lecture exam 3 Flashcards
long, cylindrical, striated, multinucleated
skeletal muscle
short, spindled, non-striated, uninucleated
smooth muscle
short, branched, striated, uninucleated
cardiac muscle
functions of skeletal muscle
Maintain body temperature,Produce skeletal movements,Guard body entrances and exits, Support soft tissues, Maintain posture and body position, Provide nutrient reserves
Bundles of muscle fibers that are covered by the perimysium are known as
Fascicles
The connective tissue sheath that surrounds individual muscle cells is known as
Endomysium
The cell membrane of a muscle cell that surrounds the sarcoplasm is known as the
Sarcolemma
Lengthwise subdivisions within muscle fibers that are made up of bundles of protein filaments
Myofibrils
Thin filaments are made primarily of?
actin
thick filaments are made primarily of ?
myosin
Transmit action potential through cell and allow entire muscle fiber to contract simultaneously
T-tubules
what are Cisternae responsible for?
Concentrating Ca2+ (via ion pumps) and releasing Ca2+ into sarcoplasm to begin muscle contraction
strands of proteins that reach from tips of thick filaments to the Z line and stabilize the filaments
Titin
myosin filaments of muscle fibers slide past the troponin filaments during muscle contraction, while the two groups of filaments remain at relatively constant length
sliding filament theory
The role of troponin within the myofilament is?
bind tropomysoin over active site
The typical resting membrane potential is?
-70 mV
Compared to the cytosol, the ECF is ___________ in Na+ and _____________________
Higher, slightly positive
ATP can be generated from which precursors?
Creatine Phosphate, Pyruvate/Pyruvic Acid, Glycogen, Fatty Acids
Muscle hypertrophy can be characterized by?
Myofibril diameters increase, Muscle size increase
Muscle atrophy can be characterized by?
Muscle size decrease, Muscle fiber death
Rigor Mortis can be characterized by?
Depletion of ATP maintains actin – myosin cross-bridges, General muscle contraction following death
Origins are?
fixed
insertions are ?
moveable
Chiefly responsible for a movement
agonist
Assists to increase tension and/or stability
synergist
Maintain position and control rapid movement
antagonist
specialized contact points between cardiocytes that maintain structure, enhance molecular and electrical connections, and conduct action potentials
intercalated discs
When compared to slow muscle fibers, fast muscle fibers have?
Large glycogen reserves and few mitochondria
Muscles containing mostly fast fibers appear
White
muscles containing mostly slow fibers appear?
Red
tension rises until it exceeds the load so that the muscle shortens or lengthens
isotonic contractions
methods by which muscles can return to their orignonal resting length
Gravity, Elastic forces, Opposing muscle contractions
methods of ATP production that muscles utilize in the order from the least amount of amount of energy produced/number of twitches to the greatest amount of energy produced/number of twitches
Stored ATP, Use of creatine phosphate, From glycogen via the anaerobic pathways, From glycogen via aerobic pathways
Muscle fatigue is associated with the following identifiers
Decreasing calcium ion binding to troponin, Muscle exhaustion and pain, Depletion of metabolic reserves
A twitch can be defined as
A single stimulus-contraction-relaxation sequence
graph pf twitch tension development
myogram
the action potential moves through the sarcolema using calcium ions to be released
latent period
calcium ion binds to troponin, tension builds to a peak
contraction phase
calcium levels fall, active sites are covered, tension falls to resting levels
relaxation phase
stair-step series of contractions with increasing tension
treppe
a muscle producing almost peak tension during rapid cycles of contraction and relaxation
incomplete tetanus
when stimulation rates are so rapid there is no time for a the muscle to relax
complete tetnus
multiple nuclei
skeletal
Filament organization is in sarcomeres along myofibrils
skeletal/cardiac
SR is terminal cisternae in triads at the zones of overlap
skeletal
Control is voluntary, at a single neuromuscular junction
skeletal
Ca2+ released from the SR
skeletal
Contraction is rapidly onset
skeletal
Energy source derived from metabolism at moderate levels of activity and glycolysis
skeletal
Mostly mononucleated
cardiac
SR tubules contact T tubules at the Z lines
cardiac
Involuntary (pacemaker cells)
cardiac
Ca2+ sourced from extracellular fluid and released from the SR
cardiac/smooth
Contractions onset slowly
cardiac/smooth
Energy sourced from aerobic metabolism, derived from lipid or carbohydrate sources
cardiac
Mononucleated
smooth
Filaments are scattered throughout the sarcoplasm
smooth
SR is dispersed throughout the sarcoplasm and contains no T tubules
smooth
nvoluntary (pacesetter cells)
smooth
Energy derived from mostly from aerobic metabolism and anaerobic metabolism during peak activity
smooth
tension increases to peak but the muscle neither shortens nor lengthens
isomeric contractions
