SLHS 261 Week 2 Pt 2

Divisions of the Nervous System

Functional and Anatomical Divisions

Functional Divisions

Somatic Nervous System and Autonomic Nervous System

Anatomical Divisions

Central Nervous System and Peripheral Nervous System

Somatic Nervous System

* Voluntary part of the system
* Responsible for observable actions
* Skeletal muscle control
* Allows for sensation of environmental events and \n stimuli

Autonomic Nervous System

* Involuntary part of the system
* Responsible for life-sustaining activities and sensations
* Heart function
* Digestive function
* Glandular secretions

Central Nervous System

Brain, Brainstem, and Spinal cord

Peripheral Nervous System

Contains spinal and cranial nerves

Spinal nerves

nerves coming out of the spinal cord to go to body (below head and face)

Cranial Nerves

nerves coming out of the brainstorm to go to head and face

afferent

signals which move from the periphery of the body toward the central nervous system (sensory signals)

efferent

signals which move from the central nervous system to the peripheral of the body (motor signals)

Protective coverings of CNS

Bones of Skull and vertebral column

meningeal linings

cerebrospinal fluid

meningeal linings

three layers of tissue that protect and provide nutrients of the CNS

Dura mater

outermost layer

arachnoid mater

middle layer

pia mater

inner layer

cerebrospinal fluid

located in the arachnoid space within the meningeal linings and in the ventricles of the brain

Provides a cushion for neural tissue as well as nutrient delivery and waste removal

ventricle

space within the brain that contains CSF

sulcus

groove in the brain

gyrus

fold between two clefts on the cerebral surface in the brain

longitudinal fissure

divides the left and right sides of the brain

penetrates to the corpus callosum

transverse fissure

separates the cerebrum and the cerebellum

grey matter

surface of the brain

looks grey because it is made up of the cell bodies (somas) of the neurons in the brain

white matter

subcortical tracts of the brain

looks white because it is made up of axons of the neurons in the brain

lobes of the brain

frontal, partial, occipital, temporal

central sulcus

divides the frontal from the parietal lobe

between the pre central gyrus and the post central gyrus

lateral sulcus

divides the temporal lobe from the parietal lobe

insula is located deep within this sulcus

insula

sometimes referred to as the limbic lobe

critical to speech and language functions

primary areas, secondary ares, association areas

each cerebral hemisphere is thought to be made up of

primary and secondary areas for sensory signals

Primary areas receive information and send this information to secondary areas

Secondary and association areas interpret this information

Primary and Secondary Areas for motor signals

Secondary and association motor areas plan the movement \n Primary motor areas execute the moveme

Frontal Lobe Primary Area

located on the pre central gyrus

important in executing movement

frontal lobe secondary motor area

includes premotor area and supplemental motor area

involved in planning complex movements

damage to primary motor area

can cause paralysis in the body area corresponding the the area of the primary motor cortex which is damaged

contralateral innervation

nerves on the left side of brain affect movement of limbs on the right and vice versa

speech

most speech muscles are bilaterally innervated nerves from both sides of the brain go to both sides of the body

prefrontal cortex

anterior to pre central area

important for personality, initiative, and judgement

Parietal Lobe primary somatosensory area

located on the post central gyrus

receives sensory information from body

parietal lobe secondary somatosensory area

interprets this information

somatotopic organization

correspondence of a specific point in the body to a specific point in the primary motor and sensory cortexes

size of the space dedicated to a structure is related to the amount of neural innervation

primary motor cortex

left hemisphere section controls the body’s right side

primary somatosensory cortex

left hemisphere section receives input from the body’s right side

temporal lobe primary auditory area

inferior to lateral sulcus in temporal lobe

important for auditory association-past auditory experiences to present sensations

secondary auditory area

inferior to primary area in temporal lobe

important for interpretation of sounds

Occipital lobe primary visual area

receive visual information

occipital lobe secondary visual area

surrounds the primary area

relates visual information from primary area to past experiences

lateralization

* left and right sides of the brain participate in cognitive functions differently
* Speech functions are lateralized to the left side of the \n brain generally
* 90% of right-handed people and 64% of left-handed \n people have language function lateralized to the left \n hemisphere
* Right hemisphere is important for spatial skills, nonverballanguage, and perception through touch

broca’s area

left inferior frontal gyrus

important for motor planning for speech

wernicke’s area

* LEFT temporal lobe – posterior portion of the superior \n temporal gyrus
* Receives fibers from visual and auditory cortexes
* Important for language comprehension
* Integrates auditory and visual stimuli and sends to Broca’s \n area via a bundle of nerve fibers (association fibers) called \n the arcuate fasciculus