EXAM 3 BIO 168 QUESTIONS &
ANSWERS(RATED A+)
Three types of muscular tissue - ANSWER-skeletal muscle
-cardiac muscle
-smooth muscle
Function of skeletal muscle - ANSWER-produce skeletal movement
-maintain body position/stability
-guard body openings
-maintain body temperature
tendon or aponeurosis - ANSWERendomysium, perimysium, and epimysium come
together:
-at ends of muscles
-to form connective tissue attachment to bone matrix
-i.e., tendon (bundle) or aponeurosis (sheet)
Characteristics of skeletal muscle fibers? - ANSWER-Long, become large, contain
hundred of nuclei
-L.M. of skeletal muscle fiber (muscle cells are extremely elongated, cylindrical cells
called muscle fibers, surrounded by plasma membrane called sarcolemma)
-E.M of skeletal muscle fiber
-The skeletal muscles are voluntary and striated
Sarcolemma - ANSWER-cell membrane of a muscle cell
-surrounds the sarcoplasm (cytoplasm of muscle fiber)
-a change in transmembrane potential at the _______ begins contractions
myofibrils - ANSWER-threadlike structure longitudinally arranged
-they show cross striations, alternating dark (A) bands and light (I) bands
-parallel to each other, gives muscle fiber a striated appearance
myofilament - ANSWERtwo types:
1) thin actin
2) thick myosin
contractile proteins responsible for muscle contraction
Sarcomere - ANSWERcontractile unit of the muscle
structural unit of myofibrils
formed specially organized thin actin and thick myosin myofilaments
, structural components of sarcomeres - ANSWERz line: at 2 ends of sarcomere
where the thin filaments meet
I band: consists of only thin actin filaments
A band: consists of mainly myosin filaments and overlapping actin filaments
H zone: consists of only thick myosin filaments
M line: consists of transverse filaments at midline of sarcomere, where the thick
filaments meet
sarcoplasmic reticulum - ANSWERmembranous structure surrounding each myofibril
similar in structure to smooth endoplasmic reticulum
important to store and regulate the concentration of Ca ions within the myofibrils
located along the sides of T tubules
Transverse Tubules (T tubules) - ANSWERtransmit action potential through the cell
allow entire muscle fiber to contract simultaneously
have same properties as sarcolemma
what is a skeletal muscle triad? - ANSWERformed by 1 T tubule and 2 terminal
cistern
arrangement of the two terminal cistern and centrally situated T tubule in between
them is known as triad
located at A-I junctions
What are the three connective tissue layers in the muscular system and how are
they organized? - ANSWER3 sheaths of connective tissues organized as:
1) epimysium (surrounds whole muscle)
2) perimysium (surrounds muscle bundles, contains blood vessel and nerve supply)
3) endomysium (surrounds individual muscle cells)
4 thin filament proteins - ANSWER1) fibrous F actin: 2 twisted rows of globular G
actin, active sites on G actin strands bind to myosin
2) nebulin: holds F actin strands together
3) tropomyosin: double strand, blocks the active sites on actin, prevents actin-myosin
interaction
ANSWERS(RATED A+)
Three types of muscular tissue - ANSWER-skeletal muscle
-cardiac muscle
-smooth muscle
Function of skeletal muscle - ANSWER-produce skeletal movement
-maintain body position/stability
-guard body openings
-maintain body temperature
tendon or aponeurosis - ANSWERendomysium, perimysium, and epimysium come
together:
-at ends of muscles
-to form connective tissue attachment to bone matrix
-i.e., tendon (bundle) or aponeurosis (sheet)
Characteristics of skeletal muscle fibers? - ANSWER-Long, become large, contain
hundred of nuclei
-L.M. of skeletal muscle fiber (muscle cells are extremely elongated, cylindrical cells
called muscle fibers, surrounded by plasma membrane called sarcolemma)
-E.M of skeletal muscle fiber
-The skeletal muscles are voluntary and striated
Sarcolemma - ANSWER-cell membrane of a muscle cell
-surrounds the sarcoplasm (cytoplasm of muscle fiber)
-a change in transmembrane potential at the _______ begins contractions
myofibrils - ANSWER-threadlike structure longitudinally arranged
-they show cross striations, alternating dark (A) bands and light (I) bands
-parallel to each other, gives muscle fiber a striated appearance
myofilament - ANSWERtwo types:
1) thin actin
2) thick myosin
contractile proteins responsible for muscle contraction
Sarcomere - ANSWERcontractile unit of the muscle
structural unit of myofibrils
formed specially organized thin actin and thick myosin myofilaments
, structural components of sarcomeres - ANSWERz line: at 2 ends of sarcomere
where the thin filaments meet
I band: consists of only thin actin filaments
A band: consists of mainly myosin filaments and overlapping actin filaments
H zone: consists of only thick myosin filaments
M line: consists of transverse filaments at midline of sarcomere, where the thick
filaments meet
sarcoplasmic reticulum - ANSWERmembranous structure surrounding each myofibril
similar in structure to smooth endoplasmic reticulum
important to store and regulate the concentration of Ca ions within the myofibrils
located along the sides of T tubules
Transverse Tubules (T tubules) - ANSWERtransmit action potential through the cell
allow entire muscle fiber to contract simultaneously
have same properties as sarcolemma
what is a skeletal muscle triad? - ANSWERformed by 1 T tubule and 2 terminal
cistern
arrangement of the two terminal cistern and centrally situated T tubule in between
them is known as triad
located at A-I junctions
What are the three connective tissue layers in the muscular system and how are
they organized? - ANSWER3 sheaths of connective tissues organized as:
1) epimysium (surrounds whole muscle)
2) perimysium (surrounds muscle bundles, contains blood vessel and nerve supply)
3) endomysium (surrounds individual muscle cells)
4 thin filament proteins - ANSWER1) fibrous F actin: 2 twisted rows of globular G
actin, active sites on G actin strands bind to myosin
2) nebulin: holds F actin strands together
3) tropomyosin: double strand, blocks the active sites on actin, prevents actin-myosin
interaction
