a&p lecture exam 3

1) somatic motor 2) visceral motor 3) visceral sensory 4) somatic sensory

place the information entering or exiting the gray matter of the spinal cord in order, from anterior to posterior

1) pia mater 2) arachnoid mater 3) dura mater

place the meninges that wrap the spinal cord in order, from deepest to most superficial

1) receptor detects stimulus 2) afferent neuron carries message 3) CNS integrates information 4) efferent neuron carries message 5) effector is stimulated

place the steps involved in a reflex arc in the correct order

resting membrane potential: potassium

plasma membrane is more permeable to K+ than any other ion, leaks out until electrical charge of cytoplasmic anions attracts it back in and equilibrium is reached (no more net movement of K+). if there were no other factors determining resting membrane potential the "equilibrium potential" (the membrane potential value at which there would be equal flow of K+ in and out) would be -90 mV

spinous process

posterior (dorsal) part of vertebra

knee flexion

posterior (flexor) compartment of the thigh. contains hamstring muscles, from lateral to medial: biceps femoris, semitendinosus, semimembranosus

spinal cord gray matter

posterior horns: cell bodies/axons of interneurons and axons of incoming sensory neurons anterior horns: contain somatic motor nuclei lateral horns: only present in thoracic and upper lumbar segments; contain autonomic motor nuclei

depend on which membrane channels open

postsynaptic potentials:

conductivity

respond to stimuli by producing electrical signals that are quickly conducted to other cells at distant locations

-70 mV

resting membrane potential for most neurons is:

inhibitory postsynaptic potentials (IPSPs)

result when ligand-gated potassium ion channels open, result when ligand-gated chloride ion channels open, bring the postsynaptic membrane further to threshold

second-class lever

rising on tiptoe; fulcrum is located farther from applied force, load moved is between fulcrum and force applied, and moves in same direction as the force, lever works at a mechanical advantage to move large loads a short distance with little effort

proprioceptors

specialized sense organs to monitor position and movement of body parts

reflexes

specific patterns of motor response that are triggered by specific patterns of sensory stimulation

PNS neuroglia: satellite cells

satellite cells: surround the neurosomas in ganglia of the PNS, provide electrical insulation around the soma, regulate the chemical environment of the neurons

nerve injuries

sciatic nerve injury: -sciatica: sharp pain that travels from gluteal region along the posterior side of the thigh and leg to ankle -90% of cases result from herniated intervertebral disc or osteoporosis of lower spine

secretion

secreted neurotransmitters that influence the next cell

epileptic seizures

seizures result from sudden bursts of excitatory electrical activity within a neuronal pool; may be triggered by instability in membrane potential of a single neuron. excess excitation overwhelms inhibitory circuits that normally prevent overexcitation. continuous wave of excitation spreads over part of brain (partial seizure) or entire brain (generalized seizure); no meaningful signals can be transmitted; ends due to synaptic fatigue

biceps brachii, triceps brachii

select the muscles that are named according to the number of "bellies" they have

frontalis, occipitalis, and temporalis

select the muscles that are named according to their location overlying a bone of the skull.

gluteus minimus, gluteus maximus, and gluteus medius

select the muscles that are named according to their size.

conduction

sensory/motor, tract, bundle of axons in CNS

fascia

sheet of connective tissue that separates neighboring muscles or muscle groups from each other

unipolar neuron

single process leading away from neurosoma, sensory cells from skin and organs to spinal cord

pia mater

softest meninx

conduction speed of nerve fibers

speed at which nerve signals travel along surface of nerve fiber depends on two factors presence or absence of myelin: myelin further speeds signal conduction diameter of fiber: larger fibers have more surface area and conduct signals more rapidly

zones of gray matter

spinal cord communicates with the rest of the body by way of spinal nerves nerve- a cord-like organ composed of numerous nerve fibers (axons) bound together by connective tissue mixed nerves contain both afferent (sensory) and efferent (motor) fibers

cross section: branches of spinal nerves

spinal nerve starts as 6-8 rootlets that either enter or exit cord, rootlets fuse to form either dorsal or ventral root, roots fuse to form spinal nerve (near intervertebral foramen). contains both sensory and motor information (mixed)

referred pain

spinal nerves carry both somatic and visceral pain -pain that originates in an organ can be perceived as cutaneous pain

true

spinal nerves exit the vertebral canal through intervertebral foramina

false

spinal nerves that send motor commands to the muscles of the upper limb arise from the lumbar enlargement

golgi tendon reflex

stimulated by excessive tension (force) of muscle

categories of neurotransmitters: monoamines

synthesized by amino acids by removing the -COOH group while retaining the -NH2. include the catecholamines: epinephrine, norepinephrine, dopamine. also include histamine, ATP, serotonin. broadly distributed in brain; play role in emotional behaviors and biological clock. some ANS motor neurons (especially NE). imbalances associated with mental illness

graded potential

temporary, localized change in resting potential, caused by stimulus, decreases with distance from stimulus

aponeurosis

tendon is a broad, flat sheet

posterior (dorsal) ramus

the ______ innervates the muscles, joints, and skin in the back of the body

neural integration

the ability to process, store, and recall information and use it to make decisions. chemical synapses allow for decision making

cell bodies of motor neurons

the anterior horn of the spinal cord contains:

brain, spinal cord

the central nervous system consists of:

endomysium

the connective tissue that surrounds each muscle fiber is known as:

