Chapter 5 Divisions of the nervous system/Central and peripheral Nervous systems Flashcards
Anatomical divisions of the nervous system
-Central nervous system
(CNS)
- Brain (cerebrum, subcortical structures, brainstem, and cerebellum)
- Spinal Cord
Anatomical divisions of the nervous system
-Peripheral nervous system
(PNS) Final common
pathway
- Cranial nerves
- Spinal nerves
- Sensory receptors
Functional divisions of the nervous system
-Autonomic nervous system
Involuntary functions (heart rate, digestion, breathing)
• Sympathetic system (fight or flight)
o Expends energy
• Parasympathetic system (calms)
o Conserve energyFunctional divisions of the nervous system
-Somatic system
- Voluntary motor control
• Pyramidal system (Direct)
o Initiation of voluntary
motor acts (open door)
• Extrapyramidal system
(Indirect)
o Controls background
tone and movement to
support primary motor
acts (don't overshoot door knob)Central and Peripheral Nervous System
-Cerebrum (Cerebral
cortex)
Basic Structures; Gyri
Convolutions
Central and Peripheral Nervous System
-Cerebrum (Cerebral
cortex)
Basic Structures; Sulci
Infoldings
Central and Peripheral Nervous System
-Cerebrum (Cerebral cortex)
Basic Structures;
Fissure (Sulci- infordings)
Deep pronounced infoldings
Central and Peripheral Nervous System
-Cerebrum (Cerebral
cortex)
Major Landmarks; Central fissure/sulcus (Rolandic Fissure)
• Separates the frontal lobe from parietal lobes
Central and Peripheral Nervous System
-Cerebrum (Cerebral
cortex)
Major Landmarks; Lateral fissure/sulcus (Sylvian fissure)
• Separates temporal lobe from frontal and parietal lobes
Central and Peripheral Nervous System
-Cerebrum (Cerebral
cortex)
Major Landmarks; Cerebral longitudinal fissure
• Separates left hemisphere from right hemisphere
• Left
o Linear, analytical, logical,
o Math, science, language formulation
• Right
o Holistic, imaginative, creative o Music, art, language expression
Cerebrum Lobes
Frontal lobe
planning, initiation, and inhibition of voluntary motions, and thought processes
Cerebrum Lobes
Frontal lobe
Broca’s area
o Speech motor planning o Dominant (left) hemisphere
Cerebrum Lobes
Frontal lobe
Precentral gyrus (motor
strip)
o Initiation of voluntary motor movement to contralateral side of body
o Specific portions of the motor strip control specific muscles and structures
Cerebrum Lobes
Frontal lobe
Premotor region
Motor planning
Cerebrum Lobes
Frontal lobe
Anterior portion of
frontal lobe
o Memory
o Emotion
o Thought processes (reasoning, problem solving,
judging)
not fully developed until 20’s.
poor judgment in teenagers
Cerebrum Lobes
Parietal lobe
Postcentral gyrus (primary sensory strip)
Receives sensory information
Cerebrum Lobes
Parietal lobe
Inferior parietal lobule
Interprets visual, auditory and somatic sensory information
Cerebrum Lobes
Parietal lobe
Angular gyrus
o Involved in mathematical calculation
o Reading and writing
impairment may cause Dyslexia and/or
Dysgraphia
Cerebrum Lobes
Parietal lobe
Supramarginal gyrus
Phonological development (rhyming and reading development)
Cerebrum Lobes
Temporal lobe
Heschl’s gyrus
Receives auditory information from the ears
Cerebrum Lobes
Temporal lobe
Wernicke’s area
o Processes receptive language (comprehension and formulation of spoken language) o Dominant (left) hemisphere
Cerebrum Lobes
Temporal lobe
Aphasia
o Acquired language disorder involving difficulty
producing or comprehending language (spoken
and or written)
o Generally caused by brain damage due to stroke,
trauma, or tumor near Wernicke’s area and/or
Broca’s area o Mild to severe
Cerebrum Lobes
Occipital lobe
Calcarine sulcus
Primary reception area for visual information
Cerebrum Lobes Insular lobe (Insula)
- Deep to the lateral fissure
- It is believed to be involved with speech function, the limbic system (emotion/memory), and visceral function (involuntary/automatic)
- Gustation (taste)
Cerebrum Lobes
Cortical Connections
Projection Fibers
Tracts communicating to and from the cerebral cortex (brainstem and spinal cord)
Cerebrum Lobes
Cortical Connections
Association Fibers
• Communicating fibers between regions of the same
hemisphere
o Short association fibers: connect neurons of one
gyrus to the next gyrus
o Long association fibers: connect the lobes of the
brain in the same hemisphere
Arcuate fasciculus**
• Connects Wernicke’s
area to Broca’s area
Cerebrum Lobes
Cortical Connections
Commissural Fibers
Communicating fibers between the right and left
hemispheres
o Corpus Callosum
Angenesis of the Corpus Callosum – birth defect in which the corpus callosum is not fully formed or is only partially formed.
