Nervous System 1, 2, & 3 Flashcards Preview

A&P Exam 3 > Nervous System 1, 2, & 3 > Flashcards

Flashcards in Nervous System 1, 2, & 3 Deck (83)
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What does the central nervous system consist of?

The brain and spinal cord.


What does the Peripheral nervous system consist of?

The nerves and ganglia.


What is the afferent nervous system?

The sensory nervous system.


What is the efferent nervous system?

The motor nervous system.


Describe somatic sensory:

The detection of stimuli that we consciously perceive.


Describe visceral sensory:

The detection of stimuli that we do not consciously perceive. (blood vessels, internal organs)


Describe the somatic motor system:

The transmission of signals from the CNS to voluntary skeletal muscles.


Describe the autonomic motor system:

The transmission of signals from the CNS without conscious control.


What are the 5 characteristics of neurons?

1. Excitability (response to stimuli) or inhibitory
2. Conductivity (electrical charges across membrane)
3. Secretion (NT release)
4. Extreme Longevity (with us from birth)
5. Amitotic (do not replicate)


Describe dendrites:

Short processes extending from cell body. They receive input and transfer it to the cell body.


Describe axons:

A longer extension of the cell body that makes contact with another cell. It includes the axon hillock, synaptic knobs, and synaptic vesicles.


What does the cytoskeleton consist of?

Microfilaments, neurofilaments, and neurofibrils.


What is anterograde transport?

Signals from the cell body to the synaptic knobs.


What is retrograde transport?

Signals from the synaptic knobs to the cell body.


What are multipolar neurons?

The most common type with many dendrites and only 1 axon.


What are bipolar neurons?

They only have 1 dendrite and 1 axon. (Unique to the retina)


What are unipolar neurons?

They have 1 short neuron process that emerges from the cell and branches like a T.


What are anaxonic neurons?

They have only dendrites and no axons. They can produce electrical charges but no action potentials because their signals travel short distances.


What type of neurons does the sensory nervous system consist of?

Unipolar and bipolar. Their cell bodies are usually in the posterior root ganglia, outside CNS.


What type of neurons does the motor nervous system consist of?

All multipolar. Most cell bodies are in the CNS.


Describe interneurons:

Also association neurons. They are entirely within the CNS and receive, process, and store information. Generally multipolar.


What are the 2 types of synapses:

Chemical and electrical.


Describe chemical synapses:

The release on NT's and there is usually a delay.


Describe electrical synapses:

2 neurons are physically bound together. These signals are faster because there is no delay. In limited regions of brain and eyes.


What are glial cells?

Small non-excitatory cells that are in the PNS and CNS.


What is the function of glial cells?

To protect and nourish the neurons. They develop before neurons.


What are the functions of astrocytes?

1. Help form the blood brain barrier
2. Control movement of substances between blood and interstitial fluid.
3. Form structural network.
4. Assist neuronal development.
5. Occupy the space of dying neurons.


What are ependymal cells?

They are glial cells that line the cavities of the brain and spinal cord. They help to form the choroid plexus which forms the cerebrospinal fluid.


What are microglia cells?

Small glial cells that engulf infectious agents and eat away dead neuronal debri.


What are oligodendrocytes?

Large cells with multiple branches that wrap around an axon insulating them with a myelin sheath. They can myelinate many axons at once in the CNS.