Cells of NS, Nerve impluse, neurotransmitters, neural circuit Flashcards
What is the function of the sensory (afferent) division of the PNS?
Transmits impulses from sensory receptors to the CNS.
Somatic sensory fibers: From skin, skeletal muscles, joints
Visceral sensory fibers: From visceral organs
What is the function of the motor (efferent) division of the PNS?
Transmits impulses from the CNS to effectors like muscles and glands.
What is the function of microglial cells?
Monitor neuron health
Migrate to injured neuron
Phagocytize debris and microbes
Location: CNS
What is the function of astrocytes?
Support and brace neurons
Regulate exchanges between neurons and capillaries
Guide neuron migration
Control chemical environment
Involved in info processing
Most abundant and versatile glial cell
Location: CNS
What is the function of ependymal cells?
Line brain and spinal cord cavities
Circulate cerebrospinal fluid (CSF) via cilia
Form barrier between CSF and tissue fluid
Location: CNS
What do oligodendrocytes do?
Form myelin sheaths around thick CNS fibers.
Location: CNS
What is the function of satellite cells?
Surround neuron cell bodies in PNS and function similarly to astrocytes.
Location: PNS
What do Schwann cells do?
Form myelin sheaths around PNS axons
Aid in regeneration of damaged PNS nerve fibers
Location: PNS
What are the basic parts of a neuron?
A cell body and one or more processes (dendrites and axon).
What are ionotropic receptors and their function?
Ligand-gated ion channels
Mediate rapid synaptic transmission
Sensitive to neurotransmitters and membrane potential
Selective for specific ions
Responsible for significant membrane currents
What are metabotropic receptors and how do they function?
G-protein coupled receptors (GPCRs)
Slower, indirect, and longer-lasting effects
Single polypeptide with 7 transmembrane alpha-helices
Bind neurotransmitters like amines, peptides, and some amino acids
Where is ACh used and how is it metabolized?
Found at neuromuscular junctions, in ANS, and some CNS neurons
Synthesized by choline acetyltransferase (from acetic acid & choline)
Broken down by acetylcholinesterase (AChE)
Name the catecholamine neurotransmitters and precursor.
Dopamine, norepinephrine (NE), epinephrine
Made from tyrosine
Involved in emotional behavior and biological clock
What are the indolamines and their precursors?
Serotonin (from tryptophan)
Histamine (from histidine)
Used in the brain and ANS; imbalances linked to mental illness
Name the amino acid neurotransmitters.
Glutamate, Aspartate, Glycine, GABA
Glutamate is excitatory; GABA and glycine are inhibitory
Found widely in CNS
What are neuropeptides and their functions?
Chains of amino acids with various functions
Substance P – pain mediator
Endorphins (beta-endorphin, dynorphin, enkephalins) – natural opiates
Gut-brain peptides (e.g., somatostatin, CCK) – digestive regulation
What is the function of GABA receptors?
Mediate most inhibitory transmission in the CNS
Bind drugs like ethanol, benzodiazepines, and barbiturates
Glycine also contributes to inhibitory transmission outside of GABAergic pathways
What is a neural circuit?
A pattern of synaptic connections between neurons that determines the flow of information through the nervous system.
What is a diverging neural circuit?
A circuit where one input neuron branches out to communicate with multiple output neurons.
Function: Amplifies signals; commonly found in motor pathways.
What is a converging neural circuit?
A circuit where multiple input neurons synapse on a single output neuron.
What is a reverberating neural circuit?
A circuit where signal travels through a chain of neurons where signal is sent in a loop
Function: Maintains rhythmic activities like breathing or walking
What is a parallel after-discharge neural circuit?
A circuit where an input neuron sends signals along several parallel pathways that converge on a single output neuron, each with different synaptic delays.
Function: Produces a sustained, staggered response in the output neuron—useful in complex problem-solving or higher-level thinking.
