PHGY 215 Final Exam Questions and Answers Already Passed
The muscle tissue represents the greatest - Answers The greatest tissue mass in the body at
around half of the bodys total weight.
The majority of muscles tissue is - Answers The majority is skeletal muscle (represents 40% of
bw in men and 32% in women)
skeletal muscle - Answers striated and voluntary
straited - Answers striped
Level of skeletal muscle organization - Answers The muscle > muscle fibre > myofibrils >
sacromere
muscle - Answers tissue composed of fibers that can contract, causing movement of an organ
or part of the body
Muscle fibre - Answers a single muscle cell. They are much longer than normal cells and are
multinucleate.
Myofibrils - Answers protein structures that make up muscle fibers
A band - Answers dark area; extends length of the thick filaments
I band of sarcomere - Answers the light band between the ends of thick filaments
H zone - Answers The region at the center of an A band of a sarcomere that is made up of
myosin only. The H zone gets shorter (and may disappear) during muscle contraction.
Slightly lighter portion of A band
M line of sarcomere - Answers mid-line of sarcomere
Made of proteins that hold thick filaments together
Z line - Answers A dark thin protein band to which actin filaments are attached in a striated
muscle fiber, marking the boundaries between adjacent sarcomeres.
Sacromere - Answers Basic contracting unit of muscle cell consits of actin and myosin
filaments between z-lines in a muscle cell
Muscle cross bridge - Answers Connection formed when mobile myosin heads bind to actin
molecules in muscles
Thick filaments (myosin) - Answers Myosin myofilament with heads that bind to actin by
, reaching up and ratcheting forward
About 300/filament
Myosin - Answers The contractile protein that makes up the thick filaments of muscle fibers
Dimer of two subunits that looks like a golf club in that it has a long shaft with a globular head
Thin filaments (actin) - Answers Made up of proteins actin, tropomyosin, troponin. The main
structural component is two actin filaments
Actin - Answers A globular protein that links into chains, two of which twist helically about each
other, forming microfilaments in muscle and other contractile elements in cells.
Tropomyosin - Answers Thin double helix protein that lies end to end along the actin helix
structure. Regulatory protein that covers the actin binding sites preventing interaction of actin
and myosin
Troponin - Answers Regulatory protein complex made up of 3 polypeptides. 1 binds
tropomyosin, 1 binds actin, 1 binds Ca 2+
muscle contraction - Answers The activation of tension generating sites within muscle fibres
when a muscle contracts it shortens
sliding filament mechanism - Answers Thin filaments slide over thick filaments, by the z discs
pulling together. The I band and H zone shorten, and the A band remains the same length
concentric contraction - Answers muscle shortens
power stroke - Answers action of myosin pulling actin inward (toward the M line)
cross bridge cycle - Answers sequence of events between binding of a cross-bridge to actin, its
release, and reattachment during muscle contraction
1) binding 2) power stroke 3) detachment 4) binding
sacroplasmic reticulum - Answers specialized smooth endoplasmic reticulum, releases calcium
on demand when the muscle fiber is stimulated to contract
Runs parallel to the fibres. The lateral sacs of the SR are in close proximity to the T-tubules.
Storage sites for Ca +2
T tubules - Answers invaginations of the sarcolemma. At the junction of A & I bands, t-tubules
dip into the fibre and run perpendicular to the fibres
Acetylcholinesterase (AChE) - Answers the enzyme that breaks down acetylcholine in the
synaptic cleft
The muscle tissue represents the greatest - Answers The greatest tissue mass in the body at
around half of the bodys total weight.
The majority of muscles tissue is - Answers The majority is skeletal muscle (represents 40% of
bw in men and 32% in women)
skeletal muscle - Answers striated and voluntary
straited - Answers striped
Level of skeletal muscle organization - Answers The muscle > muscle fibre > myofibrils >
sacromere
muscle - Answers tissue composed of fibers that can contract, causing movement of an organ
or part of the body
Muscle fibre - Answers a single muscle cell. They are much longer than normal cells and are
multinucleate.
Myofibrils - Answers protein structures that make up muscle fibers
A band - Answers dark area; extends length of the thick filaments
I band of sarcomere - Answers the light band between the ends of thick filaments
H zone - Answers The region at the center of an A band of a sarcomere that is made up of
myosin only. The H zone gets shorter (and may disappear) during muscle contraction.
Slightly lighter portion of A band
M line of sarcomere - Answers mid-line of sarcomere
Made of proteins that hold thick filaments together
Z line - Answers A dark thin protein band to which actin filaments are attached in a striated
muscle fiber, marking the boundaries between adjacent sarcomeres.
Sacromere - Answers Basic contracting unit of muscle cell consits of actin and myosin
filaments between z-lines in a muscle cell
Muscle cross bridge - Answers Connection formed when mobile myosin heads bind to actin
molecules in muscles
Thick filaments (myosin) - Answers Myosin myofilament with heads that bind to actin by
, reaching up and ratcheting forward
About 300/filament
Myosin - Answers The contractile protein that makes up the thick filaments of muscle fibers
Dimer of two subunits that looks like a golf club in that it has a long shaft with a globular head
Thin filaments (actin) - Answers Made up of proteins actin, tropomyosin, troponin. The main
structural component is two actin filaments
Actin - Answers A globular protein that links into chains, two of which twist helically about each
other, forming microfilaments in muscle and other contractile elements in cells.
Tropomyosin - Answers Thin double helix protein that lies end to end along the actin helix
structure. Regulatory protein that covers the actin binding sites preventing interaction of actin
and myosin
Troponin - Answers Regulatory protein complex made up of 3 polypeptides. 1 binds
tropomyosin, 1 binds actin, 1 binds Ca 2+
muscle contraction - Answers The activation of tension generating sites within muscle fibres
when a muscle contracts it shortens
sliding filament mechanism - Answers Thin filaments slide over thick filaments, by the z discs
pulling together. The I band and H zone shorten, and the A band remains the same length
concentric contraction - Answers muscle shortens
power stroke - Answers action of myosin pulling actin inward (toward the M line)
cross bridge cycle - Answers sequence of events between binding of a cross-bridge to actin, its
release, and reattachment during muscle contraction
1) binding 2) power stroke 3) detachment 4) binding
sacroplasmic reticulum - Answers specialized smooth endoplasmic reticulum, releases calcium
on demand when the muscle fiber is stimulated to contract
Runs parallel to the fibres. The lateral sacs of the SR are in close proximity to the T-tubules.
Storage sites for Ca +2
T tubules - Answers invaginations of the sarcolemma. At the junction of A & I bands, t-tubules
dip into the fibre and run perpendicular to the fibres
Acetylcholinesterase (AChE) - Answers the enzyme that breaks down acetylcholine in the
synaptic cleft
