Flashcards in Digestive Accessory Organs Deck (66):
There are three large salivary glands, found in _______, called the _______, _______, and _______.
pairs; parotids; sub-mandibulars; sub-linguals
Lobated gland encapsulated in CT that invades the glandular elements to form septae that separate the organ into lobules
Parenchyma of each consists of secretory units on a branching duct system, arranged in lobules
Salivary secretory units are comprised of three epithelial cell types: _______, _______, and _______.
serous cells; mucous cells; myoepithelial cells
Modified epithelial cells containing actin and myosin that are found in the basal lamina surrounding acini, tubules, and the proximal ends of the duct system
They contract to squeeze the contents of the secretory unit or duct
There are three types of ducts:
Short, intralobular ducts composed of simple cuboidal epithelium that acini and tubules empty their contents into
Merge with other intercalated ducts and empty into striated ducts
Part of the intralobular duct system
Intralobular ducts composed of simple columnar epithelium that intercalated ducts empty into
Converge and drain into excretory ducts
Epithelia have basal membrane invaginations and an accumulation of mitochondria (characteristics of ion-transporting cells)
Thick interlobular ducts (found in the septa) composed of stratified cuboidal epithelium that becomes stratified columnar epithelium
Striated ducts empty their contents into excretory ducts
Somewhat basophilic due to its secretory product
Secretes zymogen granules
Find all over
Slightly eosinophilic due to its secretory product
Secretes carbohydrate-rich product
Sticky, viscous secretion
Cap of serous cells found on top of mucous acini
Secretes the protein product lysozyme that digests bacterial cell walls
The duct cells of acinus ducts can _______ secretions.
Simple cuboidal cells of intercalated ducts absorb _______ and secrete _______ to modify secretions.
Simple columnar cells of striated ducts reabsorb _______ and secrete _______ and _______ to modify secretions.
sodium; potassium; bicarbonate
Secretory ducts _______ modify secretions.
Large, entirely serous glands found on the sides of the face
Stenson's duct deposits saliva in upper part of oral cavity by the second molar
Key gland for oral digestion
Why do the parotids stain basophilic?
All acini are serous
IgA produced by the parotids functions to_______.
defend against antigens from food
Name the accessory organs of the digestive system.
How do you distinguish the parotids from the pancreas?
The pancreas has islets of Langerhans
Facial nerve can sometimes be seen in the parotids
Gland beneath the base of the mandible
Mixed gland, containing mucous acini, but predominately serous
Produces some saliva
Polarized, pyramidal, protein-secreting cells with round nuclei
Contain apical secretory granules
Contain abundant RER at the basal end
Joined together apically by tight junctions
Form a spherical unit called an acini with a very small central lumen
Salivary secretory unit made up of serous cells bound by tight apical junctions in a spherical shape
Has a very small central lumen
Cells secrete enzymes and other proteins
Somewhat columnar cells with a compressed basal nuclei
Contain apical granules with hydrophobic mucins that provide lubricating properties to saliva but cause poor cell staining
Organized into cylindrical tubules
Smallest salivary glands
Located under the tongue
Produce 120 mL in 24 hours
Starts, but doesn't finish digestion of carbohydrates
Defense via IgA, lysozyme
Lubrication of the oral cavity
Lubrication, mixing, and softening of food to aid in swallowing
Dissolve tastant molecules in food that we taste
Buffers via bicarbonate
Why doesn't saliva finish digestion of carbohydrates?
Food doesn't stay in the mouth for a long period of time
Control of salivary secretion is _______ and depends on both _______ and _______ stimulation.
autonomic; sympathetic; parasympathetic
Sympathetic stimulation of salivation
Responsible for dry mouth in fight-or-flight response
Parasympathetic stimulation of salivation
Elongated, CT-encapsulated gland under the stomach
Consists of three regions: head, body, and tail
Both exocrine and endocrine gland that produces both digestive enzymes and hormones
CT separates the parenchyma into lobules
The pancreas has both _______ and _______ functions.
