NUR 730 Exam 4 Part 1 PDF

NUR 730 Exam 4 part 1 Foramina\ ○ Vertebral\ ○ Intervertebral\ ○ Transverse\ ◆ Intervertebral Disks: Components\ Each disc consists of:\ ○ Nucleus pulposus\ ○ Annulus Fibrosus\ ○ Vertebral end plates\ Components\ ○ Protein, collagen, and water\ \ ➔ Intervertebral Disc & Herniation\ ◆ Comprise ¼...

NUR 730 Exam 4 part 1 Foramina\ ○ Vertebral\ ○ Intervertebral\ ○ Transverse\ ◆ Intervertebral Disks: Components\ Each disc consists of:\ ○ Nucleus pulposus\ ○ Annulus Fibrosus\ ○ Vertebral end plates\ Components\ ○ Protein, collagen, and water\ \ ➔ Intervertebral Disc & Herniation\ ◆ Comprise ¼ length of the spinal column\ ◆ Movement between the vertebrae\ ◆ Acts as a shock absorber\ ◆ Trauma or degenerative changes\ ◆ Herniation = protrusion of nucleus pulposus→ posterolateral annulus fibrosus - "herniated discs"\ Nerve root compression\ HNP= herniated nucleus pulposus\ ➔ Abnormal Curvatures of the Spine\ ◆ Kyphosis - "abnormal thoracic curvature - aka 'hunchback'"\ \ ◆ Lordosis - "forward curve - aka 'sway back'"\ \ ◆ Scoliosis - "side to side curvatures"\ "\40 severe → moderate and severe may\ require surgery or braces" ➔ Regional Characteristics of Vertebrae\ ◆ Atlas: C1\ Supports the skull/ head\ No body or spine\ Articulates with:\ ○ Occipital Condyles\ ○ Atlanto-occipital joint- flexion/extension of the head & neck\ ○ Axis\ ○ Atlantoaxial joint- head/neck rotation\ ◆ Axis: C2\ Smallest transverse process\ Protuberance\ ◆ Vertebra Prominens C7\ Longest spinous process - "why we palpate for this one"\ Attachments for:\ ○ Supraspinous ligaments\ ○ Ligamentum nuchae\ \ ◆ Thoracic vertebra\ Costal facets\ ○ Superior\ ○ Inferior\ Transverse Process\ ◆ L5:\ Largest body\ 2 processes\ ○ Mammillary processes\ ○ Accessory processes\ ◆ Sacrum:\ 5 fused sacral vertebrae\ 4 pairs of foramina\ Articulates with 4 bones:\ ○ Last lumbar vertebra above\ ○ Coccyx below\ ○ Illium portion of the hip bone on either side (2)\ ◆ Coccyx:\ 4 coccygeal vertebrae\ Attachment for ligaments\ ➔ Muscles that Affect the Spine\ ◆ Back muscles stabilize the spine\ Ex: Sternocleidomastoid -- head movement\ Ex: Psoas Major- thigh flexion\ ◆ Flexion, rotation, or extension\ ◆ Extensors → back of the spine → enable us to stand up and lift objects\ ◆ Flexors → front → abdominal muscles→ enable us to flex or bend forward & lift and control the arch in the lower back\ ◆ Muscles → supported by fascia\ ◆ Examples of Specific Muscles Associated with Movement of the Spinal Cord\ Thoracic Region:\ ○ Longissimus Thoracis - extension & lateral flexion of the vertebral column; rib rotation\ ○ Iliocostalis Thoracis - extension & lateral flexion of the vertebral column; rib rotation Lumbar Region:\ ○ Psoas Major - flexes the thigh at the hip joint and the vertebral column\ ○ Quadratus Lumborum - lateral flexion of the vertebral column\ Cervical region (Anterior):\ ○ Sternocleidomastoid - head movement- extension & rotation; flexion of the vertebral column\ Posterior Cervical:\ ○ Longissimus Cervicus - extends cervical vertebrae\ ○ Longissimus Capitus - head rotation/pulls backward\ ➔ What are Reflex Arcs - neural pathways that control an action reflex\ ◆ Sensory neurons receive stimulation\ ◆ Effectors - muscle cells\ ◆ Reflex actions = involuntary responses to a specific stimulus\ ◆ 2 types of reflex arcs:\ 1) Autonomic- inner organs\ 2) Somatic- muscles\ ◆ "2 types of neuron reactions":\ Monosynaptic - sensory + motor neurons\ Polysynaptic - multiple interneurons\ ◆ Consist of:\ Sensor organ\ Sensory neuron\ 1 or more synapse\ Motor neuron\ Effector -muscle\ ➔ Myotatic Reflex - Deep Tendon Reflexes\ ◆ Example: Knee Jerk Reflex - stretch reflex\ ◆ When a load is placed on a muscle → stretched → reflex contraction of the muscle→ muscle strength\ ◆ Automatic regulation of muscle length- monitored by muscle spindles\ ◆ Monosynaptic reflex - one synapse\ ◆ Physiologic function of myotatic reflex = resist gravity\ ◆ A lesion in any part of the myotatic reflex circuit will result in areflexia\ ◆ Common reflex arcs\ Brachioradialis - C5-C6\ Biceps - C6-C7\ Triceps - C6-C7\ Knee - L2-L4\ Ankle - S1\ ➔ Inverse Myotatic Reflex\ ◆ Reflex inhibition of muscle contraction that is stimulated by the active contraction of the muscle itself\ ◆ Protects a muscle from overload during extreme contraction\ ◆ Provides a tension feedback system → regulates muscle tension in sustained contraction\ ◆ Mediated →Golgi tendon organs\ AKA Golgi reflex - opposes contraction\ ➔ Reciprocal Inhibition\ ◆ Antagonistic muscle pairs\ Agonist - movement by shortening\ Antagonist - opposes the action\ ◆ In reciprocal inhibition → simple movement occurs → antagonistic muscle pairs\ ◆ Mediated by spinal interneurons\ ◆ Ex: Biceps/Triceps /// Hamstring/Quadriceps\ ➔ Spinal Ligaments & Tendons\ ◆ Ligaments connect bone to bone - help stabilize joints\ ◆ Tendons attach muscle to bone\ ◆ Limited blood supply → "makes it longer for tendon to heal"\ ➔ Spinal Cord Ligaments\ ◆ Vertebral column → stabilized by ligaments → provide flexibility & limit excessive\ movement → limit damage\ ◆ 2 Primary Spinal Ligament Systems\ ◆ Intra and Inter segmental systems\ Intra-segmental holds individual vertebrae together\ Intersegmental holds many vertebrae together\ ◆ Strongest ligament → ligamentum flavum ➔ Clinical Considerations: Tissues Involved in Epidural Placement\ ◆ Lumbar puncture:\ Tap of lumbar SA space → L3 and L4 or L4 and L5\ Allows for:\ ○ Measurement of CSF pressure\ ○ Bacteriologic and chemical examination\ ○ Introduction of anesthetics\ ◆ Caudal Anesthesia:\ Blocks spinal nerves in the epidural space\ Injection of anesthetic agents\ ◆ SAB- local anesthesia injected into the subarachnoid space\ CSF acts as carrier\ Smaller volume\ ◆ Epidural- local anesthesia injected into the epidural space- lumbar, sacral, thoracic\ Larger volume needed, no carrier fluid\ ➔ Review of Somatic Motor Systems, Tracts, Reflex Arcs, Special Senses\ ◆ Somatic Motor Systems\ The CNS has 2 neural outputs\ ○ The somatic motor system\ ○ The autonomic nervous system\ Somatic motor system (voluntary)\ Part of Peripheral Nervous System\ Controls locomotion, fine movements, body posture and equilibrium\ ○ Nearly all voluntary muscle movements\ Acts on motor neurons\ Carries motor and sensory information to/from the CNS\ Consists of nerves →skin, sensory organs, and all skeletal muscles\ Responsible for processing sensory information -- hearing, touch, & sight\ ➔ Neural Pathway for Skeletal Muscle Contraction\ ◆ Upper motor neurons in the central nervous system\ ◆ Lower motor neurons of the somatic nervous system.\ Lower motor neurons can be a part of cranial or spinal nerves\ Innervate muscle fibers & directly cause contraction\ ➔ Somatic Nervous System Motor Unit- Alpha Motor Neurons\ ◆ Single motor neuron\ Alpha motor neurons aka lower motor neurons\ Innervate skeletal muscle\ Cause muscle contractions → movement\ ◆ Motor Neuron Pool:\ Group of motor neurons that innervate fibers within the same muscle (Lower motor neurons)\ Originate in spinal cord or brain stem\ End on skeletal muscle\ Release Ach\ Stimulates muscle contraction\ Motor neuron recruitment = more tension generated\ ➔ Spinal control of Alpha Motor Neurons\ ◆ 3 Inputs:\ Upper Motor Neurons\ ○ Cortex & brainstem\ ○ Synapse with a lower motor neuron\ ○ Control the lower motor neurons → control movement\ Spinal Interneurons\ ○ Extensive spinal circuitry\ ○ Central pattern generators\ Sensory neurons\ ○ Feedback about muscle length and tension\ Motor neurons release ACH