The document discusses the nervous system including the central nervous system (CNS) comprising the brain and spinal cord, and peripheral nervous system. It describes the main parts of the brain and spinal cord. It then explains the somatic and autonomic divisions of the peripheral nervous system. The document proceeds to discuss nerve anatomy including neurons, afferent and efferent nerves. It also covers nerve conduction, myelin sheaths, synapses, and neurotransmitters. Further topics include the neuromuscular junction, motor units, muscle stimulation via volition and reflexes, proprioception, and provides examples of their function.

1. Neural Anatomy
and Function

2. NERVOUS SYSTEMS
• Central nervous system
• Peripheral nervous system

3. CENTRAL NERVOUS SYSTEM p. 33
• Brain
– Cerebral Cortex/Cerebrum
• Motor cortex
– Basal Ganglia/Diencephalon – sensory input
– Cerebellum – motor control
– Brain stem – sensory input
• Spinal Cord

4. PERIPHERAL NERVOUS
SYSTEM
• Somatic
– Sensory (Gamma) Nerves
– Motor (Alpha) Nerves
• Autonomic [FYI]
– Parasympathetic
– Sympathetic

5. Spinal Nerves p. 35

7. NERVE ANATOMY
•A single nerve cell is called a neuron
•A bundle or group of neurons make up a
nerve
•A nerve contains both afferent and efferent
nerves

8. Afferent Neuron
• Carry impulse towards the CNS (e.g. sensory
nerves)
• Synapse
Towards CNS

9. Efferent Neuron
• Carry impulse away from the CNS (e.g. motor
nerves)
2. Stimulatory
3. Inhibitory

10. NEURON ANATOMY
• Dendrite
• Cell Body
• Axon

11. AXON
1. Conduction
2. Myelin sheath
3. Synapse
4. Neurotransmitter

12. CONDUCTION
Resting State: Na outside, K inside

13. CONDUCTION
4. Na K Pump 1. Depolarization
3. Repolarization 2. Propagation

14. MYELIN SHEATH

15. SYNAPSE

16. SYNAPSE

17. SYNAPSE
•Quick Time Movie

18. NEUROMUSCULAR
JUNCTION

19. NEUROMUSCULAR
JUNCTION

21. MOTOR UNIT
• Motor unit = one motor nerve + all
the muscle fibers it innervates.
• Types
– Fast (alpha -1)
– Slow (alpha -2)

22. 3
1
2

23. MOTOR UNIT
Fast Fast Slow

24. MUSCLE TENSION or FORCE or
STRENGTH
1. Number of MU
stimulated
2. Frequency of
stimulation to each
MU
3. Type of MU
stimulated

25. MUSCLE STIMULATION:
How does it begin?

26. 1. Volitional Control
(Motor Cortex)
1. Motor cortex
2. Motor neurons
3. Muscles

27. 2. Reflex Control
1. Afferent neuron
– Sensory
neuron
2. Efferent neuron
– Motor neuron

29. PROPRIOCEPTION &
KINESTHESIS p. 37
• Proprioception
– The ability to sense the position and location
and orientation and movement of the body
and its parts
• Kinesthesis
– The ability to feel movements of the limbs and
body

30. PROPRIOCEPTION
• Proprioceptors of the joints and
skin
– Meissner’s corpuscles
– Ruffini’s corpuscles
– Pacinian corpuscles
– Krause’s end-bulbs

31. PROPRIOCEPTION
• Proprioceptors of the muscles
– Muscle spindles
– Golgi tendon organs

32. Muscle Spindles

33. muscle
spindle

35. Muscle Spindles
• Provide proprioception
• Sense the amount of stretch and the rate of
stretch
• Reflexes involving the muscle spindles is
how we ‘feel’ a movement was done
correctly
• Spindles are a part of learning; we develop
such reflexes as we practice skills and
movements

36. Golgi Tendon Organs

38. Golgi Tendon Organs
• Sensitive to muscle tension and active
contraction
• Protect muscle from excess contraction
force
• Stimulation of GTO an afferent impulse is
sent to the central nervous system
• In turn, efferent impulses are sent to the…
– Agonist muscle causing it to relax
– Antagonist muscle causing it to contract

39. Neuromuscular Summary
•An example from baseball.
•A pitcher throws a curve ball to
Sammy Sosa
•Sammy’s eyes see the ball coming
towards him and is able to identify
the pitch as a curve ball
•Sensory nerves (afferent) send that
information to the CNS
•In the CNS the sensory nerve
synapses with motor nerves
•The motor nerves in turn stimulates
the muscles (deltoid and pectoralis
major) required to swing the bat in
the proper position to hit the ball

40. Neuromuscular Summary
•Inside the fibers of the deltoid and
pectoralis major, calcium is
released
•The calcium allows myosin heads
to attach to actin
•When the heads swivel the fibers
of the deltoid muscle will shorten
•The shortening of the fibers will
pull on the humerus causing
Sammy to swing the bat
•The muscle spindles “tell” the
CNS when the arm is in the
correct position
•If all goes as planned, the deltoid
and pectoralis major will move his
arms into a position to hit the ball

41. Neuromuscular Summary
• An example from weight training.
• A man is having his muscular strength tested on the bench
press
• For his first lift, 50 pounds is put on the bar
• He will be using his pectoralis major muscle with has 500
motor units (300 slow twitch and 200 fast twitch) and his
triceps muscle
• His CNS stimulates 280 motor units leading to his pectoralis
major muscle (180 slow twitch and 100 fast twitch)
• End nerve ending stimulates
a separate muscle fiber

42. Neuromuscular Summary
• Calcium is released, myosin attaches to actin and
swivels.
• The pectoralis major and triceps muscles shortens
and his arm extends outward raising the bar with
50 pounds on it.
• After a few minutes of rest, 100 pounds is place on
the bar
• This time he stimulates 380 motor units (260 slow
twitch and120 fast twitch)
• The weight is successfully
lifted
• After a few minutes of rest,
150 pounds is place on the
bar

43. Neuromuscular Summary
• This time he stimulates 460 motor units (280 slow
twitch and 180 fast twitch)
• As the pectoralis major muscle contracts the GTO
in the pectoralis major are stimulated
• They stimulate a sensory nerve leading to the
CNS
• In the CNS, the sensory nerve synapses with a
motor nerve that will inhibit (relax) the pectoralis
major muscle
• The man is unable to
successfully lift the 150
pounds.