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122 Cards in this Set
- Front
- Back
Is the autonomic nervous system considered to be a part of the CNS or PNS?
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PNS
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Explain the location of spinal nerves in relation to their corresponding vertebral levels in the upper and lower spinal cord.
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Upper spinal cord - levels correspond closely to vertebral levels
Lower spinal cord - levels are higher than vertebral levels |
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What neuronal contents are found in gray matter?
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neuronal somata, dendrites, axonal processes, glial cells
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What neuronal contents are found in white matter?
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pathways (tracts, fasciculi) containing myelinated axons and glial cells
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In the brain where is gray matter located in respects to white matter?
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gray matter is located outside (white matter is found deep to gray matter)
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In the spinal cord where is gray matter found compared to white matter?
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Gray matter is located centrally - gray matter is found deep to white matter
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define and give an example of a multipolar neuron
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(one axon, multiple dendrites)
interneurons |
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define and give an example of a bipolar neuron
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(one axon, one dendrite)
retinal ganglion cells, olfactory neurons |
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define and give an example of a pseudounipolar neuron
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(one axon)
Dorsal root ganglion |
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What is the RER of neurons called? More specifically, where is this RER found?
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Nissl substance
found in dendrites and NEVER in axons |
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free ribosomes are very characteristic of neurons. How are they arranged in the neuron?
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arranged in polyribosomal rosettes of 5-6 ribosomes forming a central core.
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This is a prominent organelle in many types of neurons. It is found in the cell body, dendrites, and within the axons.
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SER - occupies the space between the RER
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This organelle has Nissl bodies clustered on either side of it. It functions in protein glycosylation / modification
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Golgi apparatus
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This neuron "part" contains acid phosphatases and is involved with degradation of either internal or phagocytosed materials.
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lysosomes. (note: peroxisomes are not very numerous in neurons)
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What are lipofuscin granules?
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the "wear and tear" pigment: tend to accumulate in the neuronal cytoplasm with age.
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Where are mitochondria found in the neuron?
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found in all parts of the neuron
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neuronal mitochondria are in constant motion: they travel between stacks of ER in "roads" called __________.
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plasmastrassen
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Cilia - where found in neurons, function?
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cilia are sometimes found in neurons. Function ill-defined. (may be vestigal)
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Which one (axons or dendrites) appear to taper from the cell body outwards?
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dendrites taper (axons stay the same)
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Where in the dendrite are most synapses found?
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on dendritic spines
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dendritic spines are dynamic and can change shape in response to chronic stimulation. Why would they want to do this?
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1. To increase surface area for synaptic contact
2. To alter the physioelectrical properties of the dendritic surface. |
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Dendrites can alter their size and shape in response to chronic stimulation. How do they do this?
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By filopodeous outgrowth (dendritic branch will extend)
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There are two kinds of axons (classified on how far they project). What are they called, what is the difference and which are myelinated?
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1. local circuit neurons - project locally, unmyelinated
2. projection neurons - project across long distances, myelinated |
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What is the function of the axon hillock?
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Site of integration (summation) of all the incoming stimuli to the neuron. This is where the neuron "decides" wether to fire an AP or not.
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Which part of the axon does not contain RER or a Golgi apparatus?
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The axon cylinder
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Define axoplasmic flow - elaborate on the directions of flow.
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flow/transport of molecules throughout the axon. Flow can be anterograde (forward/away from cell body) or retrograde (backward/towards cell body)
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Fast axonal transport relies on microtubules and their associated motor proteins called ___________.
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Kinesins
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What would stimulate structural change in an axon?
How is this mediated? (which cell part) |
chronic stimulation, learning and memory, response to some forms of injury
mediated via axonal growth cones |
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Two molecular signals that the filopodia of growth cones look for are?
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N-CAM (cell adhesion molecule) &
NGF (neurotrophic agent - neuronal growth factor) |
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What are the three types of synapses?
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1. chemical
2. electrical 3. neuromuscular |
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chemical synapses release ______, _________ or _______ into the synaptic cleft.
