TEAS 7 - Science (Nervous System) Flashcards
What do we call the folds on the surface of the cerebrum?
gyri
What do we call the grooves between the folds of the cerebrum?
sulci
What do we call the deep grooves between the folds of the cerebrum?
fissures
The ___ is the area between the cerebrum and brainstem.
diencephalon
The ___ is the portion of the brain in the posterior inferior region that processes information for coordination and movement.
cerebellum
The ___ is the position of joints.
proprioception
What is the specialized area in the brain that helps with the understanding of speech?
Wernicke’s Area
What is the specialized area in the brain that has to do with producing meaningful speech?
Broca’s Area
A ___ is a whitish fiber or bundle of fibers that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs.
nerve
The ___ ___ carries genetic information, maintains the neuron’s structure, and provides energy to drive activities.
cell body
___ are fibrous roots that branch out from the cell body, receiving and processing signals from the axons of other neurons.
Dendrites
The ___ ___ ___ is the processing center of the body consisting of the brain and spinal cord.
Central Nervous System (CNS)
___ are chemical substances that are released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, cause the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.
neurotransmitters
What are the long threadlike parts of nerve cells along which impulses are conducted from the cell body to other cells?
axon
___ ___ are found at the terminal ends of axons and are typically the sites where synapses with other neurons are found; neurotransmitters are stored there to communicate with other neurons via these synapses.
Axon terminals
___ ___ are the nerve fibers responsible for bringing sensory information from the outside world into the brain.
Sensory nerves (afferent nerves)
Sensory nerves are considered to be (afferent/efferent) nerves.
afferent
___ ___ transmit impulses from the CNS out to the peripheral organs to cause an effect or action.
Motor nerves
Motor nerves are considered to be (afferent/efferent) nerves.
efferent
The ___ ___ ___ is a component of the peripheral nervous system that regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal.
Autonomic nervous system (ANS)
What are the 3 divisions of the autonomic nervous system?
sympathetic, parasympathetic, and enteric
The autonomic nervous system is a(n) (voluntary/involuntary) system.
involuntary
A ___ is the junction between two nerve cells, consisting of a tiny gap across which impulses pass by diffusion of a neurotransmitter.
synapse
What are the organs of the central nervous system (CNS)?
brain and spinal cord
What are the organs of the peripheral nervous system (CNS)?
cranial nerves, spinal nerves, and the autonomic nervous system
The major parts of the brain include the outer ___ and the inner ___.
cerebrum
diencephalon
How does the brain connect to the spinal cord?
the brainstem
The cerebrum is ___ portion of the nervous system.
largest
The cerebrum consists of two ___ (right and left) connected by a white matter bridge called the ___ ___.
hemispheres
corpus callosum
On the surface of the cerebrum are folds called ___ and grooves called ___. Deep grooves are known as ___.
gyri
sulci
fissures
What are the lobes of the cerebrum?
the frontal, parietal, temporal and occipital lobes
The ___ lobe processes information involving motor movements, concentration, planning, and problem solving as well as the sense of smell and emotions.
frontal lobe
If a patient comes to the clinic and they are experiencing issues with motor movement, concentration, and planning, what lobe is most likely affected?
frontal lobe
The ___ lobes process sensory information with the exception of hearing, smell, and vision.
parietal lobes
The ___ lobes process information related to hearing, smell, and memory as well as abstract thought and making judgments.
temporal
The ___ lobe processes visual information.
occipital
The occipital lobe processes ___ information.
visual
Along the superior aspect of the cerebrum lies the ___ fissure that divides the parietal lobes.
longitudinal fissure
The ___ fissure (Sylvian fissure) is located on the lateral aspect and separates the temporal from parietal lobes.
lateral fissure
One sulcus called the ___ sulcus is located midway on the lateral aspect of the cerebrum and separates the frontal from the parietal lobes.
central sulcus
Deep in the lateral fissure is the ___ which is often referred to as a fifth lobe of the cerebrum.
insula
The ___ lies between the brainstem and cerebrum.
