Upgrade to remove ads
neuro exam 1: cellular components and neurophysiology
Terms in this set (150)
brain --> from periphery and viscera, special senses. Responses = ___
SC --> ___ bring info to and from brain
Responses = ___
2 components of PNS:
what do these supply?
ANS --> viscera
Somatic nervous system --> body
spinal nn are so vulnerable because of where they ___.
these nerves have ___ and ___ nerves together
exit the spinal column
outside brain and SC = ___
brain and SC = ___
-white matter = ___ = ___ (how it gets info from the brain to periphery and vice versa
-each spinal nerve root has very distinct symptoms;
-there are ___ pairs spinal nerve roots
-all have specific weakness/patterns (sensation, motor, reflex) --> serve the ___, but are within the ___
-PNS has ___ nerves that serve the ___ and ___
-there are ___ pairs of these
-these are considered ___ nerves; responsible for blinking, eye tracking and closing, chewing, balance, hearing
cranial, face, neck
where are cell bodies of sensory neurons found?
cell bodies of motor neurons?
dorsal root ganglion
anterior horn of gray matter
where are anterior horn cells located? is this PNS or CNS?
are their cell bodies in the CNS or PNS?
functionally, are anterior horn cells part of the PNS or CNS? why?
located in SC --> CNS
Cell bodies of PNS
functionally apart of PNS b/c polio attacks anterior horn cells and polio affects PNS.
fxnal areas of the brain:
-lobe responsible for executive, high level fxns (planning, solving, etc): ___
-lobe responsible for emotion: ___
-where all the vital centers are located in the brain. All info has to travel through here and damage is catastrophic: ___
4 ways brainstem damage can occur:
aneurysm (increased blood --> increased pressure on brain)
describe gray matter in the brain:
cell bodies of neurons are in the cortex; nuclei of gray matter is in the brainstem
describe white matter in the brain:
all info from cortex travels through white matter tracts in the brain
gray matter in spinal cord is shaped like a(n) ___
white matter in SC is ___
gray matter sends info through white matter ___ (to and from), then info collects in the ___ and ___ until it gets to level of exit
are peripheral nerves gray matter or white matter?
white matter is always made of ___
gray matter is always made of ___
where is gray matter found in the PNS?
2 cells of the nervous system:
what are neurons?
excitable cells of the nervous system
what do glial cells do?
support and protection of nervous system
glial cell functions: (4)
Stem cell pool
-a neuron is a(n) ___ cell that processes and transmits information through electrical and chemical signals
-how many neurons are in the brain? ___
-they are ___; what does this mean?
-neurons in the brain have distinct ___ regions, each with specific functions e.g.. neurons in the occipital lobe specialize in processing visual information while neurons in the frontal lobe are involved in planning.
polarized; there is an electrical difference across the cell membrane
___ unit of the NS - excitable cells
Circuits or ___
___ all information
-Each neuron can be contacted by up to ___ other neurons, and in turn connect to ___ neurons
-Neurons are organized in ___ or ___ that encode for the processing of all conscious and unconscious information in the brain and spinal cord.
neuron circuits and networks:
-Just a few interconnected neurons (a(n) ___) can perform tasks such as mediate ___, process sensory information, generate locomotion (___) and mediate learning and memory. Predetermined activity
-More complex networks (___) consist of multiple imbedded microcircuits. These mediate higher brain functions such as ___ and ___. Where info processing happens
-Biochemical networks are prevalent within neurons. These ___constitute the underlying biochemical machinery for mediating key neuronal properties such as ___ and ___ and the genesis of neuronal rhythmicity. These are located within the neuron and monitor the activity of the neuron
microcircuit, reflexes, walking
object recognition, cognition
-Neurons are the excitable cells of the NS which means that signals are propagated by electrical signals called ___ that travel along the neuronal surface
-Neurons are connected to one another at ___ to form functional networks
A neuron is surrounded by a(n) ___ cell membrane. The movement of ions across this membrane is essential for the initiation and propagation of electrical impulses in the nervous system. Membranes can change their ___ for different ions
The ___ or ___ contains the nucleus and the other organelles necessary for cellular function (e.g.. endoplasmic reticulum and mitochondria).
cell body, soma
All ___, ___, and ___ are manufactured in the soma. Histology similar to all cells. Neurons have a very high ___ rate.
proteins, hormones, neurotransmitters
what are the jobs of the following?
