Chap 10
Anatomy & Physiology 1 with Bow at State College of Florida, Manatee-Sarasota
About this deck
By: Deborah Hinkel
Textbook:
Fundamentals of Anatomy & Physiology (8th Edition)
Created: 2011-03-17
Size: 80 flashcards
Views: 92
Textbook:
Fundamentals of Anatomy & Physiology (8th Edition)Created: 2011-03-17
Size: 80 flashcards
Views: 92
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The functional unit of the muscle fiber is a
sarcomere.
The junction between a muscle cell and the neuron innervating that cell is the
neuromuscular junction.
The membranous network that surrounds each myofibril is the
sarcoplasmic reticulum.
The command to contract is conducted throughout the muscle fiber by the
transverse tubules.
The part of the sarcomere that contains thick filaments but no thin filaments is the
H zone.
Z lines
mark the boundaries between adjacent sarcomeres.
For tropomyosin to be shifted off its position covering the active sites of G actin molecules, calcium ions must bind to which structure?
troponin
The binding of calcium ions causes ACh to be released from what structure?
synaptic terminal
The binding of ACh to the motor end plate causes a change in membrane permeability to
sodium
Which of the following events in a muscle contraction marks the beginning of the relaxation of the muscle cell?
detachment of crossbridges
What happens when the myosin head splits ATP into ADP and a phosphate group?
myosin reactivation
Which of the following represents the correct sequence of events in a contraction cycle?
active-site exposure
crossbridge attachment
pivoting
crossbridge detachment
myosin reactivation
In a(n) __________ contraction, the peak tension developed is less than the resistance, and the muscle elongates due to the contraction of another muscle or the pull of gravity.
eccentric
Isometric contraction
Muscle does not change in length as tension rises
Tension never exceeds resistance (pushing against an immovable object
Which is a unique feature of smooth muscles?
plasticity
When energy reserves in a muscle are exhausted and lactic acid levels increase, __________ occurs.
Which type of muscle fiber allows for extremely quick contractions but fatigues quickly?
fast fibers
Which type of muscle fiber is supplied by extensive blood vessels?
slow fibers
What human muscles contain only fast fibers?
hand muscles
At peak levels of muscle exertion, mitochondrial activity can provide about only one third of the ATP needed. The remainder is provided through
glycolysis
The level of activity at which the muscles must begin relying on anaerobic metabolism to meet its demands is called
anaerobic threshold.
A feature found in cardiac muscle cells that is lacking in skeletal and smooth muscle cells is
intercalated discs.
Isotonic contraction
Muscle changes in length as tension rises
From smallest to largest name the levels of organization in a skeletal muscle i
Sarcomere
myofibril
muscle fiber
Endomysium
muscle fascicle
Perimysium
What are the steps in the contraction cycle in order, from 1 to 6, starting with the release of ACh into the synaptic cleft of the neuromuscular junction:
Acetylcholine binds to receptors on the muscle cell membrane
Calcium is released from the SER
Actin active sites are exposed
Crossbridges form between the actin and myosin filaments
ATP is broken down and the myosin heads pivot
Myosin heads pick up new ATP, and crossbridges detach
What is the order the events that occur during the transmission of an electrical impulse through a neuromuscular junction:
Release of acetylcholine
Arrival of an action potential at the synaptic terminal
Return to initial state
Appearance of an action potential in the sarcolemma
ACh binding at the motor end plate
Repeating contractile units that make up a myofibril are called:
sarcomeres
An individual contractile unit within a myofibril in a muscle fiber is called a(n) __________.
sarcomere
During a sarcomere contraction, the A band length does not change, while the __________ move closer together.
Z lines
** What is the name of the enzyme in the synaptic cleft that breaks down the neurotransmitter that starts a muscle contraction?
acetylcholinesterase
creatine phosphate
Stored form of ATP
Muscle performance is considered in terms of power, the maximum amount of tension that can be produced by a muscle or muscle group, and __________, the amount of time an individual can perform an activity.
Endurance
While you sit at the computer reading this question, the postural muscles in your back are involved in contractions that produce tension but do not shorten muscle length. These are called __________ contractions.
Isometric
Hypertrophy
Muscle growth
Action potentials must travel along which structure internal to the sarcolemma to cause the release of calcium ions from the sarcoplasmic reticulum?
