test 1
Exercise Science 224 with Thompson at University of South Carolina - All Campuses
About this deck
By: Ashley Johnson
Created: 2012-02-06
Size: 140 flashcards
Views: 85
Created: 2012-02-06
Size: 140 flashcards
Views: 85
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What are the functions of the nervous system
1. sensory input
2. integration
3. motor output
What are the two types of nervous tissue cells?
1. neuroglia
2. neurons
What are astrocytes
- most abundant, versatile and highly branched glial cells that cling to neurons, synaptic endings and capillaries that support and brace neurons, also help determine capillary permeability
what are microglia
small, ovoid cells with thorny processes that migrate toward injured neurons and phagocytize microorganisms and neuronal debris
what are ependymal cells
cells that are squamous or columnar and line the central cavities of the brain and spinal column and separate the CNS interstitial fluid from the cerebrospinal fluid in the cavities
what are oligodendrocytes
branched cells that wrap CNS nerve fibers forming insulating myelin sheaths
what are satellite cells
cells in the PNS that surround neuron cell bodies
myelin
what are schwann cells
surround peripheral nerve fibers and form myelin sheaths vital to regeneration of damaged peripheral nerve fibers
PNS
what are Neurons
long-lived, amitotic; high metabolic rate
what does a neurons plasma membrane function
electrical signaling
cell-to-cell interactions during development
What are characteristics of the cell body
called perikaryon or soma
-biosynthetic center of a neuron
- spherical nucleus with nucleolud
-well- developed golgi
-Rough ER called Nissl bodies
what is the axon hillock
con-shaped area from with axon arises
what are clusters of cell bodies called in the PNS & CNS
Ganglia
nuclei
What are dendrites
- receive signals from other neurons
- receptive region of a neuron
- short tapering and diffusely branched for a large surface area
- convey electrical signals toward the cell body- graded potentials
what is the axon
generates and transmits nerve impulses (action potentials)
- 1 axon with numerous terminal branches that are the secretory region of a neuron that releases neurotransmitters to excite or inhibit other cells
what is the myelin sheath
segmented protein-lipid sheath around most long or large diameter axons
functions
- protect and electrically insulate the axon
- increase speed of nerve impulse transmission
What are the myelin sheaths in the CNS and PNS
Schwann cells in the PNS
oligodendrocytes in the CNS
what is the difference of white and gray matter
white- dense collections of myelinated fibers; bundles of axons. with tracts composed
gray- mostly neuron cell bodies and unmyelinated fibers; neuron cell bodies
what are the 3 classification of neurons
sensory
motor
interneurons
what does a sensory neuron do
transmit impulses from sensory receptors toward the CNS
afferent
what does a motor neuron do
carry impulses from the CNS to effectors
efferent
what does a interneuron do
shuttle signals through CNS pathways-reflex
association neurons
ex: looking at board, comprehending what is on it and writing it down
multipolar neuron
- normal neuron; all dendrites extend except for single axon
- plasma membrane exhibits chemically gated ion channels
- most abundant in CNS
- most are interneurons or some motor neurons
bipolar neurons
- 2 process extend from cell body (fused dendrite and axon)
- plasma membrane exhibits voltage-gated NA and K channels
- RARE- found in special sensory organs--eye ear
- sensory neurons located in special sense organs
unipolar neuron
- 1 process extends from cell body and forms central and peripheral processes which compromise an axon
- plasma membrane exhibits voltage- gated CA channels
- found mainly in PNS- spinal cord and sensory ganglia of cranial nerves
- sensory neurons
what are the function of neurons
- highly irritable
- respond to adequate stimulus by generating an action potential (nerve impulse)
- impulse is always the same regardless of stimulus
what are the 4 principles of electricity
1. opposite charges attract
2. energy is required to separate opposite charges across a membrane
3. if opposite charges are separated, the system has potential energy
4. energy is liberated when the charges move toward one another
define voltage, potential difference and current
measure of potential energy generated by separated charge
voltage measured between
define voltage, potential difference and current
measure of potential energy generated by separated charge
voltage measured between two points
the flow of electrical charge (ions) between two points
define resistance, insulator and conductor
hindrance to charge flow- provided by the plasma membrane
substance with high electrical resistance
substance with low electrical resistance
what are the 2 main types of ion channels
1. leakage channels- always open; non gated
2. gated channels- chemically gated (ligand-gated), voltage- gated channels; mechanically gated channels
chemically gated channels
chemically gated ion channels open when the appropriate neurotransmitter binds to the receptor; allowing simultaneous movement of NA & K
