Flashcards in Ch 12: Skeletal Muscles Deck (121):
What happens when a muscle contracts?
The bone that moves is attached at the muscle _________?
The muscle is attached to a bone that does not move at the muscle _______?
________ muscles decrease the angle between two bones at a joint.
________ muscles increase the angle between two bones at a joint.
The prime mover of my skeletal movement is called the?
Flexors and extensors that work together are?
Skeletal muscles are surrounded by a fibrous _____.
Each fascicle of a muscle is surrounded by the?
Connective tissues called perimysium subdivides the muscle into _______.
Each fascicle is subdivided into muscle fibers surrounded by ______.
Muscle fibers have a plasma membrane called what?
________ are multinucleated and striated.
The light band of a skeletal muscle is known as the?
The dark band of a skeletal muscle is known as the
The site where a motor neuron stimulates a muscle fiber is known as?
The area of the muscle fiber sarcolemma where a motor neuron stimulates it is?
Motor end plate
Somatic motor neurons release the neurotransmitter _______ at the neuromuscular junction.
Each somatic motor neuron with all the muscle fibers it innervates is a?
Subunits of skeletal muscle cells that are composed of sarcomeres are called?
The thick filament is also called the?
____ contain only thin filaments.
_____ are the center of the A band with no thin filament overlap.
______ are found in the center of each I band
_______ are found in the center of each A band and help hold down thick filaments.
What is the area from one Z line to the next?
The protein that anchors in the thick filaments and allows elastic to coil is known as?
When a muscle contracts, sarcomeres shorten and _______ do not shorten.
When a muscle contracts, sarcomeres shorten and ______ shorten, but thin filaments do not.
When a muscle contracts, sarcomeres shorten and thin filaments side toward the ______?
Thick myofilaments are composed of the protein ______.
Myosin contains binding sites for ____and______ .
Which molecule blocks the myosin head from binding to actin in a relaxed muscle?
Sliding is produced by several cross bridges that form between ______ and _______.
Release of Pi upon binding cocks the myosin head, producing a _________ that pulls the thin filament toward the center.
After the power stroke, ____ is released and a new ATP binds.
_____ inhibits binding of myosin.
_____ binds to tropomyosin.
____ binds to calcium.
When muscle cells are stimulated, _____ is released inside the muscle fiber.
_______ is modified endoplasmic reticulum that stores Ca2+ when muscle is at rest. Most is stored in terminal cisternae.
Sarcoplasmic Reticulum (SR)
When a muscle fiber is stimulated, Ca2+ diffuses out of ______.
Calcium release channels
What are narrow membranous tunnels formed from the sarcolemma, open to the extra cellular environment, able to conduct act own potentials, and closely situated next to terminal cisternae?
When stimulating a muscle fiber, _______ is released from the motor neuron, and the end plate potentials are produced.
When stimulating a fiber, action potentials are generated and voltage gated calcium channels in transverse tubules change shape and cause calcium channels in the SR to open causing ____ to be released and bind to the Troponin C.
____ is done in vitro where one end of the muscle is fixed and the other is movable.
When studying ________, electrical simulations are applied and contractions are recorded and displayed as currents.
What is it called when a muscle quickly contracts and relaxes after a single electrical shock of sufficient voltage?
What is it called when a second shock is applied immediately after the first, and giving a piggyback look?
What is it called when increasing the frequency of electrical shocks decreases the relaxation time between twitches?
What is it called when at a certain frequency there will be no relaxation?
The inability of muscle cells to relax due to high frequency stimulation is termed?
As the voltage is increased, the number of muscle fibers used in vitro increases. This will reach a maximum value when all Muscle fibers are stimulated. If a fresh muscle is stimulated with several shocks at maximum voltage, each twitch will be progressively stronger causing a staircase effect. This is known as what?
Muscle fibers shorten when the tension produced is just greater than the load is known as what?
Muscles can't shorten because the load is too great is known as what? (can be voluntary)
A muscle fiber shortens when force is greater than the load is known as what?
A muscle may actually lengthen, despite contraction, if the load is too great is known as what?
_____ parts of the muscle and tendons must be pulled tight when muscles contract.
______ are elastic, resist distension, and snap back to resting length. They also absorb some of the tension as muscles contract.
__________ is determined by the number of fibers recruited to contract, frequency of stimulation, thickness of each muscle fiber ( thicker is stronger), and the initial length of the fiber at rest.
_____ is maximal when sarcomeres are at normal resting length.
Increasing or decreasing sarcomeres length will _______ the muscle tension.
Where do muscles get their energy when they are at rest or mild exercise?
