chapter 8 connect assignment

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what are possible outcomes of muscle contractions?

- movement of bones - squeezing of intestinal contents - secretion of hormones

what is the role of calcium in muscle contraction?

It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.

how does an electrical impulse travel into the interior of a muscle fiber?

along the transverse tubules

what term describes the muscle that is primarily responsible for opposing a particular action?

antagonist

muscles that flex the wrist are found on the ____ side of the forearm while those that extend the wrist are found on the _____ side of the forearm

anterior; posterior

what is the action of the enzyme acetylcholinesterase?

breaks down acetylcholine

What are fascicles?

bundles of muscle fibers

which of the following best describes myofibrils?

compromised of thick and thin filaments

what is muscle atrophy?

decrease in size and strength

cardiac muscle is located in the walls of blood vessels T or F

false

muscle fatigue results from a combination of insufficient calcium and an excess of acetylcholine T or F

false

Most muscles that move the thigh have their insertions on the ____.

femur

what muscles can act as a prime mover for plantar flexion of the foot?

gastrocnemius

which muscles share the same primary action?

gastrocnemius and soleus

which of the following describes smooth muscle contraction but not skeletal muscle contraction?

hormones can inhibit muscle contraction

what term refers to the attachments point for the movable end of the muscle?

insertion

describe the role of acetylcholinesterase in a stimulation of a muscle fiber

it is the enzyme that breaks down acetylcholine within the synaptic cleft, ending stimulation of the muscle fiber.

what happens to a muscle that has lost its innervation?

it undergoes atrophy

in muscle anatomy, what is an origin?

less movable end of muscle

what is an example of a partial but sustained contraction of a whole muscle?

maintenance of posture

What is a threshold stimulus?

minimum strength of stimulus required to cause muscle fiber contraction to occur

Site of ATP production

mitochondria

a ____ includes a motor neuron and all of the muscle fibers that is controls.

motor unit

the condition called ___ is inability of a muscle to continue to contract after rigorous exercise

muscle fatigue

what is an alternate name for skeletal muscle cell?

muscle fiber

Threadlike bundles of thick and thin filaments

myofibril

the characteristic reddish color of skeletal muscle is due to the presence of what substance?

myoglobin

what binds to actin at its binding sites, allowing the formation of cross bridges.

myosin

what is the name of the functional connection between a motor neuron and a muscle cell?

neuromuscular junction

motor neurons communicate with muscle cells by releasing chemicals called

neurotransmitters

what statement describes multiunit smooth muscle?

responds to stimulation by neurons and certain hormones

plasma membrane of muscle fiber

sarcolemma

functional unit of contraction within muscle fiber

sarcomere

name the functional units of contraction in a muscle fiber

sarcomeres

cytoplasm of a muscle fiber

sarcoplasm

Site for storage of calcium

sarcoplasmic reticulum

an electrical impulse traveling along the sarcolemma and into transverse tubules causes calcium ions to diffuse from the ____ into the _____.

sarcoplasmic reticulum; sarcoplasm

what type of muscle fiber is more resistant to fatigue

slow fibers

In general, oxygen debt develops as a result of:

strenuous exercise

Name the cordlike structures that connect muscles to bone.

tendons

Channel formed by invagination of plasma membrane

transverse (T) tubule

Name the membranous channels or tunnels that extend inward from multiple locations along the plasma membrane, into and through the muscle cell.

transverse tubules

calcium ions bind to ______ in order to initiate a muscle contraction

troponin

Endomysium separates individual muscle fibers from each other. T or F

true

an isotonic contraction is one that involves a change in length but not a change in tension T or F

true

transverse tubules are invaginations of the sarcolemma of a muscle cell T or F

true

a(n) _____ is a single contraction of a muscle fiber in response to a single stimulus

twitch

by what means does an electrical impulse travel deep into a skeletal muscle fiber in order to trigger a contraction?

via transverse tubules

what type of smooth muscle is found in the wall of the stomach?

visceral muscle

What is peristalsis?

wavelike smooth muscle contraction

what neurotransmitter is used to stimulate skeletal muscle contraction?

acetylcholine

in order for muscle contraction to occur, cross-bridges form between what components of the muscle fiber?

actin and myosin

what are the major proteins forming the myofibrils of skeletal muscle cells?

actin and myosin


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