Exam 3 Bio 168 |77 Questions and Answers
Three types of muscular tissue - --skeletal muscle
-cardiac muscle
-smooth muscle
-Function of skeletal muscle - --produce skeletal movement
-maintain body position/stability
-guard body openings
-maintain body temperature
-What are the three connective tissue layers in the muscular system and how are they
organized? - -3 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)
-tendon or aponeurosis - -endomysium, 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? - --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 - --cell membrane of a muscle cell
-surrounds the sarcoplasm (cytoplasm of muscle fiber)
-a change in transmembrane potential at the _______ begins contractions
-myofibrils - --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 - -two types:
1) thin actin
2) thick myosin
contractile proteins responsible for muscle contraction
, -Sarcomere - -contractile unit of the muscle
structural unit of myofibrils
formed specially organized thin actin and thick myosin myofilaments
-structural components of sarcomeres - -z 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 - -membranous 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) - -transmit action potential through the cell
allow entire muscle fiber to contract simultaneously
have same properties as sarcolemma
-what is a skeletal muscle triad? - -formed 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
-4 thin filament proteins - -1) 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
Three types of muscular tissue - --skeletal muscle
-cardiac muscle
-smooth muscle
-Function of skeletal muscle - --produce skeletal movement
-maintain body position/stability
-guard body openings
-maintain body temperature
-What are the three connective tissue layers in the muscular system and how are they
organized? - -3 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)
-tendon or aponeurosis - -endomysium, 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? - --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 - --cell membrane of a muscle cell
-surrounds the sarcoplasm (cytoplasm of muscle fiber)
-a change in transmembrane potential at the _______ begins contractions
-myofibrils - --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 - -two types:
1) thin actin
2) thick myosin
contractile proteins responsible for muscle contraction
, -Sarcomere - -contractile unit of the muscle
structural unit of myofibrils
formed specially organized thin actin and thick myosin myofilaments
-structural components of sarcomeres - -z 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 - -membranous 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) - -transmit action potential through the cell
allow entire muscle fiber to contract simultaneously
have same properties as sarcolemma
-what is a skeletal muscle triad? - -formed 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
-4 thin filament proteins - -1) 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