Subcortical Areas of the Brian
Limbic System
Functions
Involved in motivation, emotion, memory, reproduction, feeding behavior, and olfaction
Subcortical Areas of the Brian
Limbic System
Important structures for communication: Hippocampus
o Learning and memory
o Transfers memories from short term to long
term memory
Subcortical Areas of the Brian
Limbic System
Important structures for communication: Amygdala
o Involved in ascribing emotion to events and
behaviors
o Also aids in memory building
Subcortical Areas of the Brian
Basal Nuclei (basal ganglia)
Structures
• Caudate nucleus
• Globus pallidus
• Putamen
• Substantia nigra
o Contains dopamine
neurotransmittersSubcortical Areas of the Brian
Basal Nuclei (basal ganglia)
Functions
- Regulates motor control for posture, balance, and background muscle tone
- Control of precise voluntary movements through inhibition (helps to refine and smooth movements)
Subcortical Areas of the Brian
Parkinson’s Disease
- Neuromuscular disease
-Degeneration of dopamine-containing neurons in the substantia nigra - A few symptoms
• Slowness of voluntary movements
• Trembling of hand at rest
• Decreased facial expression and
monotone speech
• Shuffling gait
• Swallowing problems (dysphasia)
Subcortical Areas of the Brian
Thalamus
Function
• Relay station
o All information traveling to the cerebral cortex
(except olfaction) passes through the thalamus
o Sorts and interprets information and decides which signal should be transmitted to the cerebrum
Subcortical Areas of the Brian
Hypothalamus
Function
• Involved in sensory and motor control of visceral functions
• Regulates hormonal function, body temperature, hunger, sleep-wake cycles, blood pressure and other functions
Cerebellum
Function
- Regulate posture and coordination
• Coordinates motor commands with sensory inputs to
control movements
o Rate
o Range
o Force
- Ataxia
o Without coordination
o Caused by infections, injuries, degenerative diseases that affect the cerebellum
o May cause coordination impairment in writing, walking, speech and swallowing
Brainstem
Function
- Responsible for basic body functions to maintain life
• Site of many reflexes involved in respiration,
swallowing and digestion
—-Origin of cranial nerves
-Pathway between cerebrum, cerebellum and spinal
cord
Brainstem
Structures
Midbrain
• Contains cerebral peduncles (large bundle of nerve
pathways) that provide communication to and from the cerebrum
o Corticospinal tract
Projects muscle control to extremities
o Corticonuclear tract (corticobulbar)
Project muscle control to cranial nerves
Brainstem
Structures
Midbrain
Amyotrophic Lateral Sclerosis (ALS)
o Degenerative disease of the nervous system
o Causes muscle atrophy in the muscles of the
extremities, trunk, mouth and face
- Corticospinal involvement symptoms will show
up in fine motor movements of the extremities
first
- Corticonuclear (bulbar) involvement will show
up in speech and swallowing first
Brainstem
Structures
Pons
• Bridge to connect cerebellum and the rest of the
nervous system
• Contains olivary complex
o Aid in localization of sound and noise reduction
Brainstem
Structures
Medulla
• Pyramids
o Location where cerebral
motor commands cross (decussate) from one side of the body to the contralateral side (opposite side) of the body
Brainstem
Structures
Medulla
Unilateral motor impairment
o Muscle paresis (weakness) or paralysis (loss of muscle control on one side of the body
o Neurological damage is on the opposite side of the brain
Spinal Cord
Structures
Central canal
cerebral spinal fluid
Spinal Cord
Structures
White matter
contain sensory (ascending) and motor (descending) pathways
- Sensory (afferent) pathways – transmit information about pain, temperature, touch, and proprioception to the thalamus, cerebrum, and cerebellum
- Motor (efferent) pathways
Spinal Cord
Structures
Gray matter
site of neuron synapse
• Dorsal (posterior) horn (root) – afferent (sensory)
information
• Ventral (anterior) horn (root) – efferent (motor)
information
Spinal Cord
Structures
Spinal nerve
Contain both sensory and motor branch
o Sensory branch exits the spinal cord at the posterior root
o Motor branch enters the spinal cord at the anterior root
o The two branches converge outside the spinal cord to form the spinal nerve
31 pairs of spinal nerves o 8 Cervical o 12 Thoracic o 5 Lumbar o 5 Sacral o 1 Coccygeal
• Spinal Reflex Arc
o Simple stimulus response
-Sensory nerve ending receives a stimulus
-Sensory information travels to the spinal
cord via the posterior horn
- Synapse with a connecting neuron within
the gray matter
-Synapse with a motor neuron in the
anterior horn
-Information travels along the motor
neuron to the neuromuscular junction
-Reflexive movement
