Histology Flashcards
What type of epithelium lines the Oral Cavity?
Stratified squamous epithelium
What are the three different covered surfaces of the lips?
Internal mucous surface
Red vermilion zone
Outer surface
True or False? The Red vermillion zone of the lips is lined by non-keratinized epithelium?
FALSE!!! It is lined by very thin keratinized stratified squamous epithelium.
What type of epithelium covers the Internal mucous surface?
Thick non-keratinized epithelium.
Which covered surface of the lips does not contain salivary or sweat glands?
Red vermillion zone
What are the 4 types of Lingual papillae?
Filiform papillae
Fungiform papillae
Foliate papillae
Vallate papillae
What is the largest papillae ?
Vallate (Circumvalate ) papillae
What type of glands are found that empty into deep groove surrounding each vallate papilla providing continuous flow of fluid
over taste buds?
von Ebner glands
What type of glands are von Ebner glands?
Serous salivary glands
What type of epithelium are found in taste buds?
Stratified epithelium
What structure separates the anterior 2/3 of the tongue from the posterior 1/3 of the tongue?
Sulcus terminalis
What are the first set of teeth to grow in the human body?
Lower incisors
At what age does your third molar develop?
17-25 years
What types of papillae are NOT present on the posterior 1/3 of the tongue?
Filiform or Fungiform papillae
What number of teeth are present in each quadrant of the mouth and what is its order?
8 teeth
2 incisors
1 canine
2 premolars
3 molars
2-1-2-3
What is the name of the depression in which teeth grow into?
Dental Alveolus
Fill in the blanks? . Blood vessels and nerves enter the tooth through_________ at the root tips.
Apical Foramina
What is the name of the structure that holds the tooth to the bone of the jaw?
Periodontal ligament
What type pf nerves are present in the pulp cavity of the tooth?
Unmyelinated nerves
What is the main component contains in Dentin?
Hydroxyapatite
What type of collagen is found in the organic matrix of Dentin?
Type I collagen
What are Odontoblasts derived from?
Cranial neural crest cells in mesenchyme of developing pulp cavity (PC)
How long does it take for pre-dentin to mineralize to become dentin?
1 day
True or False? The enamel contains both Type I and Type II collagen?
FALSE!! The enamel does not contain any collagen
What is the name of the structure that produces a protein that helps in the formation of Enamel?
Ameloblasts
Fill in the blanks. “ Ameloblasts are derived from ______ (embryonic/germ layer origin ) while Odontoblasts are derived from _________ (embryonic/germ layer origin)
Ameloblast - Ectoderm
Odontoblast - Mesoderm
At what age do primary teeth begins to erupt?
6 months after birth
What is the name of the main structural protein of the developing enamel?
Amelogenin
What is the name of the structure that covers dentin of root and resembles bone, but is avascular?
Cementum
What type of fibres are found in the lamina propria?
Elastic Fibres
Which tonsil is NOT line by stratified squamous non-keratinized epithelium and what epithelium is it lined by?
Pharyngeal tonsil - Pseudostratified columnar ciliated epithelium
What is the epithelium that lines the oesophagus?
Stratified squamous non-keratinized
What are the 4 layers of the GI tract present in the oesophagus?
Mucosa
Submucosa
Muscularis externa
Adventitia
Fill in the blanks. “ The adventitia of the oesophagus contains _______ connective tissue while the submucosa of the oesophagus contains _______”
Adventitia - Loose connective tissue
Submucosa - Dense irregular connective tissue
Advent is very loose
What type of muscle fibres are present in the Upper oesophagus?
Skeletal muscle fibres
What type of muscle fibres are present in the Lower oesophagus?
Smooth muscle fibres
Fill in the blanks.” Unicellular glands are found at the _____ of the intestines while multicellular glands are found at the ______ of the intestines.
Unicellular- Epithelial lining
Multicellular - Distal and Proximal part
True or False? Exocrine glands are internally secreting glands while Endocrine glands are externally secreting glands.
FALSE!! Exocrine glands secrete EXTERNALLY
Exo - Externally while Endocrine glands secret internally
What is the average salivary production for the human body?
600-1500 ml
What types of Glands are Parotid glands?
Purely Serous
Which type of the major salivary glands is classified as a mixed gland ( both serous and mucous)?
Submandibular gland
What type of gland is the Sublingual gland?
