1. Peripheral Nervous System
Chapter 14

2. I. Spinal Nerves A. Overview Have 31 pairs
#’d by attachment site to spinal cord (C3, L2, etc)
All are “mixed” nerves (carry both sensory & motor info)

3. I. Spinal Nerves B. Branching Networks
Attached to spinal cord by 2 “roots”
These form networks called plexuses

4. I. Spinal Nerves 4 major plexuses Cervical Brachial Lumbar Sacral
B. Branching Networks
4 major plexuses
Cervical
Brachial
Lumbar
Sacral

5. I. Spinal Nerves
B. Branching Networks
Areas of skin supplied by sensory fibers from same nerve = dermatome
Areas supplied by motor fibers from same nerve = myotome

6. II. Somatic Senses Detect stimuli from internal & external sources
A. Sensory Receptors
Detect stimuli from internal & external sources
Receptors are specialized dendritic endings
Receptors exhibit “adaptation” –
magnitude of message decreases over time if signal is continuous
Example: smell of perfume

7. II. Somatic Senses Widely distributed
B. Distribution of Receptors
Widely distributed
Found in skin, mucosa, connective tissues, muscles, tendons, joints, viscera
Not uniform; some sites have many, others have few

8. II. Somatic Senses Classification by Stimulus Detected
C. Classification of Receptors
Classification by Stimulus Detected
Mechanoreceptors
Detect motion (incl. pressure & stretch)
Chemoreceptors
Detect chemicals (amounts or changes in amts)
Thermoreceptors
Detect changes in temperature
Nociceptors
Detect pain
Photoreceptors
Detect light

9. II. Somatic Senses Classification by Location
C. Classification of Receptors
Classification by Location
Exteroceptors
On or near body surface
Usually respond to external stimuli
Interoceptors (visceroceptors)
Often within viscera (body organs)
Usually detect pressure, chemical changes, etc.
Proprioceptors
Within skeletal muscles and tendons
Info about body motion, location, orientation

10. Reminder: Peripheral NS divided into… Somatic Autonomic
Msgs to/from skeletal muscles
Reflexes move through reflex arc
Autonomic
Msgs to/from glands, smooth muscles, cardiac muscle
Has sympathetic & parasympathetic divisions

11. III. Cranial Nerves A. Overview
12 pairs; Connected to brain (mostly to brainstem)
May be sensory, motor, or mixed

12. Mnemonic Devices To remember the order of the nerves:
“Oh, oh, oh, to touch and feel very good velvet, ah!”
To remember the type of nerves:
Some say marry money but my brother says big brains matter more

13. III. Cranial Nerves B. Nerve Pairs
1. Olfactory
Sensory
Sense of Smell

14. III. Cranial Nerves B. Nerve Pairs
2. Optic
Sensory
Vision

15. III. Cranial Nerves B. Nerve Pairs
3. Oculomotor
Motor
Eye movement
Pupil size
4. Trochlear

16. III. Cranial Nerves B. Nerve Pairs
5. Trigeminal
Both (Mixed)
Sensation in head/face
Chewing

17. III. Cranial Nerves B. Nerve Pairs
6. Abducens
Motor
Moves eye to side

18. III. Cranial Nerves B. Nerve Pairs
7. Facial
Both (Mixed)
Sense of taste
Facial expression
Saliva & tear secretion

19. III. Cranial Nerves B. Nerve Pairs
8. Vestibulocochlear
Sensory
Hearing
Balance and equilibrium

20. III. Cranial Nerves B. Nerve Pairs
9. Glossopharyngeal
Both (Mixed)
Senses of tongue
Swallowing motions
Saliva secretion

21. III. Cranial Nerves B. Nerve Pairs
10. Vagus
Both (Mixed)
Senses & movements of visceral organs

22. III. Cranial Nerves B. Nerve Pairs
11. Accessory
Motor
Shoulder & head movement

23. III. Cranial Nerves B. Nerve Pairs
12. Hypoglossal
Motor
Tongue movement

24. Self-Quiz: Cranial Nerves Make a chart…# 1-12
# Nerve Type Function(s) 1 2 3 4 … 12

25. Name the cranial nerves:
1. O
2. O
3. O
4. T
5. T
6. A
7. F
8. V
9. G
10. V
11. A
12. H

26. Name the cranial nerves:
1. Olfactory
2. Optic
3. Oculomotor
4. Trochlear
5. Trigeminal
6. Abducens
7. Facial
8. Vestibulocochlear
9. Glossopharyngeal
10. Vagus
11. Accessory
12. Hypoglossal
Which are sensory only?
Which are motor only?
Which are both (mixed)?

27. Name the cranial nerves:
1. Olfactory - S
2. Optic - S
3. Oculomotor - M
4. Trochlear - M
5. Trigeminal - B
6. Abducens - M
7. Facial - B
8. Vestibulocochlear - S
9. Glossopharyngeal - B
10. Vagus - B
11. Accessory - M
12. Hypoglossal - M
Which are for eye movement?

28. Name the cranial nerves:
1. Olfactory - S
2. Optic - S
3. Oculomotor - M
4. Trochlear - M
5. Trigeminal - B
6. Abducens - M
7. Facial - B
8. Vestibulocochlear - S
9. Glossopharyngeal - B
10. Vagus - B
11. Accessory - M
12. Hypoglossal - M
Which is for vision? For hearing? For smelling?

29. Name the cranial nerves:
1. Olfactory - S
2. Optic - S
3. Oculomotor - M
4. Trochlear - M
5. Trigeminal - B
6. Abducens - M
7. Facial - B
8. Vestibulocochlear - S
9. Glossopharyngeal - B
10. Vagus - B
11. Accessory - M
12. Hypoglossal - M
Which 2 deal with your face and mouth?
Which is facial movement/taste?
Which is facial sensation/chewing?

30. Name the cranial nerves:
1. Olfactory - S
2. Optic - S
3. Oculomotor - M
4. Trochlear - M
5. Trigeminal - B
6. Abducens - M
7. Facial - B
8. Vestibulocochlear - S
9. Glossopharyngeal - B
10. Vagus - B
11. Accessory - M
12. Hypoglossal - M
Which one is “out of state”?
Which body parts are affected by it?

31. Name the cranial nerves:
1. Olfactory - S
2. Optic - S
3. Oculomotor - M
4. Trochlear - M
5. Trigeminal - B
6. Abducens - M
7. Facial - B
8. Vestibulocochlear - S
9. Glossopharyngeal - B
10. Vagus - B
11. Accessory - M
12. Hypoglossal - M
Which 2 deal with your tongue movements?
Which of these also deals with tongue sensation?

32. Name the cranial nerves:
1. Olfactory - S
2. Optic - S
3. Oculomotor - M
4. Trochlear - M
5. Trigeminal - B
6. Abducens - M
7. Facial - B
8. Vestibulocochlear - S
9. Glossopharyngeal - B
10. Vagus - B
11. Accessory - M
12. Hypoglossal - M
What does the last nerve move?

33. The End