1. Chapter 6 The Nervous System-Introduction and Central NS
Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 6 The Nervous System-Introduction and Central NS
Lecture Slides in PowerPoint by Jerry L. Cook
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

2. Nervous System – By the numbers
100 billion – # of neurons in brain
1300 grams – mass of adult brain (2.85 lbs)
400 grams – mass of newborn brain
20% - portion of blood that goes to brain

3. Organization of the Nervous System
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Figure 7.2

4. Functions of the Nervous System
1. SENSORY INPUT
Monitor changes (stimuli) occurring inside/outside body 1
2. INTEGRATION
Process/interpret sensory input
Decide if action is needed 2 3
3. MOTOR OUTPUT
Response (activation of muscle or gland) to stimuli
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 7.2

5. Central Nervous System (CNS)
CNS develops from the embryonic neural tube, during first month of fetal development
Neural tube becomes brain and spinal cord
Opening of neural tube becomes ventricles, which are four chambers within the brain that are filled with cerebrospinal fluid.

6. Protection of the CNS Scalp and skin Skull and vertebral column
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Figure 7.16a

7. Protection of the CNS Scalp and skin Skull and vertebral column
Cerebrospinal fluid
Meninges:
dura mater (tough, outer membrane)
arachnoid mater (mesh, middle membrane)
pia mater (soft, inner membrane; lines brain)
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Figure 7.16a

8. Protection of the CNS Scalp and skin Skull and vertebral column
Cerebro-spinal fluid
Meninges
Blood-brain barrier
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Figure 7.16a

9. Blood Brain Barrier
Low permeability of capillaries in the brain tissue that helps to keep out many potentially harmful substances.
However, some substances can pass through, such as:
Fats and fat soluble molecules
Respiratory gases
Alcohol
Nicotine
Anesthesia

10. Regions of the Brain 1. 3. 2. 4. (Cerebrum) Figure 7.12
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Figure 7.12

11. 1. CEREBRUM Consists of two hemispheres (right and left)
Each hemisphere has four lobes
Surface has ridges (gyri), shallow grooves (sulci), and deeper grooves (fissures)

12. Cerebral Hemispheres (Cerebrum)
Central Sulcus
Parietal Lobe
Frontal Lobe
Occipital Lobe
Temporal Lobe
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Figure 7.13a

13. Layers of the Cerebrum
GRAY MATTER - Outer layer composed mostly of neuron cell bodies
WHITE MATTER - Fiber tracts inside the gray matter
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Figure 7.13a

14. (consolidates short- and long-term memory; spatial navigation)
Specialized Area of the Cerebrum
(thought, intelligence, motivation, personality)
(complex sensory memory patterns)
Hippocampus
(consolidates short- and long-term memory; spatial navigation)
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Figure 7.13c

15. Parts of the Brain – Brain Stem
Corpus Callosum (connects hemispheres)
Third Ventricle
Thalamus
(encloses 3rd ventricle)
Pineal Body
(in the epithalamus)
Hypothalamus
Optic Chiasma
Corpora Quadrigemina
Pituitary Gland
Pons
Fourth Ventricle
Medulla
Cerebellum
Figure 7.15a
Spinal Cord
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16. 2. CEREBELLUM Located at the base of the brain
Two hemispheres with convoluted surfaces
Provides involuntary coordination of body movements

17. 3. DIENCEPHALON (on top of brain stem)
Made of three parts
Thalamus – relays sensory input
Hypothalamus
One of the last areas to develop
Helps regulate body temperature and metabolism
Part of limbic system (emotions)
Epithalamus – houses pineal body
Produces melatonin (controls day/night cycle)

18. 4. BRAIN STEM Attaches to the spinal cord Composed of three parts:
Midbrain - reflex center for vision and hearing
Pons - controls breathing
Medulla Oblongata - controls heart rate, blood pressure, breathing, swallowing, vomiting

19. SPINAL CORD Extends from the medulla oblongata to the T12 vertebrae
Runs through the foramen magnum (large hole) in the skull
Below T12 is called the cauda equine (a collection of spinal nerves that fan out)
Protected by meninges
Central canal filled with cerebrospinal fluid.

20. SPINAL CORD Cervical enlargement Meninges Thoracic enlargement
(end of spinal cord)
Cauda equina
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Figure 7.18

21. Spinal Cord Anatomy Central canal filled with cerebrospinal fluid
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 7.19

22. Traumatic Brain Injuries
Concussion
Slight brain injury
No permanent brain damage
Contusion
Brain tissue destruction occurs
Brain tissue does not regenerate
Cerebral edema
Swelling due to the inflammatory response
May compress and kill brain tissue

23. Cerebrovascular Accident (CVA)
Commonly called a STROKE
Blood to a region of the brain is blocked, cutting off O2 to the brain tissue
Caused by a blood vessel that ruptures or is clogged with a clot
Causes loss of some functions or death

24. Transient Ischemic Attack (TIA)
“Mini-stroke” that does not cause permanent damage
Can be a warning sign of a true stroke

25. Alzheimer’s Disease
Progressive degenerative brain disease mostly seen in the elderly
Abnormal protein deposits and twisted fibers cause structural changes in the brain
Causes memory loss, irritability, confusion and ultimately, hallucinations and death