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chemical signals
neurotransmitters neuromodulators |
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A chemical synapse that releases a neuromodulator acts via which mechanism?
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second messenger system response
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What exactly is an electrical synapse?
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A gap junction that allows direct communication between adjacent cells. (Uses ions, Na+, K+, Ca++)
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Of chemical and electrical synapses: which one is unidirectional? Which one is bidirectional?
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unidirectional - chemical
bidirectional - electronic |
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in the neuromuscular junction the neurotransmitter is always _______ and it is always ________ (+) or (-).
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acetylcholine
excitatory (+) |
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neurotransmitter receptors embedded in the postsynaptic membrane are usually what type of receptor/channel?
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usually chemically - gated ion channels
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Which is more abundant in the CNS - neurons or glial cells?
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glial cells (~10 times more)
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Are astrocytes and oligodendrocytes classified as microglia or macroglia?
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macroglia
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Where are protoplasmic astrocytes located?
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In the gray matter of the CNS
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Where are fibrous astrocytes located?
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In the white matter
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The functions of astrocytes are many. If summarized, what would you say they are?
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Support cells for the neurons
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What is the glia limitans and what makes it up?
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glia limitans - shields CNS from overlying pia mater and CSF; made from the cell bodies or end feet of astrocytes
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How do astrocytes contribute to the Blood-Brain-Barrier?
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by forming a wall of end feet that surrounds the parenchymal side of capillary endothelium
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Which one (oligodendrocytes or Schwann cells) can individually provide myelin for many different axons?
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Oligodendrocytes (Schwann cells can only provide myelin for one axon)
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Where are interfascicular oligodendrocytes found?
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inbetween nerve fibers in the white matter
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Are oligodendrocytes found in gray matter? If so, where are they found?
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Yes. They are found associating with nerve fibers or forming satellite cells that associate with the neuronal perikaryon
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Oligodendrocytes are found in the ____; Schwann cells are found in the _____.
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O's -> CNS
S -> PNS |
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What is the scoop on microglia?
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microglia are normally quiescent, but on occasion they can mediate neuro-immune interactions by becoming phagocytically active and demonstrating antigen presentation.
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What will activate microglia?
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cerebral trauma, ischemia, seizure activity, infection
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Where are ependymal cells found and what is their function?
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line the ventricles and central canal of spinal cord.
function - cilia produce current for directional flow of CSF. |
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What makes up the dura mater?
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a heavy connective tissue sheet covered by a thin layer of sinple squamous epithelium.
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What is the name of the space between the dura and the arachnoid?
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The subdural space
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How many choroid plexi do we have and where are they?
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Four. One in the medial wall of each lateral ventricle; one in the third and one in the fourth ventricles.
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Function of choroid plexus?
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make CSF from plasma
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Total volume of CSF made in the average human per day?
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~400 mL
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What are the ventricles embryologically derived from?
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the lumen of the neural tube
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What structure connects the lateral ventricles with the third ventricle?
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THe foramen of Monro (interventricular foramen)
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What structure connects the IIIrd ventricle with the IVth?
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The cerebral aqueduct (of Sylvius)
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How does the CSF exit into the subarachnoid space?
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via the IVth ventricle foramina: lateral (2) - Foramen of Luschka and medial - Foramen of Magendie
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Where is the vasculature that supplies the dura found?
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in the subarachnoid space
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What is the name of the structures that anchor the arachnoid menix to the pia mater?
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arachnoid trabeculae
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Which CSF cistern is used clinically to tap for CSF and at what part of the body is it at?
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The Lumbar Cistern
Vertebral levels L4-5 (the spinal cord ends at L1-2) |
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The choroid plexus secretes about 80% of CSF. Where does the other 20% come from?
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metabolic water (12%) and secretions by the ependyma of ventricles (8%)
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What types of molecules are transported through the blood brain barrier?
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ions and proteins
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How much CSF (on average) is found in the CNS?
