Central Nervous System Flashcards
CNS consists of…
brain + spinal cord
brain consists of…
- forebrain (cerebrum + diencephalon)
- midbrain
- hindbrain (pons, medulla oblangata, cerebellum)
FOREBRAIN: cerebrum
- largest portion of the brain
- 2 hemispheres separated by longitudinal fissure
- 5 lobes
5 lobes of the cerebrum
- frontal: motor function
- temporal: memory function
- parietal: sensory function
- occipital: visual function
- insula: visceral sensations
fissures in brain
- longitudinal fissure: divides hemispheres
- transverse fissure: separates cerebrum + cerebellum
sulcus’ in brain
- central sulcus: separates frontal lobe + parietal lobe
- lateral sulcus: separates temporal lobe + cerebrum
what are gyri
- elevated folds over most brain surface
- separated by sulcus
gyri in the brain
- precentral gyrus: in frontal lobe
- postcentral gyrus: in parietal lobe
cerebral hemispheres main regions
- cerebral cortex
- white matter
- basal nuclei
cerebrum: cerebral cortex
- gray matter visible on surface
- 2-4mm thick
- 3 functional areas
cerebral cortex: motor area
- in frontal lobe
- controls skeletal muscle movement
- primary area, premotor area, Broca’s area
primary area location in motor area
on precentral gyrus
premotor area location in motor area
anterior to precentral gyrus
Broca’s area in motor area
only in one hemisphere (controls speech muscles)
cerebral cortex: sensory area
- processes sensory info
- in postcentral gyrus (pain, temp, touch + pressure)
specialized senses of sensory area
- VISION: occipital lobe
- AUDITORY + OLFACTORY: temporal lobe
- TASTE: insular lobe
- VISCERAL SENSATIONS
cerebral cortex: association area
- in parietal, occipital + temporal lobes
- allows recall/recognition of memories
- intellect is in frontal lobe
cerebrum: white matter
- composed of myelinated axons
- has association, commissural + projection tracts
white matter: association tracts (cerebrum)
transmit info from gyrus to gyrus is same hemisphere
white matter: commissural tract (cerebrum)
transmit info from gyrus to gyrus in opposite hemisphere
corpus callosum
white matter: projection tracts (cerebrum)
- runs vertically
- transmit info b/w brain + spinal cord
cerebrum: basal nuclei
- paired masses of gray matter in white matter of cerebrum
- function to modify skeletal movements
FOREBRAIN: diencephalon
- consists of thalamus + hypothalamus
diencephalon: thalamus
- from 2 lobes connected by bridge of gray matter (intermediate mass)
- superior to midbrain
- relay center from sensory impulses to cortex
diencephalon: hypothalamus
- inferior to thalamus + superior to pituitary gland
- made of gray matter
- both endocrine + nervous function
hypothalamus function
major regulator of internal environment
blood pressure + heart rate
midbrain
- connects pons and diencephalon
- contains the cerebral aqueduct
- anterior portion
- posterior portion
anterior portion of the midbrain
contains projection tracts (cerebral peduncles)
posterior portion of the midbrain
- corpora quadrigemina (4 nuclei)
corpora quadrigemina
- 2 superior nuclei (superior colliculi: control visual reflexes allow movement of head + eyes
- 2 POSTERIOR NUCLEI (inferior colliculi: control auditory reflexes - relay center for impulses that arise at receptors)
midbrain cranial nerves
III: oculomotor
IV: trochlear
hindbrain consists of…
- pons, medulla + cerebellum
HINDBRAIN: pons
- anterior to cerebellum
- connects medulla to midbrain
- forms portion of 4th ventricle
- home of pontine respiratory center
pons cranial nerves
V: trigeminal
VI: abducens
VII: facial
pontine respiratory center function
assists medulla in maintaining normal breathing rhythms
HINDBRAIN: medulla oblongata
- begins at foramen magnum and blends brain into spinal cord
- forms part of 4th ventricle
- contain 2 pyramids
- brainstem consists of midbrain, pons + medulla
medulla oblongata pyramids
- large motor tracts (corticospinal tracts)
- decussate before spinal cord > brain controls opposite sides of body
medulla oblongata cranial nerves
IX: glosspharyngeal
X: vagus
XI: accessory
XII: hypoglossal
medulla oblongata vital centers
CARDIAC: adjusts force of contraction + heart rate
VASOMOTOR: adjusts blood vessel diameter
RESPIRATORY: works w/ pontine nuclei
medulla oblongata non-vital centers
- swallowing
- coughing
- vomiting
- sneezing
HINDBRAIN: cerebellum
- located on dorsal portion of brain (posterior to pons and medulla)
- contains folds: folia
- houses portion of 4th ventricle
cerebellum: cortex
- formed from gray matter
- inside is white matter (arbor vitae)
cerebellum functions
- skeletal muscle contraction
- posture
- balance
functional systems of the brain
1) limbic system
2) reticular formation
limbic system
- regulate emotions and emotional behaviours
- network of nuclei in cerebral hemispheres + diencephalon
reticular formation
- located in brainstem, midbrain, pons + medulla
- function: keep alert + attentive
- anesthetics + sleeping pills affect this area
what occurs to inhibition of reticular formation?
results in sleep
what happens when reticular formation is damaged?
places them into a coma
spinal cord flow
- begins below foramen magnum
- terminates in lumbar region (CONUS MEDULLARIS > exit vertebral foramina [cauda equina])
spinal cord contains
- cervical, thoracic, lumbar, sacral segments (correspond to vertebral sections)
- filum terminale: from CT extension of pia mater
spinal cord functions
take in sensory information and generate motor output and reflexes
spinal cord cross-section
- separated into right and left halves
- anterior median fissure (ventral side)
- posterior median sulcus (dorsal side)
- central canal (middle)
spinal cord: gray matter
- contains cell bodies + dendrites of motor neurons + interneurons
- dorsal horns integrate sensory info
- ventral + lateral horn generate motor output
spinal cord: white matter
- myelinated axons of ascending [sensory info] and descending [motor info] tracts
- in dorsal, ventral + lateral columns
