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. |