diencephalon
What are the important structures of the diencephalon?
thalamus and hypothalamus
The ___ is the largest part of the diencephalon.
thalamus
The thalamus carries all ___ information to the cerebral cortex except for the sense of ___. It is sometimes referred to as a relay station for sensory information.
sensory
smell
Sensory information that the thalamus carries includes ___, visual, and ___ information.
auditory
motor
The thalamus is also intimately involved in ___ due to its connections to the limbic system.
emotions
The hypothalamus lies ___ and anterior to the thalamus.
inferior
The ___ lies inferior and anterior to the thalamus.
hypothalamus
A stalk-like projection called the ___ projects anterior and inferior and connects to the pituitary gland.
infundibulum
The infundibulum is a stalk-like projection of the hypothalamus that connects to the ___ ___.
pituitary gland
The hypothalamus is intimately connected with the ___ ___ and helps to regulate hormones.
endocrine system
The ___ also regulates body temperature, thirst, hunger and sexual drive and is involved in processing emotions, mood, and sleep along with the reticular activating system.
hypothalamus
Posterior to the diencephalon is the ___ gland which is a small endocrine gland that secretes the hormone melatonin.
pineal gland
Posterior to the ___ is the pineal gland which is a small ___ gland that secretes the hormone melatonin.
diencephalon
endocrine
What does the pineal gland secrete?
melatonin
What does melatonin do?
helps to regulate sleep-wake cycles
Fill in the blanks:
Cerebrum –> ___ –> ___ –> Spinal Cord
Diencephalon
Brainstem
What does the brainstem consist of?
midbrain
pons
medulla oblongata
The ___ ___ is the most inferior portion of the brainstem and contains a number of centers for controlling heart rate, respiration, swallowing, vomiting and blood vessel diameter.
medulla oblongata
What is the most inferior part of the brainstem?
medulla oblongata
Spinal pathways called tracts continue through the ___ connecting the spinal cord with the brain.
medulla
The ___ is the middle section of the brainstem. The pons contain spinal cord tracts as well as nuclei that help to control respiration and sleep.
pons
What is the middle section of the brainstem?
pons
The ___ is the most superior portion of the brainstem and helps to process motor and hearing information.
midbrain
What is the superior part of the brainstem called?
midbrain
What is located throughout the brainstem and is primarily concerned with regulating sleep-wake cycles?
the reticular formation
The limbic system consists of portions of both the ___ and diencephalon
cerebrum
The limbic system is involved in the ___ as well as reproduction and ___.
emotions
memory
The ___ ___ is involved in the emotions as well as reproduction and memory.
limbic system
The spinal cord begins at the ___ ___ of the occipital bone and extends to the second ___ vertebra.
foramen magnum
lumbar
The spinal cord ends in a cone-like structure called the ___ ___.
conus medullaris
Where does the spinal cord begin?
foramen magnum
Where does the spinal cord end?
second lumbar vertebra
A structure known as the ___ ___ (horse’s tail) extends from the inferior end of the spinal cord.
cauda equina
The cauda equina (horse’s tail) consists of nerves that extend downward to exit the foramen of the ___ and ___ vertebrae.
lumbar
sacral
The spinal cord consists of a core of ___ matter surrounded by white matter.
gray
The white matter is divided into sections called ___ (or columns). There are posterior, ___, and anterior columns.
funiculi
lateral
The gray matter is divided into ___, so there are ___, lateral and anterior horns.
horns
posterior
Both sides of the spinal cord are connected by the posterior and anterior gray ___. There is a central ___ carrying cerebral spinal fluid in the center.
commissures
canal
There is a large groove in the front of the spinal cord called the ___ ___ fissure and a shallow groove in the back called the ___ ___ sulcus.
anterior median fissure
posterior median sulcus
Both the brain and spinal cord are covered by the ___.
meninges
What are the 3 layers in the meninges?
dura mater
arachnoid mater
pia mater
There are 3 layers in the meninges, these include the ___ dura mater, the ___ arachnoid mater, and the ___ pia mater.
