Anatomy - Nervous System Flashcards
CNS components
Brain
Spinal Cord
PNS components
Spinal nerves
Cranial nerves
Autonomic nerves
(All nerve tissue that is not CNS)
Neurone components
Dendrites, body, axon of nerve fibre and myelin sheath
Ganglion
Collection of nerve cell bodies (PNS)
Nerve
Bundle of axons (PNS)
CN I
Olofactory Nerve
Sensory
Cribiform Plate of the Ethmoid Bone
CN II
Optic Nerve
Sensory
Optic Canal
CN III
Oculomotor Nerve
Motor
Superior Orbital Fissure
CN IV
Trochlear Nerve
Motor
Superior Orbital Fissure
CN V (1, 2 and 3)
Trigeminal Nerve Both sensory and motor CNV1 = Superior Orbital Fissure CNV2 = Foramen Rotundum CNV3 = Foramen Ovale
CN VI
Abducent Nerve
Motor
Superior Orbital Fissure
CN VII
Facial Nerve
Both sensory and motor
Internal Acoustic Meatus
CN VIII
Vestibulcochlear Nerve
Sensory
Internal Acoustic Meatus
CN IX
Glossopharyngeal Nerve
Both sensory and motor
Jugular Foramen
CN X
Vagus Nerve
Both sensory and motor
Jugular Foramen
CN XI
Spinal Accessory Nerve
Motor
Jugular Foramen
CN XII
Hypoglossal Nerve
Motor
Hypoglossal Canal
Which part of the floor of the cranial cavity does the spinal cord pass through?
Foramen Magnum
At which level does the spinal cord end?
L1/L2 disc level (conus medullaris)
Cervical Spinal Nerves
C1-C8
Thoracic Spinal Nerves
T1-T12
Lumbar Spinal Nerves
L1-L5
Sacral Spinal Nerves
S1-S5
Coccygeal Spinal Nerves
Co
Vertebral Column =
7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae 5 sacral vertebrae (fused) 4 coccygeal vertebrae (fused)
Naming spinal nerves
Named according to vertebrae above (except for cervical nerves, which are named for vertebrae below)
Spinal Nerve anatomy
Located within the intervertebral foramina.
Connect to soma via rami.
Connect to spinal cord via roots and rootlets.
T4 dermatome
Male Nipple
T10 dermatome
Umbilicus
Cervical plexus
C1-C4 anterior rami
Posterior scalp, neck wall, diaphragm
Brachial plexus
C5-T1 anterior rami
Upper limb
Lumbar plexus
L1-L4 anterior rami
Lower limb
Sacral Plexus
L5-S4 anterior rami
Lower limb, gluteal region, perineum
Sympathetic outflow exits spinal cord at…?
T1-L2
Parasympathetic outflow exits at…?
CN III, VII, IX & X
Sacral spinal nerves
Subdivisions of Nervous System
Somatic = Soma and external environment Autonomic = Visceral motor system (organs) and internal environment
Define efferent and afferent
Efferent = Motor. Brain to body Afferent = Sensory. Body to brain
Sensory innervation
Soma = Somatic sensory
Organs = Visceral afferent
Special sense organs = Special sensory
Motor innervation
Soma = Somatic motor
Organs = Sympathetic and parasympathetic
Special sense organs = Sympathetic and parasympathetic
Somatic Sensation
Somatic sensory mechanoreceptors stimulated
APs conduct along axons to anterior ramus, dorsal root ganglion, POSTERIOR roots and rootlets and arrive at posterior horn.
APs synapse, cross over midline and ascend to the brain
Motor Innervation
Somatic motor axons cross brainstem and descend to anterior horn
APs conducted along axons within ANTERIOR rootlets, roots then into spinal nerves
APs travel along nerves and synapse onto skeletal muscle
Spinal reflexes
Sensation signal > Axon > Spinal nerve > Posterior roots > Posterior rootlets > Synapse across grey matter > Motor signal > Anterior rootlets > Anterior roots > Spinal nerve > Axon > Reflex reaction
Motor Pathology
Upper motor neurone lesion =
Opposite side from movement
Lower motor neurone lesion =
Same side as movement
Define paralysis
A muscle without a functioning lower motor neurone. the muscle cannot contract. The muscle would have decreased tone
Define spasticity
A muscle with an intact and functioning lower motor neurone. Descending controls of the brain do not work. Muscle would have increased tone
Sympathetic Division of ANS
Supplies: internal organs, body wall organs and arterioles.
Fight or flight
Parasympathetic Division of ANS
Supply internal organs ONLY
Rest and digest