1) action potential arrives at axon terminals/synaptic knobs 2) voltage-gated calcium ion channels open 3) neurotransmitter is released into synaptic cleft 4) neurotransmitter binds to receptors 5) local potential occurs in postsynaptic cell

the correct order for events at a chemical synapse is:

both sensory and motor fibers

the dorsal (posterior) ramus carries:

true

the epicranius mechanically couples the frontalis and occipitalis muscles.

distal branches of spinal nerves

beyond the vertebra, the nerve divides into distal branches: -anterior ramus: in thoracic region, it gives rise to intercostal nerves. in other regions, anterior rami form plexuses -posterior ramus: innervates the muscles and joints in that region of the spine and the skin of the back

brachial plexus

brachial plexus near the shoulder, C5 to T1; supplies upper limb and some of shoulder and neck. 5 roots form 3 trunks: upper, middle, lower. trunks split to anterior division, posterior division. divisions fuse into 3 cords: medial, posterior, lateral

brachial plexus injuries

brachial plexus vulnerable -blow to top arm -wrench arm, stretch nerves -weak/paralyze whole arm thoracic outlet syndrome: abduct arm -compress brachial plexus median nerve: cant pincer grasp -suicide attempts -carpal tunnel

central nervous system

brain and spinal cord

neuron processes: dendrites

branches that come off the soma, primary site for receiving signals from other neurons, can generate local potentials only, dendritic trees change throughout life

triangular (convergent) muscles

broad at one end and narrow at the other

multipennate

bunches of feathers converge to single point

categories of neurotransmitters: neuropeptides

chains of 2-40 amino acids. act at lower concentrations than other neurotransmitters. longer lasting effects. stored in axon terminal as larger secretory granules. some function as hormones or neuromodulators. some also released from digestive tract

changes in membrane potential

changes in membrane potential can trigger muscle contraction, gland secretion, or transfer of information in the nervous system

local potentials

changes in membrane potential of a neuron occurring at and nearby the part of the cell that is stimulated, different neurons can be stimulated by chemicals, light, heat, or mechanical disturbance, a chemical stimulant binds to a receptor on the neuron

distribution of gated channels on a neuron

chemically gated channels: found on cell body and dendrites voltage-gated Na+ and K+ channels: along axon voltage-gated Ca2+ channels: at axon terminals

agonist (prime mover)

chiefly responsible for producing particular movement

microglial cell

clean up "cellular debris"

indirect attachment to bone by tendons

collagen fibers of the endo-, peri-, and epimysium continue into the tendon and from there into periosteum and matrix of bone

the crossed extension reflex

contraction of extensor muscles in the limb opposite from the one that is withdrawn. flexor reflex uses ipsilateral reflex arc (stimulus and response on same side) whereas crossed extension reflex uses a contralateral reflex arc (input and output are on opposite sides)

the neuron: soma

control center of the neuron, single nucleus with large nucleolus, cytoskeleton has dense mesh of microtubules and neurofibrils (bundles of actin filaments) that compartamentalizes rough ER into dark-staining Nissl bodies

the neuron: axon terminals

distal end of axon has terminal arborization: extensive complex of fine branches. synpatic knob: contains synaptic vesicles full of neurotransmitter

zones of white matter

divided into three white columns (funiculi) on each side; dorsal (posterior), lateral, and ventral (anterior), each spinal tract composed of axons with similar destinations and functions -ascending: up to higher centers (sensory inputs) -descending: from brain to cord or lower cord levels -transverse: from one side to other (commissural fibers)

connective tissue of nerves

endoneurium: loose connective tissue external to neurilemma; wraps individual axons perineurium: layers of overlapping squamous cells that wrap fascicles: bundles of nerve fibers epineurium: dense irregular connective tissue that wraps entire nerve blood vessels penetrate connective tissue coverings

CNS neuroglia: ependymal cells

ependymal cells: line internal cavities of the brain; produce, assist in producing, monitoring, and circulating cerebrospinal fluid

peripheral nervous system

everything else; composed of nerves and ganglia

beta endorphin

example of a neuropeptide

aspartate, glycine

examples of amino acid

histamine, dopamine, and norepinephrin

examples of monoamine

cord wrappings

meninges- three fibrous membranes that enclose the brain and spinal cord; they separate soft tissue of CNS from bones of cranium and vertebral canal, from superficial to deep: dura mater, arachnoid mater, pia mater

CNS neuroglia: microglia

microglia: wander through CNS looking for debris and damage and they transform into phagocytic cells, complete a brain check up every few hours, during times of rest they are the brains quiet gardeners

8

how many spinal nerves are in the cervical area?

5

how many spinal nerves are in the lumbar area?

6

how many spinal nerves are in the sacral and coccygeal area?

