicator:
Blue litmus turns pink (red) in
the presence of acid (one the
products is fatty acids)
Bile emulsifies fat….
In this activity, you will examine the effect of:
incubation temperature (0oC vs. 37oC)
and
addition of bile salts
on the reaction