Neuron Cell Anatomy
What is the fatty, insulating layer wrapped around an axon?
Myelin Sheath
What is a glial cell?
A non-neuron NS cell that protects and nourishes actual neurons; they don't transmit electrical impulses, but help to maintain cell homeostasis (protect, support, insulate, regulate, repair)
What is the Fx of the dendrites?
Somatic afferents; specialized to transmit neural impulses towards the soma
What is the role of afferent sensory neurons in the NS?
To send impulses from the PNS-->CNS; responsible for conscious perception and coordination (both motor output and sensory feedback needed for ease of coordination)
What is an action potential?
A rapid sequence of voltage changes across a neuron's cell membrane, allowing for the excitation or inhibition of a neuron's firing
What is distal from the soma, starting at the axon hillock and ending in terminal boutons?
The axon
What type of glial cell guides neurons to the correct cortex layer for them to differentiate into the correct type of neuron? (Also absorbs neurotoxins into its cytoplasm from the extracellular space, forms scars)
Astrocytes
What is the Fx of an axon?
Somatic efferent; specialized to conduct neural impulses away from the soma
What does "divergence" mean in the context of neuroscience?
The transmission of a signal from one source to multiple neurons
What type of ion is going across the neuron cell membrane into the soma during depolarization?
Na+ ions (sodium cations)
T/F: A neuron contains a cell nucleus and DNA
True
What type of glial cell provides insulation to neurons by forming and maintaining CNS myelination?
Oligodendrocytes
What is the Fx of the terminal boutons?
To release a neurotransmitter into the synaptic cleft, so the impulse can go through to the postsynaptic neuron
What does "convergence" mean in the context of neuroscience?
The receiving of a signal from multiple neurons into one neuron
What type of ion is going across the neuron cell membrane during repolarization?
K+ ions (potassium cations)
What is the space between a presynaptic and postsynaptic cell called?
Synaptic cleft
What do Schwann cells do?
They are cells that are responsible for the maintenance and regeneration of nerves, and make up the myelin sheath around axons in the PNS
What is the Fx of the neuron cell membrane?
To regulate the differences in electrical charge between the inside and outside of the soma (via the intake or expulsion of Na+ and K+ ions), resulting in depolarization, repolarization, and/or hyperpolarization for signal transmission
What is the role of efferent motor neurons in the NS?
To send efferent nerve impulses from CNS-->PNS; responsible for motor commands to the muscles and glands
At rest, is a neuron polarized, depolarized, or hyperpolarized in its mV?
The resting membrane potential for a neuron is -70mV, which is polarized (no current is flowing from one side of the membrane to the other because resting potential is the same throughout the neuron)
Which of the following is NOT a type of neuron?
-Multipolar
-Monopolar
-Bipolar
-Pseudounipolar
Monopolar
Which type(s) of glial cells remain mitotic throughout life, and can therefore form tumors in the NS (e.g., glioblastomas)?
Both astrocytes and oligodendrocytes
What is the Fx of the nodes of Ranvier?
When the action potential reaches a node, the high concentration of Na+ channels at a node allows for the rapid influx of Na+ ions (this is significantly faster than a continuous conduction in unmyelinated axons, and amplifies the electrical signal)
What is the role of interneurons in the NS?
To process information that's carried by both sensory and motor neurons; conveys information from one site within the NS to another (the majority of neurons are interneurons)
What is the mV threshold for a neuron to begin depolarization for an action potential?