79 terms

Chapter 17 - Unit 4

hormones and their actions
steroids, peptides, monoamines
Name the three chemical classes of hormones
steroid hormones
a group of hormones that is formed from cholesterol
peptide hormones
hormone composed of a short chain of amino acids
monoamines (biogenic amines)
___________ are neurotransmitters that are synthesized from amino acids.
sex steroids produced by the testes and ovaries (estrogens, progesterone, testosterone) and corticosteroids produced by the adrenal gland (cortisol, carticosterone, aldosterone, DHEA)
Give examples of steroid hormones - where do they come from?
Posterior pituitary hormones (Oxytocin, antidiuretic); Hypothalamus produces dopamine; most anterior pituitary hormones
Give examples of peptide hormones - where do they come from?
includes neurotransmitters - dopamine, epinephrine, norepinephrine, melatonin, thyroid hormones
Give examples of monoamines - where do they come from?
Dopamine, norepinephrine, and epinephrine -- important in stress response
cholesterol, amino acids, carbohydrate
All hormones are made from either __________ or _____________ with ____________ added in the case of glycoproteins
sex, interrelated
__________ steroids are interrelated in their ________ and have role in both sexes.
___________ hormones are synthesized the same way as any other protein.
a substance that is a precursor to a prohormone, has minimal effect as a hormone itself - it is a newly synthesized polypeptide that is inactive.
a substance that is a precursor to a hormone, usually modified into the hormone's final form in the endoplasmic reticulum
preproinsulin, proinsulin, connecting (C) peptide, insulin
As an example of a preprohormone, insuline, begins as _______________. When the signal peptide is removed and it become ______________. At the end, enzymes remove a large middle portion called the _________ giving us ______________.
T4, T3, target cells, iodine
The thyroid gland secretes mostly __________. A small amount of _______ comes from the thyroid, but most of it is produced in the _____________ by removing ___________ from T4.
T3, T3, T4
__________ is synthesized in small amounts by the binding of an MIT to a DIT. Most ________ is produced in the _____________ and other tissues by removing iodine from circulating _________.
an iodine containing protein that is obtained from the thyroid gland and is the precursor to thyroid hormones (T3, T4)
hydrophobic, hydrophillic
Steroids and thyroid hormones are ____________ and must bind to _______________ transport proteins to get to their destination.
bound hormone, unbound(free) hormone
A hormone attached to a transport protein is called ____________, and one that is not attached is called ______________.
hydrophobic, half-lives
Transport proteins not only enable _________ hormones to travel in the blood, but also prolong their ______________.
transport proteins, blood liver, kidneys
__________ protect circulating hormones from being broken down by enzymes in the __________ and ___________, and from being filtered out of the blood by the _____________.
free hormones
____________ may be broken down or removed from the blood within a few minutes.
albumin, thyretin, thyroxine binding globulin (TBG)
Thyroid hormone binds to 3 transport proteins in the blood plasma - name them:
TBG (thyroxine binding globuline)
Which of the thyroid transport proteins binds the greatest amount?
99, protein bound,
More than ___________% of circulating TH is ____________.
blood reservoir, 2 weeks
Bound TH serves as a long-lasting ___________, so even if the thyroid is surgically removed, no signs of TH deficiency appear for about _________
Steroid hormones bind to globulins such as ____________, the transport protein for cortisol.
aldosterone, albumin
_________________ is unusual, it has no specific transport proteins, but binds weakly to ___________ and others.
85, unbound, 20 minutes
About ____________% of aldosterone remains ___________, and correspondingly, it has a half life of only ___________.
receptors, protein, glycoprotein
Hormones stimulate only those cells that have ______ for them. They are _________ or __________ molecules.
plasma membrane, cytoplasm, nucleus
Hormone receptors are located on the __________, in the __________ or in the _______
switches, metabolic pathways.
The hormone receptors act as _____________ to turn certain ___________ on or off when the hormone binds to them.
a few thousand
A target cell usually has ____________ receptors for a given hormone.
___________ defects lie at the heart of several endocrine diseases.
receptor-hormone, ligands
___________ interactions are similar to enzyme-substrate interactions - but unlike enzymes, receptors do not chemically change their ________
specificity, saturation
Receptor-hormone interactions exhibit enzymelike ________ and __________.
nucleus, genes, steroid hormones
Some hormones enter the target cell ______ and act directly on the ________, changing target cell physiology - such is the case with ________.
activate, inhibit, protein.
