- 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
- Charles Bell (1811)
- 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
- 31 segments
- pair of nerves exit each segment
- 8 Cervical
- 12 Thoracic
- 5 Lumbar
- 5 Sacrum
- 1 coccygeal
- 8 Cervical
- Motor nerves
- 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
- Autonomic Dysreflexia
- Pain & sensory $ cause
- Increase in blood pressure
- Autonomic responses
- Motor nerves
- 12 Thoracic
- Motor nerves
- 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
- Motor nerves
- L1 Hips
- L2 Quadriceps
- L4 Hamstrings
- L5 Knees
- L4 & S1 Foot
- 5 Sacrum
- Motor nerves
- 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
- 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
- Cervical spine flexed too much
- 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
- Symptoms
- Pain
- Paralysis
- Numbness
- Incontinence
- Loss of sensation
- Bone degeneration
- Muscles
- uncontrollably contractions
- unresponsive
- weak
- atrophy
- Central Cord Syndrome
- 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
- Combines
- Terms
- Dermatome = skin area sensory info
- Myotome = muscle area motor info
- 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 System
- 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
- 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)
- Unique system
- Requires 2-neuron sequence
- preganglionic neuron fires first
- target organ neuron fires
- Smooth Muscles
- 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
- Axons of presynaptic neurons
- Quite long
- CNS to glanglion
- Very short
- Close to target organ
- Originates in medulla
- Some from sacral 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
- Come directly from brain
- 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 4th 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
- Medulla oblongata
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