Case 3 synaps
1. which cells produce myelin in the central nervous system and in the peripheral
nervous system?
- In the central nervous system the oligodendrocytes support axons and produce myelin.
In the peripheral nervous system the Schwann cells perform the same functions.
2. What is a neurotransmitters and what do they do and what do they exist of?
- Chemical endogenous substance
- Criteria
o The substance exists in presynaptic axon terminals.
o The presynaptic cell contains appropriate enzymes for synthesizing the
substance.
o The substance is released in significant quantities when action potentials reach
the terminals.
o Specific receptors that recognize the released substance exist on the
postsynaptic membrane.
o Experimental application of the substance produces changes in postsynaptic
cells.
o Blocking release of the substance prevents presynaptic activity from affecting
the postsynaptic cell
-
- Monoamine neurotransmitters are slightly larger than amino acid neurotransmitters,
and their effects tend to be more diffuse. The monoamines are present in small groups
of neurons whose cell bodies are, for the most part, located in the brain stem. These
neurons often have highly branched axons with many varicosities (string-of-beads
synapses), from which monoamine neurotransmitters are diffusely released into the
extracellular fluid. They are subdivided into two groups, catecholamines and
indolamines, on the basis of their structures
- Acetylcholine is the neurotransmitter at neuromuscular junctions, at many of the
synapses in the autonomic nervous system, and at synapses in several parts of the
central nervous system.
1
, - soluble-gas neurotransmitters, These neurotransmitters are produced in the neural
cytoplasm and immediately diffuse through the cell membrane into the extracellular
fluid and then into nearby cells. They easily pass through cell membranes because
they are soluble in lipids. Once inside another cell, they stimulate the production of a
second messenger and in a few seconds are deactivated by being converted to other
molecules.
- endocannabinoids are produced immediately before they are released.
Endocannabinoids are synthesized from fatty compounds in the cell membrane; they
tend to be released from the dendrites and cell body; and they tend to have most of
their effects on presynaptic neurons, inhibiting subsequent synaptic transmission
-
- co-localization Also called co-release. Here, the appearance of more than one
neurotransmitter in a given presynaptic terminal.
- glutamate An amino acid transmitter, the most common excitatory transmitter.
- aspartate An amino acid transmitter that is excitatory at many synapses.
- Gammaaminobutyric acid (GABA): inhibit
- Glycine: inhibit
- catecholamines A class of monoamines that serve as neurotransmitters, including
dopamine and norepinephrine.
- dopamine (DA) A monoamine transmitter found in the midbrain—especially the
substantia nigra—and basal forebrain.
- NE: produced by locus coeruleus, in the pons, and the lateral tegmental area of the
midbrain
- 5HT
2
1. which cells produce myelin in the central nervous system and in the peripheral
nervous system?
- In the central nervous system the oligodendrocytes support axons and produce myelin.
In the peripheral nervous system the Schwann cells perform the same functions.
2. What is a neurotransmitters and what do they do and what do they exist of?
- Chemical endogenous substance
- Criteria
o The substance exists in presynaptic axon terminals.
o The presynaptic cell contains appropriate enzymes for synthesizing the
substance.
o The substance is released in significant quantities when action potentials reach
the terminals.
o Specific receptors that recognize the released substance exist on the
postsynaptic membrane.
o Experimental application of the substance produces changes in postsynaptic
cells.
o Blocking release of the substance prevents presynaptic activity from affecting
the postsynaptic cell
-
- Monoamine neurotransmitters are slightly larger than amino acid neurotransmitters,
and their effects tend to be more diffuse. The monoamines are present in small groups
of neurons whose cell bodies are, for the most part, located in the brain stem. These
neurons often have highly branched axons with many varicosities (string-of-beads
synapses), from which monoamine neurotransmitters are diffusely released into the
extracellular fluid. They are subdivided into two groups, catecholamines and
indolamines, on the basis of their structures
- Acetylcholine is the neurotransmitter at neuromuscular junctions, at many of the
synapses in the autonomic nervous system, and at synapses in several parts of the
central nervous system.
1
, - soluble-gas neurotransmitters, These neurotransmitters are produced in the neural
cytoplasm and immediately diffuse through the cell membrane into the extracellular
fluid and then into nearby cells. They easily pass through cell membranes because
they are soluble in lipids. Once inside another cell, they stimulate the production of a
second messenger and in a few seconds are deactivated by being converted to other
molecules.
- endocannabinoids are produced immediately before they are released.
Endocannabinoids are synthesized from fatty compounds in the cell membrane; they
tend to be released from the dendrites and cell body; and they tend to have most of
their effects on presynaptic neurons, inhibiting subsequent synaptic transmission
-
- co-localization Also called co-release. Here, the appearance of more than one
neurotransmitter in a given presynaptic terminal.
- glutamate An amino acid transmitter, the most common excitatory transmitter.
- aspartate An amino acid transmitter that is excitatory at many synapses.
- Gammaaminobutyric acid (GABA): inhibit
- Glycine: inhibit
- catecholamines A class of monoamines that serve as neurotransmitters, including
dopamine and norepinephrine.
- dopamine (DA) A monoamine transmitter found in the midbrain—especially the
substantia nigra—and basal forebrain.
- NE: produced by locus coeruleus, in the pons, and the lateral tegmental area of the
midbrain
- 5HT
2
