1. Chapter 8 Nervous System I
Cell Types of Neural Tissue
neurons
neuroglial cells
8-1

2. Divisions of the Nervous System
Central Nervous System
brain
spinal cord
Peripheral Nervous System
peripheral nerves
cranial nerves
spinal nerves
8-2

3. Divisions of Peripheral Nervous System
Sensory Division
picks up sensory information and delivers it to the CNS
Motor Division
carries information to muscles and glands
Divisions of the Motor Division
Somatic – carries information to skeletal muscle
Autonomic – carries information to smooth muscle, cardiac muscle, and glands
8-3

4. Functions of Nervous System
Sensory Function
sensory receptors gather information
information is carried to the CNS
sensory neurons- afferent
Motor Function
decisions are acted upon
impulses are carried to effectors
motor neurons
Integrative Function
interneurons
sensory information used to create
sensations
memory
thoughts
decisions
8-4

5. Neuron Structure
8-5

6. Myelination of Axons White Matter contains myelinated axons
Gray Matter
contains unmyelinated structures
cell bodies, dendrites
8-6

7. Classification of Neurons
Sensory Neurons
afferent
carry impulse to CNS
Interneurons
link neurons
in CNS
Motor Neurons
carry impulses away from CNS
carry impulses to effectors
8-7

8. The Synapse
Nerve impulses pass from neuron to neuron at synapses
8-8

9. Synaptic Transmission
Neurotransmitters are released when impulse reaches synaptic knob
8-9

10. Reflex Arcs Reflexes – automatic, subconscious responses to stimuli
8-10

11. Brain Functions interprets sensations determines perception
stores memory
reasoning
makes decisions
coordinates muscular movements
regulates visceral activities
determines personality
Major Parts
cerebrum
two cerebellar hemispheres
diencephalon
brain stem
cerebellum
8-11

12. Brain Stem
Three Parts
Pons
Medulla Oblongata
Midbrain
8-12

13. Pons
helps regulate rate and depth of breathing
relays nerve impulses to and from medulla oblongata and cerebellum
8-13

14. Medulla Oblongata
enlarged continuation of spinal cord
conducts ascending and descending impulses between brain and spinal cord
contains cardiac, vasomotor, and respiratory control centers
contains various nonvital reflex control centers (coughing, sneezing, vomiting)
8-14

15. Reticular Formation filters incoming sensory information
arouses cerebral cortex into state of wakefulness
8-15

16. Diencephalon Thalamus
gateway for sensory impulses heading to cerebral cortex
receives all sensory impulses (except smell)
channels impulses to appropriate part of cerebral cortex for interpretation
Hypothalamus
maintains homeostasis by regulating visceral activities
temperature
sleep-wake cycles
water balance
appetite
links nervous and endocrine systems
8-16

17. Cerebellum posterior to pons and medulla oblongata
inferior to occipital lobes
posterior to pons and medulla oblongata
integrates sensory information concerning position of body parts
coordinates skeletal muscle activity
maintains posture
8-17

18. Lobes of Cerebrum
Frontal
Parietal
Temporal
Occipital
8-18

19. Structure of Cerebrum cerebral cortex corpus callosum
connects hemispheres
convolutions
bumps or gyri
sulci
grooves
longitudinal fissure
separates hemispheres
transverse fissure
separates cerebrum from cerebellum
8-19

20. Functions of Cerebrum interpretation initiating voluntary movements
storing memory
retrieving memory
reasoning
center for intelligence and personality
8-20

21. Motor and Sensory Areas
Primary Motor Areas
frontal lobes
control voluntary muscles
Cutaneous Sensory Area
parietal lobe
interprets sensations on skin
Visual Area
occipital lobe
interprets vision
Auditory Area
temporal lobe
interprets hearing
8-21

22. Hemisphere Dominance
In over 90% of population, left hemisphere is dominant
Nondominant hemisphere controls
nonverbal tasks
motor tasks
understanding and interpreting musical and visual patterns
provides emotional and intuitive thought processes
Dominant hemisphere controls
speech
writing
reading
verbal skills
analytical skills
computational skills
8-22

23. Memory Short Term working memory circuit is stimulated over and over
when impulse flow stops, memory disappears
Long Term
changes structure and function of neurons
enhanced synaptic transmission
strong emotion, repetition, and building on previous memories stimulate
8-23

24. Spinal Cord Functions center for spinal reflexes
conduit for nerve impulses to and from the brain
8-24

25. Spinal Cord Structure extends foramen magnum to 2nd lumbar vertebra
8-25

26. Meninges Meninges membranes surrounding CNS protect CNS three layers
dura mater – outer, tough
arachnoid mater - weblike
pia mater – inner, delicate
8-26

27. Cerebrospinal Fluid secreted by choroid plexus
circulates in ventricles, central canal of spinal cord, and subarachnoid space
completely surrounds brain and spinal cord
clear liquid
nutritive and protective
helps maintain stable ion concentrations in CNS
8-27

28. Peripheral Nervous System
Cranial nerves arising from the brain
Somatic fibers connecting to the skin and skeletal muscles
Autonomic fibers connecting to viscera
Spinal nerves arising from the spinal cord
Somatic fibers connecting to the skin and skeletal muscles
Autonomic fibers connecting to viscera
8-28

29. Cranial Nerves
8-29

30. Spinal Nerves mixed nerves 31 pairs 8 cervical (C1 to C8)
12 thoracic (T1 to T12)
5 lumbar (L1 to L5)
5 sacral (S1 to S5)
1 coccygeal (Co)
8-30

31. Autonomic Nervous System
functions without conscious effort
controls visceral activities
regulates smooth muscle, cardiac muscle, and glands
efferent fibers typically lead to ganglia outside CNS
Two Divisions
sympathetic – prepares body for fight or flight situations
parasympathetic – prepares body for resting and digesting activities
8-31