Test 2

1
Test 2

• 90 Multiple Choice
• 10 Short Answer
• Overall grades
• 82 8 (mean s.d. n 38)median 81 Max 97

2
1QQ 24 for 830

• Why are twitches so long in smooth myofibers?
• In smooth muscle, what is the result of
  dephosphorylation of a crossbridge while it is
  still attached to the thin filament?
• Which of the following can affect membrane
  potential (and thus contraction) in smooth
  muscle?
• NE b) EPI c) ACH d) O2 e)
  stretch f) H
• How can some smooth muscles produce action
  potentials without voltage-gated Na channels?

3
1QQ 24 for 930

• Slow waves and pacemaker potentials are
  characteristic of
• Single unit smooth muscles
• Multi-unit smooth muscles
• Muscles of the uterus
• Muscles of the iris
• How are smooth muscles involved in migraine
  headaches?
• Which of the following can affect membrane
  potential (and thus contraction) in smooth
  muscle?
• Oxytocin b) EPI c) ACH d) O2 e)
  stretch f) Prolactin

4
Local control
S 1
SpindleAfferent

• 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

5
Fig. 10.05ab
S 2
6
Fig. 10.05c
S 3
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.
7
Fig. 10.06
Proprioception pathway via dorsal column-medial
lemniscus pathway
S 4
Stretch reflex is monosynaptic Most common
example patellar reflex knee jerk reflex
8
Fig. 10.07
S 5
9
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 6
10
S 7
Joint angle detectors and cutaneous
mechanoreceptors contribute to sense of body
position (proproiception.)
11
Fig. 10.12
S 8
Pyramidal tract
Corticospinal tractCorticobulbar tract
Fine motor control, esp. of extremeties
Extra-Pyramidal tracts
Reticulospinal tractVestibulospinal tract
Originate in brainstem, more involved with
posture and equilibrium
12
S 9
Who Cares?
Video of Huntingtons Chorea
Video of Cerebellar Dysfunction
Video of Trampoline Championship