outer
middle
inner
There is a space between the arachnoid and pia mater called the ___ ___ which carries cerebral spinal fluid.
subarachnoid space
Where is the cerebral spinal fluid found?
a space between the arachnoid and pia mater called the subarachnoid space
What is the subarachnoid space?
the space between the arachnoid and pia mater
The space between the dura mater and the vertebrae is called the ___ space.
epidural
The epidural space is the space between the ___ ___ and the ___.
dura mater
vertebra
Where is the epidural injection inserted into?
the epidural space
Cerebral spinal fluid is produced by structures in the brain called ___ ___.
choroid plexi
Where are choroid plexi located?
in hollow structures in the brain called ventricles
___ ___ fluid is produced by structures in the brain called choroid plexi which are located in hollow structures in the brain called ___
Cerebral spinal fluid
ventricles
There are 2 lateral ventricles, a 3rd and 4th ventricle which connect to the ___ ___ of the spinal cord.
central canal
The CSF is absorbed by structures called ___ ___ or villi located in the arachnoid mater.
arachnoid granulations
Where is CSF absorbed?
arachnoid mater
An abnormal buildup of CSF is called ___.
hydrocephalus
Hydrocephalus can be treated by ___ or a device called a shunt that drains the excess ___ into the chest or abdomen.
surgery
fluid
The peripheral nervous system includes the ___.
cranial nerves
spinal nerves
autonomic nervous system
The peripheral nervous system is divided into two systems. What are they?
somatic nervous system
autonomic nervous system
The somatic nervous system controls ___ information such as with skeletal muscles.
voluntary
The autonomic nervous system controls ___ information such as with organs.
involuntary
There are ___ pairs of cranial nerves, and each nerve has a unique name and a different function.
12
Some nerves carry ___ information, some carry motor information and some carry ___ sensory and motor information.
sensory
both
___ ___, the olfactory nerve carries the sense of smell.
Cranial nerve I
___ ___, the optic nerve carries the sense of vision.
Cranial nerve II
___ ___ ___, the oculomotor, trochlear, and abducens nerves work together to move the eyes.
Cranial nerves III, IV, VI
___ ___, the trigeminal nerve carries sensation from the face and motor information to the chewing muscles or muscles of mastication which include the temporalis and masseter muscles.
Cranial nerve V
___ ___, the facial nerve carries sensory information for taste from the anterior 2/3 of the tongue and motor information to the muscles of facial expression.
Cranial nerve VII
___ ___, the auditory or vestibulocochlear nerve carries information for hearing, balance, and equilibrium.
Cranial nerve VIII
___ ___, the glossopharyngeal nerve carries sensory information for taste from the posterior 1/3 of the tongue and motor information to the swallowing muscles.
Cranial nerve IX
___ ___, the vagus nerve carries sensory and motor information to and from the organs.
Cranial nerve X
___ ___, the spinal accessory nerve carries motor information to the sternocleidomastoid and trapezius muscles
Cranial nerve XI
___ ___, the hypoglossal nerve carries motor information to the tongue
Cranial nerve XII
There are 31 pairs of spinal nerves and these are named after where they originate in the ___ ___.
spinal cord
The spinal nerves include ___ cervical, ___ thoracic, ___ lumbar, ___ sacral, and ___ coccygeal.
8, 12, 5, 5, 1
Spinal nerves are formed by ___ and ___ nerve roots. The nerves branch to the body with some nerves traveling to the autonomic nervous system.
dorsal
ventral
Spinal nerves carry both ___ and ___ information.
sensory
motor
The body can be divided into sections called ____ that represents a specific area of the body innervated by a spinal nerve.
dermatomes
Dermatomes are important in helping to localize peripheral nervous system ___.
injuries
What are important in helping to localize peripheral nervous system injuries?
dermatomes
The ___ ___ ___ (ANS) can control respiratory, cardiovascular, urinary, digestive and reproductive functions.
autonomic nervous system
The autonomic nervous system can be thought of as an “automatic” system because it works to maintain ___ in the body even when it is in an ___ state.
homeostasis
unconscious
The ANS does this by sending ___ impulses to viscera, cardiac, and smooth muscle.
motor
Since it sends motor impulses to viscera, the ANS is also known as a ___ ___ system.
visceral motor system
The ANS is divided into two subdivisions. What are they?
sympathetic nervous system
parasympathetic nervous system
The sympathetic is often referred to as the
“___ or ___” system.