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140 mL
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What is the relationship of glucose in the CSF vs. the plasma?
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CSF glucose is ~66% of plasma glucose
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Is there a Na+/K+/ATPase that maintains CSF concentrations?
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Yes - this pump is essential for maintaining ion concentrations in the CSF
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Compare protein levels in the CSF vs. the plasma. What are the contents of CSF protein?
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CSF protein is LOW compared to plasma protein.
CSF protein is mainly albumin (80%) with some gamma globulins (5-10%) |
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Are there red or white blood cells found in CSF?
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should be no RBCs
A few WBCs are normal (0-5/mL) |
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High RBC levels in the CSF could indicate __________?
High WBC levels in the CSF could indicate _________? |
RBCs-subarachnoid hemorrhage
WBCs-infection |
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Describe the circulation of CSF
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from ventricles (out the 3 foramina of the IVth ventricle) into the subarachnoid space - To superior sagittal sinus and it's lacunae - enters venous circulation
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What causes a movement of CSF throughout the CNS?
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Pressure differences cause CSF mvmnt. (venous circulation has low pressure, SAS has higher pressure, choroid plexus has an even higher pressure)
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Which type of hydrocephalus leads to increased intracranial pressure? What, in general, causes it?
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communicating hydrocephalus. Caused by
increased CSF production and normal reabsorption OR normal CSF production and decreased reabsorption |
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Noncommunicating hydrocephalus results from blocked CSF flow. what structures could be blocked to produce this?
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foramen of Monro, Luschka, cerebral aqueduct or decreased reabsorption across the arachnoid villi.
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Do axons of somatic motor neurons contain synapses in the PNS?
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NO. somatic motor neurons synapse in the ventral horn.
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Do axons of visceral motor neurons contain synapses in the PNS?
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YES. visceral motor neurons synapse, often in the sympathetic ganglion
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Preganglionic sympathetics arise from what spinal cord levels?
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T1-L2
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Preganglionic parasympathetics arise from what spinal cord levels?
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S2-4
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Where do dorsal and ventral roots join to form spinal nerves?
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at the intervertebral foramen
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How many vertebrae?
How many pairs of spinal nerves? |
33 vertebrae
31 pairs of spinal nerves |
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Where does C1 spinal nerve exit? What about C8?
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C1 exits ABOVE the C1 vertebra pedicle
C8 exits BELOW the C7 vertebra pedicle |
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What is different about the C1 spinal nerve compared to the other spinal nerves?
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C1 is somatic motor only. There is no DRG or dorsal root.
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Where do spinal cord levels exit after C7?
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Starting with spinal nerve C8, the nerves (and all spinal nerves below C8) exit below the corresponding vertebral pedicle.
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What do dorsal rami innervate?
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dorsal rami innervate the deep back muscles and the skin of the back of the head.
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Ventral rami may have up to 3 branches:
1. Gray communicating ramus ________. 2. White communicating ramus ______. 3. Ventral ramus ________. |
1. Grey communicating ramus is found in all spinal nerves
2. White comm. ramus is found from T1-L2 only. 3. Ventral ramus is a continuation to the periphery |
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Peripheral nerves are referred to as motor, sensory or mixed. However, what do ALL peripheral nerves have?
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ALL peripheral nerves carry visceral (sympathetic) efferents and afferents.
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What are the 4 cranial nerves that have autonomic components? (parasympathetic preganglionic)
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CN III oculomotor
CN VII facial CN IX glossopharyngeal CN X vagus |
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Cranial nerves that are SVE provide motor innervation to which muscles?
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SVE - special VISCERAL effer.
to skeletal muscles of pharyngeal arch derivation (larynx, pharynx, face, mastication) |
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Which CNs are SSA?
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CN II - sight
CN VIII -hearing, equilibrium |
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Which CNs are SVA?
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CN IX, VII - taste
Cn I - smell |
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Important cervical dermatomes:
C2 C6, C7, C8 (respectively) |
C2 - EOP
C6 - thumb, C7 - middle finger, C8 - little finger |
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What are the six internal bones of the skull?
