spinal cord and spinal nerves, Chapter 12 Spinal cord and spinal nerves
contains motor neuron axons which transmit nerve impulses from the spinal cord to effect or organs and cells
anterior/ventral root
at the center of the gray commissure is the ____ ____ which extends throughout the entire length of the spinal cord it is continuous with the 4th ____ of the brain
central canal ventricle
Which of the following spinal nerve groups is incorrect? cervical - 7 thoracic - 12 lumbar - 5 sacral 5
cervical - 7
extends from the fourth cervical to the first thoracic
cervical enlargment
present only in thoracic, upper lumbar, and sacral segments of the spinal cord contain cell bodies of autonomic motor neurons that regulate activities of involuntary effectors
lateral gray horns
on the external anatomy of the spinal cord there are two enlargements which are sites where:
nerves supplying the limbs emerge
The muscles of the back contract to straighten so that you sit at a more erect posture and subsequently the muscles are suddenly stretched as you nod off. Which of the following best represents the sequence of events when you start to nod off? (1)muscles of the back are stretched (2)the muscle spindle is stretched (3)action potentials in sensory neurons of the muscle spindles increase (4)action potentials in alpha motor neurons of skeletal muscle fibers increase (5)skeletal muscle of the back contract 1, 2, 3, 4, 5 1, 5, 2, 3, 4 1, 5, 3, 2, 4 5, 2, 3, 4, 1 4, 5, 3, 2, 1
(1)muscles of the back are stretched (2)the muscle spindle is stretched (3)action potentials in sensory neurons of the muscle spindles increase (4)action potentials in alpha motor neurons of skeletal muscle fibers increase (5)skeletal muscle of the back contract
emerging from plexuses are nerves that bear names which often describe the general regions they serve or the routes that they follow:
1. cervical plexuses 2.brachial plexuses 3. lumbar plexuses 4.sacral plexuses 5.two small coccygeal plexuses are also present
each spinal nerve is formed by the merger of two roots:
1. posterior/dorsal root 2. anterior/ventral root
2 spinal cord homeostasis functions
1. white matter tracts in the white matter of the spinal cord transmit nerve impulses between the brain and the periphery 2. gray matter of the spinal cord receives and integrates the incoming and outgoing information
___ pairs of thoracic nerves represented as ___-__
12 T1-T12
__ spinal meninges surrounding the brain and continuous with the spinal meninges are the ______ meninges
3 cranial meninges
each of the __ pairs of spinal nerves emerge from a ____ ______; the spinal nerves are named and numbered according to the region and level of the spinal cord from which they emerge
31 pairs spinal segment
___ pairs of lumbar nerves represented as ___-___
5 L1-L5
___ pairs of sacral nerves represented as __-__
5 S1-S5
myelin sheaths of PNS neurons are produced by _________. Schwann cells. oligodendrocytes. ependymal cells. leukocytes.
Schwann cells
Arrange the events of synaptic transmission in correct sequence. (1)sodium ions diffuse into the cell and cause a local potential (2)neurotransmitter binds with receptor on postsynaptic cell (3)neurotransmitter diffuses across the synaptic cleft (4)membrane permeability to sodium ions on postsynaptic cell increases (5)action potential causes release of neurotransmitter 5, 2, 3, 4, 1 5, 2, 3, 1, 4 5, 3, 4, 1, 2 5, 4, 3, 2, 1 5, 3, 2, 4, 1
53241 action potential causes release of neurotransmitter neurotransmitter diffuses across the synaptic cleft neurotransmitter binds with receptor on postsynaptic cell membrane permeability to sodium ions on postsynaptic cell increases sodium ions diffuse into the cell and cause a local potential
Given these components of a reflex arc: (1) effector organ (2) interneuron (3) motor neuron (4) sensory neuron (5) sensory receptor Choose the correct order an action potential follows after a sensory receptor is stimulated. 5,4,3,2,1 5,4,2,3,1 5,3,4,1,2 5,2,4,3,1 5,3,2,1,4
54231 sensory receptor sensory neuron interneuron motor neuron effector organ
_ pairs of cervical nerves: the first pair emerge between the ______ and the ______ bone represented as ___-___
8 pairs atlas & occipital bone C1-C8
this stretch reflex involves extension (plantar flexion) of the foot by contraction of gastrocnemius and soleus muscles in response to tapping the calcaneal (_____) tendon
