1. Divisions of the Human Nervous System
Central Nervous System-the brain and the spinal cord
Peripheral Nervous System-the nerves outside the brain and spinal cord
Two Division of the PNS
Somatic Nervous System-the nerves that convey messages from the sense organs to the CNS and from the CNS to the muscles and glands
Autonomic Nervous System-a set of neurons that control the heart, the intestines, and other organs

2. Figure 4.1  The human nervous system Both the central nervous system and the peripheral nervous system have major subdivisions. The closeup of the brain shows the right hemisphere as seen from the midline.

3. The Brain: the big picture…
The basic components of the CNS include the:
Cerebrum
Diencephalon
Cerebellum
Brain stem
Spinal cord

5. The Brain: development…
Our central nervous system has humble origins early in our development (by 3rd wk.)
A plate (neural plate) of cells develop crests (neural crests) that rise and eventually meet and fuse leaving the hollow dorsal nerve cord & and ventricles of our CNS

6. BI 201 Human Anatomy & Physiology
The Brain: development…
What happens if those crests DON’T meet and fuse?
Failure of neural arch formation can result in Spina bifida. In mild cases results in a dimple or discolored spot (S.b. occulta), severe cases (S.b. cystica), meninges, CSF and nervous tissue may protrude.

7. The Brain: from the outside in…
The brain and spinal cord are protected by meninges
3 layers: Dura mater ~ outermost, tough, continuous with periosteum
Arachnoid mater ~ middle layer, spiderweb appearance
Pia mater ~ innermost layer, not visible to naked eye

8. The Brain: from the outside in…
The dura mater helps keep the brain in position and the cerebral spinal fluid (CSF) helps cushion/protect the brain
Where does the fluid come from?
Choroid plexuses on ventricle walls
Ependymal cells allow fluids in from capillaries

9. The Brain: from the outside in…
The CSF circulates throughout the ventricles, down the central canal of the spinal cord and throughout the subarachnoid space.
CSF is reabsorbed back into blood primarily at the venous sinuses found within the dura mater.

10. Cerebral Hemispheres (Cerebrum)
Paired (left and right) superior parts of the brain
Include more than half of the brain mass
Figure 7.13a
Slide 7.28a

11. Layers of the Cerebrum Gray matter Outer layer
Composed mostly of neuron cell bodies
Figure 7.13a
Slide 7.33a

12. Layers of the Cerebrum White matter
Fiber tracts inside the gray matter
Example: corpus callosum connects hemispheres
Figure 7.13a
Slide 7.33b

13. Cerebral Hemispheres (Cerebrum)
The surface is made of ridges (gyri) and grooves (sulci)
Figure 7.13a
Slide 7.28b

14. The Lobes The Occipital Lobe-posterior end of cortex
Contains primary visual cortex
The Parietal Lobe-between occipital love the central sulcus
Contains the primary somatosensory cortex-receiving touch sensation, muscle-stretch information and joint position information
The Temporal Lobe-lateral portion of each hemisphere, near the temples
Contains targets for audition, essential for understanding spoken language, complex visual processes, emotional and motivational behaviors
The Frontal Lobe-extends from the central sulcus to the anterior limit of the brain
Contains Primary Motor Cortex-fine movements
Contributes to shifting attention, planning of action, delayed response tasks as examples

15. Lobes of the Cerebrum
Fissures (deep grooves) divide the cerebrum into lobes
Surface lobes of the cerebrum
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Slide 7.29a

16. Lobes of the Cerebrum
Figure 7.15a
Slide 7.29b

17. Specialized Areas of the Cerebrum
Somatic sensory area – receives impulses from the body’s sensory receptors
Primary motor area – sends impulses to skeletal muscles
Broca’s area – involved in our ability to speak
Slide 7.30

19. Sensory and Motor Areas of the Cerebral Cortex
Figure 7.14
Slide 7.31

20. Specialized Area of the Cerebrum
Cerebral areas involved in special senses
Gustatory area (taste)
Visual area
Auditory area
Olfactory area
Slide 7.32a

21. Specialized Area of the Cerebrum
Interpretation areas of the cerebrum
Speech/language region
Language comprehension region
General interpretation area
Slide 7.32b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

22. Specialized Area of the Cerebrum
Figure 7.13c
Slide 7.32c

23. The Brain: Cerebrum (lobes)
Cerebrum divided into 4 lobes:
Frontal: motor function, motivation, aggression, smell and mood
Parietal: reception and evaluation of sensory info.
Temporal: smell, hearing, memory and abstract thought
Occipital: visual processing

24. The Brain: Cerebrum (bumps and grooves)
The sulcus dividing frontal and parietal lobes is Central Sulcus.
Ridges on either side are Pre & Post gyri
Pre CS ~ motor cortex
Post CS ~ somatic sensory cortex
Motor
Sensory

25. Layers of the Cerebrum Basal nuclei – internal islands of gray matter
Regulates voluntary motor activities by modifying info sent to the motor cortex
Problems = ie unable to control muscles, spastic, jerky
Involved in Huntington’s and Parkinson’s Disease
Figure 7.13a
Slide 7.33c

26. Figure 4.20  Some major subdivisions of the human cerebral cortex The four lobes: occipital, parietal, temporal, and frontal.

27. The Brain: Cerebrum (makin’ waves)
Sum electrical activity can be read as waves with EEG
bio-feedback to control brain activity

28. The Brain: Cerebrum (memories)
3 types:
Sensory ~ less than a second
Short-term ~ seconds to minutes (about bits)
Long-term ~ minutes to life time
associated with re-shaping neurons and formation of memory engrams (pattern of neurons and their connections)

29. The Brain: Cerebrum (memories)
Long term memories are divided into 2 types:
Declarative memory ~ ability to recall details, names etc.
Procedural memory ~ ability to repeat behaviors or actions.
Example: Pavlov and conditioning

30. The Brain: Cerebrum (memories in “limbo”)
Deepest portion of cerebrum and brainstem associations called the Limbic system
This is involved with mood, base emotions and interacts with hypothalamus to influence food/H2O acquisition.
Major input is olfaction

31. The Brain: Cerebrum (hemispheres)
Not really a “dominant” side
Hemispheres communicate via the corpus callosum
Structurally and functionally different
Right brain -- usually Representational
Left brain -- usually Categorical
Anterior
Smell R.
Smell L.
Shape mem.
Verb. Mem.
Musical
Symbolic
Intuitive
Language
Spatial
Posterior