Histo Flashcards
ID this tissue
Tongue
List the 4 general organizational layers of the GI tract
Mucosa
Submucosa
Muscularis externa
Serosa/adventitia
List the divisions of the mucosa
Epithelium
Lamina propria
Muscularis mucosa
The submucosa consists of:
Connective tissue
The muscularis externa consists of:
Inner circular muscle layer, outer longitudinal muscular layer, and the myenteric plexus (plexus of Auerbach) in between
Where is the location of the nerve plexus which controls mucosal movement, vascular diameter, and secretion of mucosal and submucosal glands?
Submucosa
(Submucosal plexus/Meissner plexus)
What is the function of the myenteric plexus (plexus of Auerbach) located in the muscularis externa?
Control GI motility
ID this cell type and name where you would find this type of tissue
Mucous cells
Sublingual gland (mixed but mostly mucous cells)
(Weakly staining, flat nuclei)
Where in the oral cavity would you find this epithelium?
Everywhere but hard palate, gingiva, and dorsum of tongue
(Stratified squamous non-keratizined = lining epithelium)
Where in the oral cavity would you find this epithelium?
Hard palate + gingiva
(Stratified squamous keratinized or parakeratinized = masticatory epithelium)
Name this cell type and where it would predominate
Serous cells
Parotid and submandibular glands
(Dark staining cells + round nuclei)
Describe the epithelium you would expect to see on the floor of the mouth.
Lining epithelium, or stratified squamous non-keratinized
(Remember everything that’s not hard palate, gingiva, or dorsum of tongue is lining epithelium)
Name this structure
Circumvallate papillae of specialized oral mucosa
Name this structure
Filiform papillae of specialized oral mucosa
What type of mucosa is found on the lateral portion of the tongue?
Foliate papillae
Name this tissue
Filiform papillae of specialized oral mucosa
Which type of specialized oral mucosa divides the anterior 2/3 from the posterior 1/3 of the tongue?
Circumvallate papillae
Which type of specialized oral mucosa doesn’t have taste buds?
Filiform papillae
Where do you find this type of epithelium?
Scattered among filiform papillae in the anterior 2/3 of the tongue
(Fungiform papillae)
Which specialized oral mucosa is surrounded by a moat?
Circumvallate papillae
List 3 cell types found within the structure at the arrow.
Sensory cell
Supporting cell
Basal cell
(Taste bud)
The arrow is pointing to which structure? Function?
Taste pore - allows food to get down to taste bud
The blue blob points to cells whose function is to:
Synapse with afferent nerve fibers and transmit taste info
(Elongated cells in taste bud - sensory cells)
(T/F): Each taste bud contains only one type of sensory receptor.
False - each SENSORY CELL contains only one type of sensory receptor, but each taste bud contains many different sensory cells
What is the only sensory receptor restricted to a certain part of the tongue and to where is it restricted?
Bitter - back of tongue
Name this organ.
Tongue
(Only organ where muscle is in all 3 planes)
What is the arrow pointing to?
Intercalated duct in the parotid gland
(Very small ducts)
What is the arrow depicting?
Striated duct in the parotid gland
(About the size of an acinus)
What is the structure highlighted by the arrow?
Serous demuline
(Serous cells mashed to the side by mucosal cells)
What is encircled?
Lobules of salivary glands
What is this structure?
Interlobular ducts
(Ducts located in connective tissue are interlobular)
What is the function of the myoepithelial cells of the salivary glands?
Extrusion of acini cell secretions
Name this tissue.
Submandibular gland
(Mixed but mostly serous cells)
What is the function of this structure?
Secrete amylase, etc and absorb electrolytes
(Intercalated duct of salivary gland)
What is the function of these structures?
Modify salivary gland secretions
(Striated ducts of parotid gland; notice they’re the same size as the acini)
What is the function of the predominate structure in this picture?
Conduit for acini cell secretions
(Interlobular duct)
Name this tissue.
Parotid gland
(Lobules consisting solely of serous cells)
Where do you find this structure?
Mixed glands = Sublingual and submandibular glands
(Serous demuline)
What is this structure?
Striated duct
Name this tissue.
Sublingual gland
(Mostly mucous cells)
Name 5 contents of saliva
Bicarb
Digestive enzymes (amylase, lipase)
Protein
Antibodies
Ca2+ and PO4
Contraction of inner circular layer of muscle causes:
Compression and mixing of contents
Contraction of outer longitudinal layer of muscle causes:
Shortening of the tube
Forms sphincters?
Inner circular layer of muscle
Which part of the nervous system controls peristalsis?
Enteric nervous system
What type of epithelium lines the tubular part of the alimentary tract?
Lining epithelium/stratified squamous non-keratinized
Organ?
