Discuss the three components of the cytoskeleton
What will be an ideal response?
1) Microtubules, the largest of the cytoskeletal elements, are long, hollow tubes formed by two slightly different variants of globular-shaped tubulin molecules.
2) Most microfilaments, the smallest of the cytoskeletal elements, consist of two chains of actin molecules wrapped around each other.
3) The intermediate filament keratin, found in skin, is made of four keratin protofibrils twisted together. A protofibril consists of two strands, each made up of two staggered rows of keratin subunits. The composition of intermediate filaments, which are intermediate in size between the microtubules and microfilaments, varies among different cell types.
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The duct initially draining the bile from the gallbladder is the ____________________.
Fill in the blank(s) with the appropriate word(s).
Which statement is not true of nerves that supply the kidney?
A. They consist mostly of sympathetic fibers. B. They stimulate renin secretion. C. They function to regulate blood flow into and out of the glomerulus. D. Fibers originate in the superior mesenteric ganglion. E. They consist mostly of parasympathetic fibers.
Cartilage tissues are likely to be slow in healing following an injury because
A) chondrocytes cannot divide. B) chondrocytes do not have direct blood supplies. C) cartilage cells are immersed in fluids. D) the intercellular material is semisolid.
An increase in smooth muscle tension can occur at a given intracellular [Ca++] in response to:
A. opening K+ channels in the smooth muscle membrane B. inhibition of myosin phosphatase by Rho kinase in the smooth muscle C. cAMP-dependent phosphorylation of myosin light chain kinase in the smooth muscle D. release of nitric oxide from adjacent endothelial cells E. hyperpolarization of the smooth muscle membrane