Nervous system
The left and right cervical plexuses are formed primarily by the anterior rami of spinal nerves ______.
C1-C4
The left and right cervical plexuses are located deep on each side of the neck, immediately lateral to cervical vertebrae ______.
C1-C4
One important branch of the cervical plexus is the phrenic nerve, which is formed primarily from the ______ nerve and some contributing axons from ______.
C4; C3 and C5
Each brachial plexus is formed by the anterior rami of spinal nerves ______.
C5-T1
Which are characteristic of somatosensory pathways?
Each pathway transmits information to different regions of the brain.
The anterior rami of spinal nerves ______ are called intercostal nerves because they travel in the intercostal space sandwiched between ______.
T1-T11; two adjacent ribs
The nerves emerging from a sacral plexus innervate the ______ region, pelvis, perineum, posterior thigh, and almost all of the ______.
gluteal; leg and foot
Sensory nervous system pathways transmit ______.
information from somatic and special sense receptors to the central nervous system
Motor pathways in the nervous system transmit ______.
information from the central nervous system to muscles or glands; descending
In terms of their functional classification in sensory pathways, secondary and tertiary neurons are ______, and primary neurons are sensory neurons.
interneurons
In a withdrawal reflex, ______ receives sensory information and stimulates motor neurons to direct ______ muscles to contract in response.
interneurons; flexor
At each ______ foramen, the dura mater extends between adjacent vertebrae and fuses with the connective tissue layers that surround the spinal nerves.
intervertebral
Each anterior root and its corresponding posterior root unite within the ______ to become a spinal nerve.
intervertebral foramen
When both the receptor and effector organs of a reflex are on the same side of the spinal cord, the proper term is ______.
ipsilateral
A second-order neuron ______.
is an interneuron
A third-order neuron ______.
is an interneuron;; it carries the signal the rest of the way to the cerebral cortex
In the spinal cord, the gray matter may be subdivided into the following components: anterior, posterior, and________________ horns, and the gray commissure
lateral
The musculocutaneous nerve arises from the ______ cord of the brachial plexus.
lateral
In the foot, the tibial nerve splits into the ______ plantar nerves, which innervate the plantar muscles of the foot.
lateral and medial
When you step on a jellyfish with your right foot, the ______ side of your brain sends the impulse to lift your right foot.
left
The ______ enlargement of the spinal cord contains axons that extend beyond the conus medullaris, innervating the lower limbs.
lumbosacral
The ulnar nerve arises from the ______ cord of the brachial plexus and descends along the medial side of the arm.
medial
The median nerve is formed from branches of the ______ cords of the brachial plexus.
medial and lateral
The ulnar nerve wraps posterior to the ______ of the humerus and then runs along the ulnar side of the forearm.
medial epicondyle
The spinal cord has two longitudinal depressions. These are the posterior ______ and the anterior ______.
median sulcus; median fissure
The spinal cord is protected and encapsulated by spinal cord meninges, which are continuous with the cranial ______.
meninges
Spinal nerves are considered ______ nerves because they contain both motor and sensory axons
mixed
A stretch reflex is a ______ reflex that monitors and regulates skeletal muscle length.
monosynaptic
Name the type of reflex arc where the sensory axons synapse directly on the motor neurons, whose axons project to the effector.
monosynaptic
The simplest of all reflexes is the ________ reflex.
monosynaptic
Multiple anterior rootlets arise from the spinal cord and merge to form a single anterior root, which contains ______ axons only.
motor
A spinal nerve contains ______ axons.
motor and sensory
Reflexes are rapid, automatic, involuntary reactions of ______ to a stimulus.
muscles or glands
The spinal nerves connect the central nervous system to ______ and receptors.
muscles, glands
Sensory ______ in the posterior horns contain interneuron cell bodies.
nuclei
A collection of neuron cell bodies within the central nervous system is called
nuclei or nucleus
Impulses from lower motor neurons _______ skeletal muscle.
only stimulate or excite
Deep to the subarachnoid space, is a delicate, innermost meningeal layer composed of elastic and collagen fibers. This layer is known as the ______
pia mater
he spinal meninges consist of the ____________ mater, _____________ mater, and ____________ mater. (List superficial to deep.)
pia, arachnoid, and dura mater
The tibial nerve travels in the posterior compartment of the leg, where it supplies the ______ of the foot and the toe flexors.
plantar flexors
The Golgi tendon reflex is a ______ reflex that prevents skeletal muscles from tensing excessively.
polysynaptic
Just superior to the ______, the two divisions of the sciatic nerve split into two nerves.
popliteal fossa
After leaving the intervertebral foramen, a typical spinal nerve almost immediately splits into branches, termed ______.
rami
Additional rami, called the ______, are also associated with spinal nerves.
rami communicantes
A phenomenon in which pain or discomfort from one organ is mistakenly referred to a dermatome is called ______.
referred visceral pain
Awareness of the stimulus occurs after the _____________ action has been completed, in time to correct or avoid a potentially dangerous situation.
