For sophomores and juniors interested in medical school and undergraduate opportunities:

1
For sophomores and juniors interested in medical
school and undergraduate opportunities

• A visit by Dr. Paul Catalana, Al Squire, and
  other guests from Greenville Hospital System
  University Medical Center.
• In RMSC 122 (The Pit) starting at 630pm, Tuesday
  Oct 30th.
• Presentation and discussion on the new medical
  school at Greenville and undergraduate
  opportunities through their MedEx program,
  including clinical experiences and preparation
  for medical school.

2
1QQ 21 for 1030Write each letter, and circle
each correct response.

• a) Small motor units typically consist of Type II
  B myofibers.
• b) A motor unit will have at least two of the
  three types of skeletal myofibers.
• c) Sphincters are classified as tonically
  contractile.
• d) Muscle contraction in multi-unit smooth muscle
  is synchronized by gap junctions.
• e) Smooth muscles can contract even without a
  change in membrane potential.

3
1QQ 22 for 1130Write each letter, and circle
each correct response.

• a) Small motor units typically consist of Type II
  A myofibers.
• b) Large motor units generate greater tension
  than small motor units and are recruited first.
• c) Sphincters are classified as phasically
  contractile.
• d) Muscle contraction in singleunit smooth muscle
  is synchronized by gap junctions.
• e) Cardiac myofibers have action potentials and
  twitch durations that last about 1-2
  milliseconds.

4
Chapter 10 Control of somatic motor systems
S 1
29 October 2012

• Riding a bike, playing piano, swinging a bat or
  golf club.

Video of Trampoline Championship
Benjamin Zander Classical Music and Shining Eyes
Eric Mongrain playing Air Tap
5
Fig. 10.10a
S 2
Each region hasa homunculus
6
Fig. 10.02
S 3
Formerly called basal ganglia, consist of
caudate, putamen, and globus pallidus
7
Fig. 10.01
S 4
Corticospinal and corticobulbar tracts
Pathways?
Other inputs Vestibular Visual!
Examples of motor disorders Huntingtons Disease
and Cerebellar Disorder
8
S 5
Jack NicholsonOne Flew Over the Cuckoos Nest
Frontal lobotomy
9
Fig. 10.12
S 16
Pyramidal tract
Descending Pathways
Corticospinal tractCorticobulbar tract
Fine motor control, esp. of extremeties
Extra-Pyramidal tracts
Reticulospinal tractVestibulospinal tract
Originate in brainstem, more involved with
posture and equilibrium
10
S 17
Who Cares?
Video of Huntingtons Chorea
Video of Cerebellar Dysfunction
Video of Trampoline Championship
Locked-in Syndrome
11
Local control
S 6
SpindleAfferent
gamma motoneurons

• Muscle spindle
• Stretch receptor
• Intrafusal muscle fiber
• What is their role?
• The stretch reflex
• Follow the reflex arc
• Be able to differentiate function of afferent
  fibers, alpha motor neurons, and gamma motor
  neurons

Motor units ofalpha motoneurons
12
Fig. 10.05ab
S 7
This doesnt happen!
13
Fig. 10.05c
S 8
Co-activation of alpha and gamma motoneurons
insures that the stretch of muscle can be
detected regardless of the initial length or
state of contraction of that muscle.
14
Fig. 10.06
Proprioception pathway via dorsal column-medial
lemniscus pathway
S 9
One component of Stretch reflex is
monosynaptic Most common example patellar
reflex knee jerk reflex
Synergistic Antagonistic
15
Stretch Reflex
S 10
Monosynpatic excitation of motoneurons of that
muscle and synergistic muscles and polysynaptic
inhibition of motoneurons to antagonistic
muscles. Recall frog reflex lab and existence of
spinal reflexes in single-pithed frogs. Also,
example Christopher Reeve and patellar reflex.
16
Fig. 10.07
S 11
17
Golgi tendon organs involved in a reflex to
oppose excessive muscle tension.Not
monosynaptic.
Not shown ascending axons in dorsal
column-medial lemniscus tract.
S 12
18
S 13
Joint angle detectors and cutaneous
mechanoreceptors contribute to sense of body
position (proproiception.)
Plus vision and vestibular inputs!
19
S 14
Crossed-extensor reflex Common sense check the
book!
20
S 18
Lifting a loadand contraction velocity