EX 2; Endocrinology Flashcards
What is the main route of communication in the endocrine system
chemical signals (hormones) released into blood
What are two factors affecting onset and duration of signal effects
the response can be delayed; time for the blood to travel
the duration is prolonged; some hormones stay in blood
This part of the endocrine system releases hormones directly into the blood of ECF
endocrine glands
The endocrine glands for an organ system without what
physical links; hormone connection
What are the three steps in hormone travel
release
in the blood
reaching the target
The specificity of target cells is due to what
receptors on the target cells
This is any organ or tissue that secretes something; ducts (exocrine)
gland
Most hormones are made of this structure
peptides
True or False
Only very small peptides are hormones
False; thy can vary in size, from small to very larg
These are sugar residues attached to backbone, helping to protect the hormone from degradation, and to enhance specificity
glycosylations
Some peptide hormones function as neurotransmitters, what is the main difference between them
where it is released; the blood or a synapse
This is the first thing synthesized in peptide hormone synthesis it comes off of ribosomes
preprohormone
contains lots of aa’s and gets folded
This step in peptide hormone synthesis is to the RER, then off to golgi, then to secretary vesicles
prohormone
Cleavage of he pro-part (aa’s) of a pro-hormone, leads to this, that is stored in vesicles
hormones
What two things are released from the vesicles
pro fragments and hormones
the pro-hormone is cleaved to the pro fragments and hormone in the secretory vesicles
What three things are important in the packaging and storing of peptide hormones
allows a cell to store until its needed
helps regulate cell itself
prevents degradation
What are some of the glandular source of lipid hormones (steroids)
gonads
outer adrenal cortex
placenta
some brain cells
All steroids are derived from what by a series of enzymatic reactions
cholesterol
Some cholesterol needed for the membrane is produced via which method
de novo synthesis
Most cholesterol is derived from what
low density lipoproteins; LDL is up-taken by a cell via LDL receptor to an endosome where it is broken down to a cholesterol ester
This type of cell stores cholesterol esters; looks like an adipocyte
steridogenic cells
These determines which stereoid is produced
enzymes
Steroid hormone synthesis is typical stimulated by what
peptide hormones from other glands
This frees cholesterol from stores
cholesterol esterases; PKA phosphorylates cholesterol esterases to free cholesterol
This protein facilitates intracellular transport of cholesterol (to mitochondria)
steroid acute regulatory protein (StAR)
Steroids are not stored why?
they are lipid soluble; they will diffuse out of the membrane to intracellular fluid
What three things regulate steroids
enzymes
regulate peptide hormone stimulating steroidogenesis
increases cell division of steroid producing cells
Most steroid biosynthesis enzymatic reactions are what
uni-directional
What are the five different molecules along the steroid biosynthesis pathway
cholesterol –> progestagens –> corticosteroids or androgens –> estrogens
Amine hormones are all derived from which amino acid
tyrosine
What are the two hormones that are synthesized in the thyroid
thriiodothyronine (T3)
thyroxine (T4)
Thyroid hormones are steroid-like with respect to what two things
solubility and receptors
Catecholamines are synthesized in which two areas
adrenal gland
hypothalamus
What are three examples of catecholamines
norepinephrine
epinephrine
dopamine