Terms Flashcards
Neurons
Also called nerve cells
Receive stimuli and transmit action potentials to other neurons or to effector organs
Neurolgia
Support and protect neurons and perform other functions. Half of the brain’s weight
Neuron cell body
Also called soma. Has a nucleus which is the source of info for protein synthesis
Dendrite
Branching extension of cell body
Axon
Straight alignment and uniform diameter that come off a cell body
Nissl bodies
Primary site of protein synthesis in neurons. Located primarily in cell body and dendrites
Dendrite spines
Axons of other neurons form synapses with the dendrites. Dendrites receive input from axons
Axon hillock
Cone shaped area of the neuron cell body. This is where a singe axon arises
Initial segment
Beginning of the axon
Trigger zone
Where action potentials are generated. Contains the axon hillock
Axoplassm
Cytoplasm of an axon
Axolemma
Plasma membrane of the axoplasm
Sensory neurons
Conduct action potentials towards the CNS
Motor neurons
Conduct action potentials away from the CNS
Interneurons
Conduct action potentials from one neuron to another within the CNS
Multipolar neurons
Have many dendrites and a single axon. Most of the neurons in the CNS and motor neurons are multipolar
Bipolar neurons
One dendrite and one axon. Located in some sensory neurons like the retina
Pseudo-unipolar neurons
Has a single process extending from the cell body. It divides in two and one branch goes to the CNS and the other extends to the periphery and has dendrite like sensory receptors. Most sensory neurons are pseudo bipolar
Astrocytes
Star shaped neuralgia because cytoplasm processes extend from the cell body. These form a supporting framework for blood vessels and neurons. They also help regulate extra cellular composition of the brain fluid
Blood-brain barrier
Created from endothelial cells and determines what substances can pass from the blood into the nervous tissue of the brain and spinal chord.
Reactive astrocytosis
Astrocytes wall off the injury site and help limit the spread of inflammation to the surrounding healthy tissue
Ependymal cells
Line the ventricles of the brain and the central canal of the spinal cord.
Choroid plexuses
Secrete the cerebrospinal fluid that flows through the ventricles of the brain.
Microglia
Neuroglia in the CNS that become mobile and phagocytic in response to inflammation.
Oligodendrocytes
Have cytoplasmic extensions that can surround axons. If it wraps several times, it creates a myelin sheath
schwann cells
neuroglia in the PNS that wrap around axons. If it wraps around several times then it becomes a myalin sheath but only around one axon
satellite cells
surround neuron cell bodies in sensory and autonomic ganglia. provides support, nutrition, and protection
myelinated axons
extensions from schwann cells or oligodendroytes
unmyelinated axons
rest in invaginations of the schwann cells or the oligogendrocytes. Surrounds each axon but not many times
Nodes of Ranvier
Interruptions in the myalin sheath
Gray matter
Groups of neuron cell bodies and their dendrites where there is very little myalin
Cortex
Gray matter on the surface of the brain
Nuclei
Clusters of gray matter deep within the brain
Ganglion
Clusters of neuron cell bodies in the PNS
White matter
Consists of bundles of parallel axons with their myelin sheaths
Nerve tracts
White matter from the CNS which propagate action potentials from one area of the CNS to another
