1. Nervous System

2. The Nervous System

Two main divisions
– Central Nervous System
(CNS) includes the brain
and spinal cord
– Peripheral Nervous
System (PNS) contains
nerves which carry info
between the CNS and
other organs

3. Central Nervous System
 The
brain receives
impulses and sends
impulses back to the
body
 The spinal cord
connects the brain to
the body

4. CNS: The Brain (UP 5)
Cerebrum

3 major regions
– Cerebrum
– Cerebellum
– Brainstem
Cerebellum
Brainstem

5. CNS: The Cerebrum
Largest part of the brain
 Involved in voluntary activities, intelligence,
and consciousness
 Divided into 4 lobes

– Frontal - personality
– Temporal - auditory
– Parietal - senses
– Occipital - visual area
Parietal
Frontal
Occipital
Temporal

6. CNS: Cerebellum & Brainstem


Medulla
Oblongata
Brainstem
Cerebellum – balance and
coordination
Brainstem includes the
pons and medulla
oblongata
– Involuntary functions
– heart rate, breathing
Cerebellum

7. PNS: Peripheral Nervous System
 All
nerves that are NOT part of the brain
or spinal cord
 Two major divisions of the PNS:
– Sensory division sends impulses from
sense organs (ears, nose, etc.) to the CNS
– Motor division send impulses from the
CNS to the muscles or glands

8. PNS: Motor Divisions
 Motor
division is then divided into the
autonomic and somatic nervous
systems
 Somatic System – regulates activities
under conscious control such as
muscle movement
– Also involved with reflexes

9. Autonomic Nervous System
 Regulates
automatic, involuntary
actions
– Parasympathetic Nervous System
decreases heart rate and stimulates
digestion; “rest and digest”
– Sympathetic Nervous System increases
heart rate; “fight or flight”
 These
systems have opposite effects

10. Cytoplasm
Neuron
Structure (UP 83)
Dendrites
Nucleus
Cell Body
Axon
Myelin
End Brush Motor
End Plate
Muscle (effector)

11. Neurons
 Three
types:
– Sensory: carry impulses from sense
organs to CNS
– Motor: carry impulses from CNS to
muscles/glands
– Interneurons: connect motor and sensory
neurons

12. Neural Impulses

Impulses move along a neuron due to
electrical changes in the membrane

13. Neural Impulses (UP 83)
Membrane is polarized,
more negative inside
Na+ ions enter; membrane
depolarizes
Repolarization follows
depolarization
Impulse travels the axon
–http://highered.mcgraw-hill.com/olc/dl/120107/bio_d.swf

14. Neural Impulses
 Resting
potential – polarized state,
negative charge inside membrane
 Threshold –minimum stimulus needed
to activate a neuron
 Action potential – depolarization &
repolarization of membrane
 Myelin increases rate of impulse

15. Synapses

Location where one neuron
transfers an impulse to a cell
– Neuron to neuron
– Neuron to muscle/gland

Chemicals called
neurotransmitters carry signals
across a synapse
– Acetylcholine and serotonin

16. Synapses

http://www.bishopstopford.com/faculties/science/arthur/synapse.swf

17. Reflex Arc


Reflexes prevent injury
Impulse travels from sensory neuron 
interneuron  motor neuron
http://www.sumanasinc.com/webcontent/anisamples/nonmajorsbiology/reflexarcs.html

18. Reflex Arc (UP 84)
Cell Body
(Sensory Neuron)
Sensory Neuron
Synapse
Receptors
(on dendrites)
Association
Neuron
(interneuron)
Synapse
Motor Neuron
Effector (muscle)
Motor End Plates

19. Animations

Action Potential
– http://highered.mcgraw-hill.com/olc/dl/120107/bio_d.swf
– http://outreach.mcb.harvard.edu/animations/actionpotential.swf

Chemical Synapse
– http://www.bishopstopford.com/faculties/science/arthur/synapse.swf
– http://highered.mcgraw-hill.com/olc/dl/120107/anim0015.swf
– http://outreach.mcb.harvard.edu/animations/synaptic.swf

20. Electroencephalogram (EEG)


Records electrical activity of the brain
Diagnosis of neurological diseases: stroke,
epilepsy, tumors, and sleep disorders

21. EEG Activity

22. Behavior Impacts
EEG

23. EEG During Seizures

24. Diagnostic Techniques


MRI – Magnetic Resonance Imaging uses
radio waves and VERY powerful magnets to
create images of the brain
Used to image soft tissue, not bone or teeth

25. MRI of the Brain

26. CT Scan


Computerized Tomography
3-D x-ray image based on tissue density
– Bone appears white, liquids/gases are black, and
various tissues are grey

Used to diagnose tumors

27. PET Scan
Positron Emission Tomography
 Creates images based on the detection of
radiation particles
 Used to detect tumors, seizure disorders, and
evaluate patients with memory loss


28. Brain Death

Irreversible cessation of brain activity for 24
hours so that cardiopulmonary function must
be maintained by machine