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61 Cards in this Set

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hormone signaling acts by ... distance
long
which of the following second messengers also can serve as a primary messenger?
-cAMP
-cGMP
-NO
NO
what is this called?
-conversion of an extracellular signal or environmental stimuli from one physical/chemical form into another. Or more simply, the process by which a cell responds to an extracellular signal and affects change in the behavior of that cell
signal transduction
Signal transduction is important in ...genesis, reacting to your ..., simple cellular ..., and in pathologies
embryo
environment
maintenance
... are physical, chemical, or molecular in nature and can cause cells to respond in a multitude of ways (cell shape, metabolism, proliferation, movement, expression, apoptosis)
external signals
One signal binds to ... receptor; binding can result in a ... of effects
one
multitude
what is the first step in which a signal molecule is transformed or transduced into a usable form to stimulate a response? (signal binding can occur to extracellular or intracellular receptor)
primary transduction
what is this?
-series of events in which message is passed from one molecule to another
-cascades of intracellular signaling molecules (...)
-formation of second messengers
relay
signaling cascade
often during the signaling cascade the message is ... allowing for a larger and faster intracellular response.
amplified
-the signaling cascade can be ... along several different pathways at the same time.
-this distribution allows for a ... of the signal so that it may be relayed to a number of different intracellular targets (change in gene expression, change in cell shape)
distributed
divergence
each step of the signaling cascade is ... by other factors (external signals and/or second messengers)
modulated
... pathway very in complexity; simple and direct to extreme and complex branching
signaling
the 4 steps in which a message is passed from one molecule to another are...
1)primary transduction
2)relay
3)amplification
4)distribution/divergence
Flow of info during cell signaling:
-the ligand which is the primary messenger, hormone or growth factor, binds to a receptor located in the ...
plasma membrane
Flow of info during cell signaling:

-The binding causes a ... that in turn activates a secondary messenger (small molecules or ions that transmit signals from extracellular signals to the cell interior) that initiates a cascade of events in the interior of the cell
conformational change
Flow of info during cell signaling:
-... response: the secondary messenger will in some cases alter protein function that leads to a change in the cellular response (activation or inhibition of various pathways)
fast
Flow of info during cell signaling:
-... response: the secondary messenger may also impact gene expression
slow
The major players:
-extracellular or ... signals
-signal transduction ...
-variety of ... and ... enzymes (specific to the signaling pathway)
-... (molecules that are produced in the cytoplasm and move within the cell to induce another series of signaling)
primary
receptors
membrane-bound
cytoplasmic
second messengers
signaling can occur in what 3 ways?
long distance
locally
direct contact
Long distance hormones:
-chemical messengers that are distributed throughout the body
-produced by either ... or ... cells and secreted into body fluid; carried throughout the body in the ...
-act on a target cell that expresses a protein receptor ... for the hormone
-necessary in ... quantities (very effective in small amounts)
-usually regulated by hormone that is ... in nature (insulin and glucagon)
endocrine
neurosecretory
bloodstream
specific
minute
antagonistic
Local hormones: (1st type) = ... signals - local mediators

-signal molecules secreted by cells into its surrounding ... fluid
-affects target cells in the ... of the cell that secretes molecules
-local mediators include ... factors, cytokines and ...
-some cells can express receptors for the signal itself (... signaling). They self stimulate. Is common in immune system
paracrine
interstitial
neighborhood
growth
eicosanoids
autocrine
Local hormones: (2nd type) = synaptic signaling - ...

-release of these molecules into the synapse between a neuron and its target cell (neuron, muscle, etc.)
neurotransmitters
direct contact hormones:

-... of membranes
-no release of ... molecule involved
-... bound signal
-delivery of message when signal molecule in one cell membrane binds receptor molecule in another cell membrane
-... development
interface
secreted
membrane
embryonic
what are the 2 categories of signal transduction receptors?
intracellular receptors
cell-surface receptors
intracellular receptors:
-bind ... (lipids) signal molecules; tend to be ...
-... molecules readily translocate across lipid bilayers
-found in ... and ...
hydrophobic
small
hydrophobic
cytoplasm
nucleus
cell surface receptors:

-bind large ... signal molecules which are unable to cross cell membrane
-signal molecules bind to extracellular domains of receptor; receptor in turn generates ... signals
hydrophilic
intracellular
2 classes of receptors that bind either lipid soluble ligands or gases:

-cytoplasmic ... - change in gene expression

-cytoplasmic ... - produces second messenger cGMP
steroid receptor
guanylyl cyclase
which signal transduction receptor produces a trimeric G-protein?
seven-helix
which signal transduction receptor produces tyrosine phosphorylation?
receptor tyrosine kinase
the remaining cell surface receptors are:

-transmembrane
-bind ... soluble molecules: amines, peptides, proteins, glycoproteins
-effectors vary depending on ...
water
receptor
The number of different types of receptors is much (less than/greater than) the number of extracellular signals that act on them.