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ethmoid, inferior nasal concha, palatine, vomer, lacrimal, ossicles
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Which bone makes up a portion of both the cranial vault and the internal bones?
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The ethmoid bone
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When the skull cap, brain and meninges are removed the cranial fossa are exposed. What are the three cranial fossae?
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anterior
middle posterior |
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The foramen cecum is found in the _________ cranial fossa. What structure passes through it?
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* anterior cranial fossa
* The emissary vein passes through it |
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Through which foramina do the posterior and anterior ethmoidal nerves and vessels pass?
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anterior and posterior ethmoidal foramina
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Through which foramen do the olfactory nerves (CN I) pass through?
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The cribiform plate
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The optic canal has what structures pass through it?
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optic nerve (CN II)
Opthalminc artery |
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Which structures pass through the superior orbital fissure?
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CNs III (oculomotor), IV (trochlear), VI (abducens), branches of V1 (opthalmic of trigeminal - frontal, nasociliary, lacrimal), superior opthalmic vein
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V2, the maxillary division of the trigeminal nv. passes through which foramen?
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foramen rotundum
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The foramen ovale has what structures pass through it?
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V3 (mandibular division of trigeminal)
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What passes through the foramen spinosum?
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middle meningeal artery
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which foramen do the internal carotid artery and carotid nerve plexus pass through?
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the carotid canal
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The lesser petrosal nerve is a branch of __________.
The greater petrosal nerve is a branch of _________. |
lesser petrosal -> branch of CN IX (glossopharyngeal)
greater petrosal -> branch of CN VII (facial) |
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what structures pass through the internal acoustic meatus?
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CN VII (facial)
CN VIII (vestibulocochlear) labrynthine artery |
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what structures pass through the jugular foramem?
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CN IX (glossopharyngeal)
CN X (vagus) CN XI (spinal accessory) inferior petrosal sinus sigmoid sinus posterior meningeal artery |
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What are the two layers of the dura mater?
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1. endosteal layer (bound by Sharpey's fibers to cranium)
2. menigeal layer |
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From what does the dura mater recieve its sensory innervation?
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mainly V1, V2, V3
also CNs X and XI |
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what is the name of the major blood vessel that supplies the dura mater?
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middle meningeal vessels
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A rupture in the middle meningeal vessels will result in a ___________ hematoma.
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extradural hematoma
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where is the falx cerebri found?
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the falx cerebri is found inbetween the cerebral hemispheres.
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a rupture in the superior cervical vein would cause what type of hemorrhage?
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subdural hemorrhage
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a cerebral aneurism would cause what type of hemorrhage?
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subarachnoid hemorrhage
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the common carotid artery is a branch of the _________ artery.
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brachiocephalic
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Which carotid has no branches in the neck?
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the internal carotid
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the vertebral arteries are branches off of the ____________ artery?
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subclavian
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which artery of the head and neck has lots of "bends" and therefore is susceptible to emboli lodging in these bends?
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the internal carotid
(bends appear as it passes through the cavernous sinus) |
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name the 6 arteries that contribute to the cerebral arterior circle
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1. internal carotid
2. PCA 3. MCA 4. ACA 5. Ant. comm. artery 6. Post. comm. artery |
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the opthalmic artery is a branch of which artery?
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the internal carotid
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T/F: the retina has arteries.
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FALSE: the retina is avascular
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there are anastomotic connections between the internal and external carotids. Describe 3 of them.
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1. dorsal nasal (from IC to opthalmic) and angular (from EC to facial)
2. dorsal nasal to infraorbital (EC to maxillary) 3. supraorbital (IC) and frontal (EC) |
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What is the common drainage point for the following veins: supraorbital, supratrochlear, dorsal nasal, pterygoid plexus, emissary, opthalmic. Clinical significance?
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The canvernous sinus is the common drainage point. Bacteria that enter the cavernous sinus have easy access to the CSF -> result is meningitis
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