Neuroanatomy Flashcards
Neurons
nerve cells, are some of the most important parts of the nervous system
- important for information processing
- connected to synapses + axons
Glial Cells
provide support for and contribute to information processing neurons
- just as important as neurons
- communicate with each other and with neurons and enhanced neural activity
Neuron Doctrine
- the brain is composed of independent cells
- information is transmitted from cell to cell across synapses (the space between neurons that transmits info)
How many Neurons in the Brain:
- Over 86 billion neurons that control our body and help us interact with our environment
Neuron: Input Zone
receives information from other cells through dendrites
Neuron: Integration Zone
cell body (soma) region where inputs are combined and transformed
Neuron: Conduction Zone
single axon leads away from cell body and transmits the electrical impulse
Neuron: Output Zone
axon terminals at the end of the axon communicate activity to the other cells
Multipolar Neurons:
- (most common)
- one axon
- many dendrites
Bipolar Neurons
- one axon
- one dendrite
Unipolar Neurons
- a single extension branches in two directions, forming a receptive pole and output zone
Motor Neurons
stimulate muscles or glands
Sensory Neurons
respond to environmental stimuli
- light, odor, or touch
Interneurons
receive input and send input to other neurons
Synaptic Cleft
small space between a presynaptic neuron and postsynaptic neuron
Presynaptic Neuron
sends information to the postsynaptic neurons
- information is transmitted through the axon
Postsynaptic Neuron
receives information from the presynaptic neuron
- they contain ion channels that facilitate electrical activity
- information comes through the dendrites
Synaptic Vesicles:
small spheres in the presynaptic axon terminals that contain neurotransmitters (specialized chemical substance)
- releases neurotransmitters in response to electrical activity in the axon
Axonal Transport
the movement of materials within an axon via motor proteins
Anterograde Transport
Cell Body to Axon Terminals
Retrograde Transport
Axon Terminals to Cell Body
Axons vs. Dendrites
Axons:
- usually one per neuron with many branches
- diameter is uniform until start of branching
- axon hillock is present
- myelin sheath
- ranges from not long to very long
Dendrites:
- many a neuron
- diameter is tapered towards the end
- no hillock or myelin sheath
- shorter than axons
Glial Cells: Astrocytes
star shaped cells with many processes that monitor activity
Glial Cells: Microglia
small cells that remove debris from injured cells
Glial Cells: Oligodendrocytes
form myelin sheaths in the brain and spinal cord
Glial Cells: Schwann Cells
provide myelin to cells outside the brain and spinal cord
Myelin
to insulate and speed up connection
Nodes of Ranvier
gaps between myelin sections where the axon is exposed
Multiple Sclerosis
demyelinating disease
Central Nervous System (CNS)
the brain and the spinal cord
Peripheral Nervous System (PNS)
all parts that isn’t the brain and the spinal cord
Somatic Nervous System
for voluntary movement
- skeletal muscles and sensory systems
Autonomic Nervous System
largely unconscious regulation of bodily functions
- nerves that control viscera (internal organs: kidneys, liver, lungs, heart, etc.)