Achilles reflex (ankle jerk)
result from gentle stroking of lateral outer margin of the sole. the great toe extends, with or without fanning of the other toes. a positive _____ sign after age 1.5 is abnormal and indicates an interruption of the corticospinal tract
Babinski
If the dorsal root of a spinal nerve were to be cut, the individual would _______. have no motor responses for that nerve. have no sensory perception from that nerve. have no reflexes involving that nerve. Both have no sensory perception from that nerve and have no reflexes involving that nerve are correct
Both have no sensory perception from that nerve and have no reflexes involving that nerve are correct
Hyperpolarization in the postsynaptic cell is caused by ___________. excitatory postsynaptic potentials. inhibitory postsynaptic potentials. movement of K+ out of the cell. Both inhibitory postsynaptic potentials and movement of K+ out of the cell are correct
Both inhibitory postsynaptic potentials and movement of K+ out of the cell are correct
_ pair of coccygeal nerves represented as ___
Co1
Action potential transmission in the PNS is decreased if which cells are damaged? astrocytes microglia oligodendrocytes Schwann cells
Schwann cells
The resting membrane potential results when the tendency for _____________ to diffuse out of the cell is balanced by its attraction to opposite charges inside the cell
K+
spinal nerves and their branches are components of the ___
PNS
the anterior rami of spinal nerves, except ___-__ form networks on both right and left sides of the body that are called _______
T2-T12 plexuses
If five action potentials arrive at the same synapse in very close succession, which of the following would occur? The direction of the action potential is reversed. Temporal summation occurs. Spatial summation occurs. Hyperpolarization occurs. Depolarization always occurs
Temporal summation occurs
Which of these events occurs when a person steps on a tack with the right foot? The right foot is pulled away from the tack because of the Golgi tendon reflex. The left leg is extended to support the body because of the stretch reflex. The flexor muscles of the right thigh contract, and the extensor muscles of the right thigh relax because of reciprocal innervation. Extensor muscles contract in both thighs because of the crossed extensor reflex.
The flexor muscles of the right thigh contract, and the extensor muscles of the right thigh relax because of reciprocal innervation.
Which of the following is false? The dorsal root of the spinal cord conveys sensory (afferent) nerve impulses to the spinal cord. The posterior horn of the cord contains the cell bodies of motor neurons. The ventral root is formed by the axons of neurons in the lateral and anterior horns. The dorsal and ventral roots unite to form spinal nerves. The ventral root of the spinal cord conveys motor (efferent) nerve impulses away from the spinal cord.
The posterior horn of the cord contains the cell bodies of motor neurons
Which of the following statements concerning the structure of spinal nerves is true? The ventral root contains motor or efferent fibers. The ventral root has a prominent root ganglion. Rootlets from the surface of the spinal cord form the dorsal and ventral rami. Each spinal nerve is formed by the union of a cranial nerve and a spinal nerve. Spinal nerves do not have specific cutaneous distributions.
The ventral root contains motor or efferent fibers.
An inhibitory presynaptic neuron can affect a postsynaptic neuron by a. producing an IPSP in the postsynaptic neuron b. hyperpolarizing the plasma membrane of the postsynaptic neuron c. causing K+ to diffuse out of the postsynaptic neuron d. causing Cl- to diffuse into the postsynaptic neuron e. all of these are correct
all
Graded potentials a. spread over the plasma membrane in decremental fashion. b. are not propagated for long distances c. are confined to a small region of the plasma membrane d. can summate e. all of these are correct
all
In a chemical synapse, action potentials in the presynaptic terminal cause voltage-gated Ca2+ channels to open. neurotransmitters can cause ligand-gated Na+ channels to open. neurotransmitters can be broken down by enzymes. neurotransmitters can be taken up by the presynaptic terminal. all of the above.