• Nucleus: ___
• Rough ER: ___
• Smooth ER: ___
• Golgi apparatus: ___
• Lysosomes: ___
• Free ribosomes: ___
• Mitochondria: ___
-protein, hormones and NT synthesis
-carbohydrate metabolism, respiration, detoxification, synthesis of lipids, cholesterol, steroids
-packages proteins from ER
- Power house
___ are extensions of the soma (cell body) and the region where one neuron receives connections (input) from other neurons.
What's the purpose of these?
Dendrite spines increase surface area for synaptic contact
-how is this organized?
-info has to get past and through this
-mov't of ions across allows signals to be sent from one neuron to another
-can change ___ to ions --> how ___ happens
arranged in phospholipid bilayer
The ___ nerve fiber, is a long slender projection of a neuron that conducts electrical impulses away from the neuron's cell body or soma to the terminal regions of the neuron to connect with other neurons.
Axon nerve fiber:
-Arise from ___- where all input is summed up and the decision to propagate signal or not is made.
-Terminate in ___ (___).
axon terminals (boutons)
The ___ has the greatest density of voltage-dependent sodium channels which makes it the most easily excited part of the neuron
Axon nerve fiber:
-___= proximal part of the axon hillock- place at which the action potential is formed
-Axons can be ___, extending up to a meter or so in some human sensory and motor nerve cells. Sensory neurons have axons that run from the toes to the dorsal columns, over ___ in length in adults.
-Axons usually undergo extensive ___, enabling communication with many target cells.
long, 1.5 meters
-covered by ___ that protects and insulates
-increases speed of transmission b/c ___ allow info to jump from node to node
-present in the ___ and ___
nodes of ranvier
The ___ is the material within a living cell, excluding the cell nucleus
It comprises ___ (fluid) and the ___- the cell's internal sub-structures. The cytoplasm of the neuron is called the ___.
a microscopic network of protein filaments and tubules in the cytoplasm, giving them shape and coherence
elements of the cytoskeleton; shape-sustaining architectural struts present throughout the neuron
three structures that give the neuron structure; scaffolding of neuron. Which of these is the most important?
microtubules- most important
The microtubules of axons and dendrites serve as the major railways for cargo transport in both directions. This process is called ___.
2 types of axoplasmic transport:
describe anterograde axoplasmic transport:
Neurotransmitters and hormones produced by the cell body (soma) travel along the microtubules within the neuron and then get to the axon terminals
describe retrograde axoplasmic transport for unused NTs and neurotrophic factors:
Unused NTs are brought back to the soma from the axon terminal on the microtubules within the neuron
Neurotrophic factors are secreted by the target tissue and serve to protect cell and prevent it from dying. Therefore, these need to be transported to the soma from the terminals
explain how SSRIs work:
SSRIs block the reuptake of serotonin to cell bodies, so retrograde axoplasmic transport can't take it to the cell body, and more serotonin stays in the brain
axoplasmic transport from soma to terminal (e.g.. ___)
axoplasmic transport from terminal to soma
e.g.. 1 ___ (___) are a family of proteins that are responsible for the growth and survival of developing neurons and the maintenance of mature neurons. These are secreted by target tissue and ___ programmed cell death. These also induce differentiation of progenitor cells to form ___.
e.g..2 The movement molecules destined for ___ from the axon back to the cell body, where they are broken down by lysosomes
neurotrophic factors (neurotrophins)
Clinical Note: some viruses that attack the nervous system use ___ to get to the cell body
e.g.. ___ virus which lies dormant in the cell body until activated
retrograde axoplasmic transport
what's it called when a virus (opportunistic infection) catches a ride on microtubules and get to the cell body to cause damage through retrograde axoplasmic transport
types of neurons by function:
types of neurons by structure:
biploar (sensory, vision, smell)
what are sensory neurons?
