1. Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb 12 The Central Nervous System Part A

2.  nervous system originates from neural tube & neural crest  CNS from neural tube  PNS from neural crest cells  three-phase process of neural development:  Proliferation of neural cells  Migration  Differentiation of neuroblasts Development of Neurons

3.  Scaffold of glial fibers & ECM  Attractants released by target cells  Release of NGF by astrocytes  Neurotrophins released by other neurons  Interactions of repulsive guiding molecules Guiding Axonal Growth

4. Embryonic Development: Week 1  Fertilization  Movement to uterus  Implantation  Blastocyst formation

5. Blastocyst & Gastrulation

6. Neurulation: Specialization of Ectoderm Figure 28.9a, b

7. Neurulation Figure 28.9c,d

8. Neural Tube & Primary Brain Regions Week 3

9. Neural Tube & Primary Brain Regions Week 3Week 4

10. Neural Tube & Primary Brain Regions Week 3Week 4Week 5 LV 3 rd 4 th

11. Brain Development Figure 12.3

12. Ventricles of the Brain Figure 12.5  Ventricles are filled with cerebrospinal fluid  Fluid moved by ciliary motion of ependymal cells

13. Basic Pattern of the Central Nervous System  Spinal Cord  Core - gray matter – soma  Edges - white matter - myelinated axon tracts  Brain  Highly convoluted  Cortex & nuclei - areas with mostly neuron soma  White mater organized tracts of axons

14.  Sulcus (pl sulci)  Groove resulting from folding of neural tissue  Deep sulci (fissures) divide the hemispheres into lobes  Lobe  Region of the cerebrum  Frontal, parietal, temporal, occipital, & insula  Gyrus (pl gyri)  Bulging region between shallow sulci Anatomical Features of the Cerebral Cortex

15. Cerebral Cortex Anatomy

16. Cerebral Cortex  Gray matter on the surface of the cerebrum  Location of motor, sensory & association neuron cell bodies Grey matter White matter sulcus gyrus

17. Cerebral White Matter  Myelinated fibers & their tracts  Communication between cortex & lower CNS center, & areas of the cortex  Commissures  Association fibers  Projection fibers

18. Functional Areas of the Cerebral Cortex Motor Sensory Cognition

19.  Precentral gyrus  Conscious control of voluntary movements  Pyramidal cells  axons form corticospinal tracts Primary Motor Cortex

20. Premotor Cortex  Anterior to precentral gyrus  Coordinates learned actions  Plans of movements

21. Broca’s Area  More developed in one hemisphere (usually the left)  Directs muscles involved in speech  Active as one prepares to speak

22. Frontal Eye Field  Controls voluntary eye movement

23. Primary Somatosensory Cortex  Located in the postcentral gyrus  Receives information from the skin & skeletal muscles  Exhibits spatial discrimination

24. Somatosensory Association Cortex  Integrates sensory information  Comprehensive understanding of the stimulus

25. Visual Areas  Primary visual cortex  Posterior occipital lobe & in calcarine sulcus  Receives visual info from retina  Visual association area  Surrounds primary visual cortex  Interprets visual stimuli

26. Auditory Areas  Primary auditory cortex  Superior margin of temporal lobe  Pitch, rhythm, & loudness info  Auditory association area  Posterior to the primary auditory cortex  Stores memories of sounds & permits perception of sounds  Wernicke’s area  Integrating sound & speech

27. Olfaction

28. Association & Interpretation Areas Figure 12.8a

29. Proposed Memory Circuits Figure 12.22

30. Lateralization of Cortical Function  Lateralization  Unique functions of each hemisphere  Left hemisphere  language, math, & logic  Right hemisphere  visual-spatial skills, emotion, & artistic skills  Cerebral dominance  Hemisphere dominant for language (left)