Intro to Neuro Flashcards
what is the function of the nervous system ?
- enables the body to react continuous change in its internal and external environments
- controls and integrates bodily activity
what are the two specialized cells in the nervous system ?
neurons and neuroglia
what are neurons ?
sensory + motor
what are neuroglia ?
Schwann cells
which specialized cell in the nervous system “transmits information and its myelinated cells transmit signals faster” ?
neurons
which specialized cell in the nervous system “non neural, non excitable cells, 5x as abundant as neurons and support cells for neurons”
neuroglia
describe the neuroglia cells of the CNS:
oligodendroglia, astrocytes, ependymal cells and microglia
describe the neuroglia cells of the PNS:
satellite cells, Schwann cells
what happens at the cell body ?
this is what’s going to integrate all of the signals together and decide whether or not the neurone is actually going to send an AP
what happens at the trigger zone ?
where all of those pieces of information are summed together
what happens when you reach threshold …
you get an action potential
what is an axon ?
a wire connecting the cell body to the periphery, the signals is transmitted down the axon to reach wherever its going
what does myelin sheath do ?
helps with a faster conduction
what does the axon terminal do ?
end of the neuron, where you are going to see a synapse
what do the dendrites do ?
what collect the information, going to synapse with any number of other rings, typically other neurons
where is a multipolar motor neuron found ?
ANS and skeletal muscle control
where are pseudounipolar sensory neurons found ?
sensory signalling
difference between a pseudounipolar sensory neuron and a multipolar motor neuron:
going opposite direction because sensory neurones carry info from the periphery to your brain, whereas motor neurons carry info from your brain to the periphery
what is a collection of cell bodies called ?
a ganglia
what are neuroglia ?
supportive cells for neurons
what do CNS - oligodendrocytes do ?
- forms several myelin sheaths
- myelinated sections of several axons
what do PNS - Schwann cells do ?
- forms one myelin sheath
- myelinated one secretion of an axon
what can u say about the structure of oligodendrocyte and Schwann cells ?
these cells mirror each other
can myelinated and unmyelinated axons both have Schwann cells ?
yes
describe the structure of oligodendrocytes :
- single cell body
- interacting with multiple axons and thus multiple neurons
describe the structure of Schwann cells:
- nucleus location is different because Schwann cells exist as a single myelin wrapping
- the nucleus of it exists as part of the myelin sheath
is multiple sclerosis slow or fast progession ?
slow progression
what is the onset ages of multiple sclerosis ?
20 - 50
life expectancy decreases _____ years when diagnosed with multiple sclerosis ?
7 - 14
is there a cure to multiple sclerosis ?
no cure
can oligodendrocytes repaire themseleves ?
no
describe progression of Guillain-barre syndrome:
progression over days to weeks
what are does guilain-barre syndrome afflict ?
any age (more common with over 40)
is multiple sclerosis CNS or PNS ?
CNS
is Guillain-barrre syndrom CNS or PNS ?
PNS
what is the recover rate of Guillain-barre syndrome ?
80-90% recover within 2-4 weeks
can Schwann cells repair themselves ?
yes
describe propagation + depolarization :
electrical signal propagation is caused by progressive depolarization of the cells
what is resting membrane potential ?
-80mV
what does the plasma membrane alone the outside do ?
separates the interior of the cell from the exterior of the cell
what is the “trigger zone” ?
where multiple stimuli (received through dendrites) can sum to initiate an “action potential”
describe the four steps occurring during signal propagation + depolarization:
a) resting membrane potential @ - 80mV
b) Na+ rushes in via voltage gated channels = depolarization
c) K+ flows out of cell = repolarization
d) Na+/K+ exchange pump restores balance of ions
what two factors does conduction velocity depends upon:
- large fiber diameter = faster conduction velocity
- myelination = faster conduction velocity (saltatory conduction)
what is the term described by “ once a synaptic cleft is reached, neurotransmitters must be released to continue signal transmission from one neuron to another neuron or effector organ” ?
neuronal synapse
what do we use when the electrical signal cant jump across that sign up, or that gap…
neurotransmitters
in order to continue the transmission from one neuron to another what must we release ?
neurotransmitters
what are the steps of a neuronal synapse ?
