Describe the mechanism that permits the penis to become erect.
What will be an ideal response?
A dense network of elastic fibers encircles the internal structure of the penis, surrounding three cylindrical columns of erectile tissue. This tissue is a three-dimensional maze of vascular channels incompletely separated by partitions of elastic connective tissue and smooth muscle fibers. At rest, the arterial branches are constricted and the muscular partitions are tense, reducing blood flow into the erectile tissue. Under parasympathetic stimulation the smooth muscle partitions relax, the vessels dilate, blood flow increases, the vascular channels become engorged with blood, and erection occurs.
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A) Premolars B) Incisors C) Molars D) Secondary teeth E) Cuspids
The skin appears yellowish if a person eats too much
A) melanin. B) cyanin. C) collagen. D) carotene.
The target cells of antidiuretic hormone are ____________________.
uterus and mammary glands