Esophagus
(Convoluted lumen = esophagus)
Cardiac glands vs. esophageal glands proper
Cardiac glands = in mucosa/lamina propria
Esophageal glands = in submucosa
Both are mucous glands
The mucosa of this organ contains:
Stratified squamous non-keratinized epithelium
GALT
Cardiac glands
(Esophagus)
Describe the muscularis externa of this organ.
Upper 1/3 is skeletal muscle
Middle 1/3 is skeletal + smooth muscle
Lower 1/3 is smooth muscle
(Convoluted lumen = esophagus)
Where are the esophageal proper glands located in this tissue section?
Submucosa
Name the structure to which the black arrow is pointing. What cell type is located within this structure?
Gastric pit
Surface mucus cells
(Stomach)
What is this structure? Where is it found?
Mamillated fold
Stomach
The area marked by the black arrow is the ____. The area marked by the green arrow is the ____.
Gastric pits (Composed of surface mucosal cells)
Gastric glands (composed to mucous neck, chief, parietal, enteroendocrine, and stem cells)
What is the area marked by the black area? What is its function?
Rugae
Allow distention of the stomach
Name this organ.
Stomach
(Notice the surface mucous cells + gastric pits)
What is the function of the cells in the picture?
Secrete alkaline mucous to protect stomach lining
(Surface mucous cells)
What is contained in the tissue surrounding the gastric pits and glands?
Lymphocytes and plasma cells
(Lamina propria surrounds the gastric pits AND the gastric glands below the pits)
List the 5 cell types contained in the gastric glands
Mucous neck cells
Chief cells
Parietal cells
Enteroendocrine cells
Stem cells
What is the function of the cell marked by the arrow?
Secretion of pepsinogen
(Basophilic cells in gastric gland = chief cells)
What is the function of the cell marked by the arrow?
Secretion of HCl and intrinsic factor (aids in B12 absorption)
(Pink pyrimidal cell in gastric gland = parietal cell)
The predominate cell in the upper part of the gastric glands is:
Parietal cell
The predominate cell in the deeper portion of the gastric glands is the:
Chief cell
Where does stem cell division occur in gastric glands? Describe the process.
At the isthmus (division between pit and gland)
Most cells travel up and become surface mucous cells, while some travel down and become gland cells
What is the function of the gastric gland cell found throughout the gland?
Secrete gastric hormones
(Enteroendocrine cells are found throughout; stem cells are at the isthmus; parietal cells and mucous neck cells are at the top; chief cells are at the bottom)
Your patient had this finding on EGD. Among other management, you prescribed a PPI to prevent further pathology. Two months later your patient presents with excess fatigue and lack of energy. Explain.
The PPI inhibits parietal cells, which, along with HCl, secrete intrinsic factor, which is necessary for absorption of B12, a deficiency of which is likely causing the new symptoms
Function of stomach vs. small intestine
Stomach = digestion
Small intestine = absorption
List the 3 modifications of the small intestine that increase surface area and by how much
Plicae circulares - 3x
Villi - 10x
Microvili - 100x
Name this structure. Where is it most commonly found?
Plicae circulares
Jejunum
Name the structures marked by the arrows.
Crypts of Lieberkuhn
(Indented glands in the surface epithelium of small intestine)
Name one disease associated with pathology of these structures.
Celiac disease
(Gluten triggers immune response that destroys vili of small intestine)
What is unique about this structure found in the small intestine?
It contains actin that contracts the microvilus to help spread it out and increase surface area for absorption
List the 6 cell types in the small intestine epithelium
Enterocytes
Paneth cells
Goblet cells
M cells
Intermediate (stem) cells
Enteroendocrine cells
What is the tissue to the left? Right?
Left - stomach (notice the surface mucous cells
Right - small intestine (notice the enterocytes between goblet cells)
Name this organ.
Duodenum
(Notice the enterocytes, goblet cells, and Brunner’s glands in the submucosa)
Black arrow?
Green arrow?
Red arrow?
Villus
Crypts of Lieberkuhn (glands)
Brunner’s glands
(Glands in the submucosa = duodenum)
What are the functions of the cell diagramed here?
Absorption in vili, glands, and general surface and secretion of water and electrolytes in glands
(Tall, ciliated cell = enterocyte)
What are the arrows pointing to?
Goblet cells
Name the organ.
Jejunum or ileum
(Vili + plicae circulares without glands in submucosa = jejunum of ileum; if lymphoid tissue present = ileum)
Where are the cells found and what is their function?
Bottom of crypts of Lieberkuhn
Secrete lysozyme + other antibacterial substances; phagocytose bacteria and protozoa (so regulate flora)
Function of M cells
Endocytose microorganisms and macromolecules and discharge them to underlying lymphatic tissue
Stem cell location in stomach versus small intestine
Stomach - isthmus of gastric pit and glands
SI - lower half of glands
Which part of GI tract can have 3 muscle layers and what are they?
