7 - Exocrine Tissues Flashcards
Where is the parotid gland?
Wraps around the mandibular ramus (angle of the jawbone)
Anterior to the mastoid process, level with head of the mandible
What type of acini are found most commonly in the parotid gland?
Serous acini
The striated ducts in the parotid glands are made up of what type of epithelium?
How are these cells different from the way this type of epithelium usually appears?
Simple columnar epithelium
Nuclei are closer to the apical surface (normally closer to the basement membrane)
What types of acini are found in:
a) parotid glands
b) submandibular glands
c) sublingual glands
a) almost all serous acini
b) serous and mucous acini
c) almost all mucous acini
Where is the submandibular gland?
Lies behind the body of the mandible. In two parts, superficial and deep (separated by mylohyoid muscle)
How is salivary secretion regulated?
Only by neural control - no hormones
Parasympathetic - serous secretion rich in enzymes (large volume)
Sympathetic - mucous secretion
Describe the hepatic blood supply.
- Hepatic artery - supplies liver with oxygenated blood from the aorta
- Hepatic vein - returns deoxygenated blood from the liver to the inferior vena cava
- Hepatic portal vein - connects capillary bed in stomach/intestine to the sinusoids in the liver
HA –> GI capillaries –> HPV –> liver sinusoids –> HV
What percentage of the hepatic blood supply comes from the portal vein?
70-75%
Remainder from the hepatic artery
In a liver sinusoid, a triad of vessels comes together, what are these vessels?
Where do the vessels drain into?
Triad - hepatic artery, portal vein, bile canaliculus
artery and portal vein drain into central vein –> hepatic vein
Bile canaliculus drains in opposite direction into the bile duct
What is a sinusoidal vessel?
Where in the body are these found?
- Irregularly shaped blood vessel with large gaps between the cells (intercellular gaps)
- Cells can get through into the blood
- Incomplete basement membrane
Liver, spleen, bone marrow, lymph nodes
How many sinusoid segments (acini) make up a liver lobule? How are they arranged?
6
Hexagonal arrangement - portal triads around the edges draining into the central vein
Hepatocytes usually have …. or …. nuclei because the cells need to make lots of ………..
2 or 3, proteins
What do pit cells do in the liver?
Form of natural killer (NK) cell
Kills tumour cells that enter the sinusoids
What do stellate cells do in the liver?
Pick up and store vitamin A (retinoic acid) in cytoplasmic vacuoles
In hepatocytes, specialisations are on the ……………… surface of the cells, facing the sinusoids
Basolateral
Normally on apical surface in most cells