all
Which of these statements about ion movement through the plasma membrane is true? Movement of Na+ out of the cell requires energy (ATP). When Ca2+ binds to proteins in ion channels, the diffusion of Na+ into the cell is inhibited. There are specific ion channels that regulate the diffusion of Na+ through the plasma membrane. All of the above.
all
A dermatome is the area of skin supplied by a pair of spinal nerves. exists for each spinal nerve except C1 can be used to locate the site of spinal cord or nerve root damage. all of the above.
all of the above
Summation a. is caused by combining two or more graded potentials b. occurs at the trigger zone of the postsynaptic neuron c. results in an action potential if it reaches the threshold potential d. can occur when two action potentials arrive in close succession at a single presynaptic terminal e. all of these are correct
all of these are correct
Action potentials are conducted more rapidly in small-diameter axons than in large-diameter axons. in unmyelinated axons than in myelinated axons. along axons that have nodes of Ranvier. all of the above.
along axons that have nodes of Ranvier
When a neurotransmitter binds to its receptor and increases the permeability of the postsynaptic membrane to sodium ions, ____________. the membrane will be hyperpolarized. more chloride ions will also diffuse into the cell. an excitatory postsynaptic potential (EPSP) will result. the membrane will become impermeable to potassium ions. the sodium ions diffuse out of the cell.
an excitatory postsynaptic potential (EPSP) will result.
contain cell bodies of somatic motor neurons and motor nuclei which provide nerve impulses for contraction of skeletal muscles
anterior (ventral) gray horns
serves the muscles and structures of the limbs and the skin of the lateral and anterior surfaces of the trunk
anterior (ventral) ramus
anterior to the gray commissure is the ___ (____) ____ ______ which connects the white matter of the left and right sides of the spinal cord
anterior (ventral) white commissure
deep wide groove on ventral side of internal spinal cord
anterior median fissure
Sensory neurons are multipolar and carry impulses toward the CNS. are pseudounipolar and carry impulses toward the CNS. are bipolar and carry impulses away from the CNS. are multipolar and carry impulses away from the CNS
are pseudounipolar and carry impulses toward the CNS
Leak ion channels open in response to small voltage changes. open when a ligand binds to its receptor. are responsible for the ion permeability of the resting plasma membrane allow substances to move into the cell but not out. all of the above.
are responsible for the ion permeability of the resting plasma membrane
A neuroglial cell that is a major component of the blood-brain barrier is the ___________. astrocyte. microglial cell. oligodendrocyte. ependymal cell. macrophage.
astrocyte
the middle meninx is the ______ ______ ______
avascular arachnoid mater
Neurotransmitter substances are stored in vesicles located in specialized portions of the neuron cell body. axon. dendrite. postsynaptic membrane
axon
Neurotransmitters are stored in synaptic vesicles in the: neuron cell body dendrite terminals axon terminals myelin sheath synaptic gutter
axon terminals
During the depolarization phase of an action potential, the permeability of the membrane a. to K+ is greatly increased b to Na+ is greatly increased c. to Ca2+ is greatly increased d. unchanged
b
Which of these terms is correctly matched with its definition or description a. depolarization; membrane potential becomes more negative b. hyperpolarization; membrane potential becomes more negative c. hypopolarization ; membrane potential becomes more negative
b
The absolute refractory period limits how many action potentials can be produced during a given period of time. prevents an action potential from starting another action potential at the same point on the plasma membrane. is the period of time when a strong stimulus can initiate a second action potential. both a and b. all of the above
both a and b
spinal cord tracts are continuous with tracts in the ____
brain
white matter consists of
bundles of myelinated axons of motor neurons interneurons sensory neurons
The major function of the sodium-potassium pump is to ; a. pump Na+ into the K+ out of the cell b. generate the resting membrane potential c maintain the concentration gradients of Na+ and K+ across the plasma membrane d. oppose any tendency of the cell to undergo hyperpolarization
c
This figure shows a dermatome map. A patient with no sensation in the left thumb would probably have a nerve damaged in _____________. T1. T5. C5. C6. L3.
c6
The bundle of nerve roots that occupy the vertebral canal from L2 to S5 is called the _________. medullary cone. cauda equina. lumbar enlargement. cervical enlargement. spinal cord.
