Ch.2.1 : Functional Neuroanatomy: The Cells and Structures of the Nervous System Flashcards
What is this?
A neuron
Name the three shape (form) classifications of neurons.
- Bipolar neuron
- Multipolar neuron
- Unipolar neuron
What part of the neuron is A?
Dendrites
What part of the neuron is B?
Cell Body
What part of the neuron is C?
Axon Hillock
What part of the neuron is D?
Myelin Sheath
What part of the neuron is E?
Axon
What part of the neuron is F?
Axon Terminals
The nervous system is made up of what two types of cells?
Neurons and Glial cells
Early in history, what were the main ideas about neurons?
A. Each neuron had a tiny gap between them (Ramón y Cajal)
B. Neurons are a continuous fused unit - like a tube (Golgi)
What is the Neuron Doctrine? (created by Ramón Y Cagal)
- Neurons are structually, metabolically, and functionally independant of one another.
- Information is transfered via tiny gaps called synapses.
What are the 4 zones of a neuron
A. Input zone
B. Conduction Zone
C. Output Zone
D. Integration zone
What happens at the input zone?
Collects and processes information
What happens in the conduction zone?
Information is electrically transmitted.
What happens in the output zone?
The transfer of information.
What happens in the integration zone?
Decision to produce a neural signal.
Which way does information flow?
A. Dendrites to axon terminals.
B. Axon terminals to dendrites.
C. Information flows both ways
A. Dendrites to axon terminals.
What does innervate mean?
Provide neural input (talk to)
What is another word for axon terminals?
Synaptic boutons
When an axon splits, the branches are called?
Axon collaterals
How are neurons classified?
By function, shape and size.
Name 3 function classifications of neurons.
A. Motor (trigger movement - ex: muscles, organs & glands)
B. Sensory (ex: detect light, sound, touch)
C. Interneurons (in the brain - receive info from other neurons, process and pass the intergrated info to other neurons)
In general, what is the length of the axon of a motor neuron?
Long
In general, what is the length of the axon of a sensory neuron?
Long
In general, what is the length of the axon of a interneuron?
Short.
In general, do larger neurons tend to have 1. More complex inputs and outputs, convey info quicker, have greater requirements for cellular activity and protein synthesis, and cover greater distances than smaller neurons.
2. Less complex inputs and outputs, convey info slower, have less requirements for cellular activity and protein synthesis, and cover smaller distances than smaller neurons.
- More complex inputs and outputs, convey info quicker, have greater requirements for cellular activity and protein synthesis, and cover greater distances than smaller neurons.
What does arborization mean?
The elaborate branching of the dendrites
Is A presynaptic or postsynaptic?
Presynaptic
Is B presynaptic or postsynaptic?
Postsynaptic
What are these little bumps called?
Dendritic spines
Is A the presynaptic or postsynaptic axon terminal?
Presynaptic
What is the purpose of the mitochondrion?
Provides metabolic energy for the cell’s processes.
What are B?
Synaptic vesicles
What is C
Presynaptic membrane
What are D?
Neurotransmitter molecules
What is E?
The synaptic cleft (or synapse)
What is F?
Postsynaptic membrane
What is G?
Dendritic spine
What is a neurotransmitter?
The chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons.
(also called synaptic transmitter, chemical transmitter or transmitter)
How does the communication process start?
In response to electrical activity in the axon, the synaptic vesicles fuse with the presynaptic membrane and rupture, releasing their payload of neurotransmitter molecules into the synaptic cleft. After diffusing across the cleft, the molecules interact with matching (cognate) postsynaptic neurotransmitter receptors. Specialized protein molecules on the postsynaptic membrane, capture and react to the molecules. This causes electrical excitation of the postsynaptic cell.
Synapse are divided into 3 principal components.
A. presynaptic membrane
B. synaptic cleft
C. postsynaptic membrane
Do neurons change or stay the same?
The configuration of synapses come and go and dendrites change their shape.
When synapses and dendrites change their shape in response to new patterns of synaptic activity and the formation of new neural circuits is called?
Neuroplasticity
What is neuroplasticity?
The ability of the nervous system to change in response to experience or the environment.
Encoded information in a stream of electrical impulses that race down the axon toward the targets that the neuron is to
Innervate (to provide neural input)
What is histology?
The study of the composition of body tissue.
Is the axon hollow tube or not hollow?
Hollow
Describe axonal transport.
Important substances (ex: enzymes and proteins) are needed for the structure and function of the axon and the axon terminals SO they travel from the cell body (where they are produced) INSIDE the axon. The Golgi apparatus (in the cell body) loads up the important substances into transport vesicles (motor proteins) and they ‘walk’ using microtubules inside the axon in both directions (cell body to axon terminals and back)
What is anterograde transport?
The movement of material toward the axon terminals.
What is retrograde transport?
The movement of material back to the cell body.
What type of transport is A?
Anterograde transport
What type of transport is B?
Retrograde transport.
What are the 4 types of glial cells?
- Astrocyte
- Microglial
- Oligodendrocytes
- Schwann
Which glial cells are responsible for myelination?
Oligodendrocytes and Schwann cells
What is an astrocyte cell?
Star shaped glial cell.
What is the purpose of the astrocyte cell?
- Regulate local blood flow.
- Surround and monitor the activity of nearby neuronal synapses (possible participation in transmission of information between neurons (‘tripartite synapse’ - 3 way synapses) although this is controversial)
- Involved in the formation and pruning of synapses.
What is the purpose of the microglial cell?
The brain’s ‘cleanup crew’ - form a spherical containment zone around sites of injury or disease in the nervous system. They might also be involved in aspects of pain perception and neuronal remodeling.
What is the purpose of oligodendrocytes and Schwann cells?
Myelination
What is myelination?
The coating of axons in a fatty insulating substance (by oligodendrocytes and Schwann cells)
What is a nodes of Ranvier?
An uninsulated patch of axonal membrane.
What is the result of myelination?
A large increase in the speed with which electrical signals pass down the axon, jumping from one node to another.
What is the difference between oligodendrocytes and Schwann cells?
Oligodendrocytes are specific to the brain and spinal cord. Schwann cells provide myelination to the rest of the body.
How long does the myelination process continue in humans?
10 - 15 years (possibly throughout life)
What are some problems with glial cells?
Because they continue to divide throughout life, they can form many types of tumors, in response to injury cause the brain to swell (edema), and possible connection to diseases like Alzheimer’s.
Why do we say that axon resemble both a wire and a pipe?
Because like a pipe it is hollow and is used to transfer substances for the axons structure and function (anterograde and retrograde transport). It is like a wire because signals are electrically send on the exterior of the axon.
