Chapter 8- The CNS

Question 1

describe protection of the CNS (eh)

Answer 1

o Enclosed by bone
 Cranium encases brain
 Vertebral column surrounds spinal cord
o Meninges
 Dura mater
 Arachnoid mater
 Subarachnoid space
 Where vasculature resides
 Pia mater
 Blood-brain barrier

Question 2

identify the function of cerebral spinal fluid (CSF)

Answer 2

o Found in ventricles
o Formed by choroid plexuses
 Ependymal cells
o Function
 Buoyancy
 Protection
 Maintenance of chemical environment
o entire CSF is replaced four times a day

Question 3

identify the five lobes of the cerebral cortex and the major functions of each

Answer 3

o Cerebral cortex
 Cortex= outer shell of gray matter that covers each hemisphere
 Central core of white matter
 Each half is divided into five major lobes: Occipital, temporal, parietal, frontal and insula
o Frontal lobe
 Contain the motor cortices
 Voluntary movement of skeletal muscle
 Executive reasoning (decisions)
 Parietal lobes
 Contain the somatosensory cortices
 Perception of senses (touch, pressure, heat, cold, pain)
 Temporal lobe
 Auditory cortex
 Perception and interpretation of auditory information
 Occipital lobe
 Visual cortex
 Perception and interpretation of visual images
 Insula
 Integration of sensory information with visceral responses
 Assessing body states

Question 4

distinguish between the functions of the right and left cerebral hemispheres

Answer 4

o Contralateral
o Left hemisphere
 Usually dominant
 Language
 Analytical ability
o Right hemisphere
 Visuospatial patterns, reading maps

Question 5

define Broca’s area and Wernicke’s area

Answer 5

o Broca’s area
 Coordinates complex fine-motor functions involved in speech (control of tongue lips, etc)
 Motor, can’t respond
o Wernicke’s area
 Responsible for ability to comprehend language and formulate words
 Cannot understand what they say

Question 6

define aphasia and differentiate between Broca’s aphasia and Wernicke’s aphasia

Answer 6

o Broca’s aphasia
 Speech is poorly articulated
 Understand what is spoken, but have difficulty responding
o Wernicke’s aphasia
 Speak easily, using real and made-up words
 Can’t understand spoken or written language
 Thus, oral and written language (hearing and vision) must project to Wernicke’s area
 Wernicke’s area projects to Broca’s

Question 7

describe the different types of memory

Answer 7

o Two basic forms
 Short-term (<30 sec)
 Long-term (> 30 sec)
 Non-declarative- memory of simple skills
 Brushing teeth
 Declarative- memory of facts and events
 Remembering your 18th birthday
 Stored in various regions
 Visual memories stored in visual

Question 8

memory consolidation

Answer 8

o Memory consolidation
 Temporal lobes (amygdala and hippocampus) involved in converting short-term memory to long-term memory. Sleep is need for this!
 Long-term memory appears to involve changes in synaptic transmission in particular neural pathway
o Emotions and memory
 Emotions sometimes strengthen and other times weaken memory formation
 If the memory has an emotional component the amygdala is involved in memory formation
 Stress impairs memory consolidation
 Memories are stored but retrieval is hindered

Question 9

alzheimer’s disease

Answer 9

 Most common form of dementia
 Characteristics
 Loss of neurons (atrophy)
 Accumulation of extracellular proteins= amyloid plaques
 Accumulation of intracellular proteins forming neurofibrillary

Question 10

describe the locations and functions of the thalamus and hypothalamus

Answer 10

• Diencephalon
  o Thalamus-relay
  o Hypothalamus
  o Functions of the hypothalamus
   Body temperature
   Thirst and urine output
   Food intake
   Controls pituitary hormone secretion
   Circadian rhythm
   Sleep/wake cycle
   Light/dark cycle
   Control of ANS

Question 11

identify the structures and functions of the mainbrain

Answer 11

o Motor movements of the eye
o Auditory processing

Question 12

describe the components and functions of the brainstem

Answer 12

o Critical link between spinal cord and higher brain regions
o Oldest structure
o Function: vegetative functions: heart rate, BP
o Consists
 Medulla
 Pons
 Midbrain
 Autonomic function

Question 13

describe the function of the cerebellum

Answer 13

o 2nd largest structure in brain
o Planning, initiating, and timing motor movements
o Maintains proper position of the body in space
o Coordination of motor activity
o Plays key role in learning skilled motor tasks

Question 14

define ataxia

Answer 14

o Damage produces ataxia= uncoordinated movement

Question 15

describe the function of the limbic system

Answer 15

o Group of cerebral nuclei
o Functions
 Emotions
 Aggression
 Fear
 “smell brain”
 Sex drive and behavior
 Goal-directed behavior
 Reward and punishment

Question 16

describe the structure and function of the reticular activating system

Answer 16

o Network of neurons in brainstem that project to cortex
 gray matter: unmyelinated
o Activated by receipt of sensory information
 Induces nonspecific arousal to cerebrum
o Many drugs act on the RAS to promote either sleep or wakefulness

Question 17

describe phases of sleep

Answer 17

o Function of sleep
o Categories of sleep
 REM: rapid eye movement, dreaming, possibly moving
 NREM
 Stage 1
 Stage 2
 Stage 3
 Stage 4

Question 18

differentiate between a descending and ascending tract in the spinal cord

Answer 18

o Part of the CNS
o Transmits sensory (afferent) and motor (efferent) information
o 31 pairs of spinal nerves leave spinal cord
o Arranged into ascending and descending fibers
o Structure
 Tracts of axons-white matter
 Ascending tracts
 Carry sensory information up to the brain (afferent)
 Descending tracts

Question 19

identify the structures of a spinal nerve and describe the neural pathways of a reflex arc

Answer 19

o PNS, not CNS
o All are mixed nerves
 Dorsal root
 Ventral root
o Integration of many basic reflexes
o Reflex
 Simple, stereotyped response to a stimulus
o Reflex arc
 Pathway mediating a reflex
 Components
 Sensory
 Afferent
 Integrating center
 Efferent
 Response

Question 20

describe components of the withdrawal reflex

Answer 20

o Nociceptor
o Afferent
o Integration
o Motor
 Stimulates flexors
 Inhibit extensors

Question 21

describe the classification of cranial nerves

Answer 21

o Part of PNS
o 12 pairs
o Arise from brain
o Carry sensory, motor or both
o Branch off brain or brain stem