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7. Endocrine System I
N/A
107
Physiology
Undergraduate 2
09/27/2012

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Term
What is the endocrine system?
Definition
it is an integrated system of small organs that involves the release of extracellular signaling molecules known as hormones
Term
What are hormones?
Definition
extracellular signaling molecules
Term
What are the the five main things that the endocrine system regulates?
Definition
metabolism, growth, development and puberty, tissue function, and mood
Term
What is endocrinology?
Definition
the field of medicine that deals with disorders of endocrine glands; a branch of the wider field of internal medicine
Term
What are exocrine glands?
Definition
glands that secrete their products into ducts
Term
What are endocrine glands?
Definition
ductless glands that secrete their products directly into the bloodstream or release hormones that affect cells nearby (paracrine signaling)
Term
What are some examples of exocrine glands?
Definition
salivary, mammary, stomach, liver, pancreas, and sweat
Term
What are the seven major endocrine glands in vertebrates?
Definition
pineal gland, pituitary gland, thyroid gland, thymus, adrenal gland, pancreas, and testis/ovaries
Term
What two organs control the rest of the endocrine glands?
Definition
the hypothalamus and the pituitary gland
Term
How many parathyroids are there?
Definition
 four
Term
The pancreas is also a(n) _____________.
Definition
exocrine gland
Term
What are the targets of hormones that are secretd by endocrine glands?
Definition
organs with appropriate receptors
Term
What are the four chemical groups used to classify hormones?
Definition
steroids, proteins and peptides, amines, and fatty acids
Term
What does the word peptide mean?
Definition
 short protein
Term
What are the four types of signaling?
Definition
endocrine, juxtacrine, autocrine, and paracrine
Term
What happens in autocrine signaling?
Definition
the target cell is the same cell
Term
What happens in paracrine signaling?
Definition
the target cell is nearby
Term
What happens in juxtacrine signaling?
Definition

Juxtacrine signals are transmitted along cell

membranes via protein or lipid components integral to the

membrane and are capable of affecting either the emitting

cell or cells immediately adjacent.

