Introduction to the Endocrine System Flashcards
Chemicals that act locally at the site of synthesis (do not travel to distant sites) are….
paracrine
chemicals that act on the same cell that synthesises the hormone (eg cytokines) are……
autocrine
chemical that are released from exocrine glands via ducts to the external environment are …..
exocrine
neuro hormones are released from…… and then they enter blood and travel to their target cells
nerves
insulin acts on the liver and increases…. and decreases…..
glycogenesis
gluconeogenesis
cells that secrete chemical that bind to receptors on the same cell act in response to …….. signals
autocrine
Chemicals diffuse in ECF to affect the neighbouring cells are in response to …… signals
paracrine
endocrine hormones have their action terminated - often via…. ….. ….
negative feedback loops
peptide (or protein) hormones are composed of
chains of amino acids
these are the most common type of hormone
Amine hormones are derived from
one of 2 amino acids
what are the 2 amino acids that amine hormones come from?
tyrosine and tryptophan
Steroid hormones are derived from
cholesterol
3 examples of peptide hormones
FSH
TRH
insulin
Peptide hormones are synthesised as
preprohormones
then prohormones that are kept in vesicles til use
Measuring inactive fragments in plasma can be useful clinically - give an example used in diabetes
C-peptide
what is C-peptide?
the inactive fragment from the insulin prohormone
levels of C-peptide are used to measure
endogenous insulin production from the pancreas
peptide hormones are water soluble so dissolved easily in …..
plasma
making transport via the blood simple and easy
generally - peptide hormones binding to receptors generally create …… biological responses
fast
most peptide hormones work via modulating what two signalling pathways?
GPCR
tyrosine kinase linked signalling pathways
therefore hydrophilic or lipophilic peptides bind to cell surface receptors that are either
GPCR
or
Tyrosine Kinase Linked Receptor
G-protein coupled receptor binding is a …… response
rapid
GPCR activates 2nd messenger and/or ion channels leading to
modification of existing proteins
Tyrosine kinase linked receptor alters
gene expression
tyrosine kinase linked receptor binding is a ……. response
slower/ longer lasting
amine hormones are mostly derived from what AA?
tyrosine
unlike other hormones, steroid hormones are synthesised directly as needed, rather than being
stored and released
What gland secretes oxytocin and vasopressin?
posterior pituitary
GH is also known as
somatotropin
what hormones does the anterior pituitary release?
prolactin
FSH
LH
TSH
ACTH
GH
what organ does GH act on?
liver
What does ACTH act on?
adrenal cortex
What does the parathyroid hormone do?
acts on the bone and kidney
regulates calcium and phosphate levels in the plasma
What hormone does the liver produce?
Insulin like growth factor 1
What are the 3 main hormones secreted from the pancreas?
insulin
glucagon
somatostatin (GHIH)
What are the two hormones secreted from the adrenal cortex?
aldosterone
cortisol
What does cortisol regulate?
stress
What does aldosterone regulate? where?
Na+ and K+ homeostasis
in the kidneys
What hormones are produced in the adrenal medulla?
epinephrine
norepinephrine
What hormone does the kidney produce?
what is its purpose?
erythropoietin
RBC production