at the NMJ ➔ Motor Tracts- Movement →\ ◆ Descending Motor Tracts\ Lateral Pathways-\ ○ Consists of upper and lower motor neurons\ ○ Involved in distal limb control\ ○ Pyramidal tracts (voluntary)\ ◆ Corticospinal tracts\ ◆ Corticobulbar tracts\ ◆ Motor pathway for upper motor neuron signals from cerebral cortex\ Ventromedial Pathways- midbrain-send upper motor neuron axons down the\ spinal cord\ ○ 4 major tracts:\ ◆ Rubrospinal tract\ ◆ Vestibulospinal tract\ ◆ Tectospinal tract\ ◆ Reticulospinal tract\ ➔ Pyramidal (corticospinal) Tract\ ◆ Corticospinal (Pyramidal) Tract:\ ◆ Cortical upper motor neurons- Brodmann's areas 1-4- 90% axons cross to the contralateral side\ ◆ Lesions above the medullary pyramids (site of decussation) will result in contralateral muscle\ weakness\ ◆ Remaining 10 % axons descend on the ipsilateral side\ ◆ Lesions below the medullary pyramids will produce ipsilateral muscle weakness\ ➔ Extrapyramidal (ventromedial) Tracts\ ◆ Control the large, postural muscles of the axial skeleton\ ◆ Originate in the brainstem\ ◆ Help maintain head position and posture\ ◆ 4 tracts: R V T R\ Rubrospinal- responsible for regulation of flexion and extension tone, fine motor\ control; minor in humans\ Vestibulospinal tract- provides a link between the sensors for balance and the\ extensor muscles\ Tectospinal tract- directs the head and eyes to move toward a selected object in\ the visual field\ Reticulospinal tract- facilitates fine control of posture by acting on the extensor\ muscles of the lower limb\ ➔ Lesions on Motor Neurons\ ◆ Upper: inhibitory\ Spastic paresis- weakness or partial paralysis\ Hyperreflexia\ Hypertonia\ + Babinski sign after age 2\ ◆ Lower:\ Flaccid paralysis\ Hypotonia\ Absent Babinski sign\ Fasciculations\ Atrophy\ ➔ Clinical Application: Poliomyelitis\ ◆ ➔ Amyotrophic Lateral Sclerosis: Upper and Lower Motor Neuron Disease\ ◆\ ➔ Somatosensory System\ ◆ 5 cutaneous sensory modalities\ Vibration\ Touch\ Pressure\ Pain\ Temperature\ ◆ Proprioception\ Sense of movement, action, location\ ◆ Dermatomes: 30- part of somatosensory system\ Area of skin supplied with afferent nerve fibers by a single dorsal spinal nerve root\ ◆ Myotomes- group of muscles innervated by a single ventral nerve root\ ➔ Vertebrae, Spinal nerves, & Dermatomes\ ◆ Spinal Segments\ 33 vertebrae → human spinal cord\ 31 pairs of spinal nerves\ 30 dermatomes- start at C2- Why?\ ○ C1 -- no sensory nerve root\ ○ Dermatomes have a segmented distribution- unique to each person\ ○ Torso and core dermatomes- horizontal distribution\ ○ Limbs -- vertical pattern\ ◆ Spinal Nerves & Dermatomes\ 31 pairs- 8 cervical, 12 thoracic, 5 lumbar, 1 coccygeal\ Dermatomes exist for each spinal nerve starting at C2\ Help localize sensory levels\ ➔ Myotome Nerve Roots & Muscle Actions\ ◆ C4: shoulder shrugs\ ◆ C5: shoulder abduction and external rotation; elbow flexion\ ◆ C6: wrist extension\ ◆ C7: elbow extension and wrist flexion\ ◆ C8: thumb extension and finger flexion\ ◆ T1: finger abduction\ ◆ L2: hip flexion\ ◆ L3: knee extension\ ◆ L4: ankle dorsiflexion\ ◆ L5: big toe extension\ ◆ S1: ankle plantarflexion\ ◆ S4: bladder and rectum motor supply\ ➔ Dermatomic Symptoms of Spinal Nerve Infections\ ◆ Viruses may infect spinal nerves → painful dermatomic area\ ◆ Herpes zoster → migrates along spinal nerve → affects area of sin served\ by the nerve ➔ Dorsal Column Medial Lemniscus Pathway\ ◆ Conveys discriminative touch, vibration, and proprioceptive sensory input\ ◆ Decussation at the medulla\ ◆ Any unilateral damage ↓medulla → ipsilateral loss of sensation\ ◆ Damage ↑medulla → contralateral loss of sensation\ ◆ Main pathway involves a three - neuron chain\ ◆ First order neuron - somatosensory receptor neuron\ ◆ Second order neuron - dorsal column