Synapses
No, dead neurons in the cortex are not typically replaced by new neurons. The brain has limited capacity for neurogenesis, especially in the cortex. Dead neurons are usually not replaced, but the brain can adapt and reorganize to compensate for lost function through processes like synaptic plasticity.
A neurotransmitter is a chemical or peptide in synapses, usually between neurons, a neuron and muscle or a neuron and other organ. The neurotransmitter transmits information to and from and within the brain. When a neurotransmitter is released from the presynaptic cell in response to depolarization of the cell by an action potential, it diffuses across the synaptic cleft and binds a receptor or ligand-gated ion channel on the postsynaptic cell. Binding on the postsynaptic cell alters the resting potential of the postsynaptic cell in either an inhibitory or excitatory manner, making the cell less susceptible or more susceptible (respectively) to an action potential. Examples include, but are not limited to, acetylcholine, GABA, noradrenaline, serotonin and dopamine.
No, ATP (adenosine triphosphate) is not a neurotransmitter. It is a molecule that provides energy for cellular processes. Neurotransmitters are chemical messengers that transmit signals between neurons in the nervous system.
For a substance to be considered a neurotransmitter at a synapse, it must be synthesized within the presynaptic neuron, released in response to an action potential, be present in sufficient quantities to produce a physiological response, and have specific receptors on the postsynaptic neuron that it can bind to in order to transmit a signal. Additionally, it should be capable of being broken down or removed from the synaptic cleft to terminate its signaling action.
Neurotransmitters are stored in synaptic vesicles located at the terminals of presynaptic neurons. When an action potential reaches the terminal, these vesicles release neurotransmitters into the synaptic cleft to facilitate communication between neurons.
Synapses
No, dead neurons in the cortex are not typically replaced by new neurons. The brain has limited capacity for neurogenesis, especially in the cortex. Dead neurons are usually not replaced, but the brain can adapt and reorganize to compensate for lost function through processes like synaptic plasticity.
A neurotransmitter is a chemical or peptide in synapses, usually between neurons, a neuron and muscle or a neuron and other organ. The neurotransmitter transmits information to and from and within the brain. When a neurotransmitter is released from the presynaptic cell in response to depolarization of the cell by an action potential, it diffuses across the synaptic cleft and binds a receptor or ligand-gated ion channel on the postsynaptic cell. Binding on the postsynaptic cell alters the resting potential of the postsynaptic cell in either an inhibitory or excitatory manner, making the cell less susceptible or more susceptible (respectively) to an action potential. Examples include, but are not limited to, acetylcholine, GABA, noradrenaline, serotonin and dopamine.
No, ATP (adenosine triphosphate) is not a neurotransmitter. It is a molecule that provides energy for cellular processes. Neurotransmitters are chemical messengers that transmit signals between neurons in the nervous system.
For a substance to be considered a neurotransmitter at a synapse, it must be synthesized within the presynaptic neuron, released in response to an action potential, be present in sufficient quantities to produce a physiological response, and have specific receptors on the postsynaptic neuron that it can bind to in order to transmit a signal. Additionally, it should be capable of being broken down or removed from the synaptic cleft to terminate its signaling action.
It reaches the synapse and sends neurotransmitters to start a new impulse to the next neuron
The structure that connects two neurons is called a synapse. At the synapse, the axon terminal of one neuron releases neurotransmitters that travel across the synaptic cleft to bind to receptors on the dendrites or cell body of the next neuron, transmitting electrical or chemical signals between the two neurons.
Dopamine
are endogenous chemicals which relay, amplify, and modulate signals between a neuron and another cell.[1] Neurotransmitters are packaged into synaptic vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of the synapse. Release of neurotransmitters usually follows arrival of an action potential at the synapse, but may follow graded electrical potentials. Low level "baseline" release also occurs without electrical stimulation.
A polysynaptic reflex arc involves interneurons, allowing for more complex and customized responses to stimuli compared to the more simple and direct response of a monosynaptic reflex arc. This complexity can provide greater coordination and integration of sensory information in the body.
Usually, but mutations could affect the number of neurons.