Transcript Nerve & Muscle Physiology Review

Nerve & Muscle Physiology
Rahul Dave’
Rdave2@uic
9/6/2002
Lecture 1
• How can a solution be hyperosmotic, but
isotonic?
• What is the function of cholesterol in
membranes?
• Questions on other topics …
Lecture 2
• Nernst Eqn:
E
• Permeability:
60
out
log
z
in
E  60 log
• The Hodgkin Cycle
• Questions???
P [ Na]  P [ K ]  P [Cl ]
P [ Na]  P [ K ]  P [Cl ]
Na
out
K
out
Na
in
K
in
Cl
Cl

OUT
Lecture 3
• What affects conduction velocity
• How does a membrane get depolarized?
• Ionotropic vs Metabotropic receptors
• Questions???
The Autonomic Nervous System
Preganglionic
NT
Length
Postganglionic
NT
Length
Pre/Post Ratio
Sympathetic
Parasymp
Ach (N)
Short
Ach (N)
Long
Epi/Norepi
Long
High
(Diffuse)
Ach (M)
Short
Low
(Specific)
ANS continued
• Remember  constrict,  dilate:
A B
C D
(general)
• Sympathetic: Epi, but Norepi controls BP.
• 1 = heart, 2 = lung (1 heart, 2 lungs).
Even more ANS …
• Sympathetic Responses
• Parasympathetic Responses
• Pupils, HR, Micturition/Defecation
• Mike Broman’s ANS review:
http://www.geocities.com/mbroma1/Physio1.htm
Lecture 7
• Hypertrophy vs Hyperplasia
• Smooth vs Striated muscle
• Questions????
Lecture 7: The Bands
Lecture 8
• Size principle
• Large vs small motor units
• The crossbridge cycle
• Questions???
Lecture 9
• Skeletal vs. Cardiac muscle
• Length-Tension relationship
• Questions???
Lecture 10
Preload: The force (load) a muscle exerts
prior to contraction.
Pre-contraction load
Afterload: Force muscle exerts
during contraction.
After [the start of] contraction load
Lecture 11
• Oxygen Debt: Consume first, make later
– ATP > Creatine-P > lactate prod > Aerobic
• Due to Cori cycle
– Lactate formed in muscle
– Converted to glucose in liver
Fiber Types
Metabolism
White
Fast
Slow Red
Glycolysis
Fast Red
Oxid/Glyc
Oxidative
ATPase Fatigue
Contraction
activity Resistance
+
Short term
phasic
++
Sustained
tonic
+
+
Sustained
phasic
Adaptation
Example
hypertrophy
Power lift
Incr mt
myoglobin
both
Postural mm
rowing
Resting Membrane Potential
Inside
40
100
Na
K
outside
500
1
Permeability
10
1
10  500  1
V  60 log
 60 mV
10  40  100
m
LEVER MECHANICS
A muscle generates 60 grams to lift a 10 gram
object. The total length of the lever arm is
42 inches. How far from the joint is the
insertion of the muscle?
(10/60) x 42in = 7 in
POWER AND WORK
To complete 1 revolution on a bicycle, 50 Newtons
of force must be used. Each revolution covers 2
meters. During a 10 minute exercise, an individual
maintains 100 rev/min.
(1)
(2)
W = Fxd = 50 x (100x10x2) = 100,000 J
P = W/t = 100000 J/600s = 167 W
VELOCITY AND LEVERAGE
The biceps is 30 cm long and 5 cm away from the
elbow. The distance between the hand and elbow
is 25 cm. The speed of the biceps is 6 muscle
lengths per second; the speed of the hand is
approximately …
Biceps moves 6x30 = 180 cm/sec.
The hand moves 25/5 = 5 times as fast as the joint
180 cm/sec x 5 = 900 cm/sec
Efficiency Calculations
A 70-kg individual does 20 pullups, lifting his
body weight 1 meter each time. In doing so,
he consumes 4 liters of O2. Baseline is 400
ml of O2/min. Total exercise time is 5 mins.
What is his gross and net mechanical
efficiency.
Answer …
W = mgh = (70 x 9.8 x 1) x 20 reps = 13.7 kJ
= 13.7/4.186 = 3.3 kCal
Total E = 4 x 4.8 = 19.2 kCal
Net E = (4 – 0.4x5) x 4.8 = 9.6 kCal
Gross Efficiency = W/E = 3.3/19.2 = 17%
Net Efficiency = 3.3/9.6 = 34%
Don’t forget to …
• Do the TLEs and Mallard (may have
mistakes)
• Make sure you know the question sheet
• The exam will be taken from the handouts
Good Luck!!!!