nuclei of the caudal medulla\ ◆ Third order neuron - located in the thalamus\ ➔ Specialized touch receptors\ ◆ Merkel's disks: slow adapting\ Sensing steady pressure\ ◆ Meissner's corpuscles: more rapidly adapting\ Rapid changes in skin contact\ ◆ Ruffini's Endings: slowly adapting\ Local stretching of the skin\ ◆ Pacinian Corpuscles: very rapidly adapting receptors\ Vibration\ ◆ Hair follicles:\ Transduce displacement of hair\ ➔ Secondary Somatosensory Areas\ ◆ Posterior parietal cortex - integrates touch with other sensations\ ◆ Agnosia - inability to recognize objects despite the presence of normal sensations\ ◆ Astereognosis - inability to recognize objects through touch\ ➔ Diseases Affecting the DCMLS\ ◆ Vitamin B12 neuropathy & Tabes dorsalis\ Ipsilateral sensory deficits below the lesion - pathway decussates at the medulla\ ◆ Tabes dorsalis - late manifestation of syphilis\ Impaired sensations from demyelination of dorsal column -\ ○ Ataxic wide gait with loss of touch and proprioception\ ○ Paresthesias with altered sensations,\ ○ Bladder dysfunction such as urinary retention\ ○ Positive Romberg sign\ DORSALIS - mnemonic to remember\ ○ D - dorsal column degeneration\ ○ O - orthopedic pain (charcot joints)\ ○ R- reflexes decreased\ ○ S - shooting pain\ ○ A - argyll-robertson pupils\ ○ L - locomotor ataxia\ ○ I - impaired proprioception\ ○ S - syphilis\ ➔ Anterolateral System- Spinothalamic\ ◆ Sensory pathway from skin to thalamus\ ◆ Conveys pain and temperature sensory input\ ◆ Decussates - 1-2 spinal cord segments above and below the entry of the\ peripheral afferent neuron\ ◆ Damage = contralateral loss of sensation 1-2 spinal cord segments ↓lesion\ ◆ 2 types of spinothalamic tracts\ Neospinothalamic tract -- fast type A delta nerve fibers\ ○ Nerves terminate in the dorsal horn of the spinal cord -\ ○ The neurotransmitter involved is glutamate\ Paleospinothalamic tract - slow type C nerve fibers.\ ○ Nerves terminate in the substantia gelatinosa\ ○ Morphine and its derivatives work by inhibiting mu receptors there\ ◆ Disease - Syringomyelia\ Cavity formation in the cervical spine - "fluid filled cavities"\ Bilateral loss of pain and temp\ Compression of motor neurons → flaccid paralysis of upper extremities\ ➔ Transmission of Pain and Temperature Sensation\ ◆ Pain & temperature pathway- 3 neuron chain\ ◆ Pain sensation is protective ◆ Superficial pain → body surface\ Initial pain - sharp/highly localized- fast- "prickly"\ ○ Small type A delta fibers (myelinated)\ ○ Thermal or mechanical stimuli\ Delayed pain - diffuse/burning, dull, aching- poorly localized, slow\ ○ Thermal, mechanical, or chemical stimuli\ ○ Type C nerve fibers (unmyelinated)\ ◆ Deep pain - muscles & joints\ ◆ Nociceptors - pain receptors\ ◆ Pain sensation - see flowchart\ ➔ Other Types of Pain\ ◆ Visceral pain - pain arising from the internal organs-\ Dull, burning, poorly localized sensation\ ◆ Referred pain - pain arising from the viscera\ Perceived to be on the body surface\ ◆ Phantom sensations - perceptions occurring after limb or organ removal\ Sensations of pain, touch, temperature, pressure, itchiness, movement\ ◆ Phantom limb pain - feeling of pain in an absent limb or portion of a limb after amputation, congenital limb deficiency or SCI\ ◆ Phantom limb sensation- sensory phenomenon other than pain\ Felt in an absent limb or a portion of the limb\ \~ 80% of amputees experience phantom sensations\ ➔ Temperature Sensation\ ◆ Cold fibers:\ Most numerous type of thermoreceptor\ Respond to a broad range of temperatures\ ◆ Warm fibers:\ Respond to a narrower range of temperatures\ ◆ Both types are rapidly adapting\ ◆ Both help protecting against hot and cold and recognizing wet and slipperiness\ ◆ Play a minor role in control of core temperature