cauda equina
the roots of spinal nerves emerging from the lower part of the spinal cord travel inferiorly to form the _____ _____
cauda equina
the gray matter consists primarily of:
cell bodies of neurons neuroglia unmylinated axons dendrites of interneurons and motor neurons
The brain and the spinal cord comprise the __________ nervous system. somatic parasympathetic autonomic peripheral central
central
groups of axons with the endoneuria are arranged in bundles called
fasciculi
Opening of ______ gates produces an ______. chloride; IPSP sodium; IPSP calcium; IPSP potassium; EPSP calcium and sodium; IPSP
chloride; IPSP
white matter is subdivided by the anterior and posterior gray horns into ______ 1. 2. 3.
columns 1. anterior (ventral) white columns 2. posterior (dorsal) white columns 3. lateral white columns
every spinal nerve (and cranial nerve) is surrounded and protected by _____ _____ coverings
connective tissue
pia mater is a layer of ____ _____ that contains collagen fibers and some elastic fibers as well as many blood vessels that provide nutrients and oxygen to the spinal cord and brain
connective tissue
arachnoid mater consists of ____ tissue with a ____ ___-like arrangement of collagen fibers and some elastic fibers
connective tissue spider web
In the patellar tendon reflex arc, the patellar ligament is stretched, which stretches the quadriceps femoris muscle of the thigh. This reflex will cause the quadriceps femoris to contract and the antagonist muscles, the hamstrings, to relax. contract and the hamstrings also to contract. relax and the hamstrings to contract. relax and the hamstrings also to relax. relax without any effect on the hamstrings
contract and the antagonist muscles, the hamstrings, to relax
at the lower end of external spinal cord has tapering, cone=shaped portion called the _______ ______ which ends at the level of the intervertebral disc between the 1st and second lumbar vertebrae in an adult
conus medullaris
The peripheral nervous system includes the ___________. brain. spinal cord. cranial nerves. blood-brain barrier. cerebellum.
cranial nerves
During repolarization of the plasma membrane a. Na+ diffuses into the cell b. Na+ diffuses out of the cell c. K+ diffuses into the cell d. K+ diffuses out of the cell
d
dura mater is composed of ____, _____ connective tissue
dense irregular
The cutaneous sensory distribution of a spinal nerve can be mapped as a __________. dermatome. plexitome. microtome. myotome. superdome
dermatome
each spinal nerve supplies a specific, predictable segment of the body, the area of the skin that provides sensory input to one pair of spinal nerves or to cranial nerve V ( for the face and scalp) is called a
dermatone
Receptor molecules ___________. are nonspecific. are always lipids. attach to the synaptic cleft. determine whether a neurotransmitter will be excitatory or inhibitory. are not attached to ligand-gated channels.
determine whether a neurotransmitter will be excitatory or inhibitory.
A reflex response accompanied by the conscious sensation of pain is possible because of convergent pathways. divergent pathways. a reflex arc that contains only one neuron. sensory perception in the spinal cord
divergent pathways
The branch of a spinal nerve that innervates deep muscles on the dorsal thorax is the _______. ramus communicans. lateral ramus. dorsal ramus. ventral ramus. medial ramus.
dorsal ramus
enlargement which contains the cell bodies of sensory nerves in dorsal root
dorsal root ganglion
outermost meninx is the _______
dura mater
muscle or gland
effector
each axon is wrapped in a layer called the
endoneurium
Monamine oxidase inhibitors (MAO inhibitors) ________. prevent synaptic transmission. enhance the breakdown of norepinephrine. enhance the binding of norepinephrine to its receptors. prevent the release of norepinephrine by the presynaptic terminal. have no effect on the action of norepinephrine.
enhance the binding of norepinephrine to its receptors
Cells found in the choroid plexuses that secrete cerebrospinal fluid are astrocytes. microglia. ependymal cells. oligodendrocytes. Schwann cells.
ependymal cells
Overproduction of cerebrospinal fluid could be the result of over-activity of the ________. astrocytes. microglial cells. oligodendrocytes. macrophages. ependymal cells
ependymal cells
Overproduction of cerebrospinal fluid could be the result of over-activity of the ________. astrocytes. microglial cells. oligodendrocytes. macrophages. ependymal cells.
