Transcript Friday October 19th

3 November 2010
Today: Finish Chapter 9 Muscle Physiology
Chapter 10 Control of Movement
Lab this week: Human Muscle Physiology
Instruction on Website.
Soon: Chapter 12: Cardiovascular Physiology
S1
Response to training
• Resistance training
Type II change enzyme profiles: II A to II B
Type II add more actin and myosin
Type II increase cross-sectional area (hypertrophy)
• Endurance training
– Type I increases vascularity
– Type I increase number of mitochondria
End of material for Test # 2
S2
Begin material for Test # 3
Chapter 9 B Properties of
Smooth Muscle
(Cardiac muscle covered later)
How does smooth muscle differ from skeletal muscle?
(innervation, membrane potentials, excitation-contraction coupling, twitch
duration, fatigue, etc. (Table 9-6 p.292)
What are the features of membrane potential of smooth muscle?
(pacemakers and slow waves)
What are the differences between single-unit and multi-unit smooth muscle?
(location, spread of excitation)
Who cares about smooth muscles? Migraineurs!
S4
Latchbridge =latch state
S3
Figure 9.34
from SR and influx during Action Potential or graded potential
Graded potentials
result in graded
contractions
Slow twitch of SM
due to slow action
of myosin ATPase.
Lack troponin
Special situation:
Dephosphorylation &
latch bridge
S5
Comparison:
How does tension diminish?
Thank God for latch state!
Crucial for long-term tension of
sphincters.
S6
Slow waves and pacemaker potentials
Intestinal tract, uterus, small diameter blood vessels
Large airways of lungs, large arteries, ciliary muscle
Often with pacemaker cells
Control of membrane potential by neurotransmitters, hormones, local factors
for some smooth muscles (02, NO, pH, stretch, vasodilators ….)
S7
Know this table
Fig. 09.06
S8
Chapter 10: Control of somatic
motor systems
Riding a bike, playing piano,
swinging a bat or golf club….
S9
Fig. 10.10a
S 10 Somatatopy in Primary Motor Cortex
S 11
Fig. 10.02
Formerly called “basal ganglia”,
consist of caudate, putatmen, and
globus pallidus
Decision to move
S 12
Fig. 10.01
Initiates motor command
Coordinates
secondary movements
Corticospinal and
corticobulbar
tracts
Balance and
complex
learned
movements
Pathways?
Examples of
motor
disorders:
Huntington’s
Disease and
Cerebellar
Disorder
Reflex
S 13
Local control
• 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
Spindle
Afferent
S 14
Fig. 10.05ab
S 15
Fig. 10.05c
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.
S 16
Fig. 10.06
Stretch reflex is
monosynaptic
Most common
example:
patellar reflex =
“knee jerk reflex”
Proprioception
pathway via dorsal
column-medial
lemniscus pathway
S 17
Stretch Reflex
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.
S 18
Fig. 10.07
S 19
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 20
Joint angle detectors and cutaneous mechanoreceptors
contribute to sense of body position (proproiception.)
S 21
Pyramidal tract
Fig. 10.12
Corticospinal tract
Corticobulbar tract
Fine motor control, esp. of extremeties
Extra-Pyramidal tracts
Reticulospinal tract
Vestibulospinal tract
Originate in brainstem,
more involved with posture and equilibrium
Not monosynaptic!
S 22
Who Cares?
Video of Huntington’s Chorea
Video of Cerebellar Dysfunction
Video of Trampoline Championship