12

how many spinal nerves are in the thoracic area?

size, location, structural considerations, shape, location of attachments, muscle action, historical origins, muscle fiber orientation

how muscles are named

muscle actions

muscle fibers change lengths, muscles only work on joints they cross, muscles work best in the direction of their fibers

spinal meningitis

inflammation of dura, arachnoid, pia mater from virus, bacterial or other infection. lumbar puncture to check CSF for infection

first mechanism

inhibitory circuits provide a negative feedback mechanism to control activity of other neural circuits

parallel after-discharge circuit

input neuron diverges to stimulate several chains of neurons; each chain has a different number of synapses

neural circuits: diverging circuits

input neuron in the brain sends signals to multiple muscle fibers, input neuron in the spinal cord sends signals to different parts of the brain

information processing

integration of stimuli at individual cell level, response of postsynaptic cell depends on action of stimulated receptors as well as other stimuli acting on the cell at the same time

synergist

muscle that helps larger agonist work efficiently

true

muscles of facial expression are unique in that they insert onto the dermis of the skin.

antagonistic pairs

muscles that act on opposite sides of a joint

false

muscles that have convergent arrangements usually have just one action.

neural pools

neurons function in large groups, each of which consists of thousands of interneurons concerned with a particular body function; control rhythm of breathing, moving limbs rhythmically when walking

reverberating circuits

neurons stimulate each other in linear sequence but one or more of the later cells restimulates the first cell to start the process all over

excitatory cholingeric

neurotransmitter binds to a ligand-gated sodium ion channel, choline and acetate get taken back up into synaptic knobs

absolute refractory period

no stimulus of any strength will trigger AP, Na+ gates are inactive

electrical synapses

occur between some neurons, neuroglia, and cardiac and single-unit smooth muscle -gap junctions join adjacent cells. ions diffuse through the gap junctions from one cell to the next

direct fleshy attachment to bone

little separation between muscle and bone, muscle seems to emerge directly from bone

endocrine and nervous systems

maintain internal coordination

oligodendrocyte

make myelin in the CNS

schwann cell

make myelin in the PNS

anaxonic neuron

many dendrites but no axon, retina, brain, and adrenal gland

myelin sheath

many schwann cells or oligodendrocytes are needed to cover one nerve fiber

presynaptic neuron

may synapse with a dendrite, soma, or axon of postsynaptic neuron to form axodendritic, axosomatic, or axoaxonic synapses. a neuron can have an enormous amount of synapses

resting membrane potential

membrane potential of an undisturbed cell, all neural activities begin with a charge in resting potential

presynaptic facilitation

occurs when one presynaptic neuron enhances another one (opposite of inhibition). increases synaptic transmission. facilitating neuron releases serotonin; makes voltage gated calcium channels in axon terminal stay open longer

inhibitory postsynaptic potential (IPSP)

occurs when the cells voltage becomes more negative than it is at rest (it is less likely to fire). can result from Cl- entry or K+ exit from cell

CNS neuroglia: oligodendrocytes

oligodendrocytes: form myelin sheaths in CNS that speed signal conduction, myeling is composed of repeating layers of plasma membrane; arm-like processes wrap around nerve fibers, new layers push under old layers

multipolar neuron

one axon and multiple dendrites, most common- most neurons in CNS

bipolar neuron

one axon and one dendrite, olfactory cells, retina, inner ear

intersegmental reflex

one in which the input and output occur at different levels (segments) of the spinal cord -pain in foot causes contraction on abdominal muscles

temporal summation

one synaptic knob repeatedly secretes neurotransmitter while other synapses on the postsynaptic cell are quiet. if the postsynaptic cell gets to threshold, what type of summation has occurred?

spatial summation

one thousand different synapses on a postsynaptic cell "fire" at the same time. if the postsynaptic cell gets to threshold, what type of summation has occurred?

the refractory period

only a small patch of neurons membrane is refractory at one time (other parts of the cell can be stimulated)

relative refractory period

only especially strong stimulus will trigger new AP, K+ gates are still open and any effect of incoming Na+ is opposed by the outgoing K+, generally lasts until hyperpolarization end

antagonist

opposes the prime mover; prevents excessive movement

dermis of skin: muscles of facial expression

orbicularis oculi to skin around orbit

to move through transverse plane

orient parallel to transverse plane, or at an oblique

intrinsic muscles

origin and insertion within the body area it moves; within hand

neuron processes: axon

originates from a mound on the soma called the axon hillock, only one axon per neuron (some neurons have none), specialized for rapid conduction of signal to distant point, specialized terminology for membrane and cytoplasm; axoplasm and axolemma

obturator

pain, numbness, and weakness of the medial thigh may be due to damage to the ______ nerve

they begin at the trigger zone

which is true of action potentials?

schwann cells, satellite cells

which neuroglial cells are found in the peripheral nervous system?

left quadricep contracts, left hamstrings are reciprocally inhibited

which of the following apply to a stretch reflex that occurs when a rubber mallet strikes your left patellar ligament?

quadriceps contract on contralateral side, hamstrings contract on ipsilateral side

which of the following apply to a withdrawal reflex that occurs when you step on a rock with your left foot?

hamstrings contract on ipsilateral side, quadriceps contract on contralateral side

which of the following apply to a withdrawal reflex that occurs when you step on a rock with your right foot?

it is formed by the ventral rami of C1-C5, innervates skin of neck, ear, back of head, shoulders, motor branches innervate muscles in neck, gives rise to the phrenic nerve which is the major sensory and motor nerve of the diaphragm

which of the following apply to the cervical plexus?

they originate from a "mound" on the soma called the axon hillock, there is just one axon per neuron, but they can branch to form "collaterals"

which of the following are true of axons?

it results from an incomplete vertebral arch, the united states puts folic acid in certain foods to try to prevent it, it is a congenital (present from birth) defect

which of the following are true of spina bifida?