- impulse arrives at end bulb
- voltage gates Ca2 channels open, Ca2 flows into cell
- increased Ca2 causes neurotransmitter release
- neurotransmitters cross synaptic cleft to bind receptors on postsynaptic membrane
- voltage gated channels open, allowing Na to enter cell
- post synaptic cells depolarizes
- nerve impulse initiated
what is the function of the axon ?
conduct electrical synapse
what is the function of the trigger zone ?
receive input signals
what is the function of the axon terminal ?
area where electrical activity is somewhere prior to transmission
what is the function of the nucleus ?
contains genetic information of cell
what is the function of the cell body (soma) ?
contains nucleus, protein synthesis, AP generated here
what is the function of the node of ranvier ?
spaces between myelin (for salutary conduction)
what are myelin sheaths made from ?
formed from Schwann cells
what are the two division of nervous system structures ?
anatomical/structural and functional
is the CNS anatomical/structural or functional ?
anatomical/structural
what are the parts of the CNS ?
brain and spinal cord
what is the peripheral nervous system ?
everything either than brain and spinal cord
what us the autonomic nervous system ?
- viscera and glands
what is the viscera ?
involuntary smooth muscle
what is the somatic nervous system ?
everything else (either than visera and glands)
where does sensory information originate ?
in the peripheral nervous system
where does the PNS synapse ?
in a ganglia
describe cranial nerves vs spinal nerves:
basically the same thing
what are the two divisions of the nervous system ?
CNS and PNS
what are the two subdivision of the PNS ?
sensory and motor
what two divisions does sensory further divide into ?
somatic (body) and autonomic)
what two division does the motor further divide into ?
autonomic and somatic
what does motor autonomic divide into ?
sympathetic and parasympathetic
what is the sympathetic nervous system ?
fight and flight
what is the parasympathetic nervous system ?
rest and digest
what is your gray matter ?
ganglion and cortex & nucleus
what is your white matter ?
pathway and nerves
what is the gray and white matter in the CNS ?
gray = cortex and nucleus
white = pathway
what is the gray and white matter in the PNS ?
gray = ganglion
white = nerve
where is white matter found in the brain ?
inside
where is gray matter found in the brain ?
outside
what are the two types of cells in the nervous system ?
neurons and neuroglia
what are the two types of neurons ?
multipolar motor neurons & pseudounipolar sensory neurons
what are the two types of neuroglia ?
oligodendrocytes & schwann cells
why does neural signal propagation occur ?
because of progressive cell depolarization +neurotransmitter release at the synaptic cleft
what are the three parts of the brainstem ?
- midbrain
- pons
- medulla oblongata
how many hemispheres overlie the brainstem ?
two
what are the hemispheres of the brain divided by ?
longitudinal fissure
how do hemispheres of the brain communicate by ?
corpus callosum
_______ tract is a bundle of axons ?
white fiber
what is a fissure ?
deep groove
what is a sulcus ?
shallow groove
what is a gyrus ?
ridge
what are the lobes of the brain ?
- parietal lobe
- frontal lobe
- occipital lobe
- temporal lobe
what is the responsibility of the frontal lobe ?
- behaviour and emotional control
- personality
- problem solving (reasoning & judgement)
what happens if you damage the Broca’s area ?
if damaged, difficulty producing language
in what lobe is the Broca’s area located ?
frontal lobe
what is the responsibility of the parietal lobe ?
- integrated sensory information
- processing and perception of touch, pain and proprioception
what lobe is responsible for voluntary motor activity (pre-central gyrus) ?
frontal lobe
what lobe is responsible for post central gyrus sensory reception (touch) ?
parietal lobe
perception of language is found where in the brain ?
wernicke’s area
in what lobe is the wernicke’s area found ?
parietal lobe
what happens if there is damage to the wernicke’s area ?
if damaged, difficulty understanding speech
what is the responsibility of the temporal lobe ?
