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Cells with a receptor that's able to respond to the electrical or chemical signal
Receptors on/in a cell are a ______.
Where is the receptor protein located?
- Cell membrane
Define the term Ligand
A chemical signal
Gap junctions transfer both _____ and _____ signals.
Protiens that connect the cytoplasm of two cells through tunnels
Autocrine signals act on the ______ cell of secretion.
Panacrine signals act on ____ cell of secretion.
Secreted by the endocrine glands or cells into the blood for longer distances than the panacrine signal.
The autocrine, panacrine, and endocrine signals can only target cells with ______ to recieve and respond.
How are electrical signals sent?
In the form of action potential conducted along the axon part of the cell called the neuron.
What happens when the action potential gets to the end of the neuron?
It synapses with the target cell and neurotransmitters are released that bind with receptor cell.
- Where one form of signal is converted into another form
- (remember the radio signal to music analogy)
The ______ system uses a combination of chemical and electrical signals.
The Endocrine system releases _____ .
Hormones (chemical signals)
The Nervous system uses ______ and ______ signals at synapses.
- Action potentials - electrical
- Neurotransmitters - chemical
What are neurohormones?
Chemicals released by neurons into the blood with an action potential at distant target cells. (Signal transduction)
A) bind to receptors on the surface of the cell.
B) function by way of a second messenger system.
C) cannot diffuse through the cell membrane.
D) bind to receptors inside the cytoplasm or nucleus.
E) function by activating cAMP.
- D) bind to receptors inside the cytoplasm or nucleus.
- *also on the surface of the cell*
How can the original signal molecule produce a cellular response when it may not even enter the target cell?
They bind to receptors and cause electrical signals by opening the gated protien channels.
Why do different types of cells respond differently to the same signal molecule?
Because the cells have slightly different receptors that react differently to the signal.
Give an example of cells that respond differently to the same ligand:
Epinephrine binds to alpha receptors in blood vessels causing vasioconstriction, but causes vasiodilation when it binds the the beta cell receptors on skeletal muscles.
How does specificity affect cell receptors?
Specificity makes the receptors selective in which ligands it can accept to bind to it. It has to be a near perfect match/fit.
How does saturation affect cell receptors?
When all receptors on a cell are moving at a maximun rate, the cell will try to bring the response back to normal by removing receptors, which is known as Down Regulation.
What happens if cell ligand saturation is below average?
The cell may try to compensate by Up-regulation which means that the cell will create more receptors in the cell membrane to keep the response at a normal rate.
Explain Competition in regards to cell receptors
Some ligands form a close enough match to cell receptors and are accepted. These are called agonist molecules or atagonist molecules.
What is the difference between agonist molecules and antagonist molecules?
- Agonist molecules produce a normal response (but it may be more or less effective than the regular molecule's effect)
- Antagonist molecules prevent the cell's normal response by inhibiting the reception of the regular molecule.
Explain the conditions of Down Regulation
- Down regulation decreases the # of receptors
- Decreases the binding affinity
- **One reason for drug tolerence**
Explain the concept of Up-Regulation
- Ligand concentration decreases
- Increase # of receptors
- Increase binding affinity
- Cell becomes more responsive
In which type of diabetes mellitus would insulin receptors more likely be up-regulated?
Type I, because there is a difficiency of Insulin
Neurotransmitters and neurohormones both
A) are released by neurons.
B) A and B
C) affect only cells with a specific receptor.
D) A, B, and C
E) travel in the blood to their target cell.
B) A and B
travel through the blood. Neurotransmitters generally only react across the synapses.
(this multiple choice question has been scrambled)
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