Purely mucous
What type of cells are characterized by the presence of extensive smooth endoplasmic retinaculum and prominent Mitochondria?
Steroid producing cells
True or false ? Cells that are protein secreting have a well developed rough E.R and a supranuclear Golgi complex while mucin producing cells have a well developed rough E.R and a well developed Golgi complex.
TRUE!!
Where is the nucleus located in an Intercalated duct?
At the base of the cell
What type of cells lines intercalated ducts and what is the name of the larger ducts that these intercalated ducts drain into?
They are lined by secretory cells
They drain into larger ducts called Striated ducts
What type of cells lines striated ducts?
Tall columnar cells
Where is the nuclei located in a Striated duct?
To the apex of the cell
What type of enzymes and antibodies are secreted by Striated ducts?
Lysozymes and IgA
The tongue develops from which pharyngeal arches?
1st, 2nd, 3rd & 4th
From what structures is the liver developed from?
Hepatic buds from the distal end of the foregut
What are the names of the structures that derive from the hepatic bud and to what structures do they give rise to?
Main bud - Pars hepatica - which gives rise to right and left hepatic ducts and liver parenchyma.
Accessory bud- pars cystica which forms cystic duct and gallbladder.
What is the name of the sphincter that surrounds the main pancreatic duct?
Sphincter pancreaticus
What is the name of the sphincter that surrounds the common bile duct?
Sphincter choledochus (of Boyden)
What is the name of the acute angel formed between the cystic duct and the common hepatic duct ?
Cystohepatic angle.
How long is the gallbladder ?
10 cm & width 3 cm
What is the surface marking of the fundus of the gallbladder?
A little beyond sharp lower border of the liver and touches the parietal peritoneum of the anterior abdominal wall at the tip of the ninth costal cartilage, where the transpyloric plane crosses the right costal margin, at the lateral border of the right rectus sheath
What is the name of the pouch-like dilation found in the neck of the pancreas?
Hartmann’s pouch
What are the layers of the gallbladder?
Serous layer
Subserous layer
Fibromuscular layer
Mucous membrane
True or False? The serous layer of the gallbladder consists of loose areolar tissue while the subserous layer of the gallbladder is made by pertonieum.
FALSE!! The subserous layer is made up of LOOSE areolar tissue while serous layer is made up of peritoneum
What are the factors keeping the liver in position?
- Hepatic veins connecting the liver to the IVC.
- Intra-abdominal pressure maintained by the tone of
abdominal muscles - Peritoneal ligaments connecting the liver to the abdominal walls
What type of tissue is present in the submucosa of the digestive tract?
Dense irregular connective tissue
What is the name of the parasympathetic innervation of the submucosa and what is its function?
Submucosal (Meissner’s) nerve plexus - control motricity of mucosa and secretory activity of mucosal gland.
What is the name of the structures found between the inner circular smooth muscles and the outer longitudinal smooth muscle?
Connective tissue and Myenteric ( (Auerbach’s)
nerve plexus.
What type of connective tissue and epithelium is found on the serosa?
Loose connective tissue and Simple squamous epithelium
What is the name of the underlying connective tissue found in the mucosa?
Lamina propria
What is the name of the inner circular layer and outer longitudinal of smooth muscle found in the mucosa?
Muscularis mucosae
What type of connective tissue is found in the lamina propria of the stomach?
Loose connective tissue
What type of cells are found in gastric glands?
- Acidophilic parietal cells: in upper portions of glands.
- Basophilic chief (zymogenic) cells: lower portions of glands
What are the 3 layers of muscularis externa found in the stomach?
Inner oblique (not complete)
Middle circular
Outer longitudinal
What are the 3 regions of gastric glands?
- Isthmus
- Neck
- Base (fundus)
What type of cells are found in the isthmus of the gastric glands?
Epithelial cells and Acidophillic parietal cells
What type of cells are found in the Neck of the gastric glands?
Mucous neck
cells and parietal
cells
What type of cells are found in the base of gastric glands?
Chief (zymogenic cells),
basophilic
What is the name given to the junction of
gastric pit with gastric
gland ?
Isthmus
True or False? Gastric pits are deeper in the body of the stomach rather than pyloric region or fundus?
FALSE!! It is deeper in the pyloric region than the body or fundus.
What type of glands are found in the pyloric-duodenal junction?
Coiled tubular pyloric (mucous) glands located in lamina propria
What type of glands are found in the lamina propria of duodenum?
