Download SKELETAL SYSTEM LAB

DIGESTIVE SYSTEM LAB
OBJECTIVES:
1. Identify the major organs of the gastrointestinal tract on models (see list below).
2. Identify the major structures of the mouth, esophagus, stomach, small intestine, and large
intestine on models (see list below).
3. Identify the major membranes in the digestive system (see list below).
4. Identify the major accessory organs on models (see list below).
5. Identify the major structures of the liver and pancreas on models (see list below).
6. Identify the three types of salivary glands on microscope slides and identify the serous and
mucous acini in each.
7. Identify the major histological structures and layers of the esophagus, stomach, stomach,
duodenum and ileum (see list below).
8. Identify acini and ducts of the pancreas on microscope slides.
9. Identify the major histological structures of the liver on microscope slides (see list below).
10. Identify the gall bladder on microscope slides.
11. Trace the pathway of bile from the liver to the duodenum on models.
12. Identify major histological structures of villi on models (see list below).
MATERIALS:
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disgestive system models
specimen slides
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Microscopes
INTRODUCTION:
The digestive system is the system of the body that mechanically and chemically breaks down food.
The digestive organs are usually divided into two main groups: the gastrointestinal tract (GI) tract and
the accessory structures.
The gastrointestinal (GI) tract (also called the alimentary canal) is a continuous tube
running from the mouth to the anus. It measures about 9 m (30 ft) in length. The GI tract
includes the following organs
 mouth
 small intestine
 esophagus
 large intestine
 stomach
The second group of organs consists of the accessory structures. These include the
following organs:
 teeth
 liver
 tongue
 gallbladder
 salivary glands
 pancreas.
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GASTROINTESTINAL TRACT:
_____ mouth
_____ esophagus (The esophagus transports food from the pharynx to the stomach by
peristalsis. It is a muscular, collapsible tube posterior to the trachea. It is 23 to 25
cm (10 in.) long and extends from the laryngopharynx through the esophageal
hiatus in the diaphragm and ends in the superior portion of the stomach.)
_____ stomach (This is a J-shaped organ that lies under the diaphragm. The superior
part is connected to the esophagus. The inferior part empties into the duodenum
of the small intestine. The stomach is involved in the chemical breakdown of
materials via acid and enzymes. It is also involved in the mechanical processing
of food through muscular contractions.)
_____ small intestine (The small intestine has 3 regions: duodenum, jejunum, and
ileum. The bulk of digestion and absorption of water, organic substrates,
vitamins, and ions occurs in the small intestine. It is about 6.35 m (21 ft) long.)
_____ large intestine (The large intestine has 4 regions: cecum, colon, rectum, and anal
canal. The colon is divided into the ascending colon, transverse colon,
descending colon, and sigmoid colon. The large intestine functions in the
completion of absorption of water that leads to the formation of feces and in the
expulsion of feces from the body. It is about 1 ½ m (5 ft.) long and extends from
the ileum to the anus.)
MOUTH:
_____ oral cavity (mouth) (The mouth, teeth, and tongue are involved in mechanical
processing, moistening, mixing, and in secreting enzymes.)
_____ vestibule (this is the space between the cheeks or lips and the gums)
_____ fauces (this is the opening between the oral cavity and the oropharynx)
_____ hard palate (The palate is a horizontal partition separing the oral cavity from the
nasal cavity and nasopharynx. The hard palate forms the anterior portion of the
roof of the mouth. It is formed by maxillae and palatine bones and is covered by
mucous membrane.)
_____ soft palate (The soft palate forms the posterior portion of the roof of the mouth. It is a
muscular portion between the oropharynx and nasopharynx.)
_____ uvula (During swallowing, this elevates with the soft palate to close off the
posterior entrance into the nasopharynx to prevent ingested materials from
entering the nasal region.)
_____ tongue (This is a muscle of skeletal muscle fibers. It grips food, constantly
repositions food between the teeth, mixes food with saliva, and move the food
into the pharynx.)
_____ lingual frenulum (This is a thin vertical mucous membrane that attaches the
inferior surface of the tongue to the floor of the oral cavity.)
_____ labial frenulum (This is a thin mucosal fold that attaches the internal surfaces of
the superior and inferior lips to the gums.)
SALIVARY GLANDS: All of the salivary glands secrete lubricating fluid that contains enzymes
that break down carbohydrates.
