Anatomy chapter 10

in a sacromere, thick filaments are linked laterally by proteins of the

M line

a single motor neuron together with all the muscle fibers it innervates is called

a motor unit

sacromere is best defined as

a repeating unit of striated muscle

the rapid rise and fall in force produced by a muscle fiber after a single action potential is

a twitch

during neuromuscular transmission, the axon terminals release

acetylcholine

the cytoplasm of the neuromuscular terminal contain vesicles filed with molecules of the neurotransmitters

acetylcholine

triggering of the muscle action potential occurs after

acetylcholine binds to chemically-gated channels in the end plate membrane

the biochemical reaction that consumes the majority of a muscle's ATP is the

actin myosin cross-bridge cycle

the most important factor in decreasing the intracellular concentration of calcium ion after contraction is

active transport of calcium into the sacroplasmic reticulum

creatine phosphate

acts as an energy reserve in muscle tissue

during the recovery period the body's need for oxygen is increased because

additional oxygen is required to restore energy reserves consumed during exercise

a resting muscle generates most of its ATP by

aerobic metabolism of fatty acids

which would lead to increased oxygen comsuption

all of the above

what causes the vesicle inside a neuron to fuse with the plasma membrane

an action potential in the neuron

after heavy exercise, if energy reserves in a muscle are depleted, ___ occurs

an oxygen debt

muscles are attached to bones by tendons or

aponeuroses

the sacroplasmic reticulum contains

calcium

active sites on the actin become available for binding after

calcium binds to troponin

the dense layer of connective tissue that surrounds the entire skeletal muscle is the

epimysium

synaptic vesicles contain neurotransmitters that are released by ____ when the action potential arrives

exocytosis

inside a muscle, bundles of single muscle fibers from

fascicles

the ___ type of muscle fiber has relatively few mitochondria

fast

which is not a function of smooth muscle tissue

forcing blood from heart into major arteries

slow muscle fibers compared to fast muscle fibers

generate less tension, rich in red protein myoglobin, take 3x as long to reach peak tension, have smaller fiber diameters

during the core cycle, in the liver

glucose is produced from lactic acid

fast fibers

have low resistance to fatigue and have quick twitches

muscle fibers differ from "typical cells" in that muscle fibers

have many nuclei

to increase muscle tension, the nervous system can

increase stimulation frequency, recruit large motor units, increase the number of active motor units

all of the following are found in both skeletal and cardiac muscle fibers except

intercalated disks

when a muscle contraction develops tension but doesn't shorten the muscle, the contraction is called

isometric

how would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle

it would cause spastic paralysis- muscles contract and unable to relax

muscle fatigue occurs due to a buildup of _______ and _____ in pH

lactic acid; decrease

the muscle weakness of myasthenia gravis results from

loss of acetylcholine receptors in the end-plate membrane

when acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes

more permeable to sodium ions

receptors for acetylcholine are located on the

motor end plate

the neuromuscular junction is a connection between a neuron and a

muscle fiber

in an isotonic contraction

muscle tension exceeds the load and the muscle lifts the load

skeletal muscle fibers are formed from embryonic cells called

myoblasts

which thick filament binds to actin once its active binding sites are exposed

myosin

each skeletal muscle fiber is controlled by a motor neuron at a single

neuromuscular junction

acetylcholine receptors are primarily located

on motor end plate

anaerobic glycolysis provides energy for muscle contraction when the supply of __ is limited

oxygen

during anaerobic glycolysis

oxygen is not consumed, pyretic acid and ATP produced, carbohydrate is metabolized

a thin layer of connective tissue that surrounds a muscle fascicle is called the

perimysium

ability of smooth muscle to function over a wide range of lengths is called

plasticity

skeletal muscle does each of these except

pump blood

a patient takes a medication that clocks ACh receptors of skeletal muscle fibers. What is this drug's effect on skeletal muscle contraction

reduced the muscle's ability for contraction

the role of acetylcholinesterase in the neuromuscular junction is to

remove acetylcholine from the synaptic cleft

fast muscle fibers can adapt to aerobic metabolism by generating more mitochondria in response to

repeated, exhaustive stimulation

after death, muscle fibers run out of ATP and calcium begins to leak from the sacroplasmic reticulum into the sacroplasm resulting in a condition known as

rigor mortis

what is not a characteristic of smooth muscle

s. muscle connective tissue forms tendons and aponeuroses

the plasma membrane of a skeletal muscle fiber is called the

sacrolemma

in response to an action potential along the transverse tubules, the ____ release(s) calcium ions into the sacroplasm

sacroplasmic reticulum

the series of membranous channels that surround each myofibril is the

sacroplasmic reticulum

which organelle completely surrounds each myofibril inside a muscle fiber

sacroplasmic reticulum

since each myofibril is attached at either end of the muscle fiber, when sacromeres shorten, the muscle fibers

shorten

which is true about cardiac muscle fibers

single nucleus, have long twitch duration compared to skeletal fibers, fibers branch

which type of muscle tissue has the greatest effect on the body's heat production?

skeletal

type of muscle fiber that is most resistant to fatigue is the ___ fiber

slow

what is the synaptic cleft

space between the synaptic terminal and the motor end plate

the narrow space between the synaptic terminal and the muscle fibers is the

synaptic cleft

the end of a neuron, where acetylcholine-filled vesicles are located is called the

synaptic terminal

the muscle action potentials that initiate contraction are transmitted from the interior of the muscle fiber by

t tubules

the advantage of having many nuclei in a skeletal muscle fiber is

the ability to produce large amounts of the muscle proteins needed for growth and repair

which most correctly describes excitation in the context of excitation-contraction coupling in skeletal muscle

the generation of an action potential in the sacrolemma

an action potential in the muscle fiber causes

the muscle fibers to contract

MH is a rare genetic disease. which of the following best describes how anesthesia would affect the skeletal muscles of a patient with MH

the muscles would contract because of calcium binging to troponin

when a skeletal muscle fiber contracts

the zones of overlap get lager, the h bands and i bands get smaller, zline gets closer together, width of a band remains constant

which of the following phrases best decries how excitation is couples to contraction in skeletal muscle fibers

through calcium release from the sacroplasmic reticulum

the action potential is conducted into a skeletal muscle fiber by

transverse tubules

the muscle action potential penetrates into a fiber along the

transverse tubules

t tubules and the terminal cistern are clustered into structures called

triads

which causes the active site of actin to be exposed or uncovered

tropomyosin

at rest, active sites on the actin are blocked by

tropomyosin molecules

the calcium ion binds to troponin

tropomyosin moves into the groove between the helical actin strands

to what regulatory protein does calcium bind during the initiation of the contraction cycle in skeletal muscle fibers

troponin

at rest, the tropomyosin muscle is held in place by

troponin molecules

inside a neuron, acetylcholine is contained within

vesicles

in sacromere, cross-bridge attachment occurs specifically in the

zone of overlap