Glands part 2 Flashcards
Three kinds of adipose tissue:
white adipocyte
beige adipocyte
brown adipocyte
White adipocyte is a
major endocrine receptor
Leptin is a hormone primarily produced by
white adipose tissue in proportion to the size of fat stores.
Leptin actions
Inhibits food intake
Increases energy expenditure
Regulates body fat.
Controls glycaemia (glucose in the
blood).
what is leptin?
A protein hormone made by white adipocytes
leptin maintains a
normal body weight on a long-term basis.
what does leptin regulate?
Regulates glucose and lipid metabolism centrally and peripherally.
what does leptin bind to?
Leptin binds to its specific receptor (LEP-Rb) in the brain
Leptin binds to its specific receptor (LEP-Rb) in the brain.
what next?
LEP-Rb activation and subsequent tyrosin phosphorylation recruits and activates multiple signal transduction pathways
what are the different signal transduction pathways?
STAT transcription factors
SHP2 and ERK signalling
The IRS-protein/PI3Kinase pathway
SH2B1 pathway
The Ob(Lep) gene (Ob for obese, Lep for leptin) is located on
chromosome 7 in humans.
Human leptin is a…
16-kDa protein of 167 amino acids.
what is an adipose tissue?
An endocrine tissue that produces leptin
adipose tissue regulates
appetite
Leptin is encoded by
the ob gene and mutations of this gene lead to obesity.
Leptin resistance can occur both
centrally and peripherally
Glands of the exocrine system release
fluids into the lumen or outside of the body, typically through a duct.
The pancreas has both
endocrine and exocrine functions.
endocrine and exocirine functions od the pancreas?
Endocrine: Insulin and glucagon (hormones) into the bloodstream.
Exocrine: digestive enzymes into the duodenum.
Exocrine glands examples?
Mucous glands
Sweat glands
Oil (sebaceous glands)
Salivary glands
Liver (bile secretion)
Pancreas
(+ many others!)
unicellular glands secrete directly by
exocytosis
multicellular glandds secrete via an…
epithelium walled duct that transports the secretion to the epithelial surface.
in endocrine glands, Hormones are
secreted into the blood
in exocrine glands, cheicals are secreted trhough a
duct
examples of unicellular exocrine glands
Only two important examples (mucous and goblet cells), both of which produce mucin
what is mucin
a complex glycoprotein that once secreted dissolves in water to form mucus (slimy protective coating of the digestive tract).
Epithelial lining of organs such as
the intestinal and respiratory tracts.
In goblet cells, the cuplike accumulation of
mucin distends the top of the cell, making it “goblet shaped”.
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what do holocrine glands accumulate?
accumulate their products within themselves until they rupture. They are replaced by division of underlying cells.
Sebaceous glands of the skin are
the only true representatives of holocrine glands in humans.
- these are highly active during adolescence.
A sebaceous gland that accumulates its products but fails to rupture = ?
= inflammation and infection aka a spot or ‘yellow head’