what are these aka?
carry messages from the body's sense receptors in the musculoskeletal system, special senses and visceral system to the CNS
aka afferent neurons
what are motor neurons?
what are these aka?
carry signals from the CNS to the muscles and glands
aka efferent neurons
what are interneurons?
any neuron having its cell body, axon, and dendrites entirely within the central nervous system, especially one that conveys impulses between neurons.
where are interneurons found outside of the brain?
gray matter of spinal cord
terminal region of the axon
permits a neuron to pass an electrical or chemical signal to another cell through the process of ___
One neuron can receive contacts from many different neurons - up to ___
Similarly, any one neuron can contact up to___ postsynaptic cells.
what part of the neuron is considered presynaptic? postsynaptic?
where are the greatest number of Na+ channels found?
components of a synapse (3):
-axon terminal of one neuron (presynaptic neuron)
-the synaptic cleft
-the dendrites of another neuron (post-synaptic neuron).
• Most "presynaptic" neurons are "___" to some other neuron(s).
• The presynaptic cell is not directly connected to the postsynaptic cell. The two are separated by a gap known as the ___
Synaptic transmission comes in two basic flavors: ___ and ___
In muscle- the synapse is called ___ and the distal component is called the___
motor end plate
what determines whether the synaptic transmission is excitatory or inhibitory?
determined by NTs
two types of synapses?
synapse that is most common:
synapse that is less common but very powerful
name all of the glial cells (7)
glial cell that takes up and recycles excessive NTs and works to maintain homeostasis
primary job of astrocytes:
strengthen BBB with end-feet***
-Astrocyte ___ line blood vessels and are an element of the blood brain barrier
-Shuttle excess ions to ___
-Present at synapse to increase signal by releasing ___
-Neurotransmitter ___ allow communication between astrocytes
-what are brain tumors here called?
what's the job of oligodendrocytes?
Produce the myelin sheath in CNS
how many axons can one oligodendrocytes myelinate?
-Myelin --> ___ support (cell survival - supply of one or more ___ factors)
--> protects and ___
--_ organizes distribution of ___ along the length of the axon --> signal transmission
--> gaps in sheath = ___ --> allow for ___ transmission
nodes of ranvier, faster
what's the job of the schwann cell?
Myelinating cells in PNS
how many axons can one schwann cell myelinate?
schwann cells also re-uptake excessive ___ at NM junction
what are microglia?
immune cells in CNS
-Activated by release of ___ substances; immune cells
-___ debris at site of inflammation and present ___
what's the main function of the polydendrocytes?
Serve as stem cells within the brain
-Generate ___ and ___
-type of ___cell so it can develop into any cell
-Can receive input from neurons --> Link between neuronal and glial ___
-Clinical note : Recruitment of these is important in demyelinating diseases like ___ --> these perform the first step in ___
neurons, glial cells
what's the job of ependymal cells?
Line the ventricle in the brain and central canal of SC
Separate ___ from ___
Specialist ependymal = ___--> produce CSF
CSF, nervous tissue
main job of BBB? (2)
-maintain homeostasis within the CNS
-Isolates and protects the brain from the rest of the body
• Endothelial cells linked by tight ___ plus ___ processes (___) which contact the blood vessel from brain side --> separation of brain tissue and the vessel.