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_____ parotid glands (These salivary glands lie in front of and under the ears.)
_____ submandibular glands (These salivary glands lie deep to the base of the tongue
in the posterior part of the floor of the mouth.)
_____ sublingual glands (These salivary glands are anterior to the submandibular
glands.)
PHARYNX:
_____ pharynx (This is a common passageway for the digestive and respiratory
systems. The pharyngeal muscles propel materials into the esophagus.)
ESOPHAGUS:
_____ lower esophageal sphincter (also called cardiac sphincter) (A sphincter is a
muscular ring that contracts to lose the entrance of or exit of an internal
passageway. The cardiac sphincter is located between the esophagus and the
superior portion of the stomach.)
STOMACH:
_____ lesser curvature (This is the superior concave border of the stomach.)
_____ greater curvature (This is the inferior convex border of the stomach.)
_____ cardia (This is a small, narrow, superior entryway into the stomach lumen from
the esophagus.)
_____ fundus (This is the dome-shaped region lateral and superior to the esophageal
connection with the stomach.)
_____ body (This is the region of the stomach inferior to the cardiac orifice and the
fundus.)
_____ pylorus (This is a narrow, medially directed, funnel-shaped pouch that forms the
terminal region of the stomach.)
_____ pyloric sphincter (Sphincter of smooth muscle that regulates the passage of
chime from the stomach to the duodenum. It is a thickening of the circular
muscularis layer.)
_____ pyloric antrum (This is the initial portion of the pyloric part of the stomach.)
_____ rugae (pronounced ROO-JEE) (These are folds found inside the stomach. They
allow the stomach to expand)
_____ oblique muscularis layer (innermost layer of muscle that jack-knifes the stomach
into a V-shape to move the chyme into the small intestine.)
_____ circular muscularis layer (This layer breaks food into smaller fragments.)
_____ longitudinal muscularis layer (This layer breaks food into smaller fragments.)
SMALL INTESTINE:
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_____ duodenum (This part of the small intestine begins after the stomach.)
_____ jejunum (This is the middle segment of the small intestine. An abrupt bend marks
the boundary between the duodenum and jejunum.)
_____ ileum (This is the last segment of the small intestine and ends at the large
intestine.)
_____ plicae circuluares (also called circular folds) (These are permanent, transverse
ridges of the mucosea and submucosa. They increase the area for absorption
and force the chyme to spiral through the intestinal movement.)
_____ villi (These are finglerlike projections of the mucosa made of cells specialized for
absorption.)
_____ ileocecal valve (This guards the opening between the ileum and the large
intestine.)
LARGE INTESTINE:
_____ cecum (This is a blind pouch below the ileum. The appendix is attached to the
cecum by an extension of the visceral peritoneum.)
_____ vermiform appendix (This is a blind tube connected to the cecum of the large
intestine.)
_____ ascending colon (This segment of the colon ascends on the right side of the
abdomen and turns abruptly to the left at the undersurface of the liver.)
_____ transverse colon (This segment of the colon continues across the abdomen and
curves beneath the spleen.)
_____ descending colon (This segment of the colon passes down the left side of the
abdomen.)
_____ sigmoid colon (This segment of the colon projects inward toward the midline.)
_____ hepatic flexure (also called the right colic flexure) (This is the bend made when
the ascending colon makes a 90 degree turn toward the left side of the
abdominal cavity.)
_____ splenic flexure (also called the left colic flexure) (This is the bend made as the
transverse colon makes a 90 degree turn inferiorly.)
_____ rectum (This segment is the last 20 cm (7 to 8 in.) of the colon.)
_____ anus (This is the opening of the rectum to the exterior.)
_____ internal anal sphincter (This is a sphincter of smooth muscle that contracts
involuntarily to prevent feces from leaking from the anus between defecation and
to inhibit defecation during emotional stress.)
_____ external anal sphincter (This is a sphincter of skeletal muscle that contracts
voluntarily to inhibit defecation.)
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_____ tenia coli (This is where the smooth muscle of the large intestine forms three thin,
dinstinct, longitudina bundles that bunch up the colon into many sacs, collectively
called haustra)
_____ haustra (These are the sacs formed along the large intestine.)
PERITONEUM:
_____ visceral peritoneum (The various abdominal organs are covered by the visceral
peritoneum.)