a fast response but of short duration

which of the following best explain what happens when a ligand binds to a ionotropic receptor?

a slower response but of longer duration

which of the following best explain what happens when a ligand binds to a metabotropic receptor?

voltage-gated sodium ion channels

which of the following happens first when the trigger zone reaches the threshold potential?

voltage-gated potassium ion channels open

which of the following happens to repolarize the membrane after a threshold stimulus?

thoracic

which of the following is not one of the five nerve plexuses?

threshold stimulus, depolarization, repolarization, hyperpolarization, return to RMP

which of the following is the correct sequence for phases of the action potential?

they are extensions that come off the soma of a neuron, they are the primary site for receiving signals from other neurons, they change with life experiences

which of the following is true of dendrites?

the interior of the cell becomes more negative

which of the following occurs when a ligand-gated potassium ion channel opens? assume the membrane was at resting membrane potential at the time of the stimulation

the membrane depolarizes

which of the following occurs when a ligand-gated sodium ion channel opens? assume the membrane was at resting membrane potential at the time of stimulation

slow anterograde

which of the following types of axonal transport is used to repair nerve fibers that have been damaged?

nerve fibers

which of the following types of axons may be repaired if they are damaged or severed?

F, posterior of the neck/splenius capitis

which of the indicated body regions contains a muscle that when contracted causes extension at the neck?

H, posterior of forearm/extensor carpi radialis longus, extensor carpi ulnaris

which of the indicated body regions contains a muscle that when contracted causes extension at the wrist?

I, posterior of the thigh

which of the indicated body regions contains a muscle that when contracted causes flexion at the knee?

J, posterior of the lower leg

which of the indicated body regions contains a muscle that when contracted causes plantar flexion of the foot?

J, the calf/gastrocnemius

which of the indicated body regions contains a muscle that when contracted causes plantar flexion of the foot?

vastus medialis, vastus lateralis, rectus femoris

which of the muscles listed, when contracted, cause extension of the knee joint?

obturator

which of the nerves listed does not arise from the brachial plexus?

phrenic

which of the nerves listed does not arise from the brachial plexus?

internodes

which part of a neuron is affected in "demyelinating diseases" like multiple sclerosis?

muscle spindle

which receptor is involved in a stretch reflex?

action potential jumps node to node

why faster than continuous conduction, unmyelinated? -diffusion of ions is faster with myelin sheath -ions mainly cross at nodes, fewer ions move than in unmyelinated axon

false

the matter of the spinal cord is very strong and rigid?

+35 mV

the membrane potential at which voltage-gated sodium ion channels CLOSE and voltage-gated potassium channels OPEN is:

muscle origins and insertions

the origin is the more fixed attachment of the muscle, when the muscle contracts, the insertion moves toward the origin. a simple way to remember this is "i move" toward O. the insertion is the more mobile attachment of the muscle

cell bodies/axons of interneurons and incoming sensory axons

the posterior horn of the spinal cord contains:

summation

the process of adding up postsynaptic potentials and responding to their net effect. occurs in the trigger zone

the flexor (withdrawal) reflex

the quick contraction of flexor muscles resulting in the withdrawal of a limb from an injurious stimulus. triggers contraction of the flexors and relaxation of the extensors in that limb. polysnaptic reflex arc: pathway in which signals travel over many synapses on their way to the muscle

inhibitory GABA-ergic

the receptors for neurotransmitter are ligand-gated chloride ion channels, benzodiazepines bind to the receptor in this synapse

tibial, common fibular

the sciatic nerve consists of the _______ nerves, which share a common epineurium

skin, muscles, joints

the somatic sensory division of the peripheral nervous system collects information from:

false

the spinal cord and the vertebral column are the same length

true

the spinal cord runs through the vertebral canal

subarachnoid space

the target in a "spinal tap"

epidural space

the target of numbing medication for labor/delivery

dura mater

the thickest, toughest meninx

axon hillock and initial segment of axon

the trigger zone consists of:

both sensory and motor fibers

the ventral (anterior) ramus carries:

motor fibers only

the ventral (anterior) rootlets carry:

heart, bladder, lungs

the visceral motor division of the peripheral nervous system sends information to:

bladder, heart

the visceral sensory division of the peripheral nervous system collects information from:

neural coding

the way the nervous system converts information into a meaningful pattern of action potentials

neuroglia: supportive cells

they outnumber neurons by at least 10 to 1, protect neurons and help them function, bind neurons together and form framework for nervous tissue. prevents neurons from touching each other, gives precision to conduction pathways

microglial cell

"prune" synapses while you sleep

unmyelinated signal conduction

-action potential in trigger zone opens voltage gated regulated ion channels -Na+ enters, diffuses along membrane, opens next set of ion channels, starts new action potential -ion channels along ENTIRE axon -repeats to end of axon -nerve signal= traveling wave of excitation from self-propogating action potentials -one way: refractory period travels behind AP

action potential steps

1) Na+ and K+ gates closed 2) Na+ gates open, Na+ enters cell, K+ gates beginning to open 3) Na+ gates closed, K+ gates fully open, K+ leaves cell 4) Na+ gates closed, K+ gates closing