voltage gated channels
voltage- gated ion channels open and close in response to changes in membrane voltage
when gated channels are open
ions diffuse quickly across the membrane along their electrochemical gradients
-ion flow creates an electrical current and voltage changes across the membrane
what is resting membrane potential
- potential difference across the membrane of a resting cell (approx. -70 mV in neurons)
- generated by differences in ionic makeup of ICF (inside) and ECF(outside); differential permeability of the plasma membrane
what are two types of signals
graded potentials
- dendrites and cell bodies
action potentials
- axons only
what is depolarization
the membrane potential moves toward 0 mV, the inside becoming less negative and more positive
what is hyperpolarization
the membrane potential increases, the inside is becoming more negative
what are the steps of action potential
resting- leakage channels open
depolarization- NA and K gates open slowly/ NA influx
re-polarization- NA slowly closes, K gates open
hyper-polarization- some K channels remain open for under shoot
what is repolarization
restores the resting electrical conditions of the neuron, does not restore the resting ionic conditions
*ionic redistribution back to resting conditions is restored by the thousands of sodium-potassium pumps
how does the CNS tell the difference between a weak stimulus and a strong one?
strong can generate action potential more often than weaker stimuli
- CNS determines stimulus intensity by the frequency of impulses
absolute refractory period
time from the opening of the NA channels until the resetting of the channels; ensures that each AP is an all or none event
- enforces one-way transmission of nerve impulses
relative refractory period
follows the absolute refractory period
- most NA channels have returned to their resting state
- some K channels are still open
- re-polarization is occurring
exceptionally strong stimulus may generate an AP
How do conduction velocities of neurons vary widely
effect of axon diameter
- larger diameter fibers have less resistance to local current flow and have faster impulse conduction
effect of myelination
- continuous conduction in unmyelinated axons is slower than saltatory conduction in myelinated axons
how are nerve fibers classified?
diameter
degree of myelination
speed of conduction
What are group A fibers
large diameter
myelinated
fast conduction
ex
- somatic sensory
- motor fibers
what are group b fibers
intermediate diameter
lightly myelinated
moderate fast
ex
- ANS fibers
what are group C fibers
smallest diameter
unmyelinated
slow
ex
- ANS fibers
what is the synapse
a junction that mediates information transfer from one neuron to another neuron or to an effector cell
presynaptic neuron
conducts impulses toward the synapse
postsynaptic neuron
transmits impulses away from the synapse
electrical vs chemical synapses
electrical- very rapied; unidirectional or bi-directional; in embryonic nervous tissue- brain regions-heart
chemical- specialized for the release and reception of neurotransmitters; specific with axon terminal and receptor region
how does one neuron communicate with another neuron
neurotransmitters
information transfer between neurons
1 action potential arrives at axon terminal
2 voltage gated CA channels open and CA enters terminal
3 CA entry causes neurotransmitter- containing synaptic vesicles to release their contents by exocytosis
4 neurotransmitter diffuses across the synaptic cleft and binds to specific receptors on the post synaptic membrane
5 binding of neurotransmitter opens ion channels, resulting in graded potentials
6 neurotransmitter effects are terminated by reuptake through transport proteins, enzymatic degration,
What is synaptic Delay
neurotransmitter must be released, diffuse across the synapse and bind to receptors
the delay is .3-5 ms
synaptic delay is the rate-limiting step of neural transmission
what is EPSP
excitatory post synaptic potential
what is IPSP
Inhibitory post synaptic potential
how are graded potential strengths determined
amount of neurotransmitter released
time the neurotransmitter is in the area
Graded Potentials
location- cell body/dendrites
size- various size
stimulus- chemical/sensory
no positive feed back
repolarization- voltage independent
summation- stimulus responses can be summed to increase amplitude
function- short distance signalling
initial effect- opens both NA & K
peak potential-moves to 0 then to -90
action potential
location- axon hillock/axon
size- always the same
stimulus- voltage
positive feedback
repolarization- voltage regulated
summation- all or none
function- long distance signalling
initial effect- opens NA then K
peak membrane potential- +300-50 mV
excitatory synapses and EPSPs
-neurotransmitter binds to and opens chemically gated channels that allow simultaneous flow of NA and K in opposite directions
-NA influx is greater than K Efflux, causing a net depolarization
-EPSP helps trigger AP at axon hillock if EPSP is of threshold strength and opens the voltage-gated channels
Inhibitory synapses and IPSPs