“fight or flight”
The sympathetic is often referred to as the
“fight or flight” system. It is located in the ___ and ___ spines and sends fibers to the organs.
thoracic and lumbar
The parasympathetic division begins in the ___ and ___ ___ spines and sends fibers to the same organs as the sympathetic.
cervical and lower lumbar
The ___ nervous system works to increase heart rate, dilate air passages, ___ the activity of sweat glands, ___ glucose levels in the blood, ___ the pupils, and decrease digestive activity. It can increase the amount of blood moving to the cardiac and skeletal systems while decreasing blood flow to the skin. It also decreases urinary activity.
sympathetic nervous system
increase
increase
dilate
The sympathetic and parasympathetic divisions typically have the ___ effect on organs and thus work to maintain balance. For example, the ___ ___ can increase heart rate while the ___ ___ decreases it.
opposite
sympathetic system
parasympathetic system
The parasympathetic division is sometimes called the rest and digest division and has the ___ effects on the sympathetic nervous system such as pupil constriction, ___ heart rate, and breathing, and ___ digestion.
opposite
decreasing
increasing
The parasympathetic division is sometimes called the “rest and digest” division of the peripheral nervous system.
“rest and digest”
It is important to realize that since nerves contain numerous fibers some of these fibers can carry ___ information while others carry ___ information.
sensory
motor
Nerves are bundles of fascicles, which are further composed of individual nerve fibers (___).
axons
One nerve can carry both sensory and motor information. This type of nerve is known as a ___ nerve.
mixed
The outer layer of a nerve consists of the ___.
epineurium
The epineurium consists of dense connective tissue that ___ and ___ the nerve.
surrounds and protects
Inside the nerve the fibers are bundled in fascicles with each fascicle surrounded by a sheath called a ___.
perineurium
Inside the fascicles are bundles of neurons each surrounded by a thin layer of loose connective tissue called the ___.
endoneurium
Spinal nerves can combine to form structures called ___. There are four major plexi in the human body.
plexi
The ___ nerve (C3-4-5) emerges from the cervical and brachial plexi and runs through the thorax to innervate the diaphragm.
phrenic nerve
The ___ plexus (C1-C4) innervates the posterior head and skin of the neck.
cervical plexus
The lumbar plexus consists of spinal nerves L1-L4. The sacral plexus consists of the ventral rami from spinal nerves L4-S4. Sometimes both plexi are referred to as the ___ plexus.
lumbosacral
What are 2 types of cells in the nervous system?
neurons and neuroglia
The major nerves exiting the lumbosacral plexus include the ___, ___, and ___.
obturator
femoral
sciatic
___ are the cells that transmit and store information in the nervous system.
Neurons
___ are support cells.
Neuroglia
The parts of a neuron include the ___.
dendrites, cell body, axon hillock, axon, and axon terminal
Neurons can connect and ___ with other neurons.
communicate
The connection between neurons is called a ____ and the space between neurons is called the ___ ___.
synapse
synaptic cleft
Neurons communicate with each other by sending chemical packets called ___ across the synaptic cleft.
neurotransmitters
So, the ___ neuron sends a neurotransmitter across the synaptic cleft to the ___-___ neuron.
presynaptic neuron
post-synaptic neuron
What are 2 essential messages that neurons send?
excitatory messages
inhibitory messages
The ___ message stimulates the post-synaptic neuron; the other is an ___ message that keeps the post-synaptic neuron from sending additional messages.
excitatory
inhibitory
What kind of message does the excitatory message send to the post-synaptic neuron?
stimulation of the post-synaptic neuron
What kind of message does the inhibitory message send to the post-synaptic neuron?
inhibits the post-synaptic neuron from sending additional messages
Neurons, like many other cells in the body, do not exist at equilibrium with their ___.
surroundings
There is a net ___ charge on the inside of the neuron with respect to the outside.
negative
The negative charge inside neurons exists mostly because of differences in membrane ___ to different electrolytes.
permeability.
