Chapter 13 Highlihts Flashcards
Divisions of the PNS
- Sensory (afferent)
- Motor (efferent)
Divisions of sensory PNS
- Somatic sensory
- Visceral sensory
Somatic sensory division
- Detects internal and external stimuli
- General sense receptors sense the skin
- Special sense receptors detect from special sense organs
Visceral sensory division
Relays internal information (PP) from organs of abdominopelvic and thoracic cavities
Divisions of motor division
- Somatic motor
- Visceral motor
Somatic motor division
Voluntary motor functions
Lower motor neurons
- Somatic motor neurons
- Directly triggers skeletal muscle contractions
Visceral motor division
- Autonomic motor nervous system (ANS)
- Maintains homeostasis
- Involuntary
- Innervates cardiac muscle, smooth muscle, and secretory cells of glands
Divisions of autonomic NS
- Sympathetic
- Parasympathetic
Sympathetic NS
- Fight of flight
- Homeostatic activities surround physical work and visceral responses of emotions
Parasympathetic NS
- Rest and digest
- Maintains homeostasis at rest
Peripheral nerves
- Main organs of PNS
- Axons of many neurons bound together by connective tissue
Mixed nerve
Contains both sensory and motor neurons
Sensory nerve
Contain only sensory neurons
Motor nerve
- Contain MOSTLY motor neurons
- Some sensory neurons involved in muscle stretch and tension
Spinal nerve
- Originate from spinal cord
- Innervate structures below head and neck
Collections of axons that connect PNS with spinal cord’s gray matter
- Ventral root
- Dorsal root
Ventral root
- Anterior root
- Motor neurons from anterior horn
Dorsal root
- Posterior root
- Sensory neurons from posterior horn
What kind of nerves are spinal nerves?
Mixed nerves
Dorsal root ganglion
- Swollen area in posterior root
- Houses cell bodies of sensory neurons
How does a spinal nerve form?
Posterior and anterior roots fuse just lateral to posterior root ganglion
Structures associated with spinal nerves
- Epineurium
- Perineurium
- Fascicles
- Endoneurium
- Axon
Epineurium
- Outermost layer of connective tissue
- Holds motor and sensory axons together
Perineurium
Layer of connective tissue which surrounds fascicles
Fascicles
Bundles of axons
Endoneurium
Layer of connective tissue with surrounds an axon
Cranial nerves which contain axons of ONLY sensory neurons
- Olfactory (I)
- Optic (II)
- Vestibulocochlear (VIII)
Cranial nerves which contain primarily axons of motor neurons with associated sensory axons responsible for proprioception
- Oculomotor (III)
- Trochlear (IV)
- Abducens (VI)
- Accessory (XI)
- Hypoglossal (XII)
Cranial nerves which contain axons of both sensory and motor neurons
- Trigeminal (V)
- Facial (VII)
- Glossopharyngeal (IX)
- Vagus (X)
Trigeminal neuralgia
- Tic douloureux
- Chronic tooth or molar pain
- Characterized by brief attacks of intense pain
How long does the pain from trigeminal neuralgia last?
A few seconds to 2 minutes, several times a day
Is trigeminal neuralgia typically bilateral or unilateral?
Unilateral
What stimuli triggers trigeminal neuralgia attacks?
- Chewing
- Light touch
- Vibratory stimuli
- Light breeze
What causes trigeminal neuralgia?
Unknown
Are medications effective in treating trigeminal neuralgia
Typically ineffective
How is trigeminal neuralgia treated?
Reducing aberrant transmission through nerve, often by severing it
Bell’s palsy
- Facial nerve’s motor root is impaired by virus, tumor, trauma, or unknown cause
- Weakness or complete paralysis of facial expression muscles on affected side
- Leads to problems with blinking, closing eye, and making general facial expressions
How fast does Bell’s palsy develop?
Rapid onset of symptoms
How is Bell’s palsy treated?
- Anti-inflammatory medication
- Antiviral medication
- PT
- Surgery
Remembering the cranial nerves (names)
- Oh (I, olfactory)
- Once (II, optic)
- One (III, ovulomotor)
- Takes (IV, trochlear)
- The (V, trigeminal)
- Anatomy (VI, abducens)
- Final (VII, facial)
- Very (VIII, vestibulocochlear)
- Good (IX, glossopharyngeal)
- Vacations (X, vagus)
- Are (XI, accessory)
- Happening (XII, hypoglossal)
Remembering the cranial nerves (function)
- Some (I, Olfactory – Sensory)
- Say (II, Optic – Sensory)
- Money (III, Oculomotor – Motor)
- Matters (IV, Trochlear – Motor)
- But (V, Trigeminal – Both)
- My (VI, Abducens – Motor)
- Brother (VII, Facial – Both)
- Says (VIII, Vestibulocochlear – Sensory)
- Big (IX, Glossopharyngeal – Both)
- Brains (X, Vagus – Both)
- Matter (XI, Accessory – Motor)
- More (XII, Hypoglossal – Motor)
Breakdown of spinal nerves
- 8 pairs of cervical
- 12 pairs of thoracic
- 5 pairs of lumbar and sacral
- 1 pair of coccygeal
How does a nerve plexus form?
- Anterior rami of cervical, lumbar, and sacral spinal nerves each merge
Types of reflexes
- Simple stretch reflex
- Golgi tendon reflexes
- Flexion (withdrawal)
- Crossed-extension spinal reflexes
- Cranial nerve reflex
Babinski sign
- Normal response: plantar reflex
- Positive Babinski sign: present in adults with upper motor neuron disorders