- neurotransmitter binds to and opens channels for K or CL
- causes a hyper polarization (the inner surface of membrane becomes more negative)
- reduces the post synaptic neuron's ability to produce an action potential
what are the two types of neurotransmitter receptors
1. channel- linked receptors- direct
- ACh and amino acids
2. G protein-linked receptors- indirect
- biogenic amines, neuropeptides, and dissolved gases
what are channel- linked receptors
ionotropic
- ligand- gated ion channels
- action is immediate and brief
excitatory
- receptors are channels
- NA influx-depolarization
inhibitory (hyperpolarization)
- receptors allow CL influx or K efflux
G protein-linked receptors
1. neurotransmitter binds and activates receptor
2 receptor activates G protein
3 G protein activates adenylate cyclase
4 adenylate cyclase converts ATP to cAMP
5 cAMP changes membrane permeability by opening or closing ion channels
- cAMP activates enzymes
- cAMP activates specific genes
what are neuronal pools
functional groups of neurons that integrate incoming information and forward the processed information to other destinations
Types of circuits in Neuronal pools
diverging, converging, reverbating, parallel after-discharge circuit
what is a diverging circuit
one incoming fiber stimulates an ever-increasing number of fibers, often amplifying circuits
- may affect a single pathway or several
- common in both sensory and motor systems
what is a converging circuit
opposite of diverging circuits, resulting in either strong stimulation or inhibition
- also common in sensory and motor systems
what is a reverberating circuit
oscillating
- chain of neurons containing collateral synapses with previous neurons in the chain- keeps coming back
what is a parallel after discharge circuit
incoming fiber stimulates several neurons in parallel arrays to stimulate a common output cell
what are the 2 types of neural processing
serial- reflexes,
parallel- smell may remind one of an odor and associated experiences
what are the effects of space restriction on brain development(3)
-midbrain flexure and cervical flexure cause forebrain to move toward the brain stem
-cerebral hemispheres grow posteriorly and laterally
-cerebral hemisphere surfaces crease and fold into convolutions
How are the ventricles of the brain connectied? what cells line them? What do they contain?
connected to one another and to the central canal of the spinal cord; lined by ependymal cells and contain cerebrospinal fluid
what is the cerebral cortex? What is it the site of, explain(3)?
thin superficial layer of gray matter that is 40% mass of the brain
it is the site of conscious mind: awareness, sensory perception, voluntary motor initiation
areas of the cerebral cortex(3)
motor areas- control voluntary movement
sensory areas- conscious awareness of sensation
association areas- integrates diverse information
what is the primary motor cortex? What does it allow? What is a motor homunculi?
large pyramidal cells of the pre-central gyri
long axons= pyramidal tracts
allows conscious control of precise, skilled, voluntary movements
motor homunculi- upside down caricatures representing the motor innervation of body regions
where is the premotor cortex located? What does it control? What does it coordinate?
anterior to the precentral gyrus
controls learned, repetitious or patterned motor skills
coordinates simultaneous or sequential actions
involved in the planning of movements that depend on sensory feedback
where is Brocas area? What hemisphere is it usually in? What does it do? When is it active?
anterior to the inferior region of the premotor area
present in one hemisphere (usually the left)
a motor speech area that directs muscles of the tongue
is active as one prepares to speak
where is the primary somatosensory cortex located? Where does it receive info from? What process is it capable of?
in the postcentral gyri
receives sensory information from the skin, skeletal muscles, and joints
capable of spatial discrimination: identification of body region being stimulated
where is the somatosensory association cortex located? What does it do?
posterior to the primary somatosensory cortex
integrates sensory input from primary somatosensory cortex
determines size, texture and relationship of parts of objects being felt
Where does the primary visual cortex get visual info from? where are the visual association areas? What does it use to interpret visual stimuli? What part of the brain does complex processing involve?
primary visual cortex- receives visual info from the retinas
surrounds the primary visual cortexuses past visual experiences to interpret visual stimuli
complex processing involves entire posterior half of the hemispheres
what are the 2 parts of the auditory areas? What does each do?
primary auditory cortex
- interprets information from inner ear as pitch, loudness and location
auditory association area
- stores memories of sounds and permits perception of sounds
where is the olfactory cortex? It is the region of_______________
medial aspect of temporal lobes; region of conscious awareness of odors
what do multimodal association areas do(3)? What are the 3 parts?