reflex
The spinal cord and spinal nerves are responsible for ______, which are our quickest reactions to a stimulus.
reflexes
The longest nerve in the body is the ______ nerve.
sciatic
A second-order neuron is also known as a neuron
secondary
The posterior rami of spinal nerves tend to follow a ______ pattern as they innervate the deep muscles and skin of the neck and back.
segmental
The spinal cord and its attached spinal nerves are a pathway for ______ impulses.
sensory and motor
A reflex arc is the neural wiring of a ______ reflex.
single
A dermatome is a specific segment of ______ supplied by a single spinal nerve.
skin
Interneurons of a reflex arc are located in the ______.
spinal cord
Motor axons in a spinal nerve originate in the ______.
spinal cord
A hypoactive reflex may indicate damage to a segment of the ______, or it may suggest muscle disease or damage to the ______ junction.
spinal cord; neuromuscular
Stretch in a muscle is monitored by a stretch receptor called a muscle ______.
spindle
The dura mater provides ______ to the spinal cord.
stability
A hyperactive reflex refers to an abnormally ______ response.
strong
Deep to the arachnoid mater is the ______ space, which is a real space filled with ______ fluid.
subarachnoid space; cerebrospinal fluid
Golgi tendon organs are nerve endings located within ______ near a muscle-tendon junction.
tendons
White matter on each side of the cord is also partitioned into ______ regions, each called a ______.
three; funiculus
The sciatic nerve is actually composed of two divisions wrapped in a common sheath. What are the two divisions?
tibial and common fibular
A neural pathway consists of ______.
tract and a nucleus
The axons within each white matter funiculus are organized into smaller structural units called ______.
tracts
Each set of rami communicantes extends between the spinal nerve and a ball-like structure called the sympathetic ______.
trunk ganglion
A stretch reflex is a simple monosynaptic reflex involving ______.
two neurons
The gray commissure primarily contains ______ axons and serves as a communication route between the right and left sides of the ______ matter.
unmyelinated; gray
The cell bodies of ______ motor neurons are found in the cerebral cortex.
upper
The left and right brachial plexuses are networks of nerves that supply the ______.
upper limb
Motor pathways use a(n) ______ motor neuron and a(n) ______ motor neuron.
upper; lower
The appendix is innervated by axons from the ______ regions of the spinal cord, so appendicitis typically causes referred visceral pain to the ______ dermatome in the umbilicus region rather than in the abdominopelvic region of the appendix itself.
T10; T10
The anterior rami of the ______ region of the spinal cord do not contribute to nerve plexuses.
T2-T12
The left and right sacral plexuses are formed from the ______ rami of spinal nerves ______ and are located immediately inferior to the lumbar plexuses
anterior; L4-S4
The musculocutaneous nerve innervates the ______ arm muscles that flex the humerus and ______ the forearm.
anterior; flex
The median nerve innervates most of the ______ forearm muscles, the thenar muscles, and the lateral two ______.
anterior; lumbricals
The lumbar plexus is subdivided into a(n) ______ division and a(n) ______ division.
anterior; posterior
The left and right lumbar plexuses are formed from the ______ rami of spinal nerves L1-L4 located lateral to the L1-L4 vertebrae and along with the ______ muscle in the posterior abdominal wall.
anterior; psoas major
The receptors in somatosensory pathways ______.
are located in the joints, skeletal muscles, and skin
The epidural space contains ______ connective tissue, ______, and adipose connective tissue.
areolar; blood vessels
Action potentials ______ the brain through sensory pathways.
ascend to
Pathways that transmit sensory impulses are also called ______ pathways because the information travels from sensory receptors superiorly through the spinal cord to the brain.
ascending
Each lateral funiculus contains both ______ and ______ tracts.
ascending, descending
The rami communicantes contain axons associated with the ______ nervous system.
autonomic
The ______ of the spinal cord contains the neurons that innervate the upper limbs.
cervical enlargement
Sensory/ascending tracts
conduct nerve impulses toward the brain
When the sensory impulses from a receptor organ cross over through the spinal cord to activate effector organs in the opposite limb, the proper term for this phenomenon is ______.
contralateral
When decussation occurs, information is processed on the opposite side of the brain or ______ compared to where the information is coming from or the destination of the impulse.
contralaterally
When decussation occurs, information is processed on the opposite side of the brain or ________ compared to where the information is coming from or the destination of the impulse.
contralaterally
The tapering inferior end of the spinal cord is called the ______.
conus medullaris
When viewed in cross section, the spinal cord is roughly ______, but slightly ______ both posteriorly and anteriorly.
cylindrical; flattened
Primary motor neurons of the ______ motor pathway originating in the primary motor cortex, whereas primary motor neurons of the ______ motor pathway originate in the brainstem.
direct; indirect
The ______ space lies between the dura mater and the periosteum covering the inner walls of the vertebra.
epidural
Impulses from upper motor neurons _______ lower motor neurons.
excite or inhibit
The radial nerve innervates the forearm ______ and the posterior forearm muscles.
extensors
The white matter of the spinal cord is ______ to the gray matter.
external
The epidural space contains
fat
All spinal nerves except ______ innervate a segment of skin, and so each of these nerves is associated with a dermatome.