The cell membranes of neurons are slightly permeable to ___ and ___. Although they are permeable to both sodium and potassium, they are slightly more permeable to ___.
sodium
potassium
potassium
The negatively charged ions inside the neuron ___ leave the cell. So if potassium (which is ___ charged) is allowed to move out of the cell, then the inside of the cell becomes more ___ (due to the presence of the negative ions) than the outside of the cell.
cannot
positively
negative
There are also a number of negatively charged ions ___ of the neuron’s cell membrane. These include phosphates, sulfates, ___, RNA, and ___.
inside
ATP
proteins
As this ionic gradient increases, some ___ ions are attracted back into the cell. Eventually, the cell reaches a ___ state by which potassium diffuses out of the cell at the ___ rate that it moves into the cell via the ionic gradient.
positive
steady
same
There is much more sodium ___ of the cell than inside. The neuron’s cell membrane is ___ very permeable to sodium so just a little sodium moves into the cell via its concentration gradient
outside
not
We also have the ___-___ ___working to maintain both sodium and potassium gradients by moving ___ out of the cell and ___ into the cell.
sodium-potassium pump
sodium
potassium
Remember that the sodium-potassium pump requires energy in the form of ___.
ATP
The nervous system requires a lot of ___-___ pumps in order to function. In fact, about ___ of the energy used by the nervous system is used by the sodium-potassium pumps.
sodium-potassium pumps
70%
How do neurons communicate with each other?
by sending chemical messages from one neuron to another
So, if we put all the effects together, we end up with a net negative charge on the ___ of the cell with respect to the ___.
inside
outside
Neurons communicate by sending chemical messages from one neuron to another. These chemicals are called ___.
neurotransmitters
The neurotransmitters move from one neuron to another across an area known as the ___ ___.
synaptic cleft
What do we call the neuron sending the message?
pre-synaptic neuron
What do we call the neuron receiving the message?
post-synaptic neuron
Once the neurotransmitter travels across the synaptic cleft, where does it attach to on the post-synaptic neuron?
a receptor
What are the two possible messages carried by neurotransmitters?
excitatory message
inhibitory message
The excitatory message ___ the post-synaptic neuron to send another message. This essentially moves the information ___.
triggers
forward
The function of the inhibitory message is to ___ the post-synaptic neuron (___ the information back).
inhibit
hold
In order to trigger the post-synaptic neuron the neurotransmitter will cause what to open on the post-synaptic neuron?
the opening of sodium gates
To trigger the ___-___ neuron, the neurotransmitter will cause the opening of sodium gates on the post-synaptic neuron. In other words, the ___-___ neuron is said to be excitatory.
When the sodium gates open, ___ rushes into the neuron. This changes the potential by making it ___ negative due to the positive sodium ions rushing into the cell. We say the cell is ____.
post-synaptic
pre-synaptic
sodium
less
depolarizing
In an excitatory response, the cell is ___ to begin with. Once the sodium gates ___ causing the cell to become less negative there is ___ polarization. So the cell is ___ with the opening of sodium gates.
polarized
open
less
depolarizing
If a stimulus is great enough to cause a neuron to depolarize to ___, then we say that it has reached the threshold.
Once the neuron reaches the ___ it will continue to depolarize to about ___.
The rapid change in potential from -55 mV to +30 mV is called an ___ ___.