action potential parts

1) Na+ local potential at axon hillock, depolarize membrane 2) get threshold potential -55mV typical opens voltage-gated ion channels 3) depolarize: neuron fires as voltage gates open. Na+ fast channels open first, K+ slow gates open 4) depolarization peaks +35 mV inside cell as Na+ gate closes 5) repolarization: slow K+ channels open, K+ leaves, back to negative 6) hyperpolarized: more neg than rest as K+ ion gates stay open 7) back to resting potential: Na/K pumps, K+ diffusion

reflexes

1) PNS detects and delivers stimulus to CNS 2) CNS integrates stimulus 3) PNS delivers motor response from CNS to effectors

simple stretch reflex

1) an external force stretches the muscle 2) muscle spindles detect the stretch, and primary and secondary efferents transmit an action potential to the spinal cord 3) in the spinal cord, sensory afferents synapse on alpha motor neurons and trigger an action potential 4) the alpha motor neurons stimulate the muscle to contract, and it returns to its optimal length

regeneration of nerve fibers

1) normal nerve fiber 2) fiber distal to the injury cannot survive and degenerates; macrophages clean up tissue debris at point of injury and beyond 3) soma swells, ER breaks up, and nucleus moves off center. axon stump sprouts multiple growth processes as severed distal end continues to degenerate 4) schwann cells, basal lamina, and neurilemma form a regeneration tube, cell adhesion molecules and nerve growth factor coax processes to its target 5) regeneration tube guides synapse formation 6) once contact is reestablished with original target, the soma shrinks and returns to its original appearance; nucleus returns to normal shape, atrophied muscle fibers regrow

nervous system overview

1) peripheral nervous system. sensory (afferent) neurons conduct signals from receptors to the CNS 2) central nervous system. interneurons (association neurons) are confined to the CNS 3) peripheral nervous system. motor (afferent) neurons conduct signals from the CNS to effectors such as muscles and glands

excitatory adrenergic synapse

1) unstimulated NE receptor is bound to G protein 2) binding NE to receptor causes G protein to dissociate 3) G protein binds to adenylate cyclase and activates this enzyme; enzyme converts ATP to cAMP 4) cAMP changes effects in cell in one or more of the following ways: -production of an internal chemical that binds to a ligand gated ion channel from the inside, opening the channel and depolarizing the membrane -activation of pre-existing, yet inactive, enzymes; this can lead to diverse metabolic changes -cAMP can induce gene transcription to that the cell produces new enzymes to alter metabolism

spinal nerves

31 pairs of spinal nerves. 8 cervical (C1-C8), 12 thoracic (T1-T12), 5 lumbar (L1-L5), 5 sacral (S1-S5), 1 coccygeal (Co1)

lever

any elongated, rigid object that rotates around a fixed point called a fulcrum; resistance arm and effort arm are described relative to fulcrum

epidurals

between the bony vertebrae and the dura mater

axillary

An inability to abduct the upper limb may be caused by damage to the _________ nerve.

musculocutaneous

An inability to flex the elbow joint may be caused by damage to the _________ nerve.

lumbar puncture

CSF is removed by a needle inserted between two vertebrae at level L3/L4 or L4/L5

neuronal circuits

CNS has two mechanisms that stabilize neural circuits to prevent electrical activity from becoming chaotic

regeneration of nerve fibers

CNS: no axonal regeneration PNS: if its soma is intact, at least some neurilemma remains

inhibitory GABA-ergic synapse

GABA-ergic synapse employs aminobutyric acid as its neurotransmitter, nerve signal triggers release of GABA into synaptic cleft, GABA receptors are chloride channels, Cl- enters cell and makes the inside more negative than the resting membrane potential, postsynaptic neuron is inhibited, and less likely to fire

myelinated axon saltatory conduction

Na+ inflow at node generates action potential, positive charge flows rapidly along axon and depolarizes membrane; signal weakens with distance, depolarization of membrane at next node opens Na+ channels, triggering new action potential

resting membrane potential: sodium

Na+ leaks into the cell, diffusing down its concentration and electrical gradients. this Na+ leakage makes RMP slightly less negative than it would be if RMP were determined solely by K+

the resting membrane potential

Na+/K+ pump moves 3 Na+ out for every 2 K+ it brings in. works continuously to compensate for Na+ and K+ leakage. 70% of the energy requirement of the nervous system. necessitates glucose and oxygen to be supplied to nerve tissue (energy needed to create the resting potential)

dermatomes overlap their edges as much as 50%

Necessary to anesthetize three successive spinal nerves to produce a total loss of sensation in one dermatome

deltoid, teres minor

Select the muscles that are innervated by the axillary nerve

biceps brachii, coracobrachialis, brachialis

Select the muscles that are innervated by the musculocutaneous nerve.

synaptic pruning

a natural process in which weak or redundant connections between neurons are pruned. certain alleles accelerate/intensify the pruning process in the prefrontal cortex (thinking/planning skills)

excitability (irritability)

respond to environmental changes called stimuli

inhibitory GABA-ergic

alcohol binds to the receptor in this synapse, the receptors for neurotransmitter are ligand-gated chlorine ion channels

is quick, is stereotyped, requires stimulation, is involuntary

Which of the following listed characteristics describe a reflex?

obturator, femoral

Which of the listed nerves arise from the lumbar plexus?

stretch reflex

Which of the listed reflex types is the fastest?

semimembranosus, semitendinosus, biceps femoris

Which of the muscles listed, when contracted, cause flexion of the knee joint?

