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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:
• Permeability:
• The Hodgkin Cycle
• Questions???
inout
zE log60
OUT][][][][][][log60
ClPKPNaPClPKPNaPE
ClinKinNa
CloutKoutNa
Lecture 3
• What affects conduction velocity
• How does a membrane get depolarized?
• Ionotropic vs Metabotropic receptors
• Questions???
The Autonomic Nervous SystemSympathetic Parasymp
PreganglionicNTLength
Ach (N)Short
Ach (N)Long
PostganglionicNTLength
Epi/NorepiLong
Ach (M)Short
Pre/Post Ratio High(Diffuse)
Low(Specific)
ANS continued
• Remember constrict, dilate: (general)
• Sympathetic: Epi, but Norepi controls BP.
1 = heart, 2 = lung (1 heart, 2 lungs).
DCBA
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 exertsprior to contraction.
Pre-contraction load
Afterload: Force muscle exertsduring 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 ATPase activity
Fatigue Resistance
Contraction Adaptation Example
White Fast
Glycolysis + - Short term phasic
hypertrophy Power lift
Slow Red Oxidative - ++ Sustained tonic
Incr mt myoglobin
Postural mm
Fast Red Oxid/Glyc + + Sustained phasic
both rowing
Resting Membrane Potential
Inside outside PermeabilityNa 40 500 10K 100 1 1
mV 601004010
150010log60
m
V
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) W = Fxd = 50 x (100x10x2) = 100,000 J(2) 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 musclelengths 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 joint180 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 kCalNet E = (4 – 0.4x5) x 4.8 = 9.6 kCalGross 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!!!!