11 Exocrine glands Flashcards
Paratid glands Where are they? Function? structure? stimulation? ducts? What about if old? How much saliva produced?
ONLY SEROUS
They are bilateral glands by the side of the mouth and in front of the ears and are the major salivary gland.
Function is to secrete serous secretion that contains enzymes that digest food and lubricates the bolus during swallowing. serous contains amylase for sugar digestion.
stimulated by parasympathetic.
The gland is enclosed in a tough fibrous capsule (lots of collagen). (this limits gland swelling which is painful parotitis).
has striated ducts as basal laminar is inside the cell. nucleus are towards the apex. Means can get lots of fluid out. it has all serous acini. as you age you get more and more fat laid down so as you age you get less and less saliva.
Submandibular glands
Where?
Structure?
It’s signalling?
NEURAL ONLY
under chin
Two parts: superficial and deep, they’re separated by the mylohyoid muscle.
the duct leading into the mouth is called whartons duct
It’s neuronal and stimulated by para and sympathetic nervous system. para produces large volume of watery saliva rich in enzymes and sympathetic produces small thick mucus rich saliva.
Liver
Structure
It’s blood supply?
hepatocytes nucleus
left lobe and right lobe. great regenerating properties.
It is exocrine and endocrine.
Doesn’t have much connective tissue. cirrhosis has lots of connective tissue, hard.
Blood supply: hepatic portal vein brings blood in ( been through the stomach and absorbs nutrients and toxins) and also from the hepatic artery (oxygenated). also deoxygenated from intestines and spleen.
Hepatocytes can be bi- tri- nucleated because they require lots of enzymes for their many roles
Hepatic lobule, structure?
Looks like a flower, hexagonal shaped with 6 sides.
hepatic artery, portal vein and bile duct group together on the outside. ven and art canal together into the hepatic sinusoid to the central canal. bile duct takes substances away from this canal.
3 different types of vessels?
continuous: eg the BBB, dont want blood going into the brain. complete basement membrane.
fenestrated endothelial: end of capillaries, hydrostatic pressure at end of vessels. complete basement membrane.
sinosoidal: have intercellular gaps and incomplete basement membrane which means material can pass in and out very quickly.
Other cells present in hepatic lobules
stellate cells: pick up lipids and collate between hepatocytes
pit cells: NK cells
dendritic cells: dunno why there but probably to spot infection.
Kupffer cell: special type of macrophage
Kupffer cells
specialist macrophages that form part of the sinusoidal lining. they’re 80% of the tissue macrophages in the body. constantly exposed to gut derived bacteria, microbial debris etc.
they trap and phagocytose damaged or aged erythrocytes that are missed by the spleen. If spleen damaged e.g. spleenectomy, then kupffer cells can take over it’s roles.
Ito cells (stellate)
they are full of cytoplasmic vacuoles containing vitamin A (can get it from cod liver oil)
Liver functions Produces? Stores? Other functions? Destructs?
Storage of: iron, vitamins (A,B12, D and K), glycogen, copper.
Anabolism/produces: major plasma proteins, enzymes, lipid carrier proteins, aa synthesis, haemopoeisis in fetus.
catabolism/destruction: drugs, hormone, haemoglobin, poisons/toxins.
other functions: bile production, filtering of cell debris from blood, hormones/growth factors, modifies hormones for excretion
Hepatocytes
constitutes 80% of liver population
regenerates
numerous mitochondria, lots of peroxisomes, lots of free ribosomes, lots of SER, RER, golgi and glycogen deposits.
Hepatocyte sigmnalling? 4 types
Autocrine signalling: VEGF
Paracrine signalling: succinate (hepatocyte regeneration.
Endocrine signalling: GH to IGF1
Intracrine signalling: oestrogen and thyroid hormones atimulate apolipoprotein A1 production.
