Term
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Definition
| Channels fromed between two cells, by proteins called connexins (which form connexons) |
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Term
| Gap Junctions - metabolic |
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Definition
direct metabolic coupling
EX: bone cells that are far from the bloodstream hav egap junction connections with cells closer to the bloodstream, to keep those more distant cells alive |
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Term
| Gap junctions - electrical |
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Definition
allow for direct electrical coupling
because ions can go through gap junctions, a change in membrane voltage (Vm) can be propagated from one cell to another through gap junctions
EX: muscle cell in the heart contract together Smoothe muscle cells in the intestines contract in groups because of gap junctions |
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Term
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Definition
| communcation through chemical messengers occurs when one cell releases a chemical into the interstitial fluid - secretion |
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Term
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Definition
| chemical messengers - molecules that bind to proteins reversibly |
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Term
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Definition
| 1) paracrines 2) autocrines 3) neurotransmiters 4) hormones |
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Term
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Definition
travel by diffusion
act on neighboring cells
crucial roles in developement, blood clotting, an immune system
include groups of signals called growth and clotting factors, cytokins |
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Term
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Definition
Secrete - several
transporation - diffusion
Messenger - Amin, peptides proteins |
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Term
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Definition
| messengers of the nervous system released from neurons by exocytosis diffuse a short distance ( across a synaptic cleft) the connection between cells is called a synapse |
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Term
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Definition
Secrete - Edocrine
Transportation - blood
target cell must be receptor specific |
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Term
| Examples of molecules that act as paracrine signals |
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Definition
| Histaimne Growth factors Interleukins Prostaglandins |
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Term
| Examples of molecules that act on as neurotransmitters |
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Definition
glutanmate - learning and memory
GABA - inhibitory neurotransmitter
serotonin - regulating peristalsis in the gut, and in mood, appetite, and sleep in the CNS
dopamine - reward pathways, motivation ,congnition, regulating physical movements nuropeptide
Y - stress and hunger acetyleholine - skeletal muscle, CNS ANS |
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Term
| Examples of molecules that act as a hormone |
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Definition
| estrogens, testosterone and progesterone cortisol aldosterone insulin - involved in regulation of blood glucose levels epinephrie and norepinephrin |
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Term
| Example of a molecule that acts as a neurohormone |
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Definition
| Anti-diuretic hormone (ADH) involved in the regulation of urine production |
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Term
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Definition
lipophilic
a) not stored in secretory cells
b) diffuse out of the cell as soon as they are made
c) require carrier if going long distance
d) can diffuse across the plasma membrane longer lasting |
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Term
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Definition
steriods - tend to act as homrones when they are ligands
eiosanoids - when they act as ligands they will be paracine signals |
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Term
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Definition
lipophobic - can be dissolved in water stored in vesciles by secretory cells and released by exocytosis
no carrier required
cannot diffuse across the plasma membrane
responses are faster but shorter than hydrophobic ligands |
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Term
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Definition
amino acids (building blocks of proteins)
function only as neurotransmitter messengers - glutamat, gaba, glycine
amines
proteins - insulin anti-diuretic hormone |
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Term
| Lipophobic messenger (hydrophilic) |
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Definition
Amino acids , amines, peoptides
Storage in scretory cell - secretory vesicles
Mechanism of secretion - Exocytosis
Transport in blood - dissolved
Location of receptor - Plasma membrane
Signal mechanism - Open/close channels, activate membrane-bound exymes, G proteins and second messenger systems
Response - fast
Duration - Short
half-life - Short |
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Term
| Lipophilic messenger (hydrophobic) |
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Definition
Steroids, eicosanoids, thyroid hormones
Storage in secretory cells - none
Secretion - Diffusion
Tansport in blood - bound to carrier protien
location of receptor - cytosol or nucleus
Signal transduction - alter transcription of mRNA
Response - slow
duration - long
half-life - long |
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Term
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Definition
| the process by which ligand binding to a receptor causes a response in the target cell |
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Term
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Definition
| receptors are proteins, with specific inding sites for a ligand |
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Term
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Definition
| have specificity they only bind to one (or a few closely related) ligands |
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Term
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Definition
| have promiscuity - thre is often more than one type of receptor for one ligand |
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Term
| Where do lipophilic ligands bind to |
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Definition
| receptor in cytoplasm or nucleus |
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Term
| if in the cytoplasm the messenger-receptor complexs enters the |
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Definition
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Term
| examples of hormone that acts as an intracellular receptor |
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Definition
| aldosterone,k which stumulates sythesis of that Na+/K+ pump |
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Term
