Anatomy Of The Nervous System: Neurons Flashcards
Bipolar Neurons
two projections from the cell body, sensory neurons for the distance senses (vision, hearing, smell)
Multipolar Neurons
more than two projection from the cell body, motor neurons (PNS)
Interneurons
cell in the CNS used for processing information
Local-Circuit Interneurons
stellate cells, “association neurons”
Projection Interneurons
pyramidal cells, long axon=neurotransmitter, carries info to the spinal cord
Purkinje Cells
fan shaped, carries info from the cerebellum to other parts of the brain and the spinal cord
Soma
cell body
Nucleus
DNA found here
Axon
transmits messages
Dendrites
tree like, receive chemical messages
Axon Hillock
small triangle before the axon, biological decision maker, decides whether or not to pass on a message
Myelin Sheath
fatty sheath, electrical insulation, speeds up neuroconduction, segmented (not continuous)
Node Of Ranvier
gaps of myelin sheath, where the axon is exposed
Axon Terminal
“axon ending” “terminal button” “terminal bouton”, neurotransmitters released here
Microtubules
transports material from soma to axon terminal and back
Synaptic Vesicle
special membrane bubble which contains neurotransmitters
Anterograde Transport
soma > axon terminal
Retrograde Transport
axon terminal > soma
Neuroglial Cells
“nerve glue”, outnumber neurons 10-1
Astrocytes
star shaped, provide energy to neurons, “middle men”, coordinate activity into waves
Oligodendrocytes
creates myelin sheath for axons in the CNS, when they die the sheaths die
Microglial Cells
remove dead tissue, mild form of immune system by inflammation
Schwann Cells
creates myelin sheath in the PNS
Golgi Staining
silver nitrate, only shows silhouettes
Nissl Staining
cresyl violet, penetrates membrane and binds to structures within
Electron Microscopy
10,000x magnification
Standard- 2D
Scanning- 3D (not as detailed)
Amino Acid Autoradiography
anterograde, inject substance by the cell body, transport down to the axon terminal
Horseradish Peroxidase
retrograde, inject substance (enzyme) to brain at axon terminal, transported back to soma
Neuron Conductor Speeds
Humans:
myelinated- 60 m/sec
unmyelinated- 1 m/sec
Cats: 100 m/sec
Galvani
stimulates frog legs
Bernstein
2 state theory
John Z. Young
took the axon out of the squid, large squid have large axons (1mm across)
Oscilloscope
measuring difference in voltage and displayed on a screen
Microelectrodes
intracellular- inside cell membrane in the fluid
Ion
charged particle
Potential
electrical charge
Graded Potential
electrical charges that vary in strength
Nongraded Potential
electrical charges that don’t vary in strength
Decremental Potential
electrical charges that fade in strength
Synaptic Potential
electrical charges resulted from communication across synapse, they occur in dendrites and soma
-graded & decremental
Action Potential
electrical charges in the axon
-nongraded & nondecremental
Unipolar Neurons
one projection from the cell body, sensory neurons for the contact senses (touch)
