Bio 253 Lab 1 Test 1 UPDATED ACTUAL
Exam Questions and CORRECT Answers
EMG & what does it record - CORRECT ANSWER - - recording of the electrical activity
of skeletal muscle at rest and during contraction.
- Reflects the electrical activity of *muscle fiber* at that time
-electrical activity of thousands of individual muscle fibers
motor unit - CORRECT ANSWER - A motor neuron and all of the muscle fibers it
innervates
in a surfacce EMG - CORRECT ANSWER - the recorded signal shows the skeletal muscle
membrane potential
as the number of electrically active muscle fibers increase - CORRECT ANSWER -
frequency of those muscle fibers' action potentials increase
What does EMG not measure - CORRECT ANSWER - CONTRACTILE STRENGTH.
ONLY ELECTRICAL ACTIVITY
coactivation - CORRECT ANSWER - contraction of an agonist muscle leads to minor
activity in the antagonist muscle.
Evoked EMG - CORRECT ANSWER - signals are produced by the electrical stimulation
of a motor nerve supplying a muscle.
agonist muscle ("prime movers") - CORRECT ANSWER - muscle or group of muscles
that directly produce a movement
Antagonist (oppose) muscle - CORRECT ANSWER - return the muscle to its initial
position.
, Name two antagonistic pair - CORRECT ANSWER - bicep and triceps
quadricep and hamstring
which of the following regarding coactivation is false
a)Coactivation in the antagonist muscle provides an example of eccentric contraction.
b) Coactivation is associated with a smaller EMG recording from the agonist muscle compared
to that in the antagonist muscle.
c) Coactivation is seen in the antagonist muscle during isotonic contraction. - CORRECT
ANSWER -B
What is muscle fatigue? - CORRECT ANSWER - physiological inability to contract
effectively
Causes of muscle fatigue - CORRECT ANSWER - loss of central drive: psychological
motivation to complete a task
reduction in blood flow
changes in sense of effort: perceived psychological effort to complete a task
build up of lactic acid
failure of neuromuscular propagation
reduction of Ca release in ECC
three ways ATP can be remade - CORRECT ANSWER - 1. oxidative phosphorylation
(electron transport chain)
2. anaerobic glycolysis (no oxygen): pyruvate gets turned to lactic acid
3. stored as phosphocreatine
physiological causes of fatigue - CORRECT ANSWER - -ATP production < ATP demand
-excessive accumulation of lactic acid
Exam Questions and CORRECT Answers
EMG & what does it record - CORRECT ANSWER - - recording of the electrical activity
of skeletal muscle at rest and during contraction.
- Reflects the electrical activity of *muscle fiber* at that time
-electrical activity of thousands of individual muscle fibers
motor unit - CORRECT ANSWER - A motor neuron and all of the muscle fibers it
innervates
in a surfacce EMG - CORRECT ANSWER - the recorded signal shows the skeletal muscle
membrane potential
as the number of electrically active muscle fibers increase - CORRECT ANSWER -
frequency of those muscle fibers' action potentials increase
What does EMG not measure - CORRECT ANSWER - CONTRACTILE STRENGTH.
ONLY ELECTRICAL ACTIVITY
coactivation - CORRECT ANSWER - contraction of an agonist muscle leads to minor
activity in the antagonist muscle.
Evoked EMG - CORRECT ANSWER - signals are produced by the electrical stimulation
of a motor nerve supplying a muscle.
agonist muscle ("prime movers") - CORRECT ANSWER - muscle or group of muscles
that directly produce a movement
Antagonist (oppose) muscle - CORRECT ANSWER - return the muscle to its initial
position.
, Name two antagonistic pair - CORRECT ANSWER - bicep and triceps
quadricep and hamstring
which of the following regarding coactivation is false
a)Coactivation in the antagonist muscle provides an example of eccentric contraction.
b) Coactivation is associated with a smaller EMG recording from the agonist muscle compared
to that in the antagonist muscle.
c) Coactivation is seen in the antagonist muscle during isotonic contraction. - CORRECT
ANSWER -B
What is muscle fatigue? - CORRECT ANSWER - physiological inability to contract
effectively
Causes of muscle fatigue - CORRECT ANSWER - loss of central drive: psychological
motivation to complete a task
reduction in blood flow
changes in sense of effort: perceived psychological effort to complete a task
build up of lactic acid
failure of neuromuscular propagation
reduction of Ca release in ECC
three ways ATP can be remade - CORRECT ANSWER - 1. oxidative phosphorylation
(electron transport chain)
2. anaerobic glycolysis (no oxygen): pyruvate gets turned to lactic acid
3. stored as phosphocreatine
physiological causes of fatigue - CORRECT ANSWER - -ATP production < ATP demand
-excessive accumulation of lactic acid
