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Bio Test 2
Chapter 44. Muscular System
| Term | Definition |
|---|---|
| Locomotion | movement of an animal from place to place |
| Skeleton | structure that serves one or more functions related to support, protection, and locomotion |
| 3 Types of skeletons | hydrostatic, exoskeleton, and endoskeleton |
| Hydrostatic | combination of muscles and water-based fluid in the body. |
| How Hydrostatic works | Animal exerts force on the fluid that fills its body cavities, uses the resulting hydrostatic pressure to move the body |
| Exoskeleton | surrounds and protects most of the body surface. Protection from environment and predators. |
| Exoskeleton is made of | chitin |
| Exoskeleton allows for | growth |
| Disadvantage of exoskeleton | during shedding, temporarily soft making animal vulnerable. |
| Endoskeleton | provides support and protection. Protects internal structure. Doesn't protect the body surface. Protects internal organs |
| 2 parts of vertebrate endoskeleton | axial and appendicular |
| Axial skeleton | composed of bones that form the main longitudinal axis of an animal's body. Consists of skull, vertebrate, sternum and ribs |
| Appendicular skeleton | limb or fin bones and bones that connect them to axial skeleton. |
| Joint | formed where two or more bones come together |
| 3 Types of Joints | pivot, hinge, and ball-and-socket |
| Pivot joint | moving bone rotate within a ring formed from a second bone |
| Hinge joint | formed between 2 or more bones where the bones can only move along one axis to flex or extend |
| Ball-and-socket | a partially spherical end lies in a socket allowing multidirectional movement and rotation |
| Bone | living dynamic tissue with both organic and mineral components |
| Osteoblast and osteocytes | cells that form bone |
| osteoclasts | cells that break down bone |
| Collagen | gives bone strength and flexibility |
| Mineral component of bone | calcium and phosphate |
| 3 types of muscle | cardiac, smooth and skeletal |
| cardiac muscle | found in heart. Provides force required for the heart to pump blood |
| smooth muscle | surrounds and forms part of the lining of hollow organs and tubes |
| skeletal muscle | found throughout the body and directly involved in locomotion |
| In vertebrates, skeletal muscle is | electrically excitable |
| Action potentials results in increased concentrations of | calcium ions which trigger force generation |
| Muscle fibers | grouping of cells. Bound together in bundles by a succession of connective tissue layers |
| Tendons | bundles of collagen fibers. Links skeletal muscle to bone |
| Each skeletal muscle fiber is a | single cell with multiple nuclei |
| Skeletal muscle fiber is made of numerous cylindrical bundles called | myofibrils |
| Each myofibril contains numerous | thick and thin filaments |
| Thick filament | myosin |
| Thin filament | actin |
| Sarcomere | one complete unit of a repeating pattern on a myofibril |
| Order of muscle structure | muscle, fascicle (bundle of muscle fibers), muscle fiber, myofibril, actin and myosin |
| cross-bridges | spaces between overlapping actin and myosin filaments |
| During muscle contraction cross-bridges make contact with the thin filament and | exerts force on them |
| Calcium attaches to which molecule? | Troponin |
| Which molecule blocks the myosin from attaching to the actin? | Tropomyosin |
| Part of myosin that makes contact with actin | myosin head |
| Which energy molecule breaks the bond between actin and myosin | ATP |
| ATP breaks up into | ADP and P |
| Excitation | sequence of events by which an action potential in the plasma membrane of a muscle fiber leads to cross-bridge coupling. |
| Mechanism by which action potentials are initiated in a skeletal muscle involves stimulation by a | motor neuron |
| Neuromuscular junction | site where a motor neuron's axon synapses with a muscle fiber |
| Motor end plate | region of the muscle fiber plasma membrane that lies directly under the axon terminal |
| Synaptic cleft | extracellular space between the axon terminal and motor end plate |
| Different muscle fibers contain forms of myosin that differ in the | maximal rates at which they can hydrolyze ATP |
| Even though maximal rate is different the maximal ______ is the same | force |
| Slow fibers | fibers containing myosin with low ATPase activity |
| Fast fibers | fibers containing myosin with high ATPase activity |
| Oxidative fibers | contain numerous mitochondria and have a high capacity for oxidative phosphorylation. |
| Oxidative fibers contain large amounts of | myoglobin which is an oxygen-binding protein |
| Glycolytic fibers | contain few mitochondria but possess both a high concentration of proteins involved in glycolysis and glycogen (storage form of glucose) |
| Glycolytic fibers contain small amounts of | myoglobin which is an oxygen-binding protein |
| Slow-oxidative fibers have _____ ______ of myosin ATPase activity | low rates |
| Slow-oxidative fibers are good for | prolonged, regular types of movement |
| Fast-oxidative fibers have _____ ______ of myosin ATPase activity | high rates |
| Fast-oxidative fibers are good for | long-term activities with rapid actions |
| Fast- glycolytic fibers have _____ ______ of myosin ATPase activity | high rates |
| Fast-glycolytic fibers are good for | rapid intense actions |
| Increase in muscle size is because of an increase in the size of _____ ______ and not an increase in the number of muscle fibers | each fiber |
| Atrophy | reduction in the size of the muscle. Decline of muscular activity results in this condition |
| Flexors | muscles that bend a limb at a joint |
| Extensors | muscle that straighten a limb at a joint |
| Antagonists | groups of muscles that produce oppositely directed movement at a joint |
| I band | actin only |
| A band | myosin only. Thick |
| H zone | myosin only. Thin |
| Z line | anchor |
| M line | down the middle of the H zone |
| Contraction | I band and H zone reduced. A band unchanged |
| Action potential travels down | transverse tubules |
| Sarcoplasmic reticulum | releases calcium |
| Osteoporosis | condition in which both the mineral and organic portions of bone are reduced |
| Myasthenia gravis | disease characterized by skeletal muscle fatigue and weakness |
| ACh | Acetylcholine |
| Muscular dystrophy | progressive degeneration of skeletal and cardiac muscle fibers. |
Created by:
Gianna B
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