SLCC Physiology Exam 3 (Ch. 12-16)
Questions With Complete Solutions
I band one end of myosin in one sarcomere, only overlap of actin, no myosin
myosin thick filaments. shortens both sides of myofibril, pulls actin toward M line,
decreases H zone, shortens I band
actin thin filaments. made of subunits, has myosin binding sites
tropomyosin controlled by actin, long filament, when muscle is relaxed, covers binding
sites of actin
troponin changes shape when Ca binds to it. pulls tropomyosin from binding sites and
exposes actin binding sites. controlls tropomyosin
Ca controls ___________ contraction
titin acts like anchor to anchor myosin to z lines on both sides
, SLCC Physiology Exam 3 (Ch. 12-16)
Questions With Complete Solutions
sliding filament model The idea that muscle contraction is based on the movement of thin
(actin) filaments along thick (myosin) filaments, shortening the sarcomere
Cross-bridge cycle myosin grabs actin, pulls actin toward cent of sarcomere (towards m
line), ATP provides energy to detach myosin head and cock it back to original shape, process
repeats.
No calcium- no contraction
No ATP- no release
excitation-contraction coupling of skeletal muscle -depolarization of sarcolemma
(excitation)
-depolarization of T-tubule
-DHP receptors in membrane respond to voltage change
-release of calcium from sarcoplasmic reticulum
-calcium binds to troponin which moves topomyosin away from the binding sites
-cross bridge cycle (contraction of muscle)
Does skeletal muscle have pacemaker cells? No
, SLCC Physiology Exam 3 (Ch. 12-16)
Questions With Complete Solutions
termination of contraction calcium gets pumped quickly back into SR, stops sending
signal
isometric and isotonic twitches ...
summation and tetanus 1. summation is where muscle contractions combine and become
stronger and more prolonged
2. tetatnus is the continous sustained contraction where muscle cannot relax. will release if
maintained.
fiber diameter increased diameter --> increased myofibrils in parallel --> increased force
production
length and tension Max length that skeletal muscle can be stretched (stretched too far it
loses the ability to contract b/c actin and myosin heads are too far to bind)
motor units a single motor neuron and all muscle fibers innervated by it
Questions With Complete Solutions
I band one end of myosin in one sarcomere, only overlap of actin, no myosin
myosin thick filaments. shortens both sides of myofibril, pulls actin toward M line,
decreases H zone, shortens I band
actin thin filaments. made of subunits, has myosin binding sites
tropomyosin controlled by actin, long filament, when muscle is relaxed, covers binding
sites of actin
troponin changes shape when Ca binds to it. pulls tropomyosin from binding sites and
exposes actin binding sites. controlls tropomyosin
Ca controls ___________ contraction
titin acts like anchor to anchor myosin to z lines on both sides
, SLCC Physiology Exam 3 (Ch. 12-16)
Questions With Complete Solutions
sliding filament model The idea that muscle contraction is based on the movement of thin
(actin) filaments along thick (myosin) filaments, shortening the sarcomere
Cross-bridge cycle myosin grabs actin, pulls actin toward cent of sarcomere (towards m
line), ATP provides energy to detach myosin head and cock it back to original shape, process
repeats.
No calcium- no contraction
No ATP- no release
excitation-contraction coupling of skeletal muscle -depolarization of sarcolemma
(excitation)
-depolarization of T-tubule
-DHP receptors in membrane respond to voltage change
-release of calcium from sarcoplasmic reticulum
-calcium binds to troponin which moves topomyosin away from the binding sites
-cross bridge cycle (contraction of muscle)
Does skeletal muscle have pacemaker cells? No
, SLCC Physiology Exam 3 (Ch. 12-16)
Questions With Complete Solutions
termination of contraction calcium gets pumped quickly back into SR, stops sending
signal
isometric and isotonic twitches ...
summation and tetanus 1. summation is where muscle contractions combine and become
stronger and more prolonged
2. tetatnus is the continous sustained contraction where muscle cannot relax. will release if
maintained.
fiber diameter increased diameter --> increased myofibrils in parallel --> increased force
production
length and tension Max length that skeletal muscle can be stretched (stretched too far it
loses the ability to contract b/c actin and myosin heads are too far to bind)
motor units a single motor neuron and all muscle fibers innervated by it