To change the target cell physiology, hormones like steroids either ___________ or _________ transcription of the gene for for a metabolic enzyme or other __________.
progesterone, estrogen, progesterone receptors
_____________ has no effect on the uterine lining unless ________ has been there earlier and prepared the way by inducing the synthesis of __________
Laron dwarfism
hereditary defect of teh GH receptors
Androgen insensitivity syndrome
is due to an androgen receptor defect or deficiency - it causes genetic males to develop feminine genitalia and other features.
___________ stimulates the growth of some malignant tumors with these receptors.
95, thyroxine (T4), metabolic
_______% of the TH secreted by teh thyroid gland is ______________, yet it has very little __________ effect.
sodium-potassium pump
One of the genes activated by T3 is the _____________.
beta-adrenergic, myosin, heartbeat
T3 also activates the transcription of genes for ___________ receptors and is a component of the muscle protein ___________, thus enhancing responsiveness of cells such as cardiac muscle to sympathetic stimulation and incrasing the strength of the _____________
steroid, thyroid
______________ and __________ hormones typically require several hours to days to show an effect.
genetic transcription, translation, protein product, metabolism
The lag effect of the steroid and thyroid hormone is due to the time required for _____, ________ and accumulation of enough__________ to have a significant effect on the target cell _________.
peptides, catecholamines, indirectly
__________ and _________ are hydrophilic and cannot penetrate into a target cell, so they must stimulate its physiology ________.
cAMP (cyclic adenosine monophosphate)
The best known second messenger system is _____________
__________ inhibits cAMP synthesis.
second messengers, phosphodiesterase
__________ do not linger in the cell for long, for example - cAMP is boken down very quickly by an enzyme called_______ and the hormal effect is therefore short-lived.
cGMP (cyclic guanosine monophosphate), DAG (diacyclglyceral), IP3 (inositol triphosphate)
cAMP is the best known second messenger system, but there are others - name a few:
hydrophilic, metabolic action
The general idea of second messengers is that _____________ hormones cannot enter the target cell - but by binding to a receptor, they can create a flurry of _________ within the cell
quick, OT (oxytocin)
Hormonal effects mediated through surface receptors tend to be relatively _______, for example _______.
same, IP3, cAMP
A given hormone doesn't always involve the ____ 2nd messenger. ADH (antidiuretic hormone) employs _______ in smooth muscle, but _______- in the kidney tubules.
Hormones are very _________ chemicals
enzyme amplification (cascade effect)
Through a mechanism called _____, one hormone can trigger the synthesis of not just one enzyme molecule, but an enormous amount.
sensitivity, receptors
Target cells can adjust their _________ to a hormone, but changing the number of __________
a cell increases the number of hormone receptors and becomes more sentitive to the hormone
a cell reduces its receptor population and thus becomes less sensitive to a hormone.
In late pregnancy, the uterus produces oxytocin receptors, preparing for the surge of oxytocin that will occur during childbirth - this is an example of________
This sometimes happens as a response to a long term exposure to a high hormone concentration, such as the adipocytes exposed to high concentrations of insulin and cells of the testes ________ in response to high concentrations of LH
pharmalogical doses, undesirable
Hormone therapy often involves long-term use of abnormally high _______________ of hormone, which may have _________ side effects,
bone metabolism
Long term treatment of inflammation with hydrocortisone, has undesirable effects on ______
mimic, convert
Undesirable effects of long term hormone treatment occurs for 2 reasons -- excess hormone may bind to receptor sites for other related hormones and __________ their effects; or a target cell might __________ one hormone to another
more than one
Most cells have ___________ receptors
synergistic, permissive, antagonistic
Hormones may have 3 kinds of interactive effects:
synergistic effect
two or more hormones act together to produce an effect that is greater than the sum of their separate effects
permissive effect
one hormone enhances the target organ's response to a second hormone that is secreted
antagonistic effect
one hormone opposes the action of another
synergistic effect
Neither FSH nor testosterone alone can stimulate significant sperm production - but when they act together, they produce some 300K sperm per minute - this is an example of:
permissive effect
Estrogen stimulates the up-regulation of progesterone receptors in the uterus - without being primed, the uterus would respond poorly to progesterone. Estrogen thus has a ______ on progesterone action
antagonistic effect
Insulin lowers blood glucose level and glucagon raises it - this is an example of:
hormone signals, liver, kidneys, bile, urine
____________ must be turned off when they have served their purpose. Most hormones are taken up and degraded by the _____ and ________ and then excreted into the __________ and _______.
target cells
Some hormones are degraded by their __________.
transport proteins
Hormones that bind to ______________ are removed from the blood much more slowly than hormones that do not.
MCR (metabolic clearance rate)
the rate of hormone removal is called
the length of time required to clear 50% of the hormone from the blood is called the
The faster the ________, the slower the half-life.