Transcript Digestive System Cells

Digestive System Cells
Digestive System
 Differentiated cells dependent upon location within
the system
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Oral Cavity
Esophagus
Stomach
Small Intestine
Large Intestine
Accessory Organs/Glands
Liver
 Gall Bladder
 Pancreas
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Oral Cavity
 Oral Mucosa
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Lines the entire Oral Cavity
Stratified Squamous Cells (some areas keratinized)
Protection
 Palate
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Hard Palate
Anterior, superior portion of oral cavity
 Partially keratinized epithelium; osteocytes
 Protection
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Soft Palate
Posterior, superior portion of oral cavity
 Non-keratinized epithelium, layer of skeletal muscle cells, glandular
cells
 Separation from nasal cavity, muscle cells provide lifting action,
glandular tissue provides saliva
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Oral Cavity
Oral Mucosa
Palate
Oral Cavity
 Tongue
 Located in the floor of the oral cavity
 Striated muscle fibers (cells)
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Myelinated nerve fibers
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Sensation
Filiform Papillae contain keratin at the tip
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Movement
Provides a roughness to the surface of the tongue for controlling
food
Fungiform Papillae contains taste buds (Clusters of elongated
cells around a sensory cell)
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Taste sensation sent from the tongue to the brain
Tongue
Striated muscle fibers
Oral Cavity
 Tonsils
 In mucosa of tongue, palate, & pharynx
 Made of lymphocytes; stratified squamous in the tongue and
palate; pseudostratified columnar in the pharynx
Esophagus Cells
 Cells found lining the esophagus from the oral cavity
to the stomach
 Non-keratinized stratified squamous epithelium
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Protection
 Mucus secreting cells
 Provide lubrication for ease of moving food
 Muscle fibers
 Striated muscle (upper 1/3)
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Movement of food by swallowing
Non-striated muscle (lower 2/3)
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Movement of food by peristalsis
Esophagus Cells
Stomach Cell Types
 Surface Mucus Cells
 Inner surface of the stomach
 Unlike other mucus cells,
their nuclei are not
compressed
 Secrete mucus that is not
digested by the stomach
acid or enzymes
Stomach Cell Types
 Mucus Neck Cells
 Located in the upper neck
region of the fundus
 Typical epithelial mucus cell
with compressed nucleus
and cytoplasm filled with
mucus
 Function unknown
Stomach Cell Types
 Enteroendocrine cells
 Typically located in the neck, deep in the gastric glands, and in
the intestinal crypts
 Columnar epithelial cells scattered among the absorptive cells
and exocrine cells of the GI tract
 Secrete a hormone that influences gastrointestinal secretions
or motility
Stomach Cell Types
 Gastric Chief Cells
 Located deep in the fundus
toward the muscular
mucosa
 Typical appearance of a
serous-secretory epithelial
cells
 Secrete digestive enzymes
(Pepsin)
C: Chief Cells; P: Parietal Cells
Stomach Cell Types
 Gastric Parietal Cells
 Found most commonly in the middle region of the fundis
 Large cells with 1-2 oval shaped nuclei; packed full of
mitochondria; have deep invaginations called intracellular
canaliculus that are covered with microvilli
 Secrete acid by pumping hydrogen ions across the cell
membrane
Stomach Cell Types
 Stem Cells
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Located in the stomach at the glands as they open into the pits; also
in the intestinal mucosa to replace the goblet and absorptive cells
Undifferentiated epithelial cells
Retain the ability to divide and replace cells which die
Intestinal Cell Types
 Absorptive Cells
(Enterocytes)
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Located in the small
intestine and colon
Epithelial cells with
microvilli (brush border)
Microvilli increase the
surface area to increase
the absorptive capabilities
of each cell
 Goblet Cells
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Scattered among the
absorptive cells in the
small intestine and colon
Shaped like a “goblet”:
narrow at the base and
wide at the top
Produce mucus to aid in
the movement of material
through the bowel
Intestinal Cell Types
 Brunner’s Glands (mucus
cell)
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Located in the duodenum
Specialized epithelial cell
Produce and secrete
mucus
 Paneth Cells
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Located at the end of the
intestinal crypts
Typical serous-secretory
appearance with the
vacuoles containing
lysosomal enzymes
Secrete anti-bacterial
proteins to protect the
stem cells in the area
Liver Cell Types
 Hepatocytes
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Throughout the liver
Cuboidal cells with 1-2 nuclei, an
abundance of organelles; cells
connect into cords with the space
of Disse between the cords
Functions:
Form & secrete bile
 Store glycogen
 Synthesize urea
 Metabolize cholesterol & fat
 Synthesize plasma proteins
 Detoxify many drugs
 Process steroid hormones and
vitamin D
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Liver Cell Types
 Fenestrated Endothelial Cells
 Lining the sinusoids of the liver
 Simple squamous cells with “holes” between the cells and no
basement membrane
 In the liver these cells permit blood plasma to wash over the
hepatocytes; secrete substances that control blood flow and
coagulation; also assist in bringing in WBCs during
inflammatory response
 Ito Cells
 Located within the space of the Disse (between the cords of
hepatocytes)
 Satellite hepatocytes
 Function as storage for fat and Vitamin A
Liver Cell Types
 Kupffer Cells
 In the sinusoids of the liver
 Specialized macrophage
cells
 Responsible for cleaning out
bacteria from the blood of
the hepatic portal system;
also removes worn-out RBC
and recycles the hemoglobin
Gall Bladder
 Surface Epithelium of the gall bladder
 Columnar cells and Goblet cells
 Columnar cells aid in absorption; Goblet cells secrete mucus
 Smooth muscle layer
 Contract to expel bile
 Serous Coat
 Outer Layer of Cells
 Protection for the gallbladder
Pancreas Cells
 Pancreatic Acinar Cells
(Serous Cells)
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Located within the pancreas
Glandular epithelial cells
with a high concentration of
ribosomes on rough
endoplasmic reticulum
Function to release enzymes
that assist in digestion
 Endocrine Cells –
discussed in the
endocrine cell lecture