-55 mV
threshold
+30 mV
action potential
If the stimulus is ___ enough to cause enough of a change in the potential to reach a certain level, the neuron will react by opening ___ sodium gates and depolarizing at a rapid ___.
strong
more
rate
Where do action potentials generate?
axon hillock of neurons
When a stimulus causes ___ to the threshold, the voltage-gated sodium channels open causing ___ voltage-gated channels to open resulting in a large influx of ___ into the cell.
depolarization
more
sodium
There are a large number of ___ gates that react to changes in membrane potential. These sodium gates are called ___-___ sodium channels because they open in response to a change in membrane potential.
sodium gates
voltage-gated
The action of sodium channels causing more sodium channels to open is a ___ feedback system.
positive feedback system
Voltage-gated potassium channels also open at the ___ time as the sodium channels.
same
After the ___ depolarization is reached at about +30mV to +40mV, the sodium gates ___ and the potassium gates remain ___ allowing potassium to diffuse out of the cell.
This causes the membrane potential to become more ___. This occurs until the ___ membrane potential is reached.
maximum
close
open
negative
resting
The potassium channels work more ___ than the sodium channels. The result is that some potassium diffuses out of the cell but much ___ sodium diffuses in.
slowly
more
Neurotransmitters are like tiny packets of ___ that are sent from one neuron to another.
messages
The first neuron is called the ___-___ neuron and the second is the ___-___ neuron.
pre-synaptic
post-synaptic
The neurotransmitter moves across the ___ ___ from the pre to the post synaptic neuron.
synaptic cleft
There are ___ neurotransmitters that promote the opening of ___ channels on the post-synaptic neuron and ___ neurotransmitters that promote the opening of ___ channels.
excitatory
sodium
inhibitory
potassium
Excitatory neurotransmitters include ___ and ___ (adrenaline and noradrenaline).
epinephrine and norepinephrine
Epinephrine and norepinephrine are secreted by ___ neurons, so they cause the effects of the sympathetic nervous system on the body.
sympathetic neurons
Epinephrine and norepinephrine are considered adrenergic-like ___ so they connect to ___ receptors on other neurons.
adrenaline
adrenergic
Dopamine is generally considered ___, but it can be inhibitory depending on the neurons.
excitatory
Dopamine plays a role in ___ and motivation.
pleasure
Drugs like methamphetamine attach to dopamine receptors to ___ the effects of dopamine. Cocaine blocks the proteins involved in recycling dopamine so the result is ___ dopamine in the synaptic cleft.
stimulate
more
Which excitatory neurotransmitter is secreted by parasympathetic neurons and motor neurons attaching to muscles to stimulate muscle contraction?
acetylcholine
An inhibitory neurotransmitter is ___ ___ ___ ___ (GABA) which plays a role in anxiety and promotes a calming effect. GABA also helps to ___ blood pressure and plays a role in pain and sleep.
Gamma amino butyric acid
decrease
Acetylcholine is considered cholinergic, so it will connect to ___ receptors on neurons.
cholinergic
Another inhibitory neurotransmitter is ___, which plays a role in memory, learning and depression.
Serotonin
One important type of breakdown of neurotransmitters is called ___.
reuptake
Serotonin is secreted by the pre-synaptic neuron then moves to the post-synaptic neuron to attach to receptors. The serotonin in the synaptic cleft will re-enter the pre-synaptic neuron through a transport protein. Once inside, it is broken down by monoamine oxidase.
What is this an example of?
reuptake
(an important type of breakdown of neurotransmitters)
Drugs such as selective serotonin reuptake inhibitors (or ___) block the transport protein causing ___ serotonin to remain in the cleft.
SSRIs
more
___ are involuntary responses to stimuli that occur unconsciously.
Reflexes
Reflexes are ___ responses to stimuli that occur unconsciously.
involuntary
The ___ ___ ___ consists of a muscle, nerve pathway and the spinal cord.
The muscle contains a ___ receptor that senses changes in ___ of the muscle. This receptor is called a muscle spindle. The muscle spindle contains motor neurons called ___ ___ ___. These neurons begin in the spinal cord and extend to the muscle spindle.
deep tendon reflex
sensory
stretch
gamma motor neurons
What does the deep tendon reflex consist of?
muscle, nerve pathway, and the spinal cord
When the tendon of the muscle (of the deep tendon reflex) is tapped by a reflex ___ the muscle spindle senses the change in the ___ of the muscle and sends a message via a ___ neuron (usually in a spinal nerve) to the spinal cord.