perineurium

_____ wraps a bundle of nerve fibers known as a fascicle

tract

a bundle of axons in the central nervous system is known as a:

nerve

a bundle of axons in the peripheral nervous system is known as a:

nucleus

a collection of cell bodies in the central nervous system is known as a:

ganglion

a collection of cell bodies in the peripheral nervous system is known as a:

dermatome map

a diagram of the cutaneous regions innervated by each spinal nerve

electrical potential

a difference in concentration of charged particles between one point and another

true

a fixator is a specialized synergist that helps an agonist by preventing movement of another joint.

electrical current

a flow of charged particles from one point to another

muscle compartment

a group of functionally related muscles enclosed by fascia; also contains nerves and blood vessels that supply the muscle group

dermatome

a specific area of the skin that receives sensory input from a pair of spinal nerves

both sensory and motor fibers

a spinal nerve carries

fixator

a synergist that assists an agonist by preventing movement at another joint; biceps contraction would pull scapula, rhomboideus holds scapula for more efficient movement of biceps

excitatory postsynaptic potential (EPSP)

a voltage change from RMP toward threshold. usually results from Na+ flowing into the cell

the neurotransmitter at the neuromuscular junction

acetylcholine

long bones

act as levers to enhance the speed or power of limb movements

each action potential triggers another in the next section of axon

action potentials self-propagate because:

excitatory adrenergic

activation of a second messenger occurs, amplification of response is likely, neurotransmitter is norepinephrine

acetylcholine

acts at the neuromuscular junction

extrinsic muscles

acts within body area, but origin elsewhere; originate at forearm, move hand

radial

an inability to extend the elbow joint may be caused by damage to the _____ nerve

membrane potential

an unequal distribution of charge across a cell membrane, results from differences in membrane permeability to various ions and active transport

knee extension

anterior (extensor) compartment of the thigh. contains large quadriceps femoris muscle. prime mover of knee extension, most powerful muscle in the body, has four heads- rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius

vertebral body

anterior (ventral) part of vertebra

nerve plexuses

anterior rami branch and anastomose repeatedly to form five nerve plexuses somatosensory function- carry sensory signals from bones, joints, muscles, and skin proprioception: information about body position and movements motor function: primarily to stimulate muscle contraction

initial segment

area betweek axon hillock and first glial cell

internode

area of fiber covered with myelin

lumbar plexus

arises from L1-L4, innvervates anterior thigh, abdominal wall, and genitalia. femoral- motor: part of iliopsoas, pectineus, quads, sartorius obturator- motor: adductor muscles of medial thigh

perimysium

around bundle of cells; bundle = fascicle

action potential steps

arrival of current at axon hillock depolarizes membrane, depolarization must reach THRESHOLD: critical voltage (about -55 mV) required to open voltage-regulated gates

schwann cell

assist in the regeneration of nerve fibers

ligand-gated chloride ion channel, ligand-gated potassium ion channel

assume that an area of dendritic membrane is at resting membrane potential. opening which of the following will lead to a hyperpolarization?

CNS neuroglia: astrocytes

astrocytes: anchor structures, regulate extracellular environment, feed neurons, blood-brain barrier, form scar tissue after injury

brachial plexus: five important nerves

axillary- motor to: deltoid, teres minor musculotaneous- muscular innervation: biceps brachii, and brachialis, coracobrachialis median- muscle innervation: forearm flexors and some hand ulnar- muscle innervation: some forearm flexors, most intrinsic muscles of hand radial- muscle innervation: essentially all extensor muscles of posterior arm and forearm

trigger zone

axon hillock and initial segment. start nerve signal firing along axon

retinaculum

band of CT covers tendons of several muscles

chemical synapse

can utilize extensive neural integration, contains a 5 msec delay at each synapse

locomotion

central pattern generators (CPGs), neural circuits that specialize for a particular function

spina bifida

congenital heart defect in which one or more vertebrae fail to form a complete vertebral arch for enclosure of the spinal cord; common in lumbosacral region, most serious form: spina bifida cystica

spinal cord white matter

consists of bundles of axons that course up and down the cord providing communication between different levels of the CNS, columns or funiculi- three pairs of these white matter bundles; posterior (dorsal), lateral, anterior (ventral) columns on each side, tracts- subdivisions of each column

epidural space

contains adipose tissue

subarachnoid space

contains cerebrospinal fluid

electrical synapse

contains gap junctions, can be bidirectional

diseases of the myelin sheath

multiple sclerosis: oligodendrocytes and myelin sheaths in the CNS deteriorate

qualitative information

depends on which neurons fire

action potentials

dramatic change in membrane polarity produced by voltage-gated ion channels. only occurs when there is a high enough density of voltage-regulated gates- if excitatory local potential reaches trigger zone and is still strong enough, it can open these gates and generate an action potential

first-class lever

dribbling a basketball; fulcrum is located between applied force and load to be moved, force applied and load moved are in opposite directions, lever works at a mechanical advantage or disadvantage, depending on location of fulcrum

labeled line code

each sensory nerve fiber to the brain leads from a receptor that recognizes a specific stimulus type

action potential

electrical event that involves one location on the axon membrane, triggered by sufficiently large graded potential, spreads along the surface of the axon toward axon terminals