C1
Match the reflex with the correct description: 1. spinal reflex 2. Visceral reflex 3. Polysynaptic reflex 4. Ipsilateral reflex
1. The integration center in this type of reflex is the spinal cord. 2. A gland may be the effector in this type of reflex. 3. This reflex includes one or more interneurons. 4. The receptor and effector in this reflex are located on the same side of the body.
The spinal cord is associated with ______ pairs of spinal nerves.
31
A typical adult spinal cord ranges between ______ centimeters (cm) in length.
42 and 45
a. white matter b. gray matter c. posterior median sulcus d. anterior median fissure e. spinal nerve
In the picture of the spinal cord, match the structures with the indication in the diagram.
The spinal cord extends inferiorly from the brain through the foramen magnum, then through the vertebral canal, and ends at the level of the ______ vertebra.
L1
1. Stimulus activates receptor 2. Nerve impulse travels through sensory neuron to the spinal cord Nerve impulse travels through sensory neuron to the spinal cord 3. Nerve impulse is processed in the integration center by interneurons 4 Motor neuron transmits nerve impulse to effector Motor neuron transmits nerve impulse to effector 5. Effector responds to impulse from motor neuron Effector responds to impulse from motor neuron
Match the steps in a reflex arc with its description.
a. epidural space B. dura mater c. spinal cord d. body of vertebra
Match the structure or space with the letter indicated.
a. dorsal root b. ventral root c. arachnoid mater d. dura mater e. pia mater
Match the structure with the indication on the diagram of the spinal cord.
a. tertiary sensory neuron b. secondary sensory neuron c. primary sensory neuron d. upper motor neuron e. lower motor neuron.
Match the types of neurons provided in the figure to their letters.
A reflex arc always begins at a receptor in the ______, communicates with the ______, and ends at a peripheral effector, such as a muscle or gland cell.
PNS; CNS
Identify the correct statement(s) describing the relationships of primary, secondary, and tertiary neurons in somatosensory pathways.
Secondary neurons synapse with tertiary neurons in the thalamus when transmitting conscious sensations.
______ sensory nuclei receive information from sensory receptors, such as pain or pressure receptors in the skin.
Somatic
Lateral horns are found in the ______ parts of the spinal cord only.
T1-L2
The ______ horns primarily house the cell bodies of somatic motor neurons.
anterior
The ______ ramus is the larger of the two main branches of a spinal nerve.
anterior
The tibial nerve is formed from the ______ divisions of the sciatic nerve.
anterior
After splitting from the spinal nerve, the anterior ramus divides into multiple other branches, which innervate the ______ portions of the trunk, the upper limbs, and the lower limbs.
anterior and lateral
A nerve plexus is a network of interweaving ______ of spinal nerves.
anterior rami
The lateral cord of the brachial plexus is lateral to the axillary artery and is formed from the ______ divisions of the superior and middle trunks; thus, it contains portions of nerves ______.
anterior; C5-C7
The medial cord is medial to the axillary artery and is formed by the ______ division of the inferior trunk; it contains portions of nerves ______.
anterior; C8-T1
Spinal nerve T12 is called a subcostal nerve because it arises ______ the ribs.
below
Inferior to conus medullaris, nerve roots collectively called the ______ project inferiorly from the spinal cord.
cauda equina
The gray commissure is a horizontal bar of gray matter that surrounds a narrow ______.
central canal
The gray matter in the spinal cord is ______ located, and its shape resembles a letter H or a ______.
centrally; butterfly
The spinal cord is partitioned into a ______ gray matter region and a ______ white matter region.
deep; superficial
The gray matter of the spinal cord is dominated by the ______ and ______ of neurons.
dendrites; cell bodies
Pathways that transmit motor impulses are also called _____________ pathways because the information travels inferiorly from the brain, through the spinal cord, to muscles or glands.
descending
Some individual fasciculi conduct motor impulses as ______ from the brain to the spinal cord.
descending tracts
A first-order neuron ______.
detects a stimulus and transmits a signal to the spinal cord or brainstem
The phrenic nerve travels through the thoracic cavity to innervate the ______.
diaphragm
The ______ ramus is the smaller of the two main branches of a spinal nerve.
posterior
The radial nerve arises from the ______ cord of the brachial plexus.
posterior
The two main branches of a spinal nerve are the ventral and _________ rami.
posterior
Which spinal nerve rami do not form plexuses?
posterior rami
A first-order neuron is also known as a _______ neuron.
primary
The neurons in sensory pathways are termed ______.
primary, secondary, and sometimes tertiary neurons
Primary motor neurons of the direct motor pathway issue impulses for ______ control of skeletal muscles; primary motor neurons of the indirect motor pathway issue impulses for ______ control of skeletal muscles.
voluntary/conscious; involuntary/subconscious