| Fast ligan-gated ion channels |
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Definition
receptor itself is an ion channel
channel opens when the ligand binds, and closes when the ligand releases |
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Term
| Fiast ligand-gated ion channels opening and closing of ion channels either |
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Definition
1)changes electrical properties of the target cell or,
2) if Ca++ is the ion, can lead to several kinds of changes in cells |
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Term
| what receptor is the most crucial mechanism of moment-to-moment regulation of muscle and nervous tissue |
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Definition
| fast ligand-gated ion channels |
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Term
| Examples of fast ligand-gated ion channels |
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Definition
| glutamate, GABA, Acetylcholine, |
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Term
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Definition
the receptor ifself is an enzyme
tyrosine kinase receptors-most common - play a role in growth metabolism and othe processes |
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Term
| What type of enzyme adds a phosphate group to the target proteins in the cell |
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Definition
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Term
| G-protein linked receptors |
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Definition
| the activated G protein binds to an ion channel or an enzyme (the effector). as long as it is bound it will act on the efector. The G protein may either stiulate or inhibit that effector |
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Term
| What activats a protein called G protein |
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Definition
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Term
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Definition
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Term
| What are two types of second messengers pathways |
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Definition
| cAP pathway and the Ca++ pathway |
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Term
| Enzyme effector generates cAMP, which leads to |
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Definition
| phosphorylation of target proteins |
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Term
| what other processes area affected by cAMP pathways |
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Definition
| heart rate control, female sex hormone produciton in ovaries, breakdown of glucose in the liver, perception of sweet tastes, formation of simple memory traces in the brain |
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Term
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Definition
| an enzyme generates moleculoes that liberate Ca++ from endoplasmic reticulum |
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Term
| Other processes affected by Ca++ pathway |
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Definition
| inflammation, metabolism pathways, memory, immune responses |
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Term
| Signal transduction cascades |
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Definition
| When enzymes activated second messengers, as happens often in GPCR signaling, a multi-step cascade of events occurs inside the cell |
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Term
| What does Ca++ bind to that will lead to phophoryloation of target proteins in the cell |
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Definition
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Term
| What does Ca++ bind to that will lead to phophoryloation of target proteins in the cell |
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Definition
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Term
| What other processes are affected by Ca++ pathway |
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Definition
| inflammation, metbolism pathways, memory, immune response |
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Term
| Vison works via a ________ called _______ recognizes photons of light |
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Definition
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Term
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Definition
are chemicals that communicate with neightboring cells - Target cell must be close enough for simple diffusion
EX: growth factors, clotting factors, and cytokines |
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Term
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Definition
| are proteins that stimulate proliferation and fifferentiantion of cells |
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Term
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Definition
| ar proteins that stimulate formatin of a blood clot |
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Term
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Definition
| are peptides usually released from immune cells, that function in coordination the body's defense |
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Term
| What is an example of a paracrine messenger |
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Definition
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Term
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Definition
| act on the same cell that secreted them thus the target cell is the secretory cell |
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Term
| Where are neurotransmitters released from |
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Definition
| axon terminal which would be close to the target cell |
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Term
| What would be an example of a neurotrasmitter |
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Definition
| acetylcholine - which is released by the neurons that trigger contractin of skeletal muscles |
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Term
| What is a example of a neurohormone |
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Definition
| vasopressin, or ADH (antidiuretic hormone), which is synthesized by neurosecretory cells originating in an area of the brain called the hypothalamus |
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Term
| Amino acids Messengers are they lipophobic or lipophilic |
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Definition
| lipophobic, they dissolve in water but do not cross plasma membranes |
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Term
| Amine Messengers are they lipophobic or lipophilic |
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Definition
| lipophobic - they dissove in water and do not cross the plasma membrane |
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Term
| Peptide/Protein Messengers are they lipophobic or lipophilic |
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Definition
| lipophobic - they disvolve in water and do not cross the plasmsa membrane |
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Term
| Steroid Messengers are they lipophobic or lipophilic |
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Definition
| lipophilic, cross plasma membrane and are insoluble in water |