bipennate

fascicles approach tendon from both sides

unipennate

fascicles approach tendon from one side

pennate muscles

feather shaped

astrocyte

feed nutrients to neurons

to move through the saggital plane

fiber orient vertically on front and back of our body

epimysium

fibrous sheath surrounding entire muscle

characteristics of action potential

follows an all or none law; if threshold is reached, neuron fires at its maximum voltage, if threshold is not reached, it does not fire. nondecremental: do not get weaker with distance irreversible: once started, goes to completion and cannot be stopped

postsynaptic potentials

for a cell to fire an action potential it must be excited to its threshold level (typically -55 mV). some chemical messages inhibit the postsynaptic cell by hyperpolarizing it

circular muscles (sphincters)

form rings around body openings

astrocyte

form scar tissue in the CNS

cervical plexus

formed by ventral rami (C1-C5), most branches form cutaneous nerves (sensory), innervate skin of neck, ear, back of head, and shoulders. motor branches of these nerves innervate muscles in neck. phrenic nerve: major motor and sensory nerve of diaphragm (receives fibers from C3-C5)

movement, joint stabilization, control of openings and passageways, heat generation, glycemic control

functions of skeletal muscles

the posterior root ganglion

ganglion- cluster of neurosomas outside the CNS; enveloped in an epineurium continuous with that of that nerve, among neurosomas are bundles of nerve fibers leading into and out of the ganglion, posterior root ganglion associated with spinal nerves

nodes of ranvier

gaps in myelin sheath

categories of neurotransmitters: amino acids

glutamate: very common excitatory NT in brain and spinal cord, learning and memory GABA: gamma-amino butyric acid, thalamus, hypothalamus, cerebellum, cerebrum occipital, retina, most common inhibitor in the brain aspartate: spinal cord, excitatory glycine: inhibits in brain, spinal cord, retina, most common inhibitor in spinal cord

properties of local potentials

graded: vary in magnitude with stimulus strength decremental: get weaker the further they spread from the point of stimulation reversible: if stimulation ceases, the cell quickly returns to its normal resting potential either excitatory or inhibitory: some neurotransmitters make the membrane potential more negative- hyperpolarize it- so it becomes less likely to produce an action potential

compartment syndrome

if a blood vessel in a compartment is damaged, blood and tissue fluid accumulate, fascia enclose muscle compartments snugly and prevent expansion

dopamine

important in the "reward circuit"

PNS neuroglia: schwann cells

in PNS, schwann cell spirals repeatedly around a single nerve fiber. neurilemma: thick outermost coil of myelin sheath (contains nucleus and most of its cytoplasm), assist in regeneration of damaged fibers

fulcrum

in a lever system in the human body, ________ is the pivot point.

plexuses

in all but the thoracic region, the anterior ramus gives rise to _______

away from the soma

in anterograde axonal transport, motor proteins carry cargo

tendon reflex

in response to excessive tension on the tendon: -inhibits muscle from contracting strongly -moderates muscle contraction before it tears a tendon or pulls it loose from the muscle or bone

toward the soma

in retrograde axonal transport, motor proteins carry cargo

bipolar neuron

in terms of structural classification, a neuron that has one axon and one dendrite is a:

dipolar neuron

in terms of structural classification, a neuron that has one axon and one dendrite is a:

thoracic

in the ________ region, the anterior ramus gives rise to intercostal nerves

serotonin

is important in regulation of mood and pain control

glycine

its action can be blocked by tetanus toxin

changing the membrane potential: ion channels

large proteins serve as selective membrane ion channels, leakage (nongated) channels; always open, gated channels

glutamate

most common excitatory neurotransmitter in the brain

Compartment syndrome treatment

mounting pressure triggers a sequence of degenerative events. treatment = immobilization of limb and fasciotomy (incision to relieve compartment pressure)

anterograde transport

movement down the axon away from the soma

retrograde transport

movement up the axon toward the soma

neural circuits: converging circuits

multiple input neurons from sensory receptors converge onto a neuron in the brain

presynaptic inhibition

process in which one presynaptic neuron suppresses another one. reduces or halts synaptic transmission. inhibiting neuron releases GABA; prevents voltage gated calcium channels in axon terminal from opening and so knob releases little or no neurotransmitter

ependymal cell

produce and circulate cerebrospinal fluid

tendon organs

proprioceptors in a tendon near its junction with a muscle: golgi tendon organ; 1 mm long, nerve fibers entwined in collagen fibers of the tendon

third-class lever

pulling up on fishing rod; fulcrum is located closer to applied force, force applied is between fulcrum and load moved, and moves in same direction as the force, lever works at a mechanical disadvantage to move small loads a greater distance with greater speed

1) ligand-gated ion channels open to depolarize the dendritic/soma membrane 2) excitatory local potentials occur 3) trigger zone reaches threshold 4) voltage-gated sodium ion channels open 5) voltage-gated potassium ion channels open 6) voltage-gated calcium ion channels open

put the following electrical events in order in which they occur in a neuron

1) dendrites 2) trigger zone 3) axon 4) axon terminals 5) synaptic knobs

put the following parts of a neuron in order, from the area that receives the signal to the area that sends the signal.

