Histology Flashcards
What is parenchyma?
Secretory epithelial cells
What is the stroma?
Connective tissue of glands that divides them into lobes and lobules
The shape of secretory epithelium may be ___?
Tubular or acinar/alevolar
Define exocrine glands
Secrete into ducts connected to a surface
Define endocrine glands
Secrete directly into blood vessels
Define merocrine secretion and give example
exocytose vessicles, serrous glands (exocrine pancreas, salivary, goblet cells)
Define apocrine secretion and give an example
Apical portion of gland is shed with lipid secretion (mammary gland, prostate)
Define holocrine secretion
Cell undergoes apoptosis, releasing secretory contents (sebaceous glands)
List six major functions of saliva
Buffering, breakdown (amylase lipase), bacteria control (lysozyme, IgA, lactoferrin), moisture, mineralization (Ca2+, K+), Protective film (protein)
What are the functions of striatedd ducts?
Production of bicarbonate, reabsorption of sodium chloride
What are the 3 types of secretion
Serous, mucous, mixed
Describe serous secretion. What gland has serous acini?
Proteinaceous, watery consistency, parotid gland
Describe mucous secretion. Which gland has mucous acini?
Glycoproteinaceous, complex polysaccharides, viscous. Sublingual gland.
What secretory gland of the upper GI system has mixed acini?
Submandibular gland, mixed acini result in serrous demilunes
Describe striated ducts
Pizza shaped epithelial cells with basal plasma membrane infoldings and mitochondria
Describe the difference between serous and mucous acini?
Serous acini- the cytoplasm is basophilic basally (RNA), eosinophlic apically (zymogen), small lumen, round nuclei, intercellular cannaliculi.
Mucous acini- flattened nuclei on basal side, lighter staining, bigger lumen.
What cells surround secretory acini? What can they be stained with?
Myoepithelial cells, F-actin stain
What are the 4 types of papillae found on the tongue?
Foliate, fungiform, filiform, circumvallate
Which papillae of the tongue do not have taste buds?
Filiform papillae
What are von Ebner’s glands?
Serrous secreting glands in the furrow of circumvalate papilla
What are the 3 layers of the tongue?
Stratified squamous epithelium, connective tissue, skeletal muscle (oblique and longitudinal)
Describe taste buds
Onion shape with sensory and supporting cell “petals,” taste pore at surface, basal stem cells, afferent nerve terminals on sensory cells
Describe the structure of the teeth
Enamel, dentin, odontoblasts, pulp chamber, root canal, periodontal ligament, alveolar bone
What cells produce enamel? What happens to them?
Ameloblasts produce enamel towards the odontoblasts. They die when the cell breaks the surface.
Name and describe the layers of the GI tract
Mucosa (epithelium, lamina propria, muscularis mucosa), submucosa (DICT), muscularis externa (smooth muscle bilayer), serosa (mesothelium) OR Adventitia (DICT)
Describe the muscularis externa in general
Inner circular smooth muscle, outer longitudinal smooth muscle
Where is Auerbach’s plexus?
The myenteric plexus- between the layers of the muscularis externa
Where is Meissner’s plexus?
Submucosa- allows the muscularis mucosa to contract independently of the muscularis externa.
Dscribe the muscularis externa in the esophagus
Upper 1/3 = skeletal muscle,
Middle 1/3 = skeletal and smooth muscle
Lower 1/3 = smooth muscle
What type of epithelium does the stomach have?
Simple columnar epithelium
What type of epithelium does the esophagus have?
Stratified squamous non-keratinized epithelium
Where are cardiac glands and what do they do?
In the stomach near the esophageal orifice, they secrete bicarbonate rich mucous
What is the difference between exocrine and endocrine glands?
Exocrine glands have ducts with a lumen which travel to the apical side of the cell to discharge secretions, endocrine glands secrete on the basal side of the cell directly into the bloodstream (hormones) and thus have no lumen.