ependymal cells
surrounding the dura mater is the ______ ______ filled with fat and connective tissue which provide additional protection to the spinal cord
epidural space
groups of fasciculi collectively form a nerve which is covered by the
epineurium
Presynaptic inhibition is the opposite of __________. coding. integration. recruitment. summation. facilitation
facilitation
Presynaptic inhibition is the opposite of __________. coding. integration. recruitment. summation. facilitation.
facilitation
and extension of the pia mater called the ____ _____ extends inferiorly from the conus medullaris to attach the spinal cord to the coccyx
filum terminale
A nurse pricks your finger to type your blood. You flinch at the pain, pulling your hand back. This is called the pain reflex. stretch (myotatic) reflex. flexor (withdrawal) reflex. tendon reflex. crossed extension reflex
flexor (withdrawal) reflex
dura mater extends from the level of the _____ ________ to the ____ _____ vertebra where it is ____-ended
foramen magnum second sacral vertebra close-ended
Clusters of nerve cell bodies within the peripheral nervous system are ganglia. fascicles. nuclei. laminae
ganglia
region of gray matter that connects the two wings of the butterfly
gray commissure
spinal cord contains ___ _____. shaped like a butterfly when viewed in cross section, tat surrounded by ____ _____
gray matter white matter
Chemical synapses have a delayed impulse transmission. utilize gap junctions. occur when two nerve cells are in direct contact with each other. do not require the release of neurotransmitters
have a delayed impulse transmission
Decreasing the extracellular concentration of K+ affects the resting membrane potential by causing
hyperpolarization
Inhibitory postsynaptic potentials (IPSPs) are associated with ____________. depolarization of the cell membrane. repolarization of the cell membrane. hyperpolarization of the cell membrane. no change of the cell membrane potential. no change of the threshold
hyperpolarization of the cell membrane
If the permeability of the plasma membrane to K+ increases, resting membrane potential _____________. This is called _____________. increases, hyperpolarization increases, depolarization decreases, hyperpolarization decreases, depolarization
increases, hyperpolariations
Local hyperpolarization in a synapse is called a(an) ____________. excitatory postsynaptic potential. resting membrane potential. inhibitory postsynaptic potential. gap junction potential. action potential.
inhibitory postsynaptic potential
one or more regions of gray matter in CNS
integrating center
the anterior rami of spinal nerves t2-T12 do not enter into the formation of plexuses that are called _______ or _____ nerves they travel directly to the ______ regions and the nearby muscles and the skin regions that they innervate
intercostal or thoracic nerves intercostal
Damage to a postsynaptic membrane would _______. increase neurotransmitter release. decrease the release of neurotransmitter. increase neurotransmitter production. interfere with the ability to respond to neurotransmitter. destroy vesicles containing neurotransmitter
interfere with the ability to respond to neurotransmitter.
Which portion of a reflex arc is most likely to be located entirely within the central nervous system? sensory neuron motor neuron effector cell interneuron receptor cell
interneuron
the merger of a posterior root and an anterior root which occurs at an _______ _______ results in every spinal nerve being a ____ ____ called a ____ ____ ____
intervertebral foramen mixed nerve spinal nerve trunk
extends from the ninth to the twelfth thoracic vertebra
lumbar enlargement
Rapid removal or destruction of neurotransmitter in the synaptic cleft ____________. may affect the ability of the postsynaptic membrane to generate action potentials. generates local potentials in the presynaptic terminal. is necessary for synaptic transmission. may lead to action potentials. may stop exocytosis.
may affect the ability of the postsynaptic membrane to generate action potentials
Reflex arcs __________. require the actions of the brain. do not utilize somatic motor nerves. generally rely on the actions of the hypothalamus. may have a single synapse.
