BIOL 251 Exam #2 Review questions with verified
detailed accurate solutions |100%accurate
answers
Muscles make up how much of your weight? - answer ✔✔-about 1/2
What are the three types of muscles? - answer ✔✔-skeletal, smooth, cardiac
Muscles are specialized to convert ____ energy to ____ energy. - answer ✔✔-chemical, mechanical
How many skeletal muscles are in the human body? - answer ✔✔-more than 600
Skeletal muscle includes: - answer ✔✔-skeletal muscle tissue, connective tissues, nerves and blood
vessels
Skeletal muscles do not contract until what occurs? - answer ✔✔-They are stimulated by a nerve to do
so. This is different from cardiac and smooth muscle.
Skeletal muscle cells are also called - answer ✔✔-muscle fibers
What are the connective tissues of muscles? - answer ✔✔-endomysium, perimysium, epimysium,
fascia
Endomysium - answer ✔✔-Thin sleeve that surrounds each muscle fiber, creates room for capillaries
and nerve fibers to reach every muscle cell.
Perimysium - answer ✔✔-Sheath that bundles muscle fibers into units called fascicles. Larger blood
vessels, nerves, and stretch receptors will be found within this sheath.
Epimysium - answer ✔✔-Fibrous sheath that surrounds the entire muscle and bundles multiple
fascicles together.
Fascia - answer ✔✔-Sheet of connective tissue outside of the epimysium that separates muscles from
one another.
What is direct vs indirect attachment? - answer ✔✔-Direct: looks like directly attached, but is not, short
connection of collagen fibers.
Indirect: attaches by tendon, obvious band.
What are the characteristics of muscle? - answer ✔✔-excitability: muscle cells can become excited
electrically
conductivity: electrical signals will travel along the cell
contractility: muscle cells and shorten when stimulated
extensibility: muscle cells can stretch between contractions
elasticity: when a muscle cell is stretched and then released, it recoils to a shorter length.
Is skeletal muscle voluntary or involuntary? - answer ✔✔-voluntary
Why are there striations in muscle fibers (skeletal muscle)? - answer ✔✔-Due to the overlapping
arrangement of contractile proteins.
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, Structure of skeletal muscle fibers - answer ✔✔-Sarcolemma: plasma membrane with T tubules
(infoldings).
Sarcoplasm: cytoplasm. Made of long proteins called myofibrils/myofilaments. Myoglobin, glycogen
strorage.
Sarcoplasmic reticulum: smooth endoplasmic reticulum, surround each myofibril. High amounts of
calcium, which is important for contraction, are stored there.
Sacrolemma - answer ✔✔-Plasma membrane of a muscle fiber that forms T tubules (tubular
infoldings).
Sarcoplasm - answer ✔✔-Cytoplasm of a muscle cell. Made of long proteins called myofibrils.
Contains a large amount of glycogen as well as myoglobin (an oxygen binding protein).
Sarcoplasmic reticulum - answer ✔✔-Smooth endoplasmic reticulum, surround each myofibril. High
amounts of calcium, which is important for contraction, are stored there.
What are the three kinds of myofilaments? - answer ✔✔-thick, thin, elastic
What is the structure of thin, thick, and elastic myofilaments? - answer ✔✔-Thick: consists of many
molecules of protein myosin
Thin: is made of two intertwined strands of actin. Each bead of the actin has an active site that can
bind to the head of a myosin molecule. Also includes the protein tropomyosin, which covers these
active sites at rest. Each tropomyosin has troponin bound to it.
Elastic: composed of titin, anchors the ends of thick filaments to the Z line.
Overall structure of striations and sarcomere - answer ✔✔-~ Striated muscle has dark A bands (thick
filaments side by side, part of the A band is where thick and thin filaments overlap) alternating with
lighter I bands
~ In the middle of an A band, there is a H band, where thin filaments do not reach
~ In the middle of the H band, the M line links thick filaments together
~ I bands have thin filaments, not thick filaments. Each I band is bisected by the Z line, which provides
anchorage for thin and elastic filaments
~ Sarcomere: z line to z line, functional contractile unit of muscle fiber
What are Z lines and what is anchored to them? - answer ✔✔-Z line provides anchorage for thin and
the elastic filaments. Thin filaments are anchored to Z lines.
What is a sarcomere? - answer ✔✔-Contractile unit of muscle, z line to z line
Z lines are pulled closer during what? - answer ✔✔-When a muscle contracts.
Innervate definition: - answer ✔✔-to supply with nerves
What do we call neurons that innervate skeletal muscle cells? - answer ✔✔-Somatic motor neurons.
What is a motor unit? - answer ✔✔-One nerve fiber and all the muscle fibers it innervates.
What is a synapse? - answer ✔✔-The point where a nerve fiber meets any target cell.
What is a neuromuscular junction? - answer ✔✔-Point of contact between a motor neuron and a
skeletal muscle cell.
What is a neurotransmitter? - answer ✔✔-A chemical that travels from one neuron to another,
chemical messenger.
