Chapter 10: muscle tissue
Hypertrophy results from an increase in the number of ____ in a muscle cell.
myofibrils
myofibrils consist of bundles of short __________
myofilaments
After stimulation of ACh receptors, a muscle impulse spreads quickly along the ______ and into the muscle fiber along T-tubules.
sarcolemma
within a myofibril, Z discs separate the functional units known as _________
sarcomeres
the ________ filament theory explains how muscle fibers shorten during contraction
sliding
An individual has better proficiency in performing repeated contractions under aerobic conditions if he or she has a greater percentage of ______ fibers in specific muscles
slow
Slow fibers or type 1 fibers are also called _________ fibers because they contain the pigment myoglobin
slow oxidative
Over longer distances, runners who have higher proportions of ______ muscle fibers in their leg muscles are able to outperform runners who have a greater number of ______ muscle fibers in their leg muscles.
slow; fast
transports the action potential from the sarcolemma throughout the entire muscle fiber
t-tubule
deep invagination of sarcolemma are called _______
t-tubules
narrow, tubular extensions of the sarcolemma into the sarcoplasm
t-tubules
what is the arrow pointing to?
t-tubules
a thick cordlike structure that attaches muscle to a bone is called a __________
tendon
as a result of ACh stimulation, calcium ions are released from the ________ of the sarcoplasmic reticulum
terminal cisternae
Bind to thin filaments and cause contraction
thick filament
bind to thick filaments and cause contraction
thin filament
an action potential is carried along the sarcolemma, then down _______ tubules to the terminal cisternae of the sarcoplasmic reticulum
transverse
Athletes have more defined muscles than non-athletes even while at rest because they have ______ motor units contracting all the time
more
the vascular supply to slow muscle fibers is ________ than the network of capillaries around fast muscle fibers
more extensive
in a motor unit, a single ________ neuron typically controls numerous muscle fibers in a muscle
motor
a motor unit is composed of a single ________ and all of the muscle fibers it controls
motor neuron
what is 2 referring to?
I band
metabolic activities; contraction
muscle fiber
when an action potential travels down t-tubules to the terminal cisternae of the SR, what ion is released into the sarcoplasm?
calcium
functionally, troponin provides a binding site for _____ ions
calcium (Ca2+)
the amount of additional oxygen that must be inhaled in order to restore pre-exercise levels is called oxygen __________
debt
muscle cells are said to have what characteristic because they can respond to stimulation from the nervous system?
excitability
The majority of skeletal muscle fibers in the body are ______ fibers
fast glycolytic
which of the three skeletal muscle fiber types has the largest diameter and provides both power and speed?
fast glycolytic
after the cross bridges are formed, ATP is required to detach the _________ and complete the sequence of cyclic events
myosin head
thick and thin filaments maintain their ______, whether the muscle is relaxed or contracted
same length
what is the arrow pointing to?
synaptic cleft
what is this pointing to?
synaptic vesicle
The deep invaginations of the sarcolemma that extend into the sarcoplasm of skeletal muscle fibers as a network of narrow membranous tubules are called ______.
transverse tubules
a tropomyosin molecule is a short, thin, twisted filament that covers small sections of the _______ strands
actin
binding site for myosin to shorten a sarcomere
actin
each myosin head in a thick filament can bind to the protein in a thin filament called
actin
two intertwined strands; each bead has a myosin-binding site
actin
what protein is found in a thin filament?
actin
each myosin strand has a free _______ and an attached tail
head
the act of shivering is an example of skeletal muscle performing what function?
heat production
If a muscle cell is stimulated to contract, allowed to partially relax, then stimulated again, its force of contraction the second time will be ______
higher
the diameter of a muscle fiber will predict _______
how much power it will produce
An increase in the number of mitochondria can be observed in ______. Multiple choice question.
hypertrophy
There are two types of isotonic contractions, which include eccentric and _______
concentric
In an isometric contraction, the muscle ______ body movement.
doesn't produce
muscle tissue demonstrates the property of ______ when its done contracting and returns to its resting legnth
elasticity
what is the arrow pointing to? (surrounding the muscle cell)
endomysium
the three connective tissues layers that surround the individual components of a muscle are called what?
endomysium, perimysium, epimysium
what is the arrow pointing to? (surrounding the muscle)
epimysium
a skeletal muscle cell is also called a muscle ______
fiber
When a nerve impulse reaches the end of an axon of a neuromuscular junction, calcium flows _______ the synaptic knob
into
What is the arrow pointing to?
mitochondrion of mucle fiber
what is the force generated when a skeletal muscle is stimulated to contract called?
muscle tension
contain myofilaments that are responsible for muscle contraction
myofibrils
the sarcoplasm of a skeletal muscle fiber contains hundreds to thousands of long, cylindrical structures called _________ that extend the length of the cell.
