When blood calcium levels are low, pth stimulates:
excretion of calcium from the kidneys.
excretion of calcium from the intestines.
osteoblasts.
osteoclasts.

Which would be an adaptation in a rainforest, but not in a tundra? a. ability to store water for a long time b. fur that blends in with snow c. strong claws for killing prey d. a beak that can dig into thick trees

Describe the relationship between isotonic solutions, equilibrium, and water movement into and out of a cell.

Choose the incorrect statement (a) the motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials. (b) propagation of an action potential through the t-tubules into the sarcoplasmic reticulum triggers the release of ca++ into the cytoplasm of a skeletal muscle fiber. (c) the generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron. (d) a greater amount of ach would be found in the presynaptic vesicles of a motor unit that fired several action potentials after exposure to botulinum toxin, than in a motor unit that fired several action potentials after exposure to the venom of the krait snake (which contains α-bungarotoxin).