Define lever, and describe the three classes of levers
What will be an ideal response?
A lever is a rigid structure — such as a board, a pry bar, or a bone — that moves on a fixed point called the fulcrum. There are three classes of levers: In a first-class lever, the fulcrum lies between the applied force and the load; in a second-class lever; the load lies between the fulcrum and applied force; and in a third-class lever, the applied force is between the fulcrum and the load. Third-class levers are the most common type in the body.
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In the diagram, which organelle aids movement of the cell?
a) A b) G c) H d) D e) I
Which of the following tissues are classified as "connective tissue proper"? 1. areolar connective tissue 2. adipose tissue 3. fibrocartilage 4. dense irregular connective tissue
A) 3 and 4 B) 1, 2, and 3 C) 1 and 2 D) 1, 2, and 4 E) 1 and 3
Which of the following statements best describes the structure of the blood-brain barrier that provides its functional characteristics?
a) Processes of astrocytes wrap tightly around capillaries in the brain. b) Tight junctions tightly seal endothelial cells of capillaries in the brain. c) Gap junctions tightly seal endothelial cells of capillaries in the brain. d) Spot desmosomes tightly link capillary endothelial cells together. e) The basement membrane of capillaries in the brain contains extremely small pores.
The function of the urinary bladder is to
A. produce urine. B. store sperm and semen. C. store urine until it is expelled. D. None apply.