• Transport occurs by ___ of small lipophilic molecules and ___ of larger ones
junctions, astrocyte (end feet)
diffusion, active transport
made of ___ and ___
astrocytes secrete ___
• Clinical note: BBB limits access to the brain of ___ as well as harmful chemicals e.g.. ___ - a neurotransmitter deficient in Parkinson's disease. Unfortunately, peripherally administered dopamine cannot penetrate the blood brain barrier and thus is ineffective. The precursor of dopamine is ___. It can penetrate the blood brain barrier where it is then converted to dopamine by an enzyme. However, it is mostly metabolized before reaching the brain so ___ doses are required. To offset this, ___ is combined with the ___ to reduce the breakdown of ___ and allow more to reach the brain. This combination of drugs is called ___
carbidopa, levodopa, levodopa
1. Movement of ions across a membrane --> ___ and ___ occur along the neuron (___ stimulus)
2. ___: communication across synapses (___ and ___ stimulus)
action potential, signal transduction (electrical)
Synaptic transmission (chemical and electrical)
chemical stimuli allow ___ stimuli to occur
what causes an AP?
Movement of ions across a membrane (electrical)
There are different concentrations of ions on the inside versus the outside of the neuron cell membrane which creates a(n) ___. The movement of the ions across the membrane generates a(n) __ gradient for each ion and the sum of these electrical gradients creates the ___ or ___
membrane potential, electrical potential
The important ions in the nervous system are ___, ___, ___, and ___ There are also some negatively charged protein molecules ___
• K+ higher ___ the cell
• Na+ is higher ___ the cell
• Negative ions higher ___ the cell
Na+, K+, Ca2+, Cl-
ion(s) used during synaptic transmission:
ion(s) used during AP:
Na+, K+, Cl-
only ion tht can exit cell without difficulty and requires only passive diffusion:
• When a neuron is not sending a signal, it is "at rest." When a neuron is at rest, the inside of the neuron is ___ relative to the outside: (this equals ___).
• The concentrations of the different ions cannot balance out to 0mv because:
At rest, there are relatively more sodium ions ___ the neuron and more potassium ions ___ that neuron which could balance each other out but the cell membrane differentially allows passage of ions via ion channels.
a. K+ can cross through the membrane from inside to outside ___ easily than Na+ which leads to a net loss of ___ ions inside making K+ essential to the resting potential of a neuron.
b. ___ ions have a more difficult time crossing. Plus the ___ charged protein molecules
___ inside the neuron cannot cross the membrane.
• In addition to these selective ion channels, there is an ion pump that uses energy to return ion balance but it moves ___ sodium ions out of the neuron for every ___ potassium ions it puts in.
• Finally, when all these forces balance out, and the difference in the voltage between the inside and outside of the neuron is measured, you have the resting potential. The resting membrane potential of a neuron is about ___
Neurons normally have a resting membrane potential of -70mv.
• Any decrease in the negative charge = ___;
• Any increase in the negative charge constitutes ___.
• Return to -70mv constitutes ___.
The electrical properties of the ___ allow the processing and transmission of information to occur in the nervous system. Neurons are able to harness the ion differentials to generate ___ signals that can be transmitted through the axons and electrical circuits.
Movement of ions across a membrane causes ___ and ___ to occur
___= the basic events the nerve cells use to transmit information from one place to another.= ___ impulse = ___ impulses = changes in ___. The underlying mechanism for APs is the changes in membrane ___ for different ions.
AP and signal transduction:
Changes in permeability occur in:
a) ___ gated ion channels which are regulated by membrane potential => change in ___ opens the ion channel pore e.g.. Na+
b) ___ -gated ions channels which are regulated by a specific molecule (usually a(n) ___) that binds to a membrane protein on the channel which opens a pore and allows the ions to move through e.g.. post-synaptic neurotransmitter receptors
c) ___ gated ion channels - passage of ions occurs when mechanical ___ pulls an ion channel open - e.g.. touch receptors
d) ___ regulated ion channels regulated by temperature and changes in temp which open the ion channel
voltage, membrane potential
If a neuron is sufficiently depolarized (to ___) it will undergo a series of ion channel events that lead to a temporary reversal of polarity. This is called the ___
An action potential occurs when a neuron sends information down a(n) ___, away from the ___
-This is an explosion of ___ activity that is created by a(n) ___ current.
A(n) ___ causes the resting potential to move toward 0 mV. When the depolarization reaches about ___ a neuron will fire an action potential. This is the ___.
