Exocrine And Specialised Glands Flashcards
Where are the main reference points in the location of the parotid gland?
Parotid=next to ear
Points= head of mandible, mastoid process (bottom of ear), middle of masseter, and 2cm below the angle of mandible
What cells make up the parotid gland?
It’s a serous gland so manly serous cells (no visible lumen), very few mucus cells a few striated ducts. Also zygotes granules containing amylase.
The 3 salivary glands have different ratios of serous and mucus cells state them.
Parotid= almost totally serous
Submandibular=mostly serous but some mucus
Sublingual=almost completely mucus
What separates the superficial and deep sections of the submandibular gland.and how are they linked together?
They’re separated by the mylohyoid muscle and the Wharton’s Duct links them together.
What is the secretin difference between the superficial and deep submandibular glands?
The outer superficial is mainly mucus acini
The inner deep is mainly serous acini
How are salivary glands stimulated?
The simulation is Nueral only,
Parasympathetic = produce a large volume of watery salami rich in enzymes _rest and digest
Sympathetic = produces a small, thick secretion of saliva rich I mucus_fighr or flight
Describe the parts and functions of the hepatic blood supply.
Hepatic portal vein - arterial blood goes to intestines to become nutrient and toxin rich, then travels to liver to deliver nutrients and toxins, then back to inferior vena cava. This blood is O2 poor.
Hepatic artery- O2 rich blood from aorta and spleen join in hepatic artery
What is the % of oxygenated and deoxygenated blood the liver receives?
25-30% oxygenated from hepatic artery
70-75% deoxygenated from portal vein
What does each liver lobule contiain?
A bile duct and canal A portal venule A hepatic arterial Hepatic sinusoids All linking to a central canal
What is a hepatic sinusoid?
An irregularly shaped tube through which deoxy nutrient rich blood travels to the central canal. Sinusoidal cells have large gaps between them called sinusoids to allow lots of exchange.
What is the function of each lobule’s central canal?
It joined all the other canals and blood supplies in the lobule back up to the hepatic vein ready to send to the heart.
Describe a continuous blood vessel and where it can be found in the body.
A tightly joined endothelial layer (many tight junctions) covered in an enclosed basement membrane. Used in the brain and most of the body.
Describe a Fenestrated blood vessel and where it can be found in the body
It’s endothelial layer contains many tiny holes to allow fast exchange across membrane. Has a continues basement layer acting as a slight barrier. Found in the pituitary, SI, kidney and some endocrine glands.
Describe a sinusoid blood vessel and where it can be found in the body.
Has intracellular gaps and gaps in the basement membrane. Allows large molecules and cells to get through. Newly made cells enter here ie rbc’s and hormones. Found in the spleen, bone marrow, liver and lymph nodes.
Describe the shape and design of a liver lobule.
Hexagonally shaped. Each of the 6 points contains a triad of blood vessels. The sinusoids are sigmoidal (travel in all directions not just laterally)
Describe an unusual characteristic of hepatocytes that Male them easier to identify in histology
They are often bi or tri uncleared (this is because they make a lot of protiens)
What is used to make bile?
Cholesterol
What does the space of disse contain?
It contains serous fluid that allows movement of molecules and cell. Also has many microvilli form basolateral surface of hepacyte cells.
What is unusual about hepatoctye cells membranes?
The apical membrane is one the sides of the cell (opp each other), the basolateral membranes lie on the top and bottom of the membrane and this is where the specialisations are. Not on the apical membrane as normal.
What is a Kupffer cell?
A specialist macrophage that form part of sinosoidal lining. Only called Kupffer cells in liver. Constantly exposed to gut-derived bacteria, microbial debris, cell debris and bacterial endotoxins.
What is the function of a Kupffer cell?
To trap and phagocytise and damaged/aged erythrocytes (rbc’s) missed by the spleen. (Takes over this role entirely if spleen removed)
The material from the erythrocytes is re-used in the liver (bilirubin is one of those materials, hence jaundice in liver failure)
What is a Stellate or Ito cell and what is its function?
A cell full of cytoplasmic vacuoles that contain vitamin A. They act as the bodies vitamin A store.
What happens to ITo cells in liver cirrhosis?
The cells loose their storage capability and differentiate into myofibroblasts (squeeze the fibre then lay down collagen). This is depositing in the perisinusoidal space resulting in liver fibroids.
What are the livers storage functions?
Stores- Iron Vitamins A, B12, D and K (all lipid soluble) Glycogen Copper
What anabolic processes occur in the liver?
Makes over 60% of bodies protiens- Major plasma protiens_ Albumin Enzymes- such as catalase and coagulation factors Lipid carrier protiens Amino acids Haemopoiesis in foetus (week 5-32)
What catabolic reactions take place in the liver?
The liver catabolises Drugs Hormones Heamoglobin (bilirubin passed to gallbladder) Poison Toxins Rbc’s after a splenectomy
What re the other functions of the liver?
Bile production - exocrine
Filter cell debris from blood
Hormones/growth factor- endocrine
Modifies hormones for excretion or functions
What do hepatocytes contain?
Numerous mitochondria Many Peroxisomes Numerous free ribosomes Numerous SER Numerous RER Numerous Golgi complexes Glycogen deposisits
