Lecture 1 (applied Neuroscience, Corticospinal Tracts, Motor System Activation) Flashcards
What are the principal roles of the NS?
-cognitive functions
-sensory-motor functions
-motivation and emotion
-regulatory function and homeostasis (autonomic NS)
What is the functional unit of NS? What does it consist of?
Neuron; soma, dendrites, axon and presynaptic terminals
What are the four different types of neurons?
-Motor
-Sensory
-Interneuron
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What does gray matter contain?
cell body/soma, nuclei or ganglia
What does white matter contain?
axons with myelin
Where is gray and white matter found in the brain? Spinal cord?
Brain - gray outside and white inside
SC - gray inside and white outside
What are fasciculi/fasciculus?
white matter pathways or tracts
What is a nucleus?
group of functionally related nerve cells
What is ganglia?
group of multiple nerve cells
What is a column or tract? Examples?
group of nerve cell bodies and their axons that are related in function
Ex. cerebral cortex and spinal cord
What does the CNS consist of?
spinal cord and brain
What does the PNS consist of?
-autonomic NS (parasympathetic and sympathetic)
-peripheral nerves -> cranial nerves (exception CN II)
Posterior root ganglion (ganglia)
group of nerve cell bodies lying in a peripheral nerve root (forms visible knot)
Root or ramus
peripheral structure w/ parallel axons
Afferent vs efferent
Afferent: input, going towards the brain and spinal cord
Efferent: output
What is the sequence sensory info travels?
sensory neuron, posterior root and ganglion -> synapses and dendrites in SC -> anterior horn cell -> motor neuron, anterior root -> nerve root
What is the parasympathetic NS know as? What type of nerves?
“rest and digest”; cranial and sacral
What is the sympathetic NS known as? Where do the nerves come from?
“fight or flight”; thoracic and lumbar
What are glial cells? What does glial mean?
Glial cell: support cells, provide critical support network for neurons
Glial = “glue”
What are the four types of glial cells?
Astrocytes “star”, oligodendrocytes, ependymal cells, microglia cells
What are the purposes of astrocytes? What % of brain cells?
-signal clean up crew, nutrition for neurons, involved in memory, release neurotransmitters
-30-65%
What is the purpose of oligodendrocytes?
provide myelin in CNS
What are the purposes of ependymal cells?
produce cerebrospinal fluid, waste clearance
What is the purpose of microglial cells? What % of brain cells?
function as immune system in NS
10%
What mediates neuroinflammation?
microglia and astrocytes
**What conditions are abnormal microglia found in?
Alzheimer’s, MS, Parkinson’s, head injury
What NS are satellite cells found? Functions?
PNS
-surround neuron cell bodies in ganglia
-regulate O2, CO2, nutrient and neurotransmitter levels around neurons in ganglia
What NS are Schwann cells found? Functions?
PNS
-myelination of peripheral axons
-participate in repair process after injury
What cells are found in CNS?
oligodendrocytes, astrocytes, microglia, ependymal cells
How does MS occur? What NS does it impact?
immune system attacks oligodendrocytes; CNS disease
What happens in Alzheimer’s disease?
microglial increase neuroinflammation (release of cytokines and free radicals) which lead to beta Amyloid plaques
What are the three planes a brain can be cut?
sagittal, brain coronal, brain horizontal
What areas of the brain are known as the “planning area”?
supplementary motor area and premotor cortex
What area of the brain is the “initiator”?
primary motor cortex
How many lobes are in the brain? What are they?
4; frontal, parietal, occipital, temporal
How many layers or lamina are in the motor cortex?
6
What is a Betz cell? Where do most originate from? What do they synapse w/?
-type of pyramidal neuron; connects to axon and descend to spinal cord via corticospinal tract
-over 50% from primary motor cortex, from lamina V and VI
-anterior horn cells
Pathway for motor impulses
primary motor cortex -> through brain -> brainstem (midbrain, pons, medulla) -> through spinal cord
What are the two corticospinal tracts?
lateral corticospinal tract and anterior corticospinal tract
Lateral vs anterior corticospinal tract
-Lateral: crosses at cervicomedullary junction (decussation); right side of the brain controls left side
-Anterior: doesn’t split, goes to both sides and ends at mid thoracic
**What are the four areas of the motor system?
- Posterior cortex (primary somatosensory and parietal association cortex)
- Prefrontal cortex
- Premotor cortex
- Primary motor cortex
What are functions of the four