Short simple tubular intestinal glands (crypts of Lieberkuhn)
What types of glands are found in the submucosa of the upper duodenum?
Duodenal glands (Brunner’s)
Which type of stomach cells contain proenzyme pepsinogen, an inactive precursor of pepsin which is responsible for converting almost all solid food into semiliquid chyme?
Chief cells/ zymogenic cells
What substances are produced by parietal cells and what are their functions?
- Hcl
- Intrinsic factor -glycoprotein necessary for absorption
of vitamin B12 from small intestine. Vitamin B12 necessary in red blood cell
production in bone marrow
Which cells are responsible for secreting thick layers of mucus protecting the stomach surface from corrosive
action of acidic gastric juices secreted by cells in gastric glands?
Surface cells/ luminal cells
What is the role of Pepsin?
Pepsin digests large protein molecules into
smaller peptides .
What structure controls chief/zymogenic cells?
Autonomous nervous system and
hormone gastrin, secreted by enteroendocrine cells of pyloric region of stomach.
Where are enteroendocrine cells located in the stomach?
Pyloric region
Fill in the blanks. “ Pyloric glands & cardiac glands contain Mucus-secreting cells
also secreting _______
that destroy bacteria in
stomach.
Lysozymes
What is another name for enteroendocrine cells?
APUD cells (amine precursor uptake and decarboxylation)
What type of substance produced by the enteroendocrine cells is secreted in the fundus of stomach?
Serotonin
What type of cells are found ONLY in the Fundus or the stomach?
Chief (zymogenic) cells
Parietal cells
What are the names of the permanent folds or elevations of mucosa extending into the intestinal lumen?
Plicae circularis or Valvulae conniventes
True or False? Microvilli are non- motile while villi is motile.
TRUE!!
What type of epithelium covers the villi in small intestines?
Simple columnar epithelium
What is the name of the substance that coats microvilli?
They are coated by glycoprotein coat glycocalyx containing brush border enzymes
(e.g. lactase, peptidase, lipase)
What types of glands are located between the villi throughout the small intestines?
Intestinal glands (crypts of Lieberkuhn)
What type of cells are found at the base of the Intestinal glands (crypts of Lieberkuhn)?
Paneth cells
What type of cells are found in the small intestines?
P- Paneth cells
A- Absorptive cells
E- Enteroendocrine cells
G- Goblet cells
S- Stem cells
What is the most common cell found in intestinal epithelium?
Absorptive cell
Which type of cells phagocytose luminal antigens and present them to lymphocytes and macrophages (APCs)?
M cells
What are peyer’s patches and which part of the small intestines does not have them?
They are aggregations of lymphatic nodules.- Duodenum and Jejunum DOES NOT contain Peyer’s patches ONLY ILEUM.
What type of intestinal cells contains granules releasing antimicrobial substances through TLRs are involved in innate immunity and Protects stem cells?
Paneth cells
Which part of the duodenum is covered by Serosa?
Only the first part
The second to fourth part of duodenum is covered by what ?
Adventitia
True or False? The villi found in the Jejumum are very short in comparison to that found in the ileum - they are longer.
FALSE!! Villi in Jejunum are Long while villi in Ileum are Short
Which part of the small intestines are Brunner’s glands only found in the submucosa?
Duodenum
What type of Hormones are released from Duodenal epithelium?
Secretin and Cholecystokinin
What is the normal pH found in the jejunum?
Between 7 and 9
By what enzyme are fats broken down in the duodenum by from the pancreas into fatty acids?
Lipase
What is the name of the structure that separates the ileum from the cecum?
Ileocecal valve(ICV)
What is the function of the Ileum?
The function of the ileum is mainly to absorbvitamin B12andbile saltsand whatever products of digestion that were not absorbed by the jejunum.
What type of epithelium lines the large intestines?
Simple columnarepithelium
True or False? Intestinal glands lack panted cells at bases of the glands.
TRUE!!
True or False? Both small and large intestines have goblet cells but they are more abundant in large intestines and produce mucous for lubricating the lumen.
TRUE!!
Where are adipose cells found in the appendix?
In the serosa
Fill in the blanks. “ Absorbed products first go through the liver capillaries called __________.”
Sinusoids
What are the names of the structural units of the liver and what shape is normally given to them?
Hexagonal liver (hepatic) lobules
What is found in the middle of a Hepatic lobule?
Central Vein
What structures makes up the portal area/triad?
