Biological Psych Nerves & Spine. Spine Combines Strong bones Flexible connectors (ligaments & tendons) Large muscles Sensitive nerves

Transcription

1 Biological Psych Nerves & Spine Spine Combines Strong bones Flexible connectors (ligaments & tendons) Large muscles Sensitive nerves Multi-Layer White Matter Pia Matter = thin, waterproof Arachnoid membrane (web) Dura Matter = keeps spinal fluid in Bone = vertebral column Periosteum = bone cover Skin Terminates in Medulla Cord is shorter than structure Bell-Magendie Law Charles Bell (1811) first experimental research on spinal nerves Francois Magendie (1822) discovered anterior root is motor dorsal root is sensory One-way Dorsal is up, ventral is down 1. Conduit for sensory info up collect somatosensory info for brain 2. Conduit for motor info down distribute motor fibers to glands and muscles 3. Reflexes Eye--spine--blink Description 45 cm long in men 43 cm long in women

2 31 segments pair of nerves exit each segment 8 Cervical 12 Thoracic 5 Lumbar 5 Sacrum 1 coccygeal 8 Cervical C1-3 neck C4 diaphragm C5 shoulder C6 wrist C7 triceps C8 fingers Damage Usually results in Partial or full paralysis Quadriplegia C1-3 Breathing Ventilators Phrenic nerve pacing Diaphragm C4 Biceps & shoulders C5 Wrists & hands C6 Limited wrist usage No hand control C7 & T1 Can t function independently No dexterity in fingers Limited use of arms Nerves come out top of vertebrate So, this is also called C8 Control Heart rate, blood pressure Body temperature, sweating

3 Autonomic Dysreflexia Pain & sensory $ cause Increase in blood pressure Autonomic responses 12 Thoracic Come out bottom of vertebrates T1 Hand T2-12 Trunk T7 & L1 Abdominals T11 & L2 Ejaculations Paraplegia No trunk stability Can t control abdominals 5 Lumbar L1 Hips L2 Quadriceps L4 Hamstrings L5 Knees L4 & S1 Foot 5 Sacrum S1 Foot S2 Penile erection S3 Bowel & Bladder Injury Decreased control of hips Urinary system Legs Injury: Lower is better Less is better Injury Causes Car crashes Twist, bend, dislocation, extend Falls, sports

4 Stabs and gunshot wounds Cancer, infections, diseases Men more likely than women 80% Syndromes Central Cord Syndrome Incomplete injury Called inverse paraplegia Problems in arms, hands Legs work okay Injury to central core nerves, usually in cervical or upper thoracic Anterior Cord Syndrome Cervical spine flexed too much damage to anterior of spinal cord Damage blood supply from the anterior spinal artery Loss of pain & temp sensations Touch still works Posterior Cord Syndrome Rare damage to posterior area Damage to posterior blood supply Loss of touch but not pain Brown-Séquard Syndrome Injured on lateral side Hemisectioned (divided in half) Total hemisectioning is rare Partial lesions from gunshots & penetrating knife wounds Ipsilateral side of injury (same side) Loss of motor function Can t feel vibration & light touch Contralaterally (opposite side) Loss of pain, temp. & crude touch Tabes Dorsalis Injury to posterior region Usually from diseases (syphilis) Loss of touch sensation Conus Medullaris Injury to tip of spinal cord at L1

5 Symptoms Pain Paralysis Numbness Incontinence Loss of sensation Bone degeneration Muscles uncontrollably contracts unresponsive weak atrophy Injury Assume spinal cord injury Stabilize head and neck Hands on both sides of head Act as if spine is single unit Treatments Steroids Within 6 hours of injury High doses of methylprednisolone Terms Dermatome = skin area sensory info Myotome = muscle area motor info CONNECTIONS Peripheral Nervous System Anything not in brain & cord Not protected by bone Not protected by BBB I. Somatic Nervous System Voluntary control of muscles II. Autonomic Nervous System Control of heart, stomach, etc. I. Somatic Nervous Sys Muscles used to move the body Long cylindrical shape Striated (stripes) Each muscle moves in one direction With no acetlycholine, relaxes

