Chapter 23: Neurologic System Flashcards
What are the two main divisions of the Nervous System
Central Nervous System: Brain and spinal cord
Peripheral Nervous System: All nerve fibers outside the brain and spinal cord: 12 pairs of cranial nerves and 31 pairs of spinal nerves.
What is the difference between afferent and efferent messages?
Afferent signals: Sensory signals that are carried TO CNS from sensory receptors.
Efferent signals: Motor signals that are carried FROM the CNS out to muscles and glands, and autonomic messages that govern the internal organs and blood vessels.
What is the cerebral cortex?
the outer layer of the brain, gray matter, center for highest functions (memory, cognition, governing thought, sensation, reasoning and voluntary movement)
What are the four lobes of the cerebrum and their functions?
Frontal Lobes: personality, behavior, emotions, and intellectual function. Precentral gyrus: initiates vol. mvmt.
Parietal Lobes: postcentral gyrus is the primary center for sensation.
Occipital Lobes: Primary visual receptor center
Temporal Lobes: Primary auditory center with functions of hearing, taste, and smell
what is the Wernicke’s area?
An area in the temporal lobe responsible for language comprehension.
What is receptive aphasia?
A person’s inability to interpret speech. This occurs when damage occurs to Wernicke’s area.
What is Broca’s Area? What is the result if this is injured?
located in the frontal lobe, this mediates motor speech. If this area is injured, expressive aphasia results.
what are the basal ganglia?
large bands of gray matter buried deep within the two hemispheres that form the extrapyramidal system (subcortical associated motor system). This is responsible for initiating and coordinating movement.
what is the thalamus?
main relay station where the sensory pathways of spinal cord, cerebellum, basal ganglia, and brainstem form synapses on their way to the cerebral cortex. It is an integrating center that is crucial for emotion and creativity.
what is a synapse?
sites of contact between two neurons
what is the hypothalamus?
Major respiratory center with basic vital functions: temperature, appetite, sex drive, heart rate, BP, sleep center, ant/post pituitary gland regulator, and coord of ANS and stress response.
Damage to the cerebral cortex might cause?
loss of function, motor weakness, paralysis, loss of sensation, impaired ability to understand/process language.
What is paresthesia?
loss of sensation
what is the cerebellum?
coiled structure located under the occipital lobe that is responsible for motor coordination of muscle movements. Equilibrium and muscle tone important here.
what does crossed representation mean?
A notable feature of nerve tracts in CNS. The left cerebral cortex receives info and controls the RIGHT side of the cerebral cortex. The right cerebral cortex receives info and controls the LEFT side of the cerebral cortex.
which cranial nerves originate in the brainstem?
Cranial nerves III-XII
What are the sensory pathways?
sensory fibers that transmit and conduct sensations of pain, temperature, crude or light touch, position, vibration, finely localized touch.
what are the motor pathways?
pyramidal tract: skilled and purposeful movement, extrapyramidal tract, more primitive motor system-maintains muscle tone, controls body movement such as walking.
What are upper motor neurons? diseases associated with?
within CNS. diseases associated with stroke, CP, MS
What are LMNs? What are some examples? What are some diseases associated with LMNs?
Lower Motor Neurons: located in PNS; final direct contact with muscles. movement translated into action by LMNs.
Examples: cranial nerves, spinal nerves.
Diseases assoc. with: spinal cord lesions, poliomyelitis, amyotrophic lateral sclerosis (ALS).
What are the 5 components of deep tendon reflexes?
- intact sensory nerve-afferent
- A functional synapse at the cord
- An intact motor nerve-efferent
- The neuromuscular junction
- A competent muscle
What are cranial nerves I-VI and their functions
CN I-Olfactory-sense of smell
CN II-Optic-sense of vision
CN III-Oculomotor-most EOM of the eye, opening of eyelid, and pupil constriction, lens shape
CN IV-Trochlear-Down and inward movement of the eye
CN V-Trigeminal-Chewing, sensation of scalp, face, cornea, mucous membranes of mouth and nose.
CN VI-Abducens-lateral movement of the eye
What is the PNS comprised of and what are the functions?
Cranial and spinal nerves
Function: Somatic and autonomic
Somatic: innervate the skeletal (voluntary) muscles
Autonomic: innervate smooth (involuntary) muscles, cardiac, and glands; mediates unconscious activity.
How many spinal nerves are there? What do they contain, where do the nerves exit? Sensory and Motor signals go through what roots?:
31 pairs: 8 Cervical, 12 Thoracic, 5 Lumbar, 2 Sacral, and 1 coccygeal.
They contain both sensory and motor fibers
Nerves exit through roots
Sensory nerves: posterior (dorsal) roots
Motor nerves: anterior (ventral) roots
What are dermatomes?
circumscribed skin area supplied from the spinal cord segment through a particular spinal nerve.
What is movement directed by primarily in infants
primitive reflexes, these disappear with age.
What process results in increased motor control in infants
Increase in myelination