Branches of hepatic artery, hepatic portal vein, bile duct and lymph vessels
In the human liver , how many portal traits can be seen?
3-6 portal areas per lobule
Fill in the blanks. “These polygonal cells are joined to one another in ________.”
Anastomosing plates
Which border of the hepatocytes is modified to form bile caniculli?
Lateral face ( facing adjacent hepatocytes)
Which border of the hepatocyte is mircrovill in abundance?
Sinusoidal face
What are phagocytic cells of the liver called?
Kupffer cells
Where is the Space of Disse located?
Between the endothelium and hepatocytes.
What type of collagen makes up fine reticular fibres found in the supporting connective tissue of the liver?
Type III
True or False? Blood and bile does NOT mix.
TRUE!!
What type of cells line the bile canals of Hering?
Cuboidal epithelial cells called Cholangiocytes
What is the name of the structure into which many bile caniculi join with?
Bile canal of Hering
What is the name of the hormone which regulates bile flow?
Cholecystokinin (CCK)
True or False? Most of the pancreas is an endocrine gland.
FALSE!! It is mostly EXOCRINE .
What type of cells are found in the exocrine secretory units( acini) of the pancreas?
Acinar or zymogenic cells
What are the names given to the endocrine units of the pancreas?
Pancreatic islets (of Langerhans)
What are the four cell types can be identified by immunocytochemistry in each islet?
Alpha
Beta
Delta
Pancreatic polypeptide (PP) cells
Where are alpha cells located in the pancreas?
Primilarly at the periphery of islets.
Where are beta cells located in the pancreas?
Located in center of islets.
Fill in the blanks. “ Alpha cells produce _______ while beta cells produce _______.”
Alpha cells - glucAgon
Beta cells- Insulin
Fill in the blanks. “ __________in the pancreas produce somatostatin while _________ produce pancreatic polypeptide.”
Delta cells produce somatostatin while
Pancreatic polypeptide cells produce pancreatic polypetide.
What is the function of pancreatic polypeptides?
It inhibits production of pancreatic enzymes and alkaline secretions.
Fill in the blanks. “The exocrine pancreas is classified as a _________.”
Compound tubuloacinous gland
What type of epithelium lines the Intercalated duct of the Pancreas?
Low cuboidal, almost squamous
epithelium.
What type of epithelium lines the intralobular duct?
Cuboidal epithelium
What type of epithelium lines the small interlobular duct?
Columnar epithelium
True or False? Both hormones and vagal stimulation regulate pancreatic exocrine secretions.
TRUE!!
What type of cells are Secretin and Cholecystokinin secreted by ?
Enteroendocrine cells (APUD) cells
What substance induces the release of Secretin?
Acidic chyme in duodenum induces release of secretin.
What is the role of Secretin ?
Secretin triggers exocrine pancreas to produce watery fluid rich in sodium bicarbonate ions (role: to neutralize acidic chyme, stop action of pepsin in stomach, create a neutral pH in duodenum)
What induces the release if CCK into the bloodstream?
Fats and proteins in duodenum.
What is the response of CCK into the bloodstream?
CCK stimulates acinar cells to secrete large amounts of pancreatic amylase for carbohydrate digestion, pancreatic lipase for lipid digestion, deoxyribonuclease and ribonuclease for digestion of nucleic acids, proteolytic enzymes trypsinogen, chymotrypsinogen
Where are pancreatic enzymes first produced and what form are they in?
They are first produced in Acing cells in the Inactive form.
Where are pancreatic enzymes activated and by which hormone?
Duodenum by the the hormone enterokinase
Where is enterokinase secreted from?
The intestinal mucosa.
How are pancreatic enzymes activated by enterokinase?
This hormone converts trypsinogen into trypsin which then converts all other pancreatic enzymes into active digestive enzymes
True or False? Glucagon elevates blood glucose levels by accelerating the conversion of glycogen, amino acids and fatty acids in the hepatocytes into glucose.
TRUE!!
True or False? Insulin lowers blood glucose levels by accelerating membrane transport of glucose into hepatocytes, muscle cells and adipose cells. This accelerates the conversion of glucose into glycogen in hepatocytes. Effects of insulin on blood glucose levels are opposite to the ones of glucagon
TRUE!!
What is the life span of taste buds?
7-10 days
Which area of the Anal canal is most susceptible to to variety of carcinomas?
Anal Transitional zone ( Pectinate line)
