Flashcards in Chapter 10 (Part 2) Deck (81):
Single stimulus contraction relaxation sequence in a muscle fiber
What are the 3 parts to a muscle twitch?
latent, contraction, relaxation
Lag period between the arrival of the stimulus before contraction starts where no tension is produced
how long does the latent period last?
Repetetive power strokes pull thin filaments past thick filaments shortening the sarcomere increasing tension to a peak
Tension returns to resting levels
how long does the relaxation phase last?
force generated when a skeletal muscle is stimulated to contract
what is muscle tension based on?
frequency of stimulation
stimulus directly follows relaxation phase of previous contraction resulting in stepwise increase in strength of contraction
More calcium = ____ crossbridges forming
prior contractions produced heat which increases efficiency of molecular interactions
warming up effect
second stimulus arrives before relaxation period causing twitches to combine and produce greater tension; muscle contraction os sustained as each new wave is added to the previous
wave (temporal) summation
stimulus frequency increased resulting in rapid cycles of contraction relaxation near maximum tension
stimulus frequency so high that relaxation period is eliminated
increasing number of active motor units
all muscle fibers innervated by single motor neuron
more motor units activated = ____ force generated by muscle
variable number of motor units are always active even when not contacting
more muscle tone = ___ resting rate of metabolism
sarcomere length is at optimal range, max number of cross bridges can form; generates greatest amount of tension
normal resting length
zone of overlap decreases, less potential cross bridges that can form, decreases the amount of tension it can produce
thin filaments overlap portion of myosin tails, sarcomeres have less distance to shorten before thick filaments run into the z-line, decreases the amount of tension
contraction where muscle maintains same length even as the amount of tension changes, different tension
contraction where muscle maintains tension as it changes to cause movement; sam tension, different length
muscle shortens during contraction
what is an example of concentric contraction?
tension in biceps brachii while lifting barbell
muscle elongates, tension is less than the load than the peak tension so the muscle lengthens
what is an example of eccentric contraction?
tension in biceps brachii while lowering your coffee
contractions require ATP to ___
re-cock myosin heads, pump calcium into SR
ultimate energy stored in cells
high energy compound produced within skeletal muscles composed of amino acids
if glycogen is broken down through anaerobic respiration, ______ of work is done
if glycogen is broken down through aerobic respiration, _____ of work is done
requires no oxygen
where does glycolysis happen
what are the products of glycolysis
4 ATP (net gain 2), 2 pyruvate
where does aerobic respiration happen
what are the products of aerobic respiration
CO2, H2O, ATP
Removes hydrogen ions and electrons to be used in the electron transport chain
citric acid cycle
what are the products of the citric acid cycle?
1 ATP, 2 CO2
series of inner mitochondrial membrane proteins pass along electrons and pump across hydrogen to create a gradient which is used to create ATP with he help of ATP synthase
Electron transport chain
what are the products of the electron transport chain
6 H2O, 34 ATP
demand for ATP is low and fatty acids are broken down in mitochondria to produce ATP
muscle at rest
Extra ATP produced in muscles at rest are used to build reserves of ____ and ___
creatine phosphate, glycogen
demand for ATP increases, glucose is released down from glycogen storage and broken down using aerobic and anaerobic respiration
muscle at moderate activity levels
Not enough oxygen present for aerobic respiration to keep with demands
Muscles at peak activity levels
What is the remaining pyruvate converted to when muscles are at peak activity levels?
What does lactic acid dissociate into?
Hydrogen ion, lactate
Can be converted back into pyruvate and broken down
muscle can no longer continue to perform at the required level of activity
What are the factors attributing to muscle fatigue?
Depletion of metabolic resources, less calcium, change in concentration of potassium and sodium, elevated concentration of phosphate
Amount of oxygen required to restore the fiber back to pre-exercise conditions
Oxygen debt, EPOC
What happens to the depth and rate of breathing when debt is being replaced?
What does endurance exercise increase?
capillary network, mitochondria, myoglobin
Protein which stores oxygen in muscle fiber
What does resistance exercise increase?
Number of myofilaments
What are the 3 types of skeletal muscle fiber?
Fast, slow, intermediate
Contains sparse capillary network, few mitochondria, small amount of myoglobin, and fatigue rapidly
what color do fast fibers appear?
where are fast fibers found?
What type of respiration are fast fibers powered by?
Contains lots of capillary networks, many mitochondria, many myoglobin, fatigue slowly
what color do slow fibers appear?
what types of respiration are slow fibers powered by?
where are slow fibers found?
trunk and lower limb
contains moderate capillary network, many mitochondria, medium amount of myoglobin
what color do intermediate fibers appear?
what types of respiration are intermediate fibers powered by?
where are intermediate fibers found?
how can the ratio of intermediate to fast fibers be altered?
What determines the amount of fast and slow fibers
enlargement of stimulated muscle
what increases due to repeated stimulation in the muscle?
mitochondria, glycogen, enzymes, myofilaments, myofibrils
reduction in muscle tone, size and power
generalized skeletal muscle contraction following death
what is rigor mortis caused by?
deterioration of SR, lack of ATP
when does rigor mortis begin?
when does rigor mortis disappear?