_____ parietal peritoneum (This lines the wall of the abdominal cavity.)
_____ mesentery (This is an extension of the peritoneum. Mesentery attaches the small
intestine to the posterior abdominal wall.)
_____ greater omentum (This is a double sheet of peritoneum that attaches the greater
curvature of the stomach to the dorsal body wall. It encloses the spleen and part
of the pancreas and covers the transverse colon and a large part of the small
intestine. This is an extension of the peritoneum.)
_____ lesser omentum (This runs from the lesser curvature of the stomach and the
beginning of the duodenum to the liver.)
ACCESSORY ORGANS:
_____ liver (The liver is located inferior to the diaphragm. The liver secretes bile, which is
important for digestion of lipids in the small intestine. The liver also stores
nutrients and has many other vital functions.)
_____ pancreas (This is a soft, oblong gland posterior to the greater curvature of the
stomach. The pancreas secretes hormones (insulin and glucagons), digestive
enzymes (pancreatic juice), and buffers.)
_____ gall bladder (This is a pear-shaped sac in a fossa along the undersurface of the
liver. It stores and concentrates bile.)
LIVER:
_____ left lobe of liver
_____ right lobe of liver
_____ caudate lobe of liver
_____ quadrate lobe of liver
PANCREAS:
_____ head of pancreas
_____ body of pancreas
_____ tail of pancreas
_____ main pancreatic duct
_____ accessory pancreatic duct
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SALIVARY GLANDS: Identify the three types of salivary glands on microscope slides and
identify the serous and mucous acini in each.
_____ parotid glands (These salivary glands lie in front of and under the ears.)
_____ submandibular glands (These salivary glands lie deep to the base of the tongue
in the posterior part of the floor of the mouth.)
_____ sublingual glands (These salivary glands are anterior to the submandibular
glands.)
_____ serous acini
_____ mucous acini
ESOPHAGUS HISTOLOGY: Identify the major histological structures and layers of the
esophagus
_____ mucosa (made of thick nonkeratinized stratified squamous epithelium, lamina
propria, and muscularis mucosae)
_____ nonkeratinized stratified squamous epithelium in the mucosa
_____ submucosa (made of elastic fibers and numerous mucous glands)
_____ muscularis (made of inner circular layer and outer longitudinal layer of a mixture
of both skeletal and smooth muscle )
STOMACH HISTOLOGY: Identify the major histological structures and layers of the stomach
_____ mucosa (made of simple columnar epithelium, lamina propria, and muscularis
mucosae)
_____ simple columnar epithelium in the mucosa
_____ gastric glands in the mucosa
_____ gastric pits in the mucosa
_____ goblet cells in the mucosa
_____ submucosa
_____ muscularis (has three layers of smooth muscle)
DUODENUM HISTOLOGY: Identify the major histological structures and layers of the duodenum
(see list below).
_____ mucosa
_____ simple columnar epithelium in the mucosa
_____ submucosa
_____ muscularis (has two layers of smooth muscle)
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ILEUM HISTOLOGY: Identify the major histological structures and layers of the ileum (see list
below).
_____ mucosa
_____ simple columnar epithelium in the mucosa
_____ submucosa
_____ muscularis (has two layers of smooth muscle)
PANCREAS HISTOLOGY: Identify acini and ducts of the pancreas on microscope slides.
_____ acini (These are simple cuboidal cells organized into large clusters called lobules
that secrete pancreatic juice.)
_____ ducts
LIVER HISTOLOGY: Identify the major histological structures of the liver on microscope slides
(see list below).
_____ lobules
_____ hepatocytes
_____ central vein
_____ sinusoids
_____ bile ducts
_____ branches of the hepatic artery
_____ branches of the hepatic portal vein
PATHWAY OF BILE: Trace the pathway of bile from the liver to the duodenum on models.
_____ right hepatic duct
_____ left hepatic duct
_____ common hepatic duct
_____ cystic duct
_____ common bile duct
_____ hepatopancreatic ampulla
_____ hepatopancreatic sphincter
VILLUS MODEL: Identify major histological structures of villi on models (see list below).
_____ mucosa
_____ lamina propria
_____ muscularis mucosa
_____ submucosa
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_____ circular layer of muscularis
_____ longitudinal layer of muscularis
_____ villi
_____ crypts
_____ lacteals
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