Stop And Check 2.2 Flashcards
Chemical events at a synapse:
1) the neuron synthesizes chemicals that serve as —————–. It synthesizes the smaller neurotransmitters in the —- ——— and synthesizes neuropeptides in the cell body.
2) action potentials travel down the —-. At the presynaptic terminal, an action potential enables ——- to enter the cell. ——- releases neurotransmitters from the terminals and into the synaptic cleft, the space between the presynaptic and postsynaptic neurons.
3) the released molecules diffuse across the cleft, attach to receptors, and alter the activity of the ———— neuron.
4) the —————- molecules separate from their receptors
5) the neurotransmitter molecules may be taken back into the presynaptic neuron for ——— or they may diffuse away.
6) some postsynaptic cells send ——- messages to control the further release of neurotransmitter by presynaptic cells.
1) the neuron synthesizes chemicals that serve as neurotransmitters. It synthesizes the smaller neurotransmitters in the axon terminals and synthesizes neuropeptides in the cell body.
2) action potentials travel down the axon. At the presynaptic terminal, an action potential enables calcium to enter the cell. Calcium releases neurotransmitters from the terminals and into the synaptic cleft, the space between the presynaptic and postsynaptic neurons.
3) the released molecules diffuse across the cleft, attach to receptors, and alter the activity of the postsynaptic neuron.
4) the neurotransmitter molecules separate from their receptors
5) the neurotransmitter molecules may be taken back into the presynaptic neuron for recycling or they may diffuse away.
6) some postsynaptic cells send reverse messages to control the further release of neurotransmitter by presynaptic cells.
What was Loewi’s evidence that neurotransmission depends on the release of chemicals?
When Loewi stimulated a nerve that increased or decreased a frog’s heart rate, he could withdraw fluid from the area around the heart, transfer it to another frog’s heart, and thereby increase or decrease its rate also
What does a highly active brain area do to increase its blood supply?
In a highly active brain area, many stimulated neurons release nitric oxide, which dilates the blood vessels in the area and thereby increases blood flow to the area.
Name the three catecholamine neurotransmitters.
E———-
N————-
D——-
Epinephrine, norepinephrine, and dopamine
When the action potential reaches the presynaptic terminal, which ion must enter the presynaptic terminal to evoke release of the neurotransmitter?
Calcium
How do ionotropic and metabotropic synapses differ in speed and duration of effects?
Ionotropic synapses act more quickly and more briefly
What are second messengers, and which type of synapse relies on them?
At metabotropic synapses, the neurotransmitter attaches to its receptor and thereby releases a chemical (the second messenger) within the postsynaptic cell, which alters metabolism or gene expression of the postsynaptic cell
How are neuropeptides special compared to other transmitters?
Neuropeptides are released only after prolonged stimulation, but when they are released, they are released in large amounts by all parts of the neuron, not just the axon terminal. Neuropeptides diffuse widely, producing long-lasting effects on many neurons.
How do LSD, nicotine, and opiate drugs influence behavior?
LSD binds to one type of serotonin receptor
Nicotine binds to one type of acetylcholine receptor
Opiates bind to endorphin receptors
What happens to acetylcholine molecules after they stimulate a postsynaptic receptor?
The enzyme acetylcholinesterase breaks acetylcholine molecules into two smaller molecules, acetate and choline, which are then reabsorbed by the presynaptic terminal
What happens to serotonin and catecholamine molecules after they stimulate a postsynaptic receptor?
Most serotonin and catecholamine molecules are reabsorbed by the presynaptic terminal.
Some of their molecules are broken down into inactive chemicals, which then diffuse away.
How do amphetamine and cocaine influence dopamine synapses?
They interfere with reuptake of released dopamine
Why is methylphenidate generally less disruptive to behavior than cocaine is, despite the drugs similar mechanisms?
The effects of a methylphenidate pill develop and decline in the brain much more slowly than do those of cocaine
How do cannabinoids affect neurons?
Cannabinoids released by the postsynaptic neuron attach to receptors on presynaptic neurons, where they inhibit further release of both glutamate and GABA
Which part of the pituitary-anterior or posterior- is neutral tissue, similar to the hypothalamus?
Which part is glandular tissue and produces hormones that control the secretions by other endocrine organs?
The posterior pituitary is neutral tissue, like the hypothalamus.
The anterior pituitary is glandular tissue and produces hormones that control several other endocrine organs