6 Striated Muscles To move in two directions, need two antagonistic muscles Flexor raise arm Extensor to lower arm Biceps contract; triceps relax Myasthenia Gravis Immune system anti-bodies Attack acetylcholine receptors Motor neurons can t produce enough acetylcholine Symptoms Weakness of eye muscles (open-close eyelid) Difficulty swallowing Slurred speech Weakness in arms Rapid fatigue Unstable gait Feel better after rest II. Autonomic Nervous System Control of heart, stomach, etc. Visera (general term) Heart Stomach Intestines Sensation (afferent) neurons Mostly unconscious Visceral sensations Not divided into parasympathetic and sympathetic fibers Conducted by general visceral afferent fibers Automatic, reflexive Always working Notice it when Fight or flight Rest & digest Regulates: Smooth Muscles stomach, intestines & bladder around blood vessels (skin, iris) Cardiac muscle (heart)

7 Unique system Requires 2-neuron sequence preganglionic neuron fires first target organ neuron fires Reflex arcs Normally undetectable Sometimes send pain signals Referred pain non-localized Also called dermatomes Three divisions Sympathetic nervous system Parasympathetic nervous system Enteric nervous system 1. Sympathetic nervous system Speeds things up Increases blood pressure Increases heart rate Decreases digestion Originates in spinal cord Thoracic and lumbar regions Thoracolumbar outflow Uses acetylcholine as NT Spinal cord to ganglion Uses norepinephrine Ganglion to organ Except sweat glands (ACh) 2. Parasympathetic Nervous System Slows things down Decreases blood pressure Decreases heart rate Increases digestion Doesn t require quick action Craniosacral outflow Increase body s supply of: salivation, gastric and intestinal motility, etc

8 Axons of presynaptic neurons Quite long CNS to glanglion Very short Close to target organ Originates in medulla Some from acral region Uses ACh for NT At both ganglion and organs 3. Enteric Nervous Sys Intrinsic Nervous System Meshwork of nerve fibers Directly controls gastro-intestinal system pancreas, gall bladder, etc. 30 NT+ Includes ACh, dopamine, serotin 90% of serotonin in gut 50% of dopamine in gut Cranial Nerves Come directly from brain 12 pair 1 & 2 = cerebrum 3-12 = brainstem On old Olympic towering tops, a Finn and German viewed some hops Oh, oh, oh, to touch and feel very good velvet...ah, heaven Olfactory smell Optic vision Ocularmotor eye movement Trochlear rotates eyeball Trigeminal face & mouth Abducens eye movements Facial face & tongue Acoustic sound Glossopharyngel taste Vagas voice & taste Shoulder trapezius (accessory) Hypoglossal tongue & shallow

9 Between Brain & Cord Medulla oblongata Lower half of the brainstem Centers that control Breathing, heart rate, blood pressure, respiratory rate and vomiting Helps transfer info between brain and spinal cord Integrates inputs Last 7 cranial nerves exit here Sense of touch, position, tongue Opposite side of body Aggression? Waterboy is wrong Controls reflexes of: coughing, sneezing, sucking, vomiting and salivating Both white & gray matter--reversed White on outside, gray on inside Two parts: open and closed Open: top of stem Front of 4 th ventricle Open to the ventricle Closed Lower portion Closed = covered by nerve fibers & central canal in middle Pons Looks like bulge on medulla Sensory signals to thalamus Motor signals from cerebrum to cerebellum & medulla Nuclei that deal with Hearing, taste & eye movements Facial expressions & sensations Sleep, respiration, swallowing Equilibrium, posture Bladder control Central Pontine Myelinosis Disease of demyelination difficulty with balance & walking difficulty swallowing & speaking