If the neuron does not reach this critical threshold level, then no action potential will fire. Also, when the threshold level is reached, an action potential of a(n) ___ sized will always fire.
AP is a(n) "___" phenomenon - the neuron either does not reach the threshold or a full action potential is fired
AP is ___
AP is ___: impulses typically travel along neurons at a speed of anywhere from 1 to 120 mps
all or none
Action potentials are caused by movement of ___ across the neuron membrane. The change in permeability of the membrane to ___ causes the AP.
1. A ___ first causes ___-gated ___ channels to open. This creates a(n) ___ --> sodium ions rush into the neuron --> the neuron becomes more ___ and becomes ___.
2. It takes longer for ___ channels to open. When they do open, this rushes ___ of the cell, ___ the depolarization.
3. Also at about this time, ___ channels start to close. This causes the action potential to go back toward -70 mV (a(n) ___).
potassium, out, reversing
4. The action potential actually goes past -70 mV (a ___) because the ___ channels stay open a bit too long.
5. Gradually, the ion concentrations go back to resting levels and the cell returns to ___.
6. After each AP, the Na channels have a(n) ___ when a new AP cannot be generated. This also prevents current flowing ___
7. After an AP, the ___ restore homeostasis for a(n) ___ price
refractory period, backwards
Na/K pumps, energy
name the steps of the AP very broadly:
-Na+ channels open, Na+ rushes into neuron, neuron depolarizes
-potassium channels open while Na+ channels close, K+ rushes out of cell, reversing depolarization, and causing AP to go back toward -70mV, repolarizing the neuron
-K+ channels stay open too long and cause hyperpolarization (AP goes past -70mV)
-Na+/K+ pump restores homeostasis at energy price
Electrical impulse propagation:
Because ___ can leak through the membrane of the axon as the AP travels towards the terminal endings the charge could dissipate as it travels.
The electrical impulse is propagated along the axon by
a) ___- shuttling of the charge along the axon
b) ___ = movement of Na + through ion channels inserted throughout the length of the axon.
• The impulse travels by ___ conduction in unmyelinated axons
• The impulse travels by ___ in myelinated axons
explain why saltatory conduction is fast:
what can be found in the gaps?
Faster speeds occur as the current jumps from node of Ranvier to node of Ranvier.
The sodium channels are accumulated in the gaps.
what is synaptic transmission?
signals crossing synapses
1. ___ - gap junctions that allow ions and small molecules move between cells
2. ___- no direct movement of ions. Communication achieved through neurotransmitters
The AP is an all or none phenomenon but synaptic transmission can be ___ in response
Steps in neurotransmitter function and synaptic transmission occur by passing through ___ --> ___ --> ___
Presynaptic terminal --> synaptic cleft --> post synaptic terminal
Name the 5 steps in neurotransmitter function and synaptic transmission
1. NT Synthesis:
a) occurs in the ___ from precursors (e.g. ___, ___, and ___)
b) synthesized by enzymes in the ___ (e.g. ___ - e.g. dopamine, norepinephrine and epinephrine, serotonin)
c) by ___ of cell body and need to be transmitted to axon terminal (e.g. ___ )
brain (glutamate, GABA and glycine)
axon terminal (biogenic amines)
ER, (opioid peptides)
a) Stored in ___ in axon terminal ready for release
a) Release from vesicles into synaptic cleft is triggered by influx of ___ ions through voltage sensitive channels opened by ___ of pre-synaptic cell membrane
a) NT ___ diffuses across cleft to post-synaptic membrane where it binds to a receptor called a(n) ___. What happens there depends on the specific ___ and the specific ___
e.g. glutamate causes ___ channels to open --> a ___ of the neuron membrane and generates an action potential --> signal transmission - excitation --> ___
e.g. GABA --> ___ channels to open --> ___ of the neuron membrane --> signal blocked - inhibition -->___
b) ___ is required to elicit the AP i.e. Post synaptic neuron requires the cumulative effect of thousands of synapses on a post-synaptic neuron to have the power to bring the neuron to threshold potential for firing.