T Tubles
In which part of the sarcomere are myosin heads able to form crossbridges with actin?
zone of overlap
Aponeurosis
A blending of all 3 layers of connective tissue ( epimysium, perimysium, and endomysium ) form a broad sheet at the end of a muscle is known as a(n):
Skeletal muscles are often called voluntary muscles because:
they contract when stimulated by motor neurons of the central nervous system
Nerves and blood vessels are contained within the connective tissues of the:
epimysium and perimysium
The thinfilaments consist of:
a pair of protein strands together to form chains of actin molecules
The thick filaments consist of:
a helical array of myosin molecules
All of the muscle fibers controlled by a single motor neuron constitute a:
Motor unit
The reason that control over leg muscles is less precise than control over the muscles of the eye is:
The sliding filament theory explains that the physical change that takes place during contraction is that:
The thin filaments are sliding toward the center of the sarcomere alongside the thick filaments
Troponin and tropomyosin are two proteins that can prevent the contractile process by:
covering the active site and blocking the actin-myosin interaction
The amount of tension produced by an individual muscle fiber ultimately depends on the:
number of pivoting crossbridges
The amount of strength is directly proportionate to overlap of thin & Thick myofiliaments
the transmission of an action potential along the T tubules stimulates the release of calcium from which structure in the sarcomere?
terminal cisternae
Peak tension production occurs when all motor units in the muscle contract in a state of:
In an isotonic contraction, the:
crossbridges must produce enough tension to overcome the resistance
What is an example of an isometric contraction?
holding a heavy stack of books above the ground
A high blood concentration of the enzyme creatine phosphokinase (CPK) usually indicates:
serious muscle damage
Mitochondrial activities are relatively efficient, but their rate of ATP generation is limited by the:
Which of the following has been correlated with muscle fatigue?
a decline in pH within the muscle altering enzyme activities
During the recovery period, the body's oxygen demand is:
elevated above normal resting levels
The length of time a muscle can continue to contract while supported by mitochondrial activities is referred to as:
aerobic endurance
What type(s) of muscle tissue do(es) not contain sarcomeres?
smooth
Structurally, smooth muscle cells differ from skeletal muscle cells because smooth muscle cells:
lack myofibrils and sarcomeres
The area of the A band in the sarcomere consists of:
M line, H band, zone of overlap
The order of the sequential-cyclic reactions that occur at an active site during cross-bridging is:
attach, pivot, detach, return
Excitation-contraction coupling forms the link between:
electrical activity in the sarcolemma and the initiation of a contraction
The phases of a single twitch, in sequential order, are:
latent period, contraction phase, relaxation phase
After contraction, a muscle fiber returns to its original length through:
elastic forces and the movement of opposing muscles
A muscle producing peak tension during rapid cycles of contraction and relaxation is said to be in:
incomplete tetanus
The process of reaching complete tetanus is obtained by:
increasing the rate of stimulation until the relaxation phase is completely eliminated
Functions of Muscle Tissue
Produce body movement
***Stabilizing body position***
Storing and moving substances within the body - Glycogen storage
Generating heat - thermogenesis
At rest, active sites on actin are covered by
tropomyosin
The _______________ contains vesicles filled with acetylcholine
Synaptic end bulb
Synaptic cleft
The space between the neuron and the muscle
The __________________ contains receptors for acetylcholine
Motor end plate
The release of AchE (acetylcholine esterase causes the closure of ____________ ion channels
Na+
The binding site for calcium would most likely be found on
troponin
In order for the myosin head to detach from actin it must be recharged with
ATP
Anaerobic respiration requires
no oxygen
Makes small amount of ATP
Aerobic respiration requires
oxygen
Makes most ATP
Fatigue
A state of physiological inability to contract
What is the latin word for mouse
musculus
About this deck
By: Deborah Hinkel
Textbook: Fundamentals of Anatomy & Physiology (8th Edition)
Created: 2011-03-17
Size: 80 flashcards
Views: 92
Textbook:
Fundamentals of Anatomy & Physiology (8th Edition)Created: 2011-03-17
Size: 80 flashcards
Views: 92
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
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“I have used this website for three exams, and I see a huge difference in my test results.”
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