Ch 12: The Central Nervous System (CNS) Flashcards


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1

CNS

consists of brain and spinal cord

-part of the nervous system that centrally integrates the information and coordinates the activities of all parts of the body

2

Embryonic Development of CNS

  • rises from ectoderm germ layer
  • neural crest give rise to primary brain vesicles
  • the primary brain vesicles give rise to secondary brain vesicles
  • differentiation (subdivision: telencephalon, diencephalon, mesencephalon, myelencephalon)
  • the secondary vesicles give rise to an adult brain structure
3

Adult Brain Regions

  1. Cerebral hemispheres (superior part of the brain)
  2. Diencephalon (interbrain)
  3. Brain stem (midbrain, pons, and medulla)
  4. Cerebellum
4

Spinal Cord

  1. central cavity surrounded by a gray matter core
  2. external white matter composed of myelinated fiber tracts
5

Ridges

Gyri

6

Sulci

shallow grooves

7

fissures

deep grooves

8

5 Lobes

  1. Frontal
  2. Parietal
  3. Parietal
  4. Occipital
  5. Insula
9

Cerebral Cortex (executive Suite)

  • thin (2-4 mm) superficial layer of gray matter
  • 40% of the mass of the brain
  • site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding
  • each hemisphere connects to contralateral side of body
  • there is lateralization of cortical function in the hemispheres
10

3 functional areas of the cortex

1. Motor areas- control voluntary movement

2. sensory areas - conscious awareness of sensation

3. association areas- integrate diverse information

11

Sensory Areas

  • Primary somatosensory cortex
  • Somatosensory association cortex
  • visual areas
  • auditory areas
  • olfactory cortex
  • gustatory cortex
  • visceral sensory area
  • vestibular cortex
12

Limbic System

  • provides emotional impact that helps establish memories
  • motivation
  • emotional response to odors
  • interacts with the prefrontal lobes, therefore:
    -we can react emotionally to things we consciously understand to be happening
    -We are consciously aware of emotional richness in our lives
13

Amygdala

recognizes angry or fearful facial expressions, assess danger, and elicits the fear response

Hippocampus and amygdala- play a role in memory

14

Cingulate gyrus

plays a role in expressing emotions via gestures, and resolves mental conflict

15

Left Hemisphere

controls language, math, and logic

16

Right Hemisphere

insight, visual-spatial skills, intuition, and artistic skills

*left and right hemispheres communicate via fiber tracts in the cerebral white matter

17

Cerebral White Matter

  • Myelinated fibers and their tracts
  • responsible for communication
    -Commissures (in corpus callosum) connect gray matter of the 2 hemispheres
    -Association fibers- connect different parts of the same hemisphere
    -projection fibers - (corona radiata) connect the hemispheres w/ lower brain or spinal cord
18

Diencephalon

3 Paired Structures:
1. Thalamus
2.Hypothalamus
3. Epithalamus

encloses the third ventricle

19

Thalamus

  • 80% of diencephalon
  • superolateral walls of the third ventricle
  • connected by the interthalamic adhesion (intermediate mass)
  • contains several nuclei, named for their location
  • nuclei project and receive fibers from the cerebral cortex
20

Thalamas Functions

1. Gateway to the cerebral cortex
2. Sorts, edits, and relays information
-Afferent impulses from all senses and all parts of the body
-impulses from the hypothalamus for regulation of emotion and visceral function
-impulses from the cerebellum and basal nuclei to help direct the motor cortices

3. Mediates sensation, motor activities, cortical arousal, learning, and memory