Stomach
Inner oblique, middle circular, outer longitudinal
What is the function of the structure highlighted by the arrow?
Absorption of fat
(Lacteal = lymphatic channel in lamina propria extending into villi of small intestine)
What is GALT?
GI-associated lymphoid tissue = Peyer’s patches, lymphocytes, plasma cells, and lacteal in lamina propria of small intestine
What is the function of the structure indicated by the green arrow?
Secretion of buffer to make acid from stomach more alkaline
(Brunner’s gland in submucosa of duodenum)
Name the organ.
Ileum
(Notice the Peyer’s patches)
Name this organ.
Large intestine
(Straight glands with non-ciliated simple columnar epithelium)
List the 4 cells of the large intestine epithelium
Intermediate (stem) cells
Enteroendocrine cells
M cells
Enterocytes
(Notice no paneth cells)
List 5 differences between small and large intestines
- No paneth cells in LI
- LI has straight glands
- LI has tinea coli
- LI has no lymphatic vessels
- LI doesn’t have vili
Organ?
Large intestine
(Straight glands + non-ciliated columnar epithelium)
What is this structure? What is it composed of?
Tinea coli of large intestine
Band of outer longitudinal muscle
Why do colon cancer spread slowly?
No lymphatic vessels in lamina propria
(Although well developed GALT is present)
Organ?
Appendix
(Straight glands + lymphoid tissue + debris in lumen)
Portal triad
Portal vein, hepatic artery, bile duct; continues throughout entire liver
Portal canal
Portal triad + lymphatic vessels, nerves, connective tissue,
Route of blood flow through liver
Hepatic artery + portal vein
V
Mix in sinusoids
V
Central vein
V
Sublobular vein
V
Hepatic vein
V
IVC
What do the black arrows indicate? Purple?
Black - portal canals
Purple - central vein
(This is the lobular organization of the liver)
The dotted line is encasing:
A lobular unit of the liver
(Six-sided prism with a portal canal at each corner
The predominate cell type in this picture is rich in:
ER and Golgi
(Enterocytes - make lots of protein)
Deficiency of which cell type in the liver could result in blindness?
Ito (Stellate) cells
(They store vitamin A, which is crucial in phototransduction)
What are the two cell types commonly found in sinusoids and depicted here?
Kupffer cells (macrophages, black arrow)
Epithelial cells (blue arrow)
What structure is the arrow pointing to and what is contained within that structure?
Perisinusoidal space (between fenestrated endothelium of sinusoids and hepatocytes)
Microvili of basal surface of hepatocytes project into perisinusoidal space)
Bile flow through liver
Bile canaliculi
V
Canal of Herring
V
Interlobular bile ducts
V
Right or left hepatic duct
V
Common hepatic duct
V
Common bile duct
Part of bile that’s recycled to intestine? Part that’s eliminated?
Electrolytes, phospolipids, bile salts/acids - recycled
Bile pigment - eliminated
Name of this model of the liver? Based on?
Classic lobule model
Blood flow
Name of this model?
Based on?
Portal lobule model
Bile drainage
Name of this model?
Based on?
Liver acinus model
Blood flow, metabolism, pathology
Which zone is best oxygenated? Least?
Zone 1 is best
Zone 3 is least
Arrow pointing to?
Bile canaliculus
What is the orangish material in the liver?
Hemosiderin from RBC breakdown
Blue arrows?
Orange arrow?
Portal triads
Central vein
What is the structure in the center of the picture?
Portal canal
Yellow arrows?
Green arrow?
Black arrow?
Bile ducts
Hepatic artery
Portal vein
(Can have more than one triad component within a single canal)
Kupffer cell in sinusoid (macrophage)
Sinusoidal endothelial cell
What is this structure?
Herring canal
(Cuboidal lined, not running with a component of portal triad)
What is this structure?
Hepatic vein
(Lined by lots of connective tissue; not running with any component of portal triad; received central veins)
Site of bile synthesis? Concentration? Storage?
What causes its release from the gallbladder?
Made in liver, concentrated and stored in gallbladder
CCK
Organ?
Gallbladder
(Notice simple cuboidal epithelium with no glands or goblet cells; also NO MUSCULARIS MUCOSA OR SUBMUCOSA)
What’s the function of the tissue within the box?
Excretion of bile into the cystic duct
(Muscularis externa)
Describe the process of bile concentration in the gallbladder.
Osmotic gradient forces water into intercellular space, then hydrostatic pressure forces water into lamina propria then into capillaries and venules
What is the function of the system depicted below?
Secretion of zymogens from acinar cells into duct system to intestines to become activated
Flow of zymogens from centriacinar cells to intestine
Intercalated ducts
V
Intralobular ducts
V
Interlobular ducts
V
Main pancreatic duct
