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The _____ is the region of the eye where photoreceptors are most highly concentrated. (Activity 49A)
|
| lens |
| fovea |
| optic nerve |
| pupil |
| sclera |
|
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What name is given to the tough layer that forms the "white" of the eye? (Activity 49A)
|
| blind spot |
| choroid |
| fovea |
| sclera |
| aqueous humor |
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The _____ changes shape to focus light on the retina. (Activity 49A)
|
| vitreous humor |
| blind spot |
| cornea |
| lens |
| optic nerve |
|
|
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What name is given to the opening that allows light into the interior of the eye? (Activity 49A)
|
| sclera |
| pupil |
| ligament |
| optic nerve |
| retina |
|
|
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Which of these is a component of a human's appendicular skeleton? (Activity 49B)
|
| ribs |
| sternum |
| femur |
| skull |
| vertebral column |
|
|
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What type of joint allows you to open and close your mouth? (Activity 49B)
|
| ball and socket |
| hinge |
| pivot |
| saddle |
| none of the above |
|
|
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What type of joint allows you to shake your head "no"? (Activity 49B)
|
| ball and socket |
| hinge |
| pivot |
| saddle |
| none of the above |
|
|
|
What type of joint is found where the humerus joins the shoulder blade? (Activity 49B)
|
| ball and socket |
| hinge |
| pivot |
| saddle |
| none of the above |
|
|
|
The thick filaments of sarcomeres are composed of _____. (Activity 49C)
|
| myofibrils |
| actin |
| motor neurons |
| myosin |
| Z lines |
|
|
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The thin filaments of sarcomeres are composed of _____. (Activity 49C)
|
| myofibrils |
| actin |
| motor neurons |
| myosin |
| Z lines |
|
|
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A single muscle cell is referred to as a _____. (Activity 49C)
|
| myofibril |
| muscle fiber |
| muscle neurons |
| sarcolemma |
| sarcomere |
|
|
|
During the course of muscle contraction the potential energy stored in ATP is transferred to potential energy stored in _____. (Activity 49D)
|
| the myosin head |
| the myosin tail |
| the thin filament |
| actin |
| the Z line |
|
|
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The release of _____ ions from the sarcoplasmic reticulum is required for skeletal muscle contraction. (Activity 49D)
|
| sodium |
| phosphate |
| potassium |
| chloride |
| calcium |
|
|
|
Myosin heads bind to _____, which they then pull and cause to slide toward the center of the sarcomere. (Activity 49D)
|
| thin filaments |
| Z lines |
| sarcomeres |
| myofibrils |
| thick filaments |
|
|
|
Of these events, the first to occur when a motor neuron stops sending an impulse to a muscle is _____. (Activity 49D)
|
| the pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum |
| the release of myosin heads from the thin filament |
| thin filaments slide back to their relaxed positions |
| proteins on the thin filaments block actin's myosin-binding sites |
| all of these events occur simultaneously |