Na+, depolarization, excitatory post synaptic potential (EPSP)
Cl-, hyperpolarization, inhibitory post synaptic potential (IPSP)
a) ___ by enzymes
b) ___ out of synaptic cleft and ___
Post synaptic receptors are either
a) ___: coupled with an ion channel --> opening and increased ion flow across membrane of post-synaptic neuron.
b) ___: coupled with signaling cascades and second messenger systems
NTs are released from a presynaptic neuron and cause ___ or ___ of post synaptic neuron.
name the NTs:
main excitatory NT in CNS:
main inhibitory NT in CNS:
Gamma-aminobutyric acid (GABA)
-___ neural signaling, so it's important for what? (2)
-binds to ___ receptor for pain and ___ receptor
strengthens, memory, learning
glutamate binds with receptors that cause influx of ___ --> excitatory
Gamma-aminobutyric acid (GABA):
-promotes influx of ___ which causes ___ and prevents neuron from reaching threshold for firing
what target these?
GABAa: very active; lead to treatment for anxiety --> benzos target this
GABAb: anti-seizure drug target
-excitatory/inhibitory? in CNS postsynaptic membranes by allowing influx of ___ ions
name the biogenic amines:
affects what 3 things?
Can be excitatory (___ receptors) or inhibitory (___ receptors)
motor activity, motivation, cognition (movement, emotion, cognition)
NE and Epi:
hormone and NT released in the ___ -->
___ effect - (fight or flight system). ___ levels with alertness, ___ levels with sleep --> ___, increased ___
-what's it's job?
H1, H2, H3
Can be ___ or ___. Adjusts general sensory ___ and also ___ sensory information. ___ levels = alertness, ___ levels in REM, ___ levels in depression.
what does Prozac do?
high, low, low
Prozac blocks the re-uptake of serotonin
receptors: 5-HT receptors
-adjusts general ___ of sensory info; alters ___
(cleared by ___) used by both ___ and ___
a. Neuromuscular junction: ___ and ___ at NM junction - excitatory/inhibitory?
b. Cerebral systems (CNS) --> ___ and ___, ___and ___
c. Autonomic nervous system - ___ effect on HR
communication, signaling, excitatory
memory, learning, arousal, attention
-can be ___ or ___
name the neuropeptides:
what are neuro-peptides used for/what are their major functions?
pain perception and modulation
The sensory function of substance P is thought to be related to the transmission of ___ information into the ___. Substance P coexists with the excitatory neurotransmitter ___ in primary afferents that respond to painful stimulation. Substance P and other sensory neuropeptides can be released from the peripheral terminals of sensory nerve fibers in the ___, ___, and ___
skin, muscle, joints
-___ responder to noxious stimulus --> inflammation --> transmits pain info --> pain ___ --> ___ pain. actual opioid.
Metenkapahalin:- a(n) ___ occurring, ___ opioid peptide that has opioid effects of a relatively ___ duration. Actual opioid, changes ___ perception
Use of neurotransmitters to manipulate the nervous system in disease states - examples
1. Parkinson's disease = depletion in dopamine => replace with a chemical that is converted to dopamine after it crosses the ___
2. Depression reflects changes in the parts of brain served by ___. Depression can be treated effectively with drugs that elevate the level of serotonin in the brain by blocking its re-uptake at the synaptic cleft (___).
3. ___ acts on neural system employing peptide NTs by imitating these peptides
4. Seizures are generally treated by drugs that mitigate the effects of ___ or potentiate the effects of ___.
serotonin (SSRIs: selective serotonin re-uptake inhibitors)
YOU MIGHT ALSO LIKE...
Anatomy ch 12
chapter 6 the nervous system
Ch 48 Nervous System
Biology chapter 48 neurons and Nervous system
OTHER SETS BY THIS CREATOR
peds final: health promotion and wellness
peds final: aquatics
peds final: child abuse
peds final: autism spectrum disorder