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Term
| Eicosanoid Messengers are they lipophobic or lipophilic |
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Definition
| lipophilic, readily cross the plasms membrane and are insoluble in water |
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Term
| Name the four functional classes of messengers |
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Definition
| Paracrine, Autocrine, Neurotransmitter, Hormone |
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Term
| Which messengers are transported in the blood to their target cell |
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Definition
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Term
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Definition
Nervous System: Neuron
Endocrine System: Endocrine cell |
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Term
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Definition
Nervous System: Neuron, muscle, or gland
Endrocrine System: Most cell types in the body |
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Term
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Definition
Nervous System:Neurotransmitter
Endocrine System: Hormone |
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Term
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Definition
Nervous System: Across synapse
Endocrine System: Via bloodstream |
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Term
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Definition
Nervous System: Receptors on postsynapic target cell
Endocrine System: Receptors on target celsl throughtout the body |
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Term
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Definition
Nervous system: Immediate
Endocrine system: Delayed |
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Term
|
Definition
Nervous system: Brief
Endocrine system: Long |
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Term
| Transport of Hydrophilic messengers in blood |
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Definition
| 1) Hydrophilic messengers are secreted by exocytosis, enter the blood stream, and dissovle in the plasma |
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Term
| Transport of Hydrophobic Messengers in blood |
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Definition
Hydrophobic messengers are secreted by simple diffusion and then enter the bloodstream.
Most of the messenger molecules are transported bound to carrier proteins.
Only the small amount of free hormone in the plasma is immediately availbale for binding with target cell receptors |
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Term
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Definition
| the strength of the binding between a messenger and its receptor |
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Term
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Definition
| ligands tha bind to receptors and produce a biological response |
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Term
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Definition
| are ligands that bind t recepotros but do not produce a responce |
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Term
| Effects of ADH on principal cells lining the late distal tubules and collecting ducts |
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Definition
1)ADh binds to receptors on teh membrane of principal cells
2) Activatin of a G protein activates the enzyme adenylate cyclase, which catalyzes the formation of cAMP
3) activates protein kinase A
4) The protein kinase A stimulates insertion of new water channels into the apical membrane, which increases its water permeability |
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Term
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Definition
General specific, allowing only one type of ion or class of ions to pass through them
Are Proteins, most of which can be regulated between open and closed states |
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Term
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Definition
| ion channels that open or close in response to the binding of a chemical to a receptor or to the channel |
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Term
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Definition
are a type of ligand gated channel in which the ligand is a messenger that binds to a receptor
Two types: fast channels and slow channels |
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Term
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Definition
| ar proteins that function as both receptor and ion channels - the binding of a messenger to the receptor/ion channel cause sthe channel to open, increasing the membranes permeability for the specific ion |
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Term
| Ion movement in to or out of the cell can have two differnet effects on the targe cell |
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Definition
1) ions entering and leaving can change the electrical properties of the cell
2) entering ions can interact with proteins inside the cell to induce a response such as muscle contraction, secrtion, change in metabolism, or altered transport of a substance |
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Term
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Definition
| an intracellular messenger produced by the binding of an extracellular messenger (the firs messenger) to a receptor |
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Term
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Definition
| function both as enzymes and as receptors - the receptor side faces the interstitial fluid and teh enzyme side faces the cytosol |
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Term
| G Protein-Linked Receptors |
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Definition
| work by activating special membrane proteins called G proteins - G proteins are located on the intracellular side of the plasma membrane |
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Term
| G Proteins function as links between the G protein-linked receptor and othe proteins in the plasma membrane called |
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Definition
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Term
| How do G proteins get their name |
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Definition
| from their ability to bind guanosine nucleotides, have three subunits alpha, beta and gamma |
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Term
| Slow ligand-gated ion channels are regulated by |
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Definition
| G proteins, which cause the channels to open or close in response to a messenger binding to its receptor |
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Term
| What are the two diffences between fast gated channels and slow gated channels |
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Definition
1)slow gated channels: channels can be either opened or closed by messenger binidng to the receptor
1)Fast Gated: only opens the channel does not close it
2)slow gated channels:channels are slow to open or close in response to receptor binding
2)fast gated: produces an immediated and brief response |
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