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Johnson Anatomy Lab 2

axons going to and from the spinal cord are bundled as


spinal chord begins as the _____ _____ exits the skull and enters the ____ ____ of the 1st cervical vertebra (C1)

medulla oblongata vertebral foramen

spinal chord travels within successive vertebral foramina, a passage called the _____ _____

vertebral canal

the end of the spinal chord is found at the _____ vertebra in adults


cone-shaped termination of the spinal cord is the ____ ____

conus medularis

spinal cord has a ____ ____ in the region of the upper limb

cervical enlargement

spinal cord has a _____ _____ in the region of the lower limb

lumbar enlargement

_____ _____ formed from the "segments" of the spinal cord and exit the vertebral column through the _____ _____

spinal nerves intervertebral foramina

bundle of spinal nerves that pass through the vertebral canal on their way to the appropriate intervertebral foramen

cauda equina

within cauda equina lies the ____ ____, an extension of the pia mater

filum terminale

vertebral column is composed of __ certvical, __ thoracic, ___ lumbar, ___ fused sacral, and __-__ fused coccygeal vertebrae

7 12 5 5 3 5

___ vertebral levels, each containing muscles, skin, and bones; neurons that supply instruction to/form these levels travel within ____ _____

32 spinal nerves

each of the bodies segments is supplied by a different ____ ____

spinal nerve

outermost and toughest layer that protects the spinal cord

dura mater

unlike the brain, the duramater is surrounded by a space filled with fat, the ___ ___

epidural space

dura mater extends outward around the spinal nerves and becomes known as the ____, the outermost layer of a nerve


deep to the dura, the ____ ____ and ___ ___ can be identified

arachnoid mater subarachnoid space

deepest meningal layer in direct contact with the spinal cord

pia mater

pia mater has at least 20 pairs of lateral projections called ____ ____ that anchor the spinal cord to the dura mater and limit the movement of the cord

denticulate ligaments

as the spinal cord comes to an end at the conus medularis, the pia mater continues a thin threat the anchors the end of the spinal chord to the sacrum

filum terminale

_____ ___ anchors the end of the spinal chord to the ______

filum terminale sacrum

outer region of the spinal cord; consists of myelinated axons that are oriented vertically to communicate with higher and lower regions of the CNS

white matter

____ ____ lies internal to the white matter and contains unmyelinated neurons of the CNS and interneurons; also portions of sensory neurons and motor neurons reside within

gray matter

gray matter is organized into 3 columns; the ______, ________, and _____ horns

dorsal ventral lateral

located at the center of the spinal chord; cavity in continuity with the ventricles of the brain

central canal

systems of neurons that bring info up to the brain are called ____ ____; travels along 3 neurons considered 1st, 2nd, and 3rd order neurons

ascending pathways

(ascending) ___ order sensory neuron extends form the source of the stimulus to the _____ horn where it synapses with ______

first dorsal interneurons

(ascending) ____ order ____ extends from the dorsal horn, decussates (crosses) to the ______ (opposite) side, and then it's axon enters the white matter; the axon then runs up to the ____ where it synapses

second interneuron contralateral thalamus

(ascending) ____ order _____ extends form the thalamus to the appropriate part of the somatosensory cortex

third interneuron

(descending) ____ _____ neuron aka pyramidal neuron originates in the ____ ____ _____

upper motor primary motor cortex

(desending) primary motor cortex --> white matter via upper motor interneuorn --> decussation occurs in the ____ --> tract continues down spinal chord --> at appropriate signal level axon leaves tract and enters the _____ ______ where it synapses with lower motor neuron

medulla ventral horn

_____ ____ neuron of the peripheral nervous system;leaves the spinal cord to innervate skeletal muscles

lower motor

spinal nerve forms from the joining of two major tributaries, the _____ and _____ roots

dorsal ventral

carries sensory info to the dorsal horn of the spinal cord; has a large collection of cell bodies that form the ____ ____ ____

dorsal root ganglion

____ neurons are unique in having the cell body in the middle of the course of the axon; unipolar


neurons have their cell bodies in the ventral and lateral horns of the spinal cord

ventral root

axons of the _____ _____ are entirely motor

ventral root

____ ____; to skeletal muscles: located in _____ horn

somatic motor ventral

_____ ____; to smooth muscles and glands: located in _____ horn

visceral motor lateral

_____ _____; from skin, skeletal muscles, joints: located in _____ horn

somatic sensory dorsal

_____ _____; from the viscera: located in _____ horn

visceral sensory dorsal

spinal nerve branches into _____


_____ _____ carries somatic motor and sensory to the posterior body wall

dorsal ramus

____ ____ carries somatic motor and somatic sensory to the lateral and anterior body wall

ventral ramus

gray and white _____ _____ carry visceral motor (sympathetic) and visceral sensory neurons to and from the viscera

communicating rami

_____ _____ and its ____ run parallel to the spinal cord and send branches towards the thoracic and abdominal cavities

sympathetic chain ganglia

pattern of ventral rami in thorax where ____ _____ travel along inferior surface of the ribs and send small branches to nearby muscles, bones, and skin from

intercostal nerves

spinal nerve's ventral rami join to form a network of nerves called a _____


ventral rami join to form _____ ______ formed of C5-T1 spinal nerve rami; supplies upper limb

brachial plexus

ventral rami join to form ____ ____ formed of L2-S2 rami; supplies lower limb

lumbosacral plexus

____ ____: involuntary circuits in which the brian is not involved in the response to stimulus

spinal reflexes

______ reflexes are the simplest reflexes involve a sensory neuron and its synapse with a motor neuron


monosynaptic relfexes: stimulus travels along a sensory neuron that has an axon terminal in the _____ horn where neurons are stimulated


reflex in which the stretch of the muscle reflexively causes contraction of the same muscle leading to greater stability of joints


patellar reflex is one example of a _____ reflex; which is a type of _______ reflex

stretch monosynaptic

reflex which involve one or several interneurons


withdrawal reflex is an example of a ______ reflex; most are protective in nature


______ reflex: stimulus travels along a sensory neuron that synapses with one or several interneurons; several sets of motor neurons are stimulated in your hip, thigh, and lower leg to withdraw from the painful stimulus


________ reflex pathway: 1. stimulation of stretch receptor 2. signal occurs along sensory neuron 3. synapse with motor neuron 4. signal occurs along motor neuron 5. muscle is stimulated to contract


_______ relfex pathway: 1. stimulation of pain receptor 2. signal occurs along sensory neuron 3. synapse with interneurons 4. signal occurs along motor neuron 5. muscle stimulated to contract, withdrawing limb from pain


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