Term
A single endocrine gland may produce _________ hormones.
Definition
multiple
Term
How many hormones does the anterior pituitary produce?
Definition
six
Term
A single hormone may be secreted by ________ endocrine glands.
Definition
more than one
Term
Does each hormone only have a single type of target cell?
Definition
no
Term
A single hormone can induce more than one _______. Give an example.
Definition
effect; insulin and glucagon in the liver
Term
The _____________ of some hormones varies over the course of time.
Definition
secretion rate
Term
The same chemical messenger may be a _________ or _________.
Definition
hormone, neurotransmitter
Term
What are the three types of hormones?
Definition
peptides, amines and steroids
Term
What are the two types of amines?
Definition
catecholamines and thyroid hormone
Term
What is the structure of peptides like?
Definition
chains of specific amino acids
Term
What is the primary characteristic of amines?
Definition
they are derived from the amino acid tyrosine
Term
What is the structure of catecholamines like?
Definition
tyrosine derivitive
Term
What is the structure of thyroid hormone like?
Definition
iodinated tyrosine derivitive
Term
What is the structure of steroids like?
Definition
cholesterol derivitive
Term
Are peptides hydrophobic or hydrophilic?
Definition
hydrophilic
Term
Are catecholamines hydrophobic or hydrophilic?
Definition
hydrophilic
Term
Is thyroid hormone hydrophobic or hydrophilic?
Definition
hydrophobic
Term
Are steroids hydrophobic or hydrophilic?
Definition
hydrophobic
Term
Being hydrophobic is the same as being ________.
Definition
lipophilic
Term
How are peptides secreted?
Definition
exocytosis
Term
How are catecholamines secreted?
Definition
exocytosis
Term
How are steroids secreted?
Definition
simple diffusion
Term
Where is the receptor site for peptides?
Definition
on the surface of the target cell
Term
Where is the receptor site for catecholamines?
Definition
on the surface of the target cell
Term
Where are the receptor sites for thyroid hormone?
Definition
inside the target cell
Term
Where are the receptor sites for steroids?
Definition
inside the target cell
Term
What are the six main steroid hormones?
Definition
testosterone, estrogen, aldosterone, progesterone, cortisol, and corticosterone
Term
Steroid hormones are derived from _________ by a ____________.
Definition
cholesterol; biochemical reaction series
Term
What is cholesterol synthesized from? What are they formed by?
Definition
low-density lipoproteins; lysosomal proteins
Term
How is unused cholesterol stored?
Definition
it is chemically modified and stored in a large amount as lipid droplets within steroidogenic cells
Term
What are steroidogenic cells?
Definition
steroid synthesizing cells
Term
What are most hormones classified as?
Definition
peptides
Term
What six organs secrete peptides?
Definition
pituitary, parathyroid, heart, stomach, liver and kidneys
Term
What two organs secrete amines?
Definition
the thyroid and adrenal medulla
Term
What are the large precursor proteins of peptides called?
Definition
preprohormones
Term
Where are preprohormones produced?
Definition
ribosomes in the rough ER
Term
After being produced in the ER, where do preprohormones go?
Definition
the golgi complex
Term
What happens to the preprohormone at the Golgi complex?
Definition
it is turned into prohormone and then is finally turned into the final active form
Term
After the preprohormone is turned into its final active form, what happens?
Definition
the final product is concentrated and then packaged into secretory vesicles
Term
What are some of the peptide and amine hormones?
Definition
FSH, LH, TSH, growth hormone, insulin, glucagon, vasopressin, oxytocin, PTH, renin, prolactin, epinephrine, and norepinephrine
Term
What are the two forms of catecholamines?
Definition
 epinephrine and norepinephrine
Term
Why are prostglandins called prostaglandins?
Definition
because they were first found in the prostate
Term
How many prostaglandins are there?
Definition
20 or more
Term
What are prostaglandins synthesized from? Be specific.
Definition
fatty acid; arachidonic acid
Term
Why are prostaglandins considered a hormone?
Definition
 because of their role in managing reproduction
Term
What kind of effect do prostaglandins have? Why?
Definition
It has a major effect locally because it is short-lived in the bloodstream
Term
What do prostanglandins cause? How are they inhibited?
Definition
inflammation; aspirin
Term
What do prostaglandins inhibit?
Definition
gastric secretions
Term
How are water soluble hormones transported?
Definition
dissolved in the plasma
Term
How are fat soluble proteins transported?
Definition
bound to plasma proteins
Term
What are plasma proteins?
Definition
carrier proteins
Term
What can mimic the effects of native hormones?
Definition
endocrine disrupting chemicals
Term
What are some examples of endocrine disrupting chemicals?
Definition
dioxins, PCBs, phenolics, and pesticides
Term
How do hormones produce their effects and through what?
Definition
they alter intracellular proteins through ion fluxes, second messengers, and transcription factors
Term
Do hydrophobic and hyrdrophilic preteins produce their effects in the same way?
Definition
yes
Term
How do lipophilic proteins stimulate synthesis of new hormones?
Definition
by stimulating genes
Term
Hormone actions are greatly _______ at the target cell.
Definition
amplified
Term
What is a common second messenger in a second messenger pathway?
Definition
cyclic AMP
Term
How is the concentration of hormones in the plasma regulated?
Definition
changes in the rate of secretion
Term
diagram 26
Definition
Term
How does the concentration of plasma in the blood change throughout the day?
Definition
it peaks in the morning at about six and then decreases throughout the day until midnight and then it starts to increase again
Term
What is cortisol related to?
Definition
stress
Term
What is the function of ghrelin?
Definition
it causes the feeling of hunger
Term
How does the plasma concentration of ghrelin change throughout the day?
Definition
it peaks at breakfast, linch, dinner, and at midnight
Term
How does the plasma concentration of growth hormone change throughout the day?
Definition
it peaks throughout the night but stays low during the day
Term
How can the growth of teens who stay up late be affected?
Definition
they may have stunted growth because they will not have a growth hormone peak at night
Term
What three things can influence effective plasma concentration of a hormone?
Definition
the hormone's transport, secretion, and metabolism
Term
What is the major site for metabolic hormonal activation?
Definition
the liver
Term
How are inactivated hormones released from the body?
Definition
urination
Term
Are hydrophobic or hydrophilic hormones secreted faster?
Definition
hydrophilic
Term
Why are hydrophobic hormones secreted slower?
Definition
because they are bound to plasma proteins
Term
How can the responsiveness of target cell to its hormone be varied?
Definition
this can be done by regulating the number of its hormone specific receptors
Term
What is downregulation? What machanism controls it?
Definition
a high level of hormone is controlled by downregulation of receptors by internalization followed by degradation, causing low receptor concentration by nagative feedback machanism
Term
What are the three types of hormone to hormone interaction?
Definition
permissiveness, synergism, and antagonism
Term
What is permissiveness?
Definition
it is when one hormone is needed for another hormone's effect
Term
What is synergism?
Definition
the action of several hormones' combined effect is greater than separate effects
Term
What is antagonism?
Definition
the presence of one hormone looses the other hormone's receptor. It essentially causes the receptor to hide.
Term
What three things do endocrine excess cause?
Definition
hormonal excess, deficiency, or decreased responsiveness to target cells
Term
What are the two main types of endocrine disorders with regrads to secretion? 
Definition
hyposecretion and hypersecretion
Term
What is hyposecretion?
Definition
secretion of too little hormone
Term
What is hypersecretion?
Definition
secretion of too much hormone
Term
What is primary hyposecretion?
Definition
its when an abnormal gland secretes too little
Term
What is secondary hyposecretion?
Definition
deficiency of tropic hormone
Term
What is genetic hyposecretion?
Definition
inborn absence of an enzyme to catalyze a hormone. In other words, there is no enzyme to change the preprohormone into an active hormone
Term
What is dietary hyposecretion?
Definition
a lack of a precursor or component in the diet that is part of the hormone
Term
What is chemical or toxic hyposecretion?
Definition
it is when chemicals or toxins destroy the gland
Term
What is immunological hyposecretion?
Definition
it is when an autoimmune antibody self destroys the gland
Term
What can hypersecretion contribute to?
Definition
tumors and immunological factors
Term
What makes good cholestorl good and bad cholesterol bad?
Definition
good cholesterol leaves the body while bad cholesterol gets deposited in the body
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