Exocrine and Specialised Flashcards
Where can the parotid glands be found?
By the side of the mouth and in front of the ears.
What does the parotid glands secrete?
Mainly saliva, however it only constitute 40% of saliva secreted in total.
How does the parotid glands differ to the other salivary glands?
They ONLY have serous glands, but also some adipose tissue.
What is the parotid glands function?
To secrete a serous secretion that contains enzymes that digest food and lubricates the bolus during swallowing.
Why is parotitis so painful?
Because the parotid glands are enclosed in a tough fibrous capsule. So when swelling occurs the amount is limited so it pushes on the capsule and makes the swelling very painful.
What is the stimulation of the parotid glands?
Parasympathetic in order to increase saliva production.
Where can you find the sublingual gland?
Below the tongue
How do the parotid glands and the sublingual gland differ?
Where the parotid gland is only made of serous glands the sublingual gland is almost completely mucous with numerous of demilunes.
Where can you find the submandibular glands?
Below the sublingual gland and the parotid glands.
How do the submandibular glands differ from the other two salivary glands?
The submandibular glands are made of mostly serous glands but also some mucous glands.
What is the stimulation of the salivary glands?
Parasympathetic to produce a water saliva rich in enzymes (serous)
Sympathetic to produce a small, thick secretion of saliva rich in mucus (mucous)
The control of salivary secretion is neural only.
Which is the largest exocrine gland in the body?
The liver.
What are hepatocytes?
Liver cells.
What is a sinusoid?
An irregularly shaped tube through which blood passes. However it is not a blood vessel. Can also be found in spleen and bone marrow. It has large gaps between the cells it consist of.
What are the three types of vessels?
Continuous
Fenestrated
Sinusoid
What two vessels come together in a liver acinus, what do they merge into and where do they end up?
The hepatic portal vein and the hepatic artery merge into a sinusoid and end up in the central vein.
What is a liver lobule?
A hexagonal shaped (6 sided) structure clearly seen in histology. It usually consist of 6 portal triad and consist of one single central vein.
What does a portal triad consist of?
1 hepatic artery
1 hepatic portal vein
1 bile duct
What are pit cells?
Most active form of natural killer cells. They kill tumour cells that enter the sinusoids.
What are kupffer cells?
Specialist macrophages that form part of the sinusoidal lining.
Can you find kupffer cells anywhere else in the body?
Yes, kupffer cells constitute 80% of the tissue macrophages present in the body.
What are the main roles of Kupffer cells?
To remove cell debris, bacterial endotoxins.
but especially trap phagocytose and any damaged or aged erythrocytes that were missed by the spleen.
How do the Kupffer cells in the liver relate to a splenectomy?
After a splenectomy the kupffer cells in the liver take over the removal of 120 day old (aged) erythrocytes.
What are stellate (Ito) cells?
They are full of cytoplasmic vacuoles containing vitamin A.
What happens to Ito cells during liver cirrhosis?
The hepatic Ito cells lose their vitamin A storage capability. This causes them to differentiate into myofibroblasts and therefore they start to lay down collagen within the perisinusoidal spaces resulting in liver fibrosis.
What are the main functions of the liver?
Storage Anabolism (production) Catabolism (destruction) Bile production Filtering of cell debris Hormone production
What does the liver store?
Iron
Vitamin A, B12, D and K (Lipid soluble vitamins)
Glycogen
Copper
What does the liver produce?
More than 60% of all the body's proteins: Albumin Enzymes Lipid carrier proteins Amino acid synthesis Haemopoeisis in fetus Also hormones and growth factors
What does the liver destroy?
Drugs
Hormones (Insulin, glucagon, steroids etc…)
Haemoglobin (bilirubin passed to gall bladder)
Poisins and toxins
After splenectomy RBCs
How do hepatocytes differ to other cells?
They have a lot of mitochondria. Lots of peroxisomes Lots of free ribosomes Lots of rER Lots of see Lots of Golgi
How does the liver differ to the pancreas in terms of endocrine and exocrine functions?
In the pancreas the same cells do not work as endocrine and exocrine.
In the liver the same cells work as endocrine and exocrine (hepatocytes).