Identify the anatomy of neuromuscular junction: - answer ✔✔-~ Axon terminal: at each synapse (point
where nerve fiber meets any target cell) nerve fiber ends in a bulbous swelling
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detailed accurate solutions |100%accurate
answers
Muscles make up how much of your weight? - answer ✔✔-about 1/2
What are the three types of muscles? - answer ✔✔-skeletal, smooth, cardiac
Muscles are specialized to convert ____ energy to ____ energy. - answer ✔✔-chemical, mechanical
How many skeletal muscles are in the human body? - answer ✔✔-more than 600
Skeletal muscle includes: - answer ✔✔-skeletal muscle tissue, connective tissues, nerves and blood
vessels
Skeletal muscles do not contract until what occurs? - answer ✔✔-They are stimulated by a nerve to do
so. This is different from cardiac and smooth muscle.
Skeletal muscle cells are also called - answer ✔✔-muscle fibers
What are the connective tissues of muscles? - answer ✔✔-endomysium, perimysium, epimysium,
fascia
Endomysium - answer ✔✔-Thin sleeve that surrounds each muscle fiber, creates room for capillaries
and nerve fibers to reach every muscle cell.
Perimysium - answer ✔✔-Sheath that bundles muscle fibers into units called fascicles. Larger blood
vessels, nerves, and stretch receptors will be found within this sheath.
Epimysium - answer ✔✔-Fibrous sheath that surrounds the entire muscle and bundles multiple
fascicles together.
Fascia - answer ✔✔-Sheet of connective tissue outside of the epimysium that separates muscles from
one another.
What is direct vs indirect attachment? - answer ✔✔-Direct: looks like directly attached, but is not, short
connection of collagen fibers.
Indirect: attaches by tendon, obvious band.
What are the characteristics of muscle? - answer ✔✔-excitability: muscle cells can become excited
electrically
conductivity: electrical signals will travel along the cell
contractility: muscle cells and shorten when stimulated
extensibility: muscle cells can stretch between contractions
elasticity: when a muscle cell is stretched and then released, it recoils to a shorter length.
Is skeletal muscle voluntary or involuntary? - answer ✔✔-voluntary
Why are there striations in muscle fibers (skeletal muscle)? - answer ✔✔-Due to the overlapping
arrangement of contractile proteins.
GRADESMORE.COM
, Structure of skeletal muscle fibers - answer ✔✔-Sarcolemma: plasma membrane with T tubules
(infoldings).
Sarcoplasm: cytoplasm. Made of long proteins called myofibrils/myofilaments. Myoglobin, glycogen
strorage.
Sarcoplasmic reticulum: smooth endoplasmic reticulum, surround each myofibril. High amounts of
calcium, which is important for contraction, are stored there.
Sacrolemma - answer ✔✔-Plasma membrane of a muscle fiber that forms T tubules (tubular
infoldings).
Sarcoplasm - answer ✔✔-Cytoplasm of a muscle cell. Made of long proteins called myofibrils.
Contains a large amount of glycogen as well as myoglobin (an oxygen binding protein).
Sarcoplasmic reticulum - answer ✔✔-Smooth endoplasmic reticulum, surround each myofibril. High
amounts of calcium, which is important for contraction, are stored there.
What are the three kinds of myofilaments? - answer ✔✔-thick, thin, elastic
What is the structure of thin, thick, and elastic myofilaments? - answer ✔✔-Thick: consists of many
molecules of protein myosin
Thin: is made of two intertwined strands of actin. Each bead of the actin has an active site that can
bind to the head of a myosin molecule. Also includes the protein tropomyosin, which covers these
active sites at rest. Each tropomyosin has troponin bound to it.
Elastic: composed of titin, anchors the ends of thick filaments to the Z line.
Overall structure of striations and sarcomere - answer ✔✔-~ Striated muscle has dark A bands (thick
filaments side by side, part of the A band is where thick and thin filaments overlap) alternating with
lighter I bands
~ In the middle of an A band, there is a H band, where thin filaments do not reach
~ In the middle of the H band, the M line links thick filaments together
~ I bands have thin filaments, not thick filaments. Each I band is bisected by the Z line, which provides
anchorage for thin and elastic filaments
~ Sarcomere: z line to z line, functional contractile unit of muscle fiber
What are Z lines and what is anchored to them? - answer ✔✔-Z line provides anchorage for thin and
the elastic filaments. Thin filaments are anchored to Z lines.
What is a sarcomere? - answer ✔✔-Contractile unit of muscle, z line to z line
Z lines are pulled closer during what? - answer ✔✔-When a muscle contracts.
Innervate definition: - answer ✔✔-to supply with nerves
What do we call neurons that innervate skeletal muscle cells? - answer ✔✔-Somatic motor neurons.
What is a motor unit? - answer ✔✔-One nerve fiber and all the muscle fibers it innervates.
What is a synapse? - answer ✔✔-The point where a nerve fiber meets any target cell.
What is a neuromuscular junction? - answer ✔✔-Point of contact between a motor neuron and a
skeletal muscle cell.
What is a neurotransmitter? - answer ✔✔-A chemical that travels from one neuron to another,
chemical messenger.
Identify the anatomy of neuromuscular junction: - answer ✔✔-~ Axon terminal: at each synapse (point
where nerve fiber meets any target cell) nerve fiber ends in a bulbous swelling
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