Lecture 12 - Exocrine & Specialised Glands Flashcards
Where are the parotid glands located?
Underneath the skin, the top of the glands are at the head of the mandible, the bottom is 2cm below the angle of the mandible
What colour does the parotid gland stain and why?
Purple as it is a serous gland. the pale structure is the striated duct of the gland, surrounded by simple columnar epithelial cells.
Where does saliva pool due to a blockage in the parotid gland that ultimately leads to swelling?
In the striated duct, as infections of the gland cause a blockage here which fills with saliva from acinar cells.
Where is the submandibular gland located?
What are the 2 parts and what are they separated by?
- Underneath the mandible and jaw
- Superficial and deep - separated by mylohyoid muscle
The 3 salivary glands are parotid, submandibular and sublingual - which ones are serous, mucous or both?
How can this be used to tell them apart on a H&E stain?
- Parotid = serous. Submandibular = Mostly serous, some mucous. Sublingual = Mucous
- Serous stains purple and mucous stains white, so purple = parotid, mixed = submandibular and white = sublingual
How is salivary secretions stimulated/regulated?
Via ANS supply to the salivary glands (neural ONLY)- BOTH sympathetic and parasympathetic increase saliva secretion.
What is the difference in saliva secretions when stimulated by sympathetic and parasympathetic innervation?
Parasympathetic = Watery saliva rich in enzyme Sympathetic = Small, thick secretions rich in mucous
What 2 vessels supply blood to the liver and how much does each contibute?
Is the blood from each vessel deoxygenated or oxygenated?
1) Hepatic portal vein (70-75%) - deoxygenated
2) Hepatic artery (25-30%) - oxygenated
NB: HPV also supplies the spleen, stomach and intestines.
What is the structure called that blood is fed into when the HPV and hepatic artery come together?
- A sinusoid tube (irregularly shaped)
What are the large gaps in sinusoidal cells called and why do they have them?
- Sinusoids
- So that cells can squeeze through the large gaps and enter the tissues directly, which is important for places such as the liver, spleen, bone barrow and lymph nodes.
What are the three main cells of the liver?
1) Hepatocytes
2) Kupffer cells
3) Ito (stellate) cells
What are Kupffer and what is their function in the liver?
Kupffer cells are specialised macrophages that form part of the sinusoidal lining. They trap and phagocytose any aged erythrocytes missed by the spleen (or take over this role after splenectomy) - Erythrocyte typically last 120 days/4months
What are stellate (ito) cells?
Stellate cells are the major storage site of vitamin A (in their cytoplasmic vacuoles) but also respond to hepatic injury.
Which cell constitutes to 80% of the liver cell population?
What is its function?
What organelles do they have in abundance?
- Hepatocytes
- Metabolism, detoxification, protein synthesis + has regenerative ability
- Peroxisomes, free ribosomes, RER, SER, golgi apparatus and glycogen deposits
what are the major functions of the liver?
1) Storage - iron, lipid soluble vitamins (A,B12,K), glycogen
2) Anabolism - more than 60% of body proteins, e.g.: albumin, enzymes, lipid carrier proteins, AA’s
3) Catabolism - of drugs, hormones, Hb, poisons/toxins
4) Bile production - through ducts into the gall bladder which emulsifies fats and assists in Vit K absorption from the SI
5) Production and modification of hormones