Name and give an example of the four types of exocrine glands
1) Simple tubular- luminar surface, i.e. intestinal glands
2) Simple acinar (alveoli)- sebaceous glands
3) Compund tubulo-acinar- salivary
4) Compound acinar- pancreas
Name and describe the 6 types of ducts
1) Acinus: secrete mucins, proteins, and enzymes, transport Na+, Cl-, H2O, IgA.
2) Intercolated (transport)
3) Striated: Prominent epithelial basal membrane folding to increase surface area for pumps in plasma membrane, prominent mitochondria, secrete bicarbonate, reabsorb Na+, Cl-, much larger than intercolated ducts
4-6) Intralobular, Interlobular, Lobular
Describe the parotid gland
located anterior and posterior to the ear, have long intercollated ducts, contain serous acinus (basophilic, nuclei near center of pie wedge, secrete protein, watery consistency)
Describe the sublingual gland
Have short ducts, contain mucous actinus (lighter staining, peripheral nuclei, secrete glycoproteins, mucus polysaccharides, viscous gel)
Describe the submandibular gland
Have prominent striated ducts, contain serous AND mucous acinus, serous demilunes from preparation
Describe fungiform papilla
mushroom shaped and have dorsal taste buds. CC- Riley-Day Synrome, smooth tongue
If there is a ganglia within the wall of an organ, it must be part of what nervous system?
Parasympathetic
Describe GERD and Barret’s Esophagus
GERD is the backflow of acid from the stomach, through the pyloric sphincter into the esophagus causing burning and pain. In Barret’s Esophagus, the esophagus tissue becomes damaged from chronic exposure to stomach acid and undergoes metaplasia, becoming more like simple columnar epithelium of the stomach.
What dye does mucous stain with?
PAS
What 4 types of cells make up the gastric glands?
Chief cells, parietal cells, mucus neck cells, enteroendocrine cells
Describe parietal cells of gastric glands
- secrete HCl, intrinsic factor (required for Vitamin B12 absorption)
- between chief cells, very eosinophilic, large cells
- many mitochondria, no granules
- secretory canaliculus, internal microvilli
Describe chief cells of the stomach
- low columnar with zymogen granules (pepsinogen and lipase)
- base of cell basophilic
Describe mucous neck cells of the gastric glands
- near gastric pit
- numerous secretory granules of mucin
Describe enteroendocrine cells of gastrin glands
-produce hormones: serotonin; gastrin
In what 5 ways is the SA of the small intestine increased?
(1) length of small intestine
(2) plicae circulares: (valves of Kerckring), semicircular folds of submucosa
(3) intestinal villi: finger-like projections of epithelium
(4) microvilli: increase surface area of epithelial cells
(5) glycocalyx: Glycoproteins (enterokinases) projecting from microvilli
What 2 types of cells are found in the mucous membrane of the intestine?
(1) Columnar absorptive cells
- brush border and glycocalyx
- junctional complexes
- role in absorption and digestion
(2) Goblet cells
- apical region distended with mucigen droplets
What and where are Brunner’s glands?
Submucosa of duodenum
compound tubular glands, produce mucus with an alkaline, bicarbonate content
- ducts penetrate muscularis mucosae and empty into the crypts of Lieberkuhm
Describe paneth cells
In lamina propria- secrete lysozyme, large, apical, eosinophilic granules, basal ER.
Describe enteroendocrine cells of intestines
Secrete Secretin and Cholecystokinin (CCK)
towards basal lamina
What and where are Peyer’s patches?
groups of lymphatic nodules
- in lamina propria and submucosa of ileum
- local source of lymphocytes (no lymph filtration by these nodules)
In an autimmune disease which targets the gastric mucosa, resulting in a lack of intrinsic factor, which cell type is most affected?
Parietal cells
The colon has no villi, but what cell type is abundant?
Goblet cells
What is the exocrine function of the liver?
To secrete bile into the duodenum
From where does the liver receive it’s blood?
