Lecture 9 - Glands 2 Flashcards
What is the function of a myoeptihelial cell?
Cell that has contractile function which helps squeeze out secretions from the duct
How does a goblet cell appear in a H&E stain?
No stain so white
How do goblet cells satin with Periodic acids schiff stain?
Purple/dark pink
Stains the glycoproteins (MUCIN)
What type of gland are the Parotid glands?
Exocrine gland
Serous gland
What is a serous gland?
A gland which produces a watery secretion
Where are the parotid glands located?
Near the ear
How do the parotid glands appear with periodic acid schiff stain?
Very purple (make lots of proteins/enzymes)
What type of cells are the acini in the parotid glands?
Simple columnar epithelium
What is a striated duct?
Duct lined with simple columnar epithelial cells whos cytoplasm have a striated appearance
What is the function of the striated duct?
PREVENTS WATER LOSS
so modify the saliva/consistency of the watery secretion
What type of secretion is released from the parotid gland?
Mainly serous
Where are the submandibular glands located?
Underneath the jaw
What sort of secretion do the submandibular glands produce?
Thick mucus saliva and thin enzyme saliva
More mucus secretion than Serous secretion
What type of secretion do the sublingual glands produce?
Almost all mucous
What are the 3 main salivary glands?
Parotid glands
Submandibular gland
Sublingual gland
How does the way a histological image look change the more mucus it secretes?
More mucus = more goblet cells
More goblet cells = less stain retained with H&E
What type of control is salivary secretion under?
ONLY Neural control
How does the parasympathetic nervous system stimulate salivary secretion?
Stimulates large volume of water saliva rich n enzymes (SEROUS SECRETION)
How does the sympathetic nervous system stimulate saliva secretion?
Produces a small , thick secretion of saliva rich in mucus (MUCOUS secretion)
What is the largest exocrine gland in the body?
Liver
What is citus inversus?
What causes it?
Organs in the abdomen are on opposite sides to normal
Due to cilia in embryonic development not orientating organs properly
What is the hepatic portal system?
First capillary network in stomach and intestine
Second capillary network in the liver
What blood vessels supply the liver?
Hepatic portal vein supplies blood with nutrients and toxins to the second capillary bed (sinusoids)
Hepatic artery supplies oxygenated blood to liver sinusoids
What is the shape of a liver lobule?
Hexagonal 6 sided
What is located at every node of the liver lobule (6 corners)
Portal triad
What 3 vessels are found in the portal triads?
Hepatic portal vein
Hepatic artery
Bile duct
What is located in the centre of each liver lobule?
Central hepatic vein
What is the function of the central hepatic vein in the liver lobules?
They drain blood from the liver and join up to the inferior vena cava
What is the relationship between the hepatic artery and the hepatic portal vein?
The join together to form tubes called sinusoids causing deoxygenated blood rich in nutrients and toxins from the hepatic portal vein to mix with oxygenated blood from the hepatic artery
What is a sinusoid?
An irregularly shaped tube which blood passes through that has large gaps between it’s cells
What is the function of the sinusoids in the liver?
Allow the substances in the blood in the liver to reach the hepatocytes
What are the 3 types of capillary vessel?
Continuous
Fenestrated
Sinusoid
What is a continuous capillary vessel?
Made up of an endothelial layer with cells held together by many adherence systems like tight junctions and desmosomes.
Surrounded by basement membrane
Where are continuous capillary vessels normally found?
Brain/most of body
What is a fenestrated capillary vessel?
Vessels which have fenestrations, (gaps between endothelial cells) allowing for some filtration
Surrounded by basement membrane
Where are fenestrated capillary vessels found?
Pituitary/small intestine/kidneys/some endocrine glands
What are sinusoids?
Vessels that have large gaps between cells and an incomplete basement membrane
This allows whole cells through
Where are sinusoids found?
Liver
Spleen
Bone marrow
Lymph nodes
What colour is the bile duct with H&E stain?
Very purple
How many nuclei can hepatocytes have?
2 or 3
Bi or tri-nucleated
What is the adaptation of having multiple nuclei to a hepatocyte?
Helps make lots of protein (multiple nucleolus’s)
What other adaptations do hepatocytes have for their role?
Abundant endoplasmic reticulum
Prominent and numerous Golgi apparatus
Lots of mitochondria
Lots of free ribosomes
Microvilli (LARGE SA)
Glycogen deposits
Lots of peroxisomes
How does the flow of bile relate to the flow fo blood through the sinusoids?
Counter current system
Opposite directions
How are bile ducts formed?
Bile canaliculi join to form
Bile ductules
Bile ductules join to form bile ducts forming the left andlight hepatic bile ducts
What is a Kupffer cell?
Macrophages residing in the sinusoidal lining of the liver
What is the function of Kupffer cells?
Ingest and phagocytose pathogens
Recycle old erythrocytes missed by spleen
What is the life cycle of a red blood cell?
120 days
Under what circumstances does the livers Kupffer cells become the main remover of 120 day old erythrocytes?
After a splenectomy
What is a Stellate/Ito cell?
They are storage cells of the liver
What is the function of stellate/Ito cells in the liver?
Store Vitamin A
Contain many cytoplasmic vacuoles
How do Stellate/Ito cells change in liver cirrhosis?
Lose their ability to store Vitamin A
They differentiate into myofibroblasts which deposit collagen
Causes liver fibrosis by depositing in perisinusoidal space
What are peroxisomes?
Organelles full of oxidising agents
Which cells in the liver have regenerative ability?
Hepatocytes
What does liver regeneration depend on?
The extent of the damage
What are the major functions of the liver?
Storage
Anabolism
Catabolism
Modification of hormones
Endocrine function (hormone production Thrombopoietin Angiotensinogen IGF1)
Bile production
What is the function of bile?
Emulsifies fat and helps Vitamin K absorption from small intestine
What is the livers main constitutive exocrine secretion?
Bile
Where is bile stored?
The Gall bladder
What is the livers main constitutive endocrine secretion?
Albumin
What is the livers main regulated endocrine secretion?
IGF-1
What is the name of the liver cell which carries out both its endocrine and exocrine function?
Hepatocyte
What is the blood supply to the liver?
Hepatic artery and heart supplies oxygenated blood
