Central Nervous System Part 2

Cerebrum: lobes, functions, ventriclesSpecialization AreasCerebral dominance

Disorders

Functions: • Sensory: interprets signals so

we “know: what we are seeing, hearing, tasting, smelling …

• Motor: responsible for all voluntary movement (somatic) / some involuntary (autonomic)

• Association: all intellectual activities of cerebral cortex: learning, reasoning, memory storage, recall, language abilities, even consciousness

Cerebral cortex: gray matter = cell bodies of neurons involved in hemisphere functions

Fissure or sulci Gyri or gyrus

Ventricles/CSF:

Cerebral white matter:axons 1. association (within hemispheres)2. commissure –connects

neoccortex of hemispheres (corpus callosum)

3. projection

Fig. 49-15

Speech

Occipital lobe

Vision

Temporal lobe

Frontal lobeParietal lobe

Somatosensoryassociationarea

Frontalassociationarea

Visualassociationarea

Reading

Taste

Hearing

Auditoryassociationarea

Speech

Smell

Mo

tor

cort

exS

omat

osen

sory

cor

tex

Central and Limbic lobes

• Frontal: primary motor area allows conscious movement of skeletal muscles, higher intellectual reasoning, complex memory

• Parietal lobe: somatic sensory area : impulses from sensory receptors are localized and interpreted; path are X’d, able to interpret characteristics of objects feel with hand and to comprehend spoken and written language

• Occipital lobe: visual cortex, receives visual info via thalamus (primary visual area)integrates info to formulate response (visual association area)

• Temporal lobe: emotion, personality, memory behavior, auditory and olfactory area, complex memory (both neo and old cortex)

• Limbic Lobe: (linked with temporal) ring of cortex around cerebral ventricles, connections between emotional and cognitive mechanism, emotional, autonomic, subconscious motor and sensory drives, sexual behavior, biological rhythms

• Motivation=pleasure or punishment• Limbic is the connection between emotional and cognitive

mechanisms

Basal Nuclei: grey matter deep within white matter surrounding 3rd ventricle they influence: monitoring, starting, stopping of stereotyped motor movement (voluntary)

1. subconscious movement

2. humans: planning, programming movement, information feedback with cortex,

3. help decisions about sensory input

Amygdala nucleus: part of the limbic system located deep within each hemisphere/ important part of emotional feelings linked to cognitive input (pleasure and fear emotions) Fear conditioning sends input to hypothalamus to signal the sympathetic NS to act

Complex polysynaptic path in brainstem and thalamus RF

Receives messages from neurons on spine and other parts and communicates with cerebral cortex with complex circuits

Ultimately responsible for consciousness

Extent of RAS activity determines state of alertness (focus)

Slow stimulation get sleepy and bored

Toss and turn at night due to RAS

Effects the way we react to stimuli

If damaged= deep permanent coma

Reticular Activating System: nuclei axons connect hypothalamus, thalamus, cerebellum and spinal cord to keep the cortex alert and conscious. Also acts as a filter for sensory input to the cortex … filters out 99% of sensory input as unimportant. RAS: arousal system

Specialization areas:  *p 249 primary motor in precentral gyrus,: motor cortex: control voluntary skeletal movment

primary sensory in postcentral gyrus somatosensory area:: receives info from skin, joint via thalamussomatosensory association cortexPrimary somatosensory cortex

Visual association area

Auditory association area

primary visual cortex

primary auditory cortexauditory association areaolfactory cortexgustatory cortex

Wernicke’s language areaprimary somatic motor cortex: axons from the primary motor area in the frontal lobe form major voluntary motor tract which descends into the cord, paths are crossed and body is represented upside down. Most neurons are dedicated to fine motor control of face, moth and hands. premotor cortexprimary motor areaSpatial Discrimination:  Speech area: junction of parietal and occipital and temporal lobes: allows us to understand words, make connections between words, in one hemisphereBroca’s area: base of precentral gyrus (usually inleft hemisphere) ability to speakPrefrontal

Cerebral dominance: (L) language abilities, mathematics, intellectual functions with language(R) spatiotemporal matter, recognize face, appreciates and recognizes music

DISORDERS:

• Alzheimers disease• Parkinson’s disease• Stroke• Aphasia• Concussion• Contussion• Cerebral contusion

Disorders and Clinical Applications

• Lumbar puncture• Spinal tap vs epidural• Spina Bifida• Anencaphaply• Paralysis• Spinal Shock• ALS• Poliomyelitis