may have a single synapse
reenters the vertebral canal via the intervertebral foramen and supplies the vertebrae, vertebral ligaments, blood vessels of the spinal cord, and the meninges
meningeal branch
Neuroglia that are phagocytic within the central nervous system are oligodendrocytes. microglia. ependymal cells. astrocytes. Schwann cells
microglia
transmit nerve impulses downward from the brain
motor (descending) tracts
axon conducts impulses from integrating center to effector
motor neuron
If the ventral root of a spinal nerve were cut, the regions innervated by that spinal nerve would experience complete loss of ________. sensation. movement. sensation and movement. pain. None of these choices is correct
movement
Motor neurons and interneurons are ______________ neurons. unipolar bipolar multipolar afferent
multipolar
Which of the following is not true of neuromodulators? They may Influence synaptic effectiveness Act through second messengers Be released with neurotransmitters Be the same molecules as neurotransmitters Be none of the choices
none of the choices
the nerve supply in adjacent dermatones ____ slightly or in some cases more extensively
overlaps
Which of the following is a visceral sense modality? pain touch temperature proprioception balance
pain
involves extension of the knee joint by contraction of the quadriceps femoris muscle in response to tapping the patellar ligament
patellar reflex (knee jerk)
The spinal cord is divided into all of the following regions except ___________. cervical. thoracic. lumbar. pelvic. sacral.
pelvic
each fasciculus is wrapped in a layer called the
perineurium
innermost meninx is the ___ ______
pia mater
Ventral rami of some spinal nerves join with each other to form a _________. ganglion. dermatome. cord. plexus. nerve.
plexus
Compared to the inside of the resting plasma membrane, the outside surface of the membrane is positively charged. electrically neutral. negatively charged. continuously reversing so that it is positive one second and negative the next. negatively charged whenever the sodium-potasisium pump is operating.
positively charged
contain somatic and autonomic sensory nuclei
posterior (dorsal) gray horns
serves the deep muscles and skin of the posterior surface of the trunk
posterior (dorsal) ramus
Which of the following branches of a spinal nerve have somas of solely sensory neurons? posterior (dorsal) root anterior (ventral) root posterior ramus anterior ramus meningeal branch
posterior (dorsal) root
Axons of sensory neurons synapse with the cell bodies of interneurons in the _____________ of spinal cord gray matter. anterior horn lateral horn posterior horn gray commissure lateral funiculi
posterior horn
shallow, wide groove on dorsal side of interior spinal cord
posterior median sulcus
contains sensory nerve fibers which transmit nerve impulses from the periphery into the spinal cord
posterior/dorsal root
Synaptic vesicles contain neurotransmitters and are present in the __________. dendrites. cell body. axolemma. presynaptic terminals or terminal boutons. trigger zone.
presynaptic terminals or terminal boutons
The tendon reflex causes a muscle that is being stretched to contract. makes the contralateral motor neurons contract. makes the ipsilateral motor neurons relax. prevents overcontraction of a muscle. causes a tendon to contract.
prevents over contraction of a muscle
A subthreshold stimulus a. produces an afterpotential b. produces a graded potential c. causes and all-or-none response d. produces more action potentials than a submaximal stimulus
produces a graded potential
shortly after passing through its intervertebral foramen, a spinal nerve divides into several branches called ___
rami
components of the autonomic nervous system
rami communicantes
each spinal nerve arises from the spinal cord as a series of small _____ which converge to form larger _____
rootlets roots
external anatomy of the spinal cord: roughly _____ extends from the ____ ____ to the ____ ____ of the ____ ____ _____ in an adult
roughly cylindrical and extends from the medulla oblongata to the superior border of the second lumbar vertebra in an adult
transmit nerve impulses upward to the brain
sensory (ascending) tracts
The peripheral nervous system includes the: sensory nerves and motor nerves brain and spinal cord medulla oblongata and meninges limbic system and parasympathetic division none of the above
sensory nerves and motor nerves
axon conducts impulses from receptor to integrating center
sensory neuron
the gray matter contains ___ _____ and ___ ___; the gray matter on each side of the spinal cord is subdivided into regions called _______
sensory nuclei motor nuclei horns
A neuron that conducts pain sensations to the central nervous system would be classified as a(n) _________. motor neuron. sensory or afferent neuron. efferent neuron. association neuron. interneuron.
