Muscle, bone, skin

Front

Back

"What are the three types of muscle tissue?"

"Skeletal

"What are the three major functions of muscle?"

"Body movement/support

"Which muscle type is voluntary?"

"Skeletal muscle."

"Which muscle types are involuntary?"

"Cardiac and smooth muscle."

"Which muscle type is striated and multinucleated?"

"Skeletal muscle."

"Which muscle type is striated and branched?"

"Cardiac muscle."

"Which muscle type is non-striated and spindle-shaped?"

"Smooth muscle."

"Why are skeletal muscle fibers multinucleated?"

"They undergo mitosis without cytokinesis."

"Which nervous system controls skeletal muscle?"

"Somatic nervous system."

"Which nervous system controls smooth muscle?"

"Autonomic nervous system."

"What connects muscle to bone?"

"Tendon."

"What connects bone to bone?"

"Ligament."

"What is the origin of a muscle?"

"The attachment point on the stationary bone."

"What is the insertion of a muscle?"

"The attachment point on the moving bone."

"What happens during muscle contraction?"

"The origin and insertion move closer together."

"What happens during muscle extension?"

"The origin and insertion move farther apart."

"What is a flexor muscle?"

"A muscle that decreases the angle of a joint."

"What is an extensor muscle?"

"A muscle that increases the angle of a joint."

"Besides moving bones

what else does skeletal muscle help move?"

"What involuntary process uses skeletal muscle to produce heat?"

"Shivering."

"What is the functional unit of skeletal muscle?"

"The sarcomere."

"What are the thick filaments in a sarcomere?"

"Myosin."

"What are the thin filaments in a sarcomere?"

"Actin."

"What protein binds calcium during contraction?"

"Troponin."

"What protein blocks myosin-binding sites on actin?"

"Tropomyosin."

"What is the function of titin?"

"Anchors myosin to the Z-disc and provides elasticity."

"What marks the boundaries of a sarcomere?"

"Z-discs."

"What is located at the center of a sarcomere?"

"The M-line."

"What does the I-band contain?"

"Only thin (actin) filaments."

"What does the H-zone contain?"

"Only thick (myosin) filaments."

"What does the A-band represent?"

"The entire length of the myosin filaments."

"Which bands shorten during contraction?"

"The I-band and H-zone."

"What happens to the A-band during contraction?"

"It remains the same length."

"Why does the A-band remain constant during contraction?"

"The myosin filaments do not shorten; actin slides over them."

"What is a myofibril?"

"A chain of sarcomeres arranged end-to-end."

"What surrounds each myofibril?"

"Sarcolemma and sarcoplasmic reticulum."

"What is the sarcolemma?"

"The plasma membrane of a muscle fiber."

"What are T-tubules?"

"Invaginations of the sarcolemma that conduct action potentials deep into the muscle."

"What is the sarcoplasmic reticulum?"

"A specialized smooth ER that stores calcium ions."

"What is a muscle fiber?"

"A single multinucleated muscle cell."

"What is a fascicle?"

"A bundle of muscle fibers."

"What is a muscle?"

"A collection of fascicles."

"What is the neuromuscular junction (NMJ)?"

"The synapse between a motor neuron and a skeletal muscle fiber."

"Is the neuromuscular junction a chemical or electrical synapse?"

"Chemical synapse."

"What neurotransmitter is released at the NMJ?"

"Acetylcholine (ACh)."

"What part of the muscle membrane receives acetylcholine?"

"The motor end plate."

"After ACh binds its receptor

what happens next?"

"Where does the muscle action potential travel after the sarcolemma?"

"Down the T-tubules."

"What does the action potential trigger in the sarcoplasmic reticulum?"

"Release of calcium ions."

"What is the immediate effect of calcium release into the cytoplasm?"

"Initiation of muscle contraction."

Front

Back

"What event initiates cross-bridge cycling?"

"Calcium ions are released from the sarcoplasmic reticulum."

"What protein does calcium bind to during muscle contraction?"

"Troponin."

"What happens when calcium binds troponin?"

"Troponin changes shape

"What is a cross-bridge?"

"The attachment of a myosin head to an actin filament."

"What molecules are bound to myosin in its high-energy state?"

"ADP and inorganic phosphate (Pi)."

"What causes the power stroke?"

"Release of ADP and Pi from the myosin head."

"What occurs during the power stroke?"

"The myosin head pivots

"What binds to myosin to release it from actin?"

"ATP."

"What happens if ATP is unavailable?"

"Myosin remains attached to actin

"What restores the myosin head to the high-energy position?"

"Hydrolysis of ATP into ADP and Pi."

"What pump returns calcium to the sarcoplasmic reticulum?"

"Ca2+-ATPase (SERCA)."

"Why is ATP required for muscle relaxation?"

"ATP powers calcium reuptake and releases myosin from actin."

"What enzyme degrades acetylcholine in the neuromuscular junction?"

"Acetylcholinesterase."

"What are the three major roles of ATP in muscle contraction?"

"Powering the myosin head

"What causes rigor mortis after death?"

"ATP depletion prevents myosin from detaching from actin."

"What is muscle fatigue?"

"Loss of contractile ability due to prolonged activity and insufficient ATP production."

"What causes oxygen debt?"

"Muscles require more oxygen than is available during strenuous exercise."

"What metabolic pathway predominates during oxygen debt?"

"Anaerobic glycolysis."

"What is the net ATP yield of glycolysis?"

"2 ATP per glucose."

"Why does fermentation occur during anaerobic exercise?"

"To regenerate NAD+ so glycolysis can continue."

"What is the end product of lactic acid fermentation in muscle?"

"Lactate."

"What happens to lactate after oxygen becomes available?"

"It is converted back to pyruvate for aerobic metabolism."

"Which muscle fibers are slow-twitch?"

"Type I fibers."

"Which muscle fibers are fast-twitch?"

"Type II fibers."

"Which muscle fiber type is most fatigue resistant?"

"Type I."

"Which muscle fiber type produces the greatest force?"

"Type II."

"Which muscle fiber type relies primarily on aerobic metabolism?"

"Type I."

"Which muscle fiber type relies primarily on anaerobic metabolism?"

"Type II."

"Which muscle fiber type contains more mitochondria?"

"Type I."

"Which muscle fiber type contains more myoglobin?"

"Type I."

"Why are Type I fibers red?"

"High myoglobin content and abundant mitochondria."

"Why are Type II fibers white?"

"Lower myoglobin content."

"Which athletes typically have more Type I fibers?"

"Marathon runners."

"Which athletes typically have more Type II fibers?"

"Sprinters."

"What is a motor unit?"

"A motor neuron and all the muscle fibers it innervates."

"How is muscle force increased?"

"By recruiting additional motor units."

"What type of muscle cells are connected by intercalated discs?"

"Cardiac muscle cells."

"What structures within intercalated discs allow electrical coupling?"

"Gap junctions."

"Which muscle type is branched?"

"Cardiac muscle."

"Which muscle type performs peristalsis?"

"Smooth muscle."

"What is the primary function of smooth muscle?"

"Move substances through hollow organs."

"How many bones are in the adult human skeleton?"

"206."

"What are the four major functions of bone?"

"Support

"What mineral is primarily stored in bone?"

"Calcium as hydroxyapatite."

"What phosphate-containing mineral makes bone rigid?"

"Hydroxyapatite."

"Which organ produces blood cells inside bones?"

"Red bone marrow."

"What type of tissue is found in bone marrow besides stem cells?"

"Adipose tissue."

"What is an endoskeleton?"

"An internal skeleton made of bone and cartilage."