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29 Cards in this Set
- Front
- Back
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What are the two main cell types that make up the nervous system?
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Neurons and neuroglia (aka glia cells)
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what is the role of glia?
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nourish, protect, support, make myelin (Schwann cells PNS, oligodendocytes CNS)
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Describe the parts of a neuron
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dendrites+axon=processes
dendrites receive signal and pass to cell body cell body (aka soma) contains the nucleus axon carries the signal away from the cell body, may be covered in a myelin sheath and ends in an axon terminal |
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What is a synapse?
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the synapse is the relay point or information between two neurons, where neurotransmitters are released between the axon terminal of the presynaptic cell and the dendrites of the postsynaptic cell
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Describe the flow of an impulse
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Presynaptic cell dendrites→ cell body/soma→ axon terminals—(synapse)→ postsynaptic cell dendrites…. And on!
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Describe a nerve/tract
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A bundle of processes with its associated connective tissue covering and vasculature
Often white from myelination In the CNS, we call it a tract In the PNS, we call it a nerve |
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What are the three types of neurons?
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Sensory (afferent, arrive to brain)
Motor (efferent, exit brain) All the rest: Interneurons |
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What are the 3 common ways to dividing the nervous system?
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1) All white matter(processes) and grey matter(cell bodies)
2) CNS(brain +spinal cord) and PNS (all other nervous tissue) 3) somatic and visceral |
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Why is white matter white?
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Due to myelination. Though not all axons are myelinated, some are covered in Schwann cell or oligodendrocyte neurolemma (myelin sheaths), which is mostly fat and appears white.
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What do you call grey matter and white matter in the PNS?
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grey=cell bodies=ganglions
white=processes=nerves |
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What do you call a nerve with both sensory afferents and motor efferent inside? Whats an example?
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A mixed nerve has both afferents an efferents bundled together. Spinal nerves are an example: both afferents and efferents are often packaged together when they have the same target region to innervate
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What are the three types of nerves in the PNS?
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Cranial, spinal, visceral
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How many spinal nerves are there? What is the breakdown by cervial, thoracic, sacral and coccygeal categories?
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31 pairs: 8 cervial, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
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Where are spinal nerves in relation to their respective vertebrae?
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Up until T1, they lie above their respective vertebrae, however because there are 8 cervical nerves and only 7 cervical vertabrae, T1 nerve must be below/inferior to the T1 vertebrae (and all following nerves will be inferior to thier vertebrae too)
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How many pairs of cranial nerves are there?
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12
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What does the somatic nervous system control?
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skeletal muscle. Note that despite intuition, the diaphram is somatically innervated
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What is the somatic nervous system derived from in neural development?
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Somites
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How many neurons does it take to connect a motor or sensory neuron from PNS--> CNS within the somatic (voluntary, skeletal muscle) nervous system
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Monosynaptic!
Unlike the visceral system, it only takes one neuron to get the signal from the target to the CNS ( note this could mean it would just be from target to ganglion, not all the way to the brain) |
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What does GSA and GSE stand for?
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general somatic (not sensory!) afferents and efferents, respectively
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What do GSAs sense in the skin?
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pain, temp, touch, pressure
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What do GSAs sense in the muscle?
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pain, proprioception
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label the following
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grey/white matter
dorsal/ventral horn dorsal root ganglion spinal nerve ramus dorsal ramus ventral ramus A/P, D/V orientation |
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what do nerves in the dorsal ramus contact?
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intrinsic (originate, insert on, act in one place) back muscles and the overlying skin
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What do nerves of the ventral ramus contact?
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everything but the intrinsic back muscles
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label the 3 horns of this section of spinal cord
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-afferents (dorsal horn, aka posterior horn)
-efferents(ventral horn, aka anterior horn) -visceral afferents/efferents (lateral horn in 14/31 segments, T1-L2) |
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What does the dorsal ramus innervate specifically?
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from superficial to deep:
skin splenius muscles erector spinae (i long for spinach: illiocostalis, longisimus, spinalis) transversospinal muscles |
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What do intercostal nerves of the somatic system innervate?
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thoracic wall (motor) and the parietal pleura and associated skin (sensory)
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clinical correlate: spinal cord injury
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can cause paraplegia, tetraplegia depending on the sinal cord segment of complete injury
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What can you use to detect where the injury is?
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use dermatome and myotome mapping to figure out what areas are no longer responsive (can't feel there in dermatome and can't move there in myotome) and deduce which spinal nerves should be innervating the region
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