myofibrils
As a result of exercise, each muscle fiber develops more myofibrils, and each myofibril contains a larger number of ______
myofilaments
Termination of the nerve impulse at an NMJ results in the passive sliding of ______ back to their original state.
myofilaments
What is the arrow pointing to?
nucleus of muscle fiber
As you struggle to twist open a jar, more motor units are called into action until you finally generate enough force to open it. This is an example of ______
recruitment
what are characteristics of oxidative fibers?
red, good for endurance, high concentration of myoglobin, use aerobic respiration
an internal membrane complex in skeletal muscle cells that is similar to the smooth endoplasmic reticulum of other cells is called the sarcoplasmic __________
reticulum
what activities are muscles in an isometric contraction?
sitting up straight, holding a yoga pose, pushing on a locked door
an individual has been proficiency in performing repeated contractions under aerobic conditions if he or she has a greater percentage of _________ fibers in specific muscles
slow
A "step-wise" increase in the force of contraction of a single muscle fiber or single motor unit due to repeated stimulation is called _______
summation
_________ distribute muscle impulses throughout the inside of the muscle fiber
t-tubule
The force generated when a skeletal muscle is stimulated to contract is muscle ________
tension
slow-twitch and fast-twitch muscle fibers differ primarily in _______
their ATPase which splits ATP
As you sit there reading this your muscles, even your relaxed ones are not completely relaxed and soft. This is because they have some background tension called resting muscle ______
tone
as the troponin changes shape (due to binding calcium), it moves the ________ molecule to which it is attached, thus exposing the active sites on the G-actin molecules
tropomyosin
covers the active sites on actin when muscle cells are at rest
tropomyosin
two intertwined strands; cover myosin-binding sites
tropomyosin
the two regulatory proteins associated with thin myofilaments are _________
tropomyosin and troponin
Upon release from the terminal cisternae, some calcium ions bind to ______ causing it to change shape.
troponin
bound to tropomyosin; can bind calcium ions
troponin
if the sarcoplasm of a muscle sell is flooded with calcium ions, to which protein will they bind?
troponin
upon release from the terminal cisternae, some calcium ions bind to ________ causing it to change shape
troponin
True or false: Most muscles contain a combination of all three muscle types, slow oxidative, fast oxidative, and fast glycolytic
true
t or f: in the absence of calcium, troponin attaches to tropomyosin to hold it in place on the surface of the F actin strand
true
A single contraction and relaxation of a muscle fiber is referred to as a muscle _______
twitch
each myosin protein molecule in a thick filament consists of ________ strands
two
what are characteristics of glycolytic fibers?
white; low concentration of myoglobin
After breaking your arm, you have a cast on it for three months. When the cast is removed, your arm looks much smaller than it did before. The process called ______ caused this to happen.
atrophy
The cyclic events of "attach, pivot, detach, return" continue as long as ______ ions remain bound to the troponin.
calcium
a muscle fiber is what level of organization in the body?
cellular
as a result of a muscle fiber contraction, thick filaments in neighboring sarcomeres move _______
closer together
stores calcium ions needed for muscle contraction
sarcoplasmic reticulum
what is the arrow pointing to? (Organelle of the muscle fiber that stores calcium)
sarcoplasmic reticulum
Concentric isotonic contractions actively ______ a muscle.
shorten
when a muscle fiber contracts, which parts of the sarcomere maintain a constant length throughout contraction?
A band
to start a muscle contraction, a nerve impulse causes _________ release at a neuromuscular junction
ACh
what is 7 referring to?
a band
ACh is an acronym for _______
acetylcholine
in a muscle cell, the short term energy is supplied by _________ respiration, whereas long term energy is supplied by ______
anaerobic; aerobic
A piano player uses her hands for brief quick movements. Which muscle fiber type would you therefore predict to be predominant in these muscles?
fast glycolytic
after you stop running, you notice that you keep breathing heavily for some time. this is because your body is in __________
oxygen debt
what is the arrow pointing to? (surrounding the fascicle)
perimysium
As you hold a barbell and begin to flex your arm in a curl, your biceps brachii slowly lifts the weight by using more and more motor units. This phenomenon, which increases the strength of the contraction, is referred to as ___________
recruitment
regulates entry and exit of materials
sarcolemma
the plasma membrane of a skeletal muscle fiber is called the _________
sarcolemma
Within a myofibril, each ______ shortens as the muscle fiber contracts.
sarcomere
A contracting skeletal muscle fiber typically shortens as all of its ______ shorten in length.
sarcomeres
site of metabolic processes for normal muscle fiber activities
sarcoplasm
the cytoplasm of a skeletal muscle cell has a specific name and is known as
sarcoplasm
at the end of muscle contraction, calcium ions are moved back into the _______ reticulum by ATP-driven ion pumps
sarcoplasmic