sensory or afferent
responds to a stimulus by producing a receptor potential
sensory receptor
the underlying skeletal muscles receive signals from _____ ____ ____ that carry impulses out of the spinal cord
somatic motor neurons
Which of the following is mismatched? central nervous system - brain autonomic nervous system - sympathetic and parasympathetic divisions peripheral nervous system - spinal nerves somatic nervous system - sensory division of PNS peripheral nervous system - sensory and motor divisions
somatic nervous system - sensory division of PNS
the skin over the entire body is supplied by ____ ____ ___ that carry nerve impulses into the spinal cord and brain stem
somatic sensory neurons
The central nervous system includes the _________. ganglia. spinal cord. spinal nerves. cranial nerves. sensory receptors.
spinal cord
pia mater is attached to the surface of the _____ _____
spinal cord
lumbar puncture (L3 & L4; L4&L5)
spinal tap
Stimulation of the Golgi tendon organs result in which of the following changes in the reflex arc? stimulation of a stimulatory association neuron stimulation of an inhibitory neuron decreased action potentials in alpha motor neurons contraction of skeletal muscle fibers stimulation of an inhibitory neuron and decreased action potentials in alpha motor neurons
stimulation of an inhibitory neuron and decreased action potentials in alpha motor neurons
You go to the movies after a long day and you begin to nod off as soon as the movie starts. Your head starts to lower a little but this reflex causes your head to rise. This is called the tendon reflex. crossed extension reflex. withdrawal reflex. stretch (myotatic) reflex. flexor (withdrawal) reflex
stretch myotatic reflex
surrounding the pia mater is the _____ ________ filled with ______ fluid
subarachnoid space cerebrospinal
surrounding the arachnoid mater is the ____ ______ filled with interstitial fluid
subdural space
Chemical synapses are characterized by ___________. the release of neurotransmitter by the presynaptic terminal. protein channels that connect the pre- and postsynaptic cells. the presence of receptors for neurotransmitters on the presynaptic terminal. the absence of gap junctions. receptors located only on the presynaptic terminal
the release of neurotransmitter by the presynaptic terminal.
In convergent pathways a. the response of the postsynaptic neuron depends on the summation of EPSPs and IPSPs b. a smaller number of presynaptic neurons synapse with a larger number of postsynaptic neurons information transmitted in ne neuronal pathway can go into two or more pathways d. all are correct
the response of the postsynaptic neuron depends on the summation of EPSPs and IPSPs
In convergent pathways, the response of the postsynaptic neuron depends on the summation of EPSPs and IPSPs. a smaller number of presynaptic neurons synapse with a larger number of postsynaptic neurons. information transmitted in one neuronal pathway can go into two or more pathways. all of the above.
the response of the postsynaptic neuron depends on the summation of EPSPs and IPSPs
ventral rami of the spinal nerves form nerve plexuses in all regions except the thoracic region. the brachial region. the cervical region. the lumbar region. the sacral region
the thoracic region
each column contains bundles of nerve axons called _______
tracts
The motor (efferent) division of the peripheral nervous system ___________. is a division of the CNS. regulates the digestion of food. transmits impulses from the CNS to skeletal muscle. has nerve cell bodies located in ganglia near the spinal cord and brain. detects a stimulus.
transmits impulses from the CNS to skeletal muscle
The same neurotransmitter may produce different effects on neurons because of differences in the _____________. type of receptors on the postsynaptic membranes of neurons. strength of the action potential. amount of neurotransmitter. size of the neurons. potassium channels.
type of receptors on the postsynaptic membranes of neurons.
Intercostal nerves are formed from the ________. thoracic plexus. ventral rami of thoracic spinal nerves. dorsal rami of thoracic spinal nerves. rami communicans of the thoracic spinal nerves. cervical plexus.
ventral rami of thoracic spinal nerves.
The motor root of a spinal nerve is also referred to as the ___________. afferent root. dorsal root. posterior root. ventral root. sensory root
ventral root
included in vertebral column
vertebrae vertebral ligaments
A reflex that protects limbs by removing them from painful stimuli is the ___________. stretch reflex. crossed extensor reflex. Golgi tendon reflex. alternating reflex. withdrawal reflex
withdrawal reflex