- receives venous blood from intestine via portal vein - receives arterial blood via hepatic
artery
List the 5 functions of the liver
(1) absorbed products of digestion are metabolized or transformed & returned to the
blood
(2) toxic substances in the blood are degraded or detoxified
(3) bile is produced for release into the intestine where it plays a role in digestion of
lipids
(4) the protein components of blood plasma is produced
(5) carbohydrates are stored as glycogen & released as glucose - maintains blood
glucose
Each portal area of the liver contains what 3/4 things?
A branch of the portal vein, a branch of the hepatic artery, a bile duct, sometimes a lymphatic vessel is also seen
The portal vein, hepatic artery and bile duct enter the liver where?
On the inferior surface at the porta hepatis
Where do the portal vein, hepatic artery, and bile duct travel?
terminal branches of artery, vein and bile duct leave the portal area and feed sinusoids
- blood leaves the sinusoids at the central vein
- the central vein passes to a collecting vein – to the hepatic veins – to the vena cava
What and where are Kupffner cells?
Situated on or between endothelial cells in sinusoids of liver
- highly phagocytic, lysosomal activity (destroy bacteria, erythrocytes)
- surface folds and processes
- support for these cells is by fine reticular fibres
What s another name for the perisinusoidal space?
Space of Disse
What is the function of hepatocytes?
Store carbohydrates as glycogen and synthesize plasma proteins
Cells secrete intrinsic factor (B12 breakdown) and HCL
Parietal Cells
The secretion granules on the apical side of serrous acini are:
Amylase and lipase
The Crypts of Lieberkuhn are contained in which layer of the GI tract?
Mucosa
The Brunner’s glands are contained in which layer of the GI tract?
Submucosa
Meissner’s plexus inner cares which layer of the GI tract?
Muscularis mucosa
This hormone is produced by the endothelial cells of the gastric mucosa and stimulates HCL secretion
Gastrin
Which GI tract cell type secretes lysozymes into the intestinal lumen?
Paneth cells
Pepsinogen and lipase are secreted into the stomach by which cell type?
Chief cells
Gastric enteroendocrine cells secrete which hormone into the gastric mucosa?
Gastrin
Intestinal enteroendocrine cells secrete which two substances into the mucosa?
Cholecystokinin and secretin
CCK and secretin are produced by which cell type in the GI tract?
Intestinal enteroendocrine cells
The walls of the duodenum are made up of what structures?
From outside: Longitudinal muscularis externa Auerbach’s plexus Circular muscularis externa Brunner’s glands Muscularis mucosa Crypts of Lieberkuhn Enterocytes
Which section of the small intestine contains lots of mucous secreting glands in the submucosa? What are these glands called?
Duodenum, Brunner’s glands
What are collections of lymphocytes in the submucosa and mucosa of the ileum?
Peyer’s patches
Smooth muscle contraction in the gallbladder is regulated by:
Cholecystokinin (CCK)
Collections of lighter staining endocrine cells in the pancreas are called:
Islets of Langerhans
The outer edges of the Islets of Langerhand contain what two types of cell?
Alpha and delta
The inner portion of the Islets of Langerhans contain what type of cells?
Beta
Alpha cells of the Islets of Langerhans secrete what hormone?
Glucagon
Beta cells of the Islets of Langerhans secrete what hormone?
Insulin
Delta cells of the Islets of Langerhans secrete what hormone?
Somatostatin
Pancreatic juice, secreted by serous acini of the pancreas, contains what enzymes?
Trypsinogen Chymotrypsinogen Carboxypeptidase Lipase Nuclease Amylase
What hormone regulates serous acini in the pancreas?
Cholecystokinin (CCK) from intestinal enteroendocrine cells
What type of ducts does the pancreas contain?
Intercollated
Intercollated ducts in the pancreas secrete what chemical?
Bicarbonate
What hormone triggers the release of bicarbonate from epithelial cells in the intercollated ducts of the pancreas?
Secretin from intestinal enteroendocrine cells