-recieve inputs from multiple sensory areads
- send outputs to multiple areas, including the premotor cortex
- allows us to give meaning to information recieved, store it, compare it and decide on actions
three parts: anterior association area, posterior association area, and limbic association area
Anterior Association Area is involved with...(3) What does it contain? What does its development depend on?
most complicated cortical region
- involved with intellect, cognition, recall and personality
- contains working memory needed for judgement, reasoning, persistence, and conscience
- development depends on feedback from social environment
Where is the posterior association area? It plays a role in...
large region in temporal, parietal and occiptal lobes
-plays a role in recognizing patterns and faces and localizing us in space
involved in understanding written and spoken language
limbic association area does what?
part of the limbic system
- provides emotional impact that helps establish memories
What do the left and right hemisphere conrtol? How do they communicate?
left- controls language math and logic
right- controls insight, visual-spatial skills, intuition, and artistic skills
* left and right communicate via fiber tracts in the cerebral white matter
What do commissures connect? Association fibers? Projection fibers
connects gray matter of the 2 hemispheres
connect different parts of the same hemisphere
connect the hemispheres with lower brain or spinal cord
functions of basal nuclei(4)
- influence muscular control
- help regulate attention and cognition
- regulate intensity of slow or stereotyped movements
- inhibit antagonistic and unnecessary movements
The Thalamus makes up how much of the diencephalon? Thalamus contains nuclei that procect and receive fibers from... WHat does the thalamus mediate(5)
80% of diencephalon
- contains several nuclei that project and receive fibers from the cerebral cortex
- gateway to cerebral cortex- sorts, edits and relays information
- mediates sensation, motor activities, cortical arousal, learning and memory
What does the hypothalamus form? What is it's autonomic control? Center for emotional response in perception of...(3)
forms the inferolateral walls of the third ventricle- contains many nuclei
autonomic control center for many visceral functions- blood pressure, heartbeat
center for emotional response- involved in perception of pleasure, fear, and rage
regulates body temp, food intake, water balance, thirts, sleep, and hormones
What is the infundibulum?
stalk that connects to the pituitary gland
What is the epithalamus? What does the pineal gland secrete?
most dorsal portion of the diencephalon, forms roof of third ventricle
- pineal gland- extends from the posterior border and secretes melatonin (regulates sleep/wake cycle)
where is the midbrain located? What are cerebral peduncles? Cerebral aqueducts?
between the diencephalon and the pons
- cerebral peduncles- contain pyramidal motor tracts
- cerebral aqueduct- channel between third and fourth ventricles
Why is the pons important?(3)
- forms part of the anterior wall of the 4th ventricle
- its the origin of cranial nerves V, VI, & VII
- nuclei help maintain normal breathing rhythm
what does the Medulla Oblongata control? Specifically controls?(3)
- controls autonomic reflex centers
- heart rate, respiratory rhythm, rate and depth of breathing
(vomiting, hiccuping, coughing sneezing)
What does the cerebellum do?(3)
- smooth muscle contraction
- provides timing and patterns of muscle contraction
- complex movements
What are the two functional brain systems
limbic system
reticular formation
what is the limbic system responsible for
the part of the brain that puts emotional responses to events and are consciously aware of emotional richness in our lives
What recognizes angry or fearful facial expressions, danger and is the fear response? What expresses emotions via gestures, resolves mental conflict?
Amygdala
Cingulate Gyrus
what is RAS? What does this do (3)
reticular activating system
- sends impulses to cerebral cortex to keep it alert
- filters out repetitive stimuli
- severe injury causes coma
what are the motor functions of the reticular formation(2)?
motor function
- regulate visceral motor functions
- coarse limb movements
What is consciousness? Loss of consciousness is a signal that...