Where do muscles get their energy for moderate exercise?
Where do muscles get their energy from for heavy exercise?
Determines whether a given exercise is light, moderate, or heavy for a given person Is called?
Maximal oxygen uptake
________ is determined by a person's age, sex, size, and athletic training.
Maximal oxygen uptake
________ is another way to determine exercise intensity for a given person.
When a person exercises, _______ is withdrawn from reserves in hemoglobin and myoglobin.
Breathing rate continues to be ______ after exercise to repay this debt.
The first 1 to 2 minutes of moderate to heavy exercise relies on ____ for ATP production.
Anaerobic respiration of glucose
What twitch caused slower contraction speed, can sustain contraction for long periods without fatigue, rich capillary supply, more mitochondria, more respiratory enzymes, and more myoglobin(slow,red fibers)?
Slow (type I)
What twitch has high oxidative capacity?
Slow (type I)
What twitch has faster contraction speed, fatigue fast, fewer capillaries, mitochondria, respiratory enzymes, and less myoglobin?
Fast (type II)
Type I skeletal muscle fibers have _________.
What has a fast-twitch but with high oxidative capacity?
Intermediate (type IIA)
Which of the following is NOT a contributing factor to skeletal muscle fatigue?
Increased intracellular K+
Adaptation to endurance training decrease in type II and _______ in type IIA muscle fibers.
Type II muscle fibrils become thicker due to increased amount of actin and myosin (more sarcomeres) is known as what?
Skeletal muscles have stem cells called ______ located near muscle fibers.
_____ is a paracrine regulator that inhibits satellite cells.
Muscle decline is due to what?
_______ is influenced by sensory feedback from muscles and tendons, and stimulation or inhibition from higher motor neurons from the brain.
Lower motor neurons
What responds to tension that a muscle puts on a tendon?
Golgi tendon organs
What responds to muscle length?
Muscle spindle apparatus
The muscle spindle apparatus is associated with _______ ?
What are the two types of muscle cells?
Nuclear bag fibers, nuclear chain fibers
What are two types of sensory cells wrap around the fibers?
Primary ( annulospiral)
Secondary ( flower-spray)
Innervate extrafusal (contracting) muscle fibers is called?
Innervate Intrafusal (stretch) muscle fibers is called?
The simplest reflex that only involves a sensory neuron synapsing on a motor neuron in the spinal cord is called?
What can be stimulated by striking the patellar ligament in the "knee jerk reflex"?
Monosynaptic stretch reflex
In the knee jerk reflex, interneurons are also stimulated in the spinal cord to inhibit antagonistic muscles on that limb is known as?
More complex reflexes require control of muscles on the contralateral limb is known as? (when you step on a tack)
Double reciprocal innervation
What sends neurons through the pyramidal tracts?
What receives information from muscle spindles and golgi tendon organs as well as other senses?
What also acts to inhibit motor activity through the rubrospinal tract?
______ and ______ muscles are involuntary and are regulated by the autonomic nervous system. The contraction is due to the myosin/actin cross bridges stimulated by calcium.
_______ muscles are striated, have myosin and actin filaments that form sarcomeres, and contraction occurs by means of sliding thin filaments.
Unlike skeletal muscle fibers (cells), these fibers are short, branched, and connected via gap junctions called _______.
A ________ is a mass of cardiac muscle cells connected to each other via gap junctions.
Action potentials that occur at any cell in a myocardium can stimulate all the cells in the _____.
The _____ of the heart compose one myocardium, and the ______ of the heart compose another myocardium.
Cardiac muscle can produce action potentials automatically that begin in a region called _______.
____ is influenced by autonomic innervation and hormones.
______ is found in blood vessel walls, bronchioles, digestive organs, urinary and reproductive tracts.
What muscle has no sarcomeres, long actin filaments attached to dense bodies, some myosin filaments, and allows contraction even when greatly stretched?
In smooth muscle cells, _______ functions in a manner analogous to Troponin.
Multiple gap junctions that make neighboring cells behave as a unit is known as?
What require individual nerve innervation (no pacemaker activity)?
_______ is released along the length of an autonomic neuron from varicosities.
The more movable end of a Muscle is called the ______.
The principle muscle responsible for a particular movement is called the _______.
Each muscle fiber is surrounded by a connective tissue layer called the _____.
The structural and functional unit of muscle is the _____.
Which of the following do not change in size during muscle contraction?
Which of the following uses calmodulin part of the ECC process?
Calmodulin take the place of _____ in muscle contraction.
The primary foodstuff for mild exercising muscle is_____.
An increase in muscle cell size is called?