excitatory adrenergic

receptor is a G-protein coupled receptor

stretch reflex

receptor is a muscle spindle

withdrawal reflex

receptor is a nociceptor, tends to produce flexion at a joint

epilepsy

recurrent episodes of abnormal, disorganized electrical activity in brain (seizures) symptoms: mild sensory disturbances to loss of consciousness to characteristic jerking movements

the nature of reflexes

reflexes: quick, involuntary, stereotyped reactions of glands or muscle to stimulation -reflexes require stimulation -reflexes are quick -reflexes are stereotyped -reflexes are involuntary

slow anterograde axonal transport

regeneration of a damaged nerve fiber utilizes the process of:

categories of neurotransmitters: acetylcholine

released at neuromuscular junctions, by some ANS neurons, by some CNS neurons: stimulates skeletal muscles, inhibits cardiac muscle (slows down), inhibit or excite smooth muscle and glands. synthesized from acetic acid and choline by enzyme choline acetyltransferase, degraded by enzyme acetylcholinesterase (AChE)

muscle spindle

stretch receptors embedded in skeletal muscles. inform the brain of muscle length and body movement

electrophysiology

study of cellular mechanisms for producing electrical potentials and currents

satellite cell

surround neurosomas in PNS ganglia

satellite cell

surround neurosomas in the PNS ganglia

synaptic transmission

synapses vary: some neurotransmitters are excitatory, others are inhibitory, and sometimes a neurotransmitters effect differs depending on the type of receptor on the postsynaptic cell. some receptors are ligand-gated ion channels and others act through second messengers

the discovery of neurotransmitters

synaptic cleft- gap between neurons was discovered by Ramon y Cajal through histological observations. otto loewi demonstrated that neurons communicate by releasing chemicals- chemical synapses. later renamed acetylcholine- the first known neurotransmitter

second mechanism

synaptic fatigue by which synaptic transmission becomes progressively weaker with prolonged and intense excitation

secretory region

synaptic knobs of a neuron are located in the _____ of a neuron

fusiform muscles

thick in the middle and tapered at each end

endomysium

thin sleeve of loose connective tissue around each fiber (cell)

brachial

thoracic outlet syndrome is due to compression of the _____ plexus

-55 mV

threshold for most neurons is:

sacral and coccygeal plexuses

tibial nerve and fibular nerve in common CT sheath (sciatic), tibial nerve: motor: hamstring muscles, posterior muscles of leg, most intrinsic foot muscles as plantar nerve fibular: motor: biceps femoris, anterior and lateral muscles of leg

fascia or tendon of other muscle attachment

transversus abdominis inserts on aponeurosis of internal oblique

axonal transport

two-way passage of proteins, organelles, and other material along an axon. many proteins made in the soma must be transported to axon and axon terminal. motor proteins (kinesin and dynein) carry materials "on their backs" while they "crawl" along microtubules

synaptic activity

typically involves release of neurotransmitters (such as ACh) by presynaptic cell, binding to neurotransmitter to receptors on the postsynaptic cell membrane changes permeability, permeability change produces graded potentials in postsynaptic membrane

parallel muscles

uniform width and parallel fascicles

to move through frontal or coronal plane

up and down on sides of the body

electrical synapse

used to synchronize activity in presynaptic and postsynaptic neurons, can be bidirectional

an excitatory cholinergic synapse

uses acetylcholine 1) nerve signal arrives at axon terminal and opens voltage-gated Ca2+ ion channels 2) Ca2+ enters terminal knob and triggers exocytosis of Ach 3) empty vesicles are refilled with Ach 4) Ach diffuses across cleft and binds to receptors on the postsynaptic neuron; the receptors are ion channels that open and allow Na+ and K+ to diffuse 5) entry of Na+ causes a depolarizing postsynaptic potential 6) acetylcholinesterase (AchE) breaks Ach down into choline and acetate 7) reuptake of neurotransmitter or choline/acetate to make new Ach 8) neurotransmitter or breakdown products diffuse away

excitatory cholingeric

uses acetylcholinesterase to break down the neurotransmitter

intermuscular septa

very thick fascia that separate one compartment from another

anterograde axonal transport

vesicles are made in the neurosoma and transported to the synaptic knobs via:

neural coding: quantitative information

weak stimuli excite only low threshold stimuli whereas strong stimuli also recruit higher threshold neurons, weak stimuli cause neurons to fire at a slower rate whereas strong stimuli cause a higher firing frequency (more action potentials per second)

axodendritic

what is the most common type of synapse?

true

when a muscle contracts, the insertion usually moves toward the origin.

the stretch reflex

when a muscle is stretched, it "fights back" and contracts -helps maintain equilibrium and posture ex: head starts to tip forward as you fall asleep, muscles contract to raise the head -stabilize joints by balancing tension in extensors and flexors, soothing muscle actions -stretch reflex is meditated primarily by the brain, but its spinal component can be more pronounced if muscle is suddenly stretched by a tendon tap (knee jerk)

negative feedback loop

when a voltage-gated potassium ion channel is triggered by a threshold stimulus, positively charged ions flow into the cell. Because the triggering stimulus was a local area of increased positive charges inside the cell, the potassium ion channel is participating in a:

positive feedback loop

when a voltage-gated sodium ion channel is triggered by a threshold stimulus, positively charged ions flow into the cell. because the triggering stimulus was a local area of increased positive charges inside the cell, the sodium ion channel is participating in a:

synapses

when it reaches the end of the axon a nerve signal can: -trigger the release of neurotransmitter -stimulate a new wave of electrical activity in the next cell across the synapse synapse between two neurons -presynaptic neuron releases neurotransmitter -postsynaptic neuron responds to neurotransmitter