SLCC Physiology Exam 3 (Ch. 12-16)
UPDATED ACTUAL Questions and
CORRECT Answers
Sarcolemma - CORRECT ANSWER - surrounding cell membrane around muscle
Sarcoplasmic reticulum - CORRECT ANSWER - The smooth ER of a muscle cell, Ca2+
reservoir, around each myofibril in the muscle cell.
myofibrils - CORRECT ANSWER - bundle of contractile proteins within muscle
sarcomere - CORRECT ANSWER - functional unit of muscle within myofibrils
Z lines - CORRECT ANSWER - dense set of proteins, has actin protein
M line - CORRECT ANSWER - not quite as dense, myosin protein stays in the middle
A band - CORRECT ANSWER - from one end to another of myosin, partial overlap of
actin/myosin
H zone - CORRECT ANSWER - only where myosin, no overlap of actin in M line
I band - CORRECT ANSWER - one end of myosin in one sarcomere, only overlap of
actin, no myosin
myosin - CORRECT ANSWER - thick filaments. shortens both sides of myofibril, pulls
actin toward M line, decreases H zone, shortens I band
,actin - CORRECT ANSWER - thin filaments. made of subunits, has myosin binding sites
tropomyosin - CORRECT ANSWER - controlled by actin, long filament, when muscle is
relaxed, covers binding sites of actin
troponin - CORRECT ANSWER - changes shape when Ca binds to it. pulls tropomyosin
from binding sites and exposes actin binding sites. controlls tropomyosin
Ca controls ___________ - CORRECT ANSWER - contraction
titin - CORRECT ANSWER - acts like anchor to anchor myosin to z lines on both sides
sliding filament model - CORRECT ANSWER - The idea that muscle contraction is based
on the movement of thin (actin) filaments along thick (myosin) filaments, shortening the
sarcomere
Cross-bridge cycle - CORRECT ANSWER - 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 - CORRECT ANSWER --
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? - CORRECT ANSWER - No
termination of contraction - CORRECT ANSWER - calcium gets pumped quickly back
into SR, stops sending signal
isometric and isotonic twitches - CORRECT ANSWER - ...
summation and tetanus - CORRECT ANSWER - 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 - CORRECT ANSWER - increased diameter --> increased myofibrils in
parallel --> increased force production
length and tension - CORRECT ANSWER - 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 - CORRECT ANSWER - a single motor neuron and all muscle fibers
innervated by it
muscle recruitment - CORRECT ANSWER - increase in the # of motor units being used to
increase strength of contraction
What are the 3 muscle fiber types? - CORRECT ANSWER - Slow oxidative, fast
oxidative, fast glycolytic
Slow oxidative - CORRECT ANSWER - Makes a lot of ATP, fatiques slowly, has to have
oxygen, small diameter, little tension, darkest color. Lots of blood taking oxygen using
myoglobin.
UPDATED ACTUAL Questions and
CORRECT Answers
Sarcolemma - CORRECT ANSWER - surrounding cell membrane around muscle
Sarcoplasmic reticulum - CORRECT ANSWER - The smooth ER of a muscle cell, Ca2+
reservoir, around each myofibril in the muscle cell.
myofibrils - CORRECT ANSWER - bundle of contractile proteins within muscle
sarcomere - CORRECT ANSWER - functional unit of muscle within myofibrils
Z lines - CORRECT ANSWER - dense set of proteins, has actin protein
M line - CORRECT ANSWER - not quite as dense, myosin protein stays in the middle
A band - CORRECT ANSWER - from one end to another of myosin, partial overlap of
actin/myosin
H zone - CORRECT ANSWER - only where myosin, no overlap of actin in M line
I band - CORRECT ANSWER - one end of myosin in one sarcomere, only overlap of
actin, no myosin
myosin - CORRECT ANSWER - thick filaments. shortens both sides of myofibril, pulls
actin toward M line, decreases H zone, shortens I band
,actin - CORRECT ANSWER - thin filaments. made of subunits, has myosin binding sites
tropomyosin - CORRECT ANSWER - controlled by actin, long filament, when muscle is
relaxed, covers binding sites of actin
troponin - CORRECT ANSWER - changes shape when Ca binds to it. pulls tropomyosin
from binding sites and exposes actin binding sites. controlls tropomyosin
Ca controls ___________ - CORRECT ANSWER - contraction
titin - CORRECT ANSWER - acts like anchor to anchor myosin to z lines on both sides
sliding filament model - CORRECT ANSWER - The idea that muscle contraction is based
on the movement of thin (actin) filaments along thick (myosin) filaments, shortening the
sarcomere
Cross-bridge cycle - CORRECT ANSWER - 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 - CORRECT ANSWER --
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? - CORRECT ANSWER - No
termination of contraction - CORRECT ANSWER - calcium gets pumped quickly back
into SR, stops sending signal
isometric and isotonic twitches - CORRECT ANSWER - ...
summation and tetanus - CORRECT ANSWER - 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 - CORRECT ANSWER - increased diameter --> increased myofibrils in
parallel --> increased force production
length and tension - CORRECT ANSWER - 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 - CORRECT ANSWER - a single motor neuron and all muscle fibers
innervated by it
muscle recruitment - CORRECT ANSWER - increase in the # of motor units being used to
increase strength of contraction
What are the 3 muscle fiber types? - CORRECT ANSWER - Slow oxidative, fast
oxidative, fast glycolytic
Slow oxidative - CORRECT ANSWER - Makes a lot of ATP, fatiques slowly, has to have
oxygen, small diameter, little tension, darkest color. Lots of blood taking oxygen using
myoglobin.
