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Anatomy of the Digestive System

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Subdivisions of the mucosa layer
Epithelium, lamina propria and muscularis mucosae
Major functions of mucosa
Secretion, absorption and protection
Subdivisions of the submucosa layer
None
Major functions of submucosa
Nutrition and protection
Subdivisions of the muscularis externa layer
Longitudinal muscle and circular muscle
Major functions of muscularis external
Regulator of gastrointestinal mobility
Subdivisions of the serosa (adventitia) layer
Epithelium and connective tissue
Major functions of serosa (adventitia)
Reduce friction and anchor & protect
The tubelike digestive system canal that extends from the mouth to the anus is known as the
Alimentary canal or gastrointestinal tract
How is the muscularis externa of the stomach modified?
Besides the usual circular and longitudinal layers of smooth muscle, it also an innermost layer of smooth muscle that runs obliquely.
How does the modification relate to the function of the stomach?
Allows stomach not only to mix, churn and move food along the tract (circular/longitudinal fiber function) but also to pummel the food, physically breaking it down into smaller fragements and to ram food into the small intenstine (oblique fiber function)
What transition in epithelial exist at the gastroesophageal junction?
Squamous cells in the esophagus to columnar cell in the gastric mucosa.
How do the epithelia of these two organs relate to their specific function?
Simple columnar for gastric is absorption & stratified squamous provides protection in esophagus
Differentiate between the colon and the large intestine
Large intestine extends from the ileocecal valve to the anus. Colon is part of the large intestine and is divided into ascending, descending, and sigmoid colon.
Structure that suspends the small intestine from the posterior body wall
Mesentry
Fingerlike extensions of the intestinal mucosa that increase the surface area for absorption
Villi
Large collections of lymphoid tissue found in the submucosa of the small intestine
Peyer's patches
Deep folds of the mucosa and submucosa that extend completely or partially around the circumference of the small intestine
Circular folds
Regions that break down foodstuffs mechanically
Appendix and oral cavity
Mobile organ that manipulates food in the mouth and initiates swallowing
Tongue
Conduit for both air and food
Pharynx
3 structures continous with and representing modifications of the peritoneum
Greater omentum, lesser omentum, and mesentary
The "gullet"; no digestive/absorptive function
Esophagus
Folds of the gastric mucosa
Rugae
Sacculations of the large intestine
Haustra
Projections of the plasma membrane of a mucosal epithelial cell
Microvilli
Valve at the junction of the small and large intestines
Ileocecal valve
Primary region of food and water absorption
Small intestine
Membrane securing the tongue to the floor of the mouth
Frenulum
Absorbs water and forms feces
Large intestine
Area between the teeth and lips/cheeks
Vestibule
Wormlike sac that outpockets from the cecum
Appendix
Initiates protein digestion
Stomach
Structure attached to the lesser curvature of the stomach
Lesser omentum
Organ distal to the stomach
Small intestine
Valve controlling food movement from the stomach into the duodenum
Pyloric valve
Posterosuperior boundary of the oral cavity
Soft palate
Location of the hepatopancreatic sphincter through which pancreatic secretions and bile pass
Small intestine
Serous lining of the abdominal cavity wall
Parietal peritoneum
Principal site for the synthesis of vitamin K by microrganisms
Large intestine
Region containing two spinchters through which feces are expelled from the body
Anus
Bone-supported anterosuperiour boundary of the oral cavity
Hard palate
Visible portion of the tooth in situ
Clinical crown
Material covering the tooth root
Cementum
Hardest substance in the body
Enamel
Attaches the tooth to bone and surrounding alveolar structures
Peridontal ligament
Portion of the tooth embeded in bone
Root
Forms the major portion of tooth structure; similar to bone
Dentin
Produces the dentin
Odontoblast
Site of blood vessels, nerves, and lymphatics of the tooth
Pulp
Entire portion of the tooth covered with enamel
Anatomical crown
In human the number of deciduous teeth is _____; the number of permanent teeth is _____.
20; 32
What's the dental formula for permanent teeth? Explain what it means.
2,1,2,3 / 2,1,2,3 x 2 = 32 ; It means 2 incisors, 1 canine, 2 premolars, and 3 molars on the upper teeth & 2 incisors, 1 canine, 2 premolars, and 3 molars on the lower teeth MULTIPLY by 2.
What is the dental formular for decidous teeth?
2,1,0,2 / 2,1,0,2 x 2 = 20
What teeth are the "wisdom teeth"?
The third molars
Produces mucus; found in the submucosa of the small intestine
Duodenal glands
Produces a product containing amylase that begins starch breakdown in the mouth
Salivary glands
Produces a whole spectrum of enzymes and an alkaline fluid that is secreted in the duodenum
Pancreas
Produces bile that it secretes into the the duedenum via the bile duct
Liver
Produces HCl and pepsinogen
Gastric glands
Found in the mucosa of the small intestine; produces intenstinal juice
Intestinal crypts
Which of the salivary glands produces a secretion that is mainly serous?
Parotid gland
What is the role of the gallbladder?
Stores bile
Name 3 structures always found in the portal regions of the liver
Hepatic artery, hepatic portal vein, and bile duct
Where would you find the Kupffer cells of the liver? What's its function?
Sinusoid walls; remove debris such as bacteria or won-out blood cells from the blood.
Why is the liver so dark red in the living animal?
High amount of blood that circulates through the liver
What are the two major populations of secretory cells in the pancreas? Which serves the digestive process?
Islets and acinar cells; acinar cells
Compare the appearance of tongue papullae in cats and humans.
Filiform papillae, especially at the anterior end of the tongue, is sharp, bristly and more abundant in the cat.
Compare the number of lobes of the liver in cat and humans.
Cat - 5 lobes; Human- 4 lobes
Does the cat have a uvula?
No
Does the cat have an appendix?
No
What's the adult dental formula in cats?
3 incicors, 1 canine, 3 premolars, 1 molar (Upper teeth) / 3 incisors, 1 canine, 2 premolars, 1 molar (Lower teeth) X2 = 30 teeth total
How do the villi differ in the duodenum and the ileum?
The vilia are large and leaflike in the duodenum since it's the intestinal site of most active absorption. In the ilem, the villi gradually narrow and shorten along the length of the small intestine.
Name the 3 sections of the small intestine.
Duodenum, jejenum, and ileum
There are 4 regions of the stomach. Name the superiomost region.
Cardiac region
Name the valve where the small intestine empties into the large intestine
Ileocecal valve
Name one retroperitoneal organ
Pancreas, kidneys
I am part of the GI tract. When undigested food is rushed through me, I cannot properly absorb water, resulting in diarrhea. Name this organ.
Large intestines
Name the glands that produce HCl and pepsinogen
Gastric glands
Name one function of the mucosa in the lumen of the alimentary canal.
Protection
Name 2 structures that increase the absorptive surface area within the digestive tract
Villi and microvilli
What is the function of the incisors?
Bite down on food
Name the mass of processed food leaving the stomach
Chyme
What causes the yellowing of tissues in jaundice?
Too much bile produced in the liver; block duct causes bile to spill into tissues.
What is the function of the gallbladder?
Store and concentrate bile salts
What is the function of the bicarbonate ions in the pancreas?
Neutralize acidity of chyme entering small intestines
Name the special phagocytic cells that line the liver sinusoids, and work to remove debris from blood as it flows past.
Kupffer cells
I am part of your teeth, I have no cells. I am very brittle, but extemely hard. I cannot be healed or replaced. What am I?
Enamel