In other words, one signal molecule may act on a ... of different receptors
greater than

variety
what is this?
-a neurotransmitter
-acts as a vasodilator and as a vasoconstrictor - acts in 2 opposing ways
acetylcholine
acetylcholine binds to a variety of receptors:

1. Ligand-gated ion channels (... acetycholine receptor)

2. G-linked protein receptor (... acetylcholine receptor) - activate other ionic channels via second messenger cascade
nicotinic
muscarinic
side note:

Foreign substances target the various cell-surface receptors and interfere with normal physiology and sensations. These substances either ... the ligand and bind to the receptor or bind to the receptor at ... site, blocking or overstimulating the receptor's normal activity.
-it acts to ... the natural signal
mimic
another
mimic
in the heart muscle cell, acetylcholine acts as a ... and decreases the rate and force of contraction
vasodilator
in the salivary gland cell, acetylcholine binds to the receptor protein and causes ...
secretion
in the skeletal muscle cell, acetycholine acts as a ... and induces contraction
vasoconstrictor
acetylcholine is also a major player in the regulation of ...
blood pressure
what are small molecules formed in or released into the cytoplasm in response to an extracellular signal that helps relay the signal to the interior of the cell?
second messengers
what are the 4 categories of second messenger?
cyclic nucleotides
lipid-derived 2nd messengers
calcium (Ca2+)
nitric oxide
cyclic nucleotides:
-two cyclic nucleosides monophosphates - ... and ...
-cyclic nucleosides synthesized by cyclases from either ... or ...
-targets include protein kinase and cyclic nucleotide-gated ion channels
cGMP and cAMP
GTP or ATP
lipid derived second messengers:

-variety of lipid second messengers; concentrate on inositol 1,4,5-triphosphate (...), diacylglycerol (...), and arachidonate/eicosanoids, which are derived from lipids in membrane (...)
-primary sources of signaling molecules are phosphatidylinositol, phosphatidylcholine, and ...
-types of enzymes that generate lipid second messengers: phospholipases, lipid kinases, and lipid ...
-produced by most signaling pathways
[IP3]
DAG
PIP2
sphingomyelin
phosphatases
Calcium (Ca2+):

-cytoplasmic concentration dependent on opening/closing of ion channels that release ion from ... and pumps that remove ion from ...
-liberated from ... stores
stores
cytoplasm
SER
nitric oxide:

-unique means of transmitting ...
signal
steroid and thyroid hormones:

-steroid hormones are synthesized from ... (adrenal glands, testis, ovaries and placenta)
-thyroid hormones derived from ... (thyroid gland)
cholesterol
tyrosine
both steroid and thyroid hormones are ... signal molecules:

-readily pass through lipid membranes of target cells
-bind to hormone receptors located either in the cytoplasm or the ...
-hormone receptors regulate gene expression; normally present in ... form
-binding of hormone causes ... change leading to activation of receptor
-transcription of a set of genes either turned ON/OFF
hydrophobic
nucleus
inactive
conformational
steroid thyroid hormone NOTE:

There is no generation of a ... cascade or the formation of a ...

Each hormone will bind a different receptor in turn regulating a different set of ...; this evokes a variety of physiological responses specific for the hormone
signaling
second messenger

genes
acetylcholine causes relaxation of smooth muscle of blood vessels through the action of ...

-NO is indirectly produced by acetylcholine binding
nitric oxide (NO)
acetylcholine:

-is produced and secreted by ... cells
-binds (G-protein) receptor on endothelium and activates NO synthase, via the second messenger Ca2+, that converts arginine to NO and ...
neurosecretory
citrulline
Nitric oxide is dissolved gas produced by ... cells surrounding smooth muscle cells
endothelial
Nitric oxide:

-acts as a local mediator (... signaling)
-produced as a second messenger by endothelial cells
-formed by the action of ... that converts arginine into citrulline and NO
-NO diffuses to ... smooth muscle
-in smooth muscle, NO will activate Guanynyl cyclase which converts GTP to ...(second messenger)
paracrine
NO synthase
neighboring
cGMP
cGMP acts as a second messenger triggering the next series of activations in the cell that leads to the cellular change:
-cGMP ...
-cGMP-...
protein kinase
gated ion channels
NO is quickly converted into nitrates and ...
nitrites
cGMP is very similar in structure to another second messenger, ...
cAMP
cGMP:

-produced by activation of cytoplasmic guanylyl cyclase by ...
-targets cGMP-protein kinase that triggers a series of events that leads to the cytoskeletal rearrangements physiological changes necessary for ... of the cell
NO
relaxation
nitroglycerine and viagra (do/do not) mix
DO NOT
nitroglycerine (non-specific)
-used as a coronary artery ..., but is non specific and causes hypotension
-rapidly converted to NO and in turn to cGMP
vasodilator
Viagra (cialis and levitra-extended action):

-erectile dysfunction
-enhancement of penile erection by blocking ... of cGMP to 5'-GMP y cGMP phosphodiesterase
degredation
-NO is released by nerve terminal in the penis triggering localized blood-vessel ... leading to penile erection

-use of erectile dysfunction drug in association with nitroglycerin has been shown to cause ..., not responsive to fluid administration or vasopressors (antidiuretics which also increase peripheral vascular resistance leading to blood shunting via vasoconstriction)
dilation
intractable hypotension
Cell surface receptors: G-protein linked receptors:

-activate membrane bound G proteins (trimeric GTP-binding protein or G protein)
-... initiated through second messengers
signaling cascade
Cell-surface receptors: Enzyme-linked receptors:

-when activated, either act as ... or rely on associated enzymes for action
-enzymatic activity generates ...
enzymes
second messengers