Exocrine function of the pancreas
Produces enzymes, collectively called pancreatic juice that is released as zymogen granules to prevent auto digestion
Duct cells secrete the fluid for pancreatic juice
Secrete bicarbonate and sodium that keep zymogens inactive until they get to the duodenum
Endocrine function of the pancreas
Islets of Langerhans scattered through the exocrine pancreas
Consist of A cells, B cells, and D cells
Highly vascularized with many fenestrated capillaries
A cells of islets of Langerhans
Alpha α cells
20% of cells
Beta β cells
Delta ∆ cells
Produces somatostatin (pleiotropic)
Peptide hormone produced by α cells of the pancreas that raises the glucose concentration in the blood
Peptide hormone produced by β cells of the pancreas that lowers the glucose concentration in the blood
Somatostatin of the pancreas
Peptide hormone produced by ∆ cells of the pancreas that regulates secretion of local insulin and glucagon
Having two opposite effects
_______ can be used to identify α, β, and ∆ cells.
What makes the zymogen granules of the exocrine pancreas?
Exocrine secretion in the pancreas is regulated mainly by two polypeptide hormones produced by enteroendocrine cells of the small intestine called _______ and _______.
Polypeptide hormone produced by enteroendocrine cells of the small intestine
Promotes water and bicarbonate secretion by the duct cells
Polypeptide hormone produced by enteroendocrine cells of the small intestine
Stimulates enzyme secretion by acinar cells
Mixed salivary glands have _______ secretory units with both _______ and _______ secretions.
tubuloacinar; serous; mucous
What produces the digestive enzymes of the pancreas?
Serous acini (exocrine portion)
Consists of serous cells around a very small lumen
No myoepithelial cells
Cells are polarized, with a round basal nuclei and apical zymogen granules (typical of protein-secreting cells)
Each acinus is drained by a short intercalated duct of simple squamous epithelium
The initial, lightly-staining cells of pancreatic intercalated ducts are called _______ and are unique to the pancreas.
Encapsulated organ in the URQ (Glisson's capsule made of fibrous CT)
Separated into 2 lobes
Peritoneum on top of capsule
What is the function of the liver?
Detoxification of blood
Produces bile salta/acids that emulsify fats for digestion
Metabolizes old RBC, especially bilirubin
Glycogenolysis (breaks glucose down when needed)
Gluconeogenesis (a.a. to glucose)
Vitamin A and D
Product of RBC metabolism
Metabolized by the liver
What proteins does the liver make?
Albumins (trafficking protein; iron, fats, steroids)
Fibrinogen (blood clotting)
The liver has two types of blood, _______ and _______ blood.
Venous blood of the liver
75% of blood
Via SI, spleen, and pancreas via hepatic portal vein
Arteriole blood of the liver
25% of blood
Via hepatic artery
What is the distinguishing feature of the liver?
Cells are arranged into lobules with a central venule and hepatocytes in cords
Every hepatic lobule has a portal triad
Every hepatic lobule has one associated with it
Bile ductule branching from a bile duct
Venule branching from the hepatic portal vein
Arteriole branching from the hepatic artery
What is the flow of blood from the hepatic triad in the liver?
Central vein --> hepatic portal veins --> inferior vena cava --> heart
Blood and bile are never _______.
Very large cells of the liver
Many are binucleate
Many are polyploid
Non-mitotic; replaced by stem cells
Organ that stores bile produced by the liver
Expands and contracts easily
What can happen to the gallbladder if someone is too dehydrated?
The bile can condensate too much and gall stones may form
Layers of the gallbladder tube
Lining of simple columnar epithelium with many microvilli
DOES NOT HAVE a submucosa
Very thick muscularis externa of smooth muscle that runs in different directions
Adventitia where it touches the liver and serosa on free surfaces