Chapter 14 Check Points And Chapter Review The Nervous System: Spinal Cord And Spinal Nerves

The cell bodies of sensory neurons are found within the dorsal root ganglion.

The cauda equina is formed from the filum terminale and the long dorsal and ventral roots that extend caudal to the conus medullaris.

The cerebrospinal fluid that surrounds the spinal cord is found in the subarachnoid space, which lies between the arachnoid mater and the pia mater.

There are three meningeal layers surrounding the spinal cord and nerve roots. From deep (closest to the spinal cord) to superficial, these three layers are the pia mater, arachnoid mater, and dura mater.

Since the poliovirus would be located in the somatic motor neurons, we would find it in the anterior horns of the spinal cord where the cell bodies of these neurons are located.

Ascending tracts carry sensory information toward the brain. Descending tracts carry motor commands into the spinal cord.

The outermost layer is called the epineurium. It surrounds the entire nerve. The middle layer, or perineurium, divides the nerve into a series of compartments that contain bundles of axons. A single bundle is called a fascicle. The endoneurium is the innermost layer, and it surrounds individual axons.

The white and gray rami connect the spinal nerve to a nearby autonomic ganglion. The white ramus carries preganglionic axons that are myelinated from the nerve to the ganglion. The gray ramus carries postganglionic unmyelinated axons from the ganglion back to the spinal nerve.

The phrenic nerves that innervate the diaphragm originate in the cervical plexus. Damage to this plexus or, more specifically, to the phrenic nerves would greatly interfere with the ability to breathe and possibly result in death by suffocation.

The brachial plexus may have been damaged.

The Brachial Plexus Spinal Segments Nerve(s) Distribution C4-C6 Nerve to subclavius Subclavius C5 Dorsal scapular nerve Rhomboid and levator scapulae C5-C7 Long thoracic nerve Serratus anterior C5, C6 Suprascapular nerve Supraspinatus and infraspinatus; sensory from shoulder joint and scapula C5-T1 Pectoral nerves (medial and lateral) Pectoralis muscles C5, C6 Subscapular nerves Subscapularis and teres major C6-C8 Thoracodorsal nerve Latissimus dorsi C5, C6 Axillary nerve Deltoid and teres minor; sensory from skin of shoulder C8, T1 Medial antebrachial cutaneous nerve Sensory from skin over anterior, medial surface of arm and forearm C5-T1 Radial nerve Many extensor muscles on the arm and forearm (triceps brachii, anconeus, extensor carpi radialis, extensor carpi ulnaris, and brachioradialis; supinator digital, extensor muscles, and abductor pollicis via the deep branch; sensory from skin over the posterolateral surface of the limb through the posterior brachial cutaneous nerve (arm), posterior antebrachial cutaneous nerve (forearm), and the superficial branch (radial portion of hand) C5-C7 Musculocutaneous nerve Flexor muscles on the arm (biceps brachii, brachialis, and coracobrachialis; sensory from skin over lateral surface of the forearm through the lateral antebrachial cutaneous nerve C6-T1 Median nerve Flexor muscles on the forearm (flexor carpi radialis and palmaris longus; pronator quadratus and pronator teres; radial half of flexor digitorum profundus, digital flexors (through the anterior interosseous nerve); sensory from skin over anterolateral surface of the hand C8, T1 Ulnar nerve Flexor carpi ulnaris, ulnar half of flexor digitorum profundus, adductor pollicis, and small digital muscles through the deep branch; sensory from skin over medial surface of the hand through the superficial branch

(1) Stimulation and activation of a receptor. (2) Activation of a sensory neuron. (3) Information processing in CNS. (4) Activation of a motor neuron. (5) Response by effector.

A monosynaptic reflex has a sensory neuron synapsing directly on a motor neuron. A polysynaptic reflex has more than one synapse between the stimulus and response.

ventral ramus

perineurium

cervical enlargement.

innervates the shoulder girdle and the upper extremity. is formed from the ventral rami of spinal nerves C59T1. is the source of the musculocutaneous, radial, median, and ulnar nerves.

they contain sensory and motor fibers

cell bodies of neurons and neuroglia

filum terminale

gray commissures

dorsal root ganglia.

anterior median fissure

upper lateral cutaneous nerve of the arm

performing a plié (shallow knee bend) in ballet sitting cross-legged in the lotus position (lateral side of the foot on the medial side of opposite thigh) riding a horse

compression of the median nerve in the carpal tunnel

The meninges provide a tough protective covering, longitudinal physical stability, and a space for shock-absorbing fluid

A reflex is an immediate involuntary response, whereas voluntary motor movement is under conscious control and is voluntary

Incoming sensory information would be disrupted

Transmission of information between neurons at synapses takes a finite amount of time. Thus, the more synapses in a reflex, the longer the delay between the stimulus and responses. In a monosynaptic reflex, there is only one synapse. It has the most rapid response time. In a polysynaptic reflex, there are multiple synapses, each contributing to the overall delay

In the cervical region, the first pair of spinal nerves, C1, exits between the skull and the first cervical vertebra. Thereafter, a numbered cervical spinal nerve exits after each cervical vertebra. For instance, nerve C2 exits after vertebra C1, nerve C3 exits after vertebra C2, and so on until nerve C8, which exits after vertebra C7

The denticulate ligaments prevent side-to-side movements of the spinal cord

The adult spinal cord extends only as far as vertebra L1 or L2. Inferior to this point in the vertebral foramen, the meningeal layers enclose the relatively sturdy components of the cauda equina and a significant quantity of CSF.

The rectus abdominis muscle is always retracted laterally, as it is innervated by T79T12, entering through the posterior aspect along the lateral margin. If the muscle were to be retracted medially, the nerves would be torn, thereby paralyzing the muscle

The part of the cord that is most likely compressed is an ascending tract

The neurons for the anterior horn of the spinal cord are somatic motor neurons that direct the activity of skeletal muscles. The lumbar segments of the spinal cord control the skeletal muscles that are involved with the control of the muscles of the hip and lower limb. As a result of the injury, Karen would have poor control of most lower limb muscles, a problem with walking (if she could walk at all), and (if she could stand) problems maintaining balance.