There it synapses with a ___ neuron (again in a spinal nerve) that sends a message to the muscle to contract.
reflex hammer
length
sensory
motor
Spinal reflexes are also influenced by ___ nervous system neurons. These neurons have an ___ effect on reflexes.
central nervous system
inhibitory
___ nervous system neurons extend from the spinal cord to the muscle.
Peripheral nervous system
One reason for eliciting reflexes is to ___ an upper motor neuron versus lower motor neuron problem. If the nervous system is intact then the reflex will look ___.
differentiate
normal
If the nervous system is ___ then the reflex will look normal. This means the brain is providing an ___ effect on the reflex. In other words, the brain is inhibiting the reflex so it appears normal.
intact
inhibitory
The reflex will look ___ with damage to upper motor neurons. This occurs in ___ victims.
exaggerated
stroke
When does a reflex look exaggerated?
when there is damage to the upper motor neurons
When does a reflex look diminished or absent?
when there is damage to the lower motor neurons
___ or ___ reflexes will result from problems with lower motor neurons.
Diminished
absent
The ___ ___ is a good example of an exaggerated reflex produced by the removal of inhibition by the central nervous system.
Babinski reflex
The Babinske reflex is present in ___ because myelination is not fully completed and the infant brain is not fully developed, so the normal inhibition is missing.
newborns
Is the Babinski reflex is normal in newborns?
Yes
Is the Babinski reflex is normal in adults?
No
*indicates central nervous system damage
The presence of a positive Babinski reflex in adults indicates central nervous system ___. We say the Babinski reflex is a ___ reflex since it indicates damage to the central nervous system.
damage
pathological
Normal reflexes are (exaggerated/inhibited).
inhibited
___ is a lipid substance created by special cells called Schwann cells.
Myelin
What cells create myelin?
Schwann cells
Myelin wraps around the ___. Myelin is what makes white matter ___. Gray matter axons do ___ have myelin.
axon
white
not
What do Schwann cells make?
myelin
Do gray matter axons have myelin?
no, they do not
Do white matter axons have myelin?
yes
myelin is what makes white matter white
There are gaps in the myelin sheath called ___ ___ ___.
Nodes of Ranvier
The Nodes of Ranvier (___) are important because they contain a large number of voltage gated ___ channels.
gaps
sodium
Where are action potentials generated?
axon hillock
Remember the action potential is generated at the ___ ___.
This action potential moves down the axon and reaches a ___ ___ ___.
At the node, a large number of ___ channels open allowing sodium to rush into the axon and the axon ___.
axon hillock
node of Ranvier
sodium
depolarizes
If you were to observe this phenomenon of an action potential moving from the axon hillock to a node of Ranvier and then to another node of Ranvier, it would look like the action potential ___ from node to node.
We call this ___ conduction.
jumps
saltatory
Saltatory conduction in myelinated axons is much ___ than in unmyelinated axons, such as in gray matter.
faster
In what kind of axon does the saltatory conduction work faster? Myelinated axons or unmyelinated axons?
Myelinated axons
In what kind of matter does the saltatory conduction work faster? Gray matter or White matter?
White matter
*white matter has myelinated axons
Regarding saltatory conduction, White matter is ___ than gray matter.
faster
Some disease and disorders actually cause neurons to lose their myelin sheaths. When myelin is lost, neurons ___ transmit as much information.
cannot
The loss of myelin can cause ___ of sensation, motor function and reflexes.
loss
loss
What happens if a patient’s neurons are losing their myeline sheaths?
the neurons will not be able to transmit much information without myelin
the loss of myelin can cause loss of sensation, motor function and reflexes.
Myelin in myelinated axons help saltatory conductions to occur (faster/slower).
faster
The lack of myelin in unmyelinated axons cause saltatory conductions to occur (faster/slower).
slower
