BIOL 251 EXAM 2 WITH 100%
CORRECT ANSWERS 2025/2026
Muscles make up how much of your weight? correct answers
>> about 1/2
What are the three types of muscles? correct answers >>
skeletal, smooth, cardiac
Muscles are specialized to convert ____ energy to ____ energy.
correct answers >> chemical, mechanical
How many skeletal muscles are in the human body? correct
answers >> more than 600
Skeletal muscle includes: correct answers >> skeletal muscle
tissue, connective tissues, nerves and blood vessels
Skeletal muscles do not contract until what occurs? correct
answers >> They are stimulated by a nerve to do so. This is
different from cardiac and smooth muscle.
Skeletal muscle cells are also called correct answers >>
muscle fibers
What are the connective tissues of muscles? correct answers
>> endomysium, perimysium, epimysium, fascia
,Endomysium correct answers >> Thin sleeve that surrounds
each muscle fiber, creates room for capillaries and nerve fibers to
reach every muscle cell.
Perimysium correct answers >> Sheath that bundles muscle
fibers into units called fascicles. Larger blood vessels, nerves, and
stretch receptors will be found within this sheath.
Epimysium correct answers >> Fibrous sheath that
surrounds the entire muscle and bundles multiple fascicles
together.
Fascia correct answers >> Sheet of connective tissue outside
of the epimysium that separates muscles from one another.
What is direct vs indirect attachment? correct answers >>
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? correct answers >>
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? correct answers
>> voluntary
Why are there striations in muscle fibers (skeletal muscle)?
correct answers >> Due to the overlapping arrangement of
contractile proteins.
Structure of skeletal muscle fibers correct answers >>
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 correct answers >> Plasma membrane of a
muscle fiber that forms T tubules (tubular infoldings).
Sarcoplasm correct answers >> 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 correct answers >> 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? correct answers >>
thick, thin, elastic
CORRECT ANSWERS 2025/2026
Muscles make up how much of your weight? correct answers
>> about 1/2
What are the three types of muscles? correct answers >>
skeletal, smooth, cardiac
Muscles are specialized to convert ____ energy to ____ energy.
correct answers >> chemical, mechanical
How many skeletal muscles are in the human body? correct
answers >> more than 600
Skeletal muscle includes: correct answers >> skeletal muscle
tissue, connective tissues, nerves and blood vessels
Skeletal muscles do not contract until what occurs? correct
answers >> They are stimulated by a nerve to do so. This is
different from cardiac and smooth muscle.
Skeletal muscle cells are also called correct answers >>
muscle fibers
What are the connective tissues of muscles? correct answers
>> endomysium, perimysium, epimysium, fascia
,Endomysium correct answers >> Thin sleeve that surrounds
each muscle fiber, creates room for capillaries and nerve fibers to
reach every muscle cell.
Perimysium correct answers >> Sheath that bundles muscle
fibers into units called fascicles. Larger blood vessels, nerves, and
stretch receptors will be found within this sheath.
Epimysium correct answers >> Fibrous sheath that
surrounds the entire muscle and bundles multiple fascicles
together.
Fascia correct answers >> Sheet of connective tissue outside
of the epimysium that separates muscles from one another.
What is direct vs indirect attachment? correct answers >>
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? correct answers >>
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? correct answers
>> voluntary
Why are there striations in muscle fibers (skeletal muscle)?
correct answers >> Due to the overlapping arrangement of
contractile proteins.
Structure of skeletal muscle fibers correct answers >>
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 correct answers >> Plasma membrane of a
muscle fiber that forms T tubules (tubular infoldings).
Sarcoplasm correct answers >> 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 correct answers >> 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? correct answers >>
thick, thin, elastic