- auditory information processing
- processes language (semantics and naming)
- process smell
what lobe is responsible for process of smell ?
temporal lobe
what is the responsibility of the occipital lobe ?
receives and processes visual information
what are the three parts of the diencephalon ?
- thalamus
- hypothalamus
- pituitary gland
what is the responsibility of the thalamus ?
gatekeeper for sensory information
what is the responsibility of the hypothalmus ?
maintain homeostasis
what is the responsibility of the pituitary gland ?
secretes hormones
what does the midbrain do ?
connect brainstem to cortex
what do the pons do ?
- connect cerebrum to cerebellum + medulla
- transmit sensory information to brain from periphery
what does the medulla oblongata do ?
- continuous with spinal cord
what are the two parts of the medulla oblongata ?
pyramid (center) and olive (lateral)
what is the function of the cerebellum ?
- coordination of voluntary movement
- controls balance and equilibrium
- integrated proposed movement with current body position
- monitors and makes adjustments to correct motor plan
what are the two types of matter of the spinal cord ?
white and gray
describe white matter:
- periphery
- longitudinal tracts of axons
sensory (to brain) & motor (from brain)
in what matter fo bundles of axons travel from you brain though the spinal cord?
white matter
why is white matter “white” ?
because of myelin on axons
describe gray matter:
- central H
- contains neuron cell bodies and glial cell bodies
dorsal horn vs ventral horn
dorsal horn = SENSORY
ventral horn = MOTOR
in which matter do synapses occur ?
gray matter
in which matter is the dorsal/ventral horn found ?
gray matter
what are ventricles ?
- large fluid filled cavities in the brain
- produce CSF which surround brain and spinal cord within the subarachnoid space
what are the three brain/spinal cord meninges ?
dura mater, arachnoid mater and pia mater
describe the dura mater:
- thickest coding
- on the exterior
- to protect the brain
- thickest layer
describe the arachnoid mater:
- white and whispy like a spider web
- little thinner
describe the Pia mater:
- thinnest
- as if been spray painted onto the brain
what do meninges do ?
- protect CNS from mechanical damage
0 supportive framework for vasculature
which meninges layer is right next to the skull ?
dura mater
what is an extracerebral hemorrhage ?
hemorrhage outside of the cranial cavity
describe the spinal cord meninges:
same three layers as brain
what happens during a lumbar puncture + epidurals ?
sticking needle in lumbar region to access spinal cord
why are lumbar puncture + epidurals done ?
to sample cerebral fluid
what do ventricles produce ?
CSF
what are the two enlarged areas of the spinal cord ?
1) cervical enlargement
2) lumbar enlargement
what are the two plexus’ of the cervical enlargarment of the spinal cord ?
cervical and brachial plexus
what are the two plexus’ od the lumbar enlargement of the spinal cord ?
lumbar and sacral plexus
where does the spinal cord end ?
L1/L2 at conus medullaris
between dorsal and ventral which is anterior/posterior ?
Dorsal = posterior
ventral = anterior
what are the contents the ventral root ?
motor neurons
what are the contents of the dorsal root ?
sensory neurons
what are the contents of the dorsal root ganglion ?
cell body of sensory neurons
what are the contents of the spinal nerve ?
sensory + motor neurons (goes through intervertebral foramen)
what are the contents of the ventral rami ?
sensory + motor neurons + autonomic (most named nerves)
what are the contents of the dorsal rami ?
sensory + motor neurons - to deep back & Z-joints (smaller branches)
what two things merge with each other to form a network called a “plexus” ?
anterior rami with another anterior rami
what is a dermatome ?
is an area of the skin that is innervated by a single spinal nerve
what is a cutaneous ?
is an area of the skin innervates by a specific cutaneous nerve
the PNS contains both ___ and ___ :
motor and sensory information
how does motor information travel ?
travelling from the spinal cord to the periphery via the anterior (ventral) root
how does sensory information travel ?
travelling from the periphery to the spinal cord via the posterior (dorsal) root