-perception of sensation, voluntary initiation and control of movement, higher mental processing
(loss of consciousness is a signal that brain function is impaired)
What are the 2 types of memory
short term and long term
what helps short term transfer to long term(4)
- emotional state
- rehearsal
- association
- automatic memory
What is declarative memory? What is non-declarative memory?
factual knowledge, explicit info, conscious thoughts and language ability, stored in LTM
less conscious, acquired through experience/repetition, hard to unlearn, skills, motor and emotional memory
What do the meninges do?(3)
covers and protects CNS, blood vessels
encloses venous sinuses
contains cerebrospinal fluid
what is CSF?
cerebrospinal fluid
- produced in choroid plexus and flows through ventricles, subarachnoid space, and absorbed into the dural venous sinuses through the arachnoid villi
what is a choroid plexus?
place where CSF is formed
what does the blood-brain barrier do? What is it's composition
helps maintain a stable environment for the brain and separates neurons from some blood borne substances
- composition, endothelium of capillary walls, basal lamina, feet of astrocytes
blood brain barrier functions are:
-allows nutrients to move by facilitated diffusion and allows any fat-soluble substances to pass (alcohol, nicotine and anesthetics)
-absent in vomiting center/hypothalamus
Where does the spinal cord begin and end? How many pairs of spinal nerves are there?
Foramen magnum to conus medullaris at L1 vertebra
31
What is the Cauda Equina?
Collection of nerve roots at the ingerior end of the verebral canal
What are first, second and third order neurons
first- conducts impulses from cutaneous receptors and proprioceptors; branches diffusely as it enters the spinal cord or medulla
second- interneuron, cell body in dorsal horn of spinal cord or medullary nuclei; axons extend to thalamus or cerebellum
third- interneuron, cell body in thalamus, axon extends to somatosensory cortex
what does the spinothalamic tract transmit?
pain, temperature, and coarse touch impulses
what does the spinocerebellar pathway
ventral and dorsal tracts
- convey information about muscle or tendon stretch
two types of spinal cord trauma
flaccid paralysis- severe damage to the ventral root or horn cells; impulses do not reach muscles, no voluntary/involuntary control of muscles; muscles atrophy
spastic paralysis- damage to upper motor neurons of the primary motor cortex; spinal neurons remain intact, muscles are stimulated by reflex activity; no voluntary control of muscles
Define peripheral nervous system (PNS)
all neural structures outside the brain
- motor endings, sensory receptors, and nerves
What are 2 types of sensory receptors
specialized and activation
how are receptors classified?
stimulus type, location and structural complexity
define mechanoreceptors
respond to touch, pressure, vibration, stretch and itch
define thermoreceptors
sensitive to changes in temperature
define photoreceptors
respond to light energy
define chemoreceptors
respond to chemicals
define nocicceptors
sensitive to pain-causing stimuli
define exteroceptors
respons to stimuli arising outside the body
define interoceptors
respons to stimuli arising in interal viscera and blood vessels
define proprioceptors
respond to stretch in skeletal muscles, tendons, joints, ligaments and connective tissue coverings of bones and musles
complex receptors vs simple receptors
vision, hearing, equilibrium, smell and taste
vs
temperature, pain, muscle sense, tactile sensations
sensation vs perception
s- the awareness of changes in the internal and external environment
p- the conscious interpretation of those stimuli
processing in general sense receptors
stimulus > receptor/generator potential in afferent neuron > action potential at first node of ranvier
processing in special sense organs
stimulus > receptor potential in receptor cell > release of neurotransmitter > generator potential in first order sensory neuron > action potentials if threshold is reached
processing first, second and third order neurons
1) conduct impulses from receptor to second order neurons in spinal cord
2) transmit impulses to thalamus or cerebellum
3) conduct impulses from thalamus to somatosensory cortex
what are the main aspects of sensory perception
feature abstraction- multiple stimulus properties
quality discrimination- sweet/sour tastes
pattern recognition- recognize familiar patterns
how do you classify nerves
afferent and efferent fibers, somatic and autonomic fibers
- cranial and spinal for peripheral nerves
How many nerves are associated with the brain
12 pairs
- 2 are only sensory
what do spinal nerve branch into?
dorsal ramus
larger ventral ramus
meningeal branch
rami communicantes
What is the dermatome
the area of skkin innervated by the cutaneous branches of a single spinal nerve
- most dermatomes overlap, so destruction of a single spinal nerve will not cause complete numbness
About this deck
By: Ashley Johnson
Created: 2012-02-06
Size: 140 flashcards
Views: 85
Created: 2012-02-06
Size: 140 flashcards
Views: 85
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis
Dennis