Bio Ch49 Activities Quiz – Flashcards
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The _____ is the region of the eye where photoreceptors are most highly concentrated.
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fovea
( Photoreceptors are most highly concentrated in the region of the retina known as the fovea.)
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What name is given to the tough layer that forms the "white" of the eye?
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sclera
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The _____ changes shape to focus light on the retina.
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lens
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What name is given to the opening that allows light into the interior of the eye?
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pupil
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Which of these is a component of a human's appendicular skeleton?
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femur
( The femur, the thigh bone, is a component of the appendicular skeleton.)
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What type of joint allows you to open and close your mouth?
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hinge
The joint between the temporal bone and the mandible is a hinge joint.
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What type of joint allows you to shake your head "no"?
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pivot
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What type of joint is found where the humerus joins the shoulder blade?
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ball and socket
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The thick filaments of sarcomeres are composed of _____.
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myosin
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The thin filaments of sarcomeres are composed of _____.
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actin
( Thin filaments are composed of actin.)
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A single muscle cell is referred to as a _____.
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muscle fiber
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During the course of muscle contraction the potential energy stored in ATP is transferred to potential energy stored in _____.
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the myosin head
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The release of _____ ions from the sarcoplasmic reticulum is required for skeletal muscle contraction.
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calcium
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Myosin heads bind to _____, which they then pull and cause to slide toward the center of the sarcomere.
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thin filaments
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Of these events, the first to occur when a motor neuron stops sending an impulse to a muscle is _____.
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the pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum
( This is the first of the events that ultimately result in the relaxation of a muscle.)
