BIOL 251 Exam #2 Review Questions
All Answered Correctly.
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.
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
~ Synaptic cleft (with junctional folds): separated from the axon terminal with narrow folds.
~ Synaptic vesicles: the axon terminal contains these, filled with acetylcholine (ACh), a
neurotransmitter.
All Answered Correctly.
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.
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
~ Synaptic cleft (with junctional folds): separated from the axon terminal with narrow folds.
~ Synaptic vesicles: the axon terminal contains these, filled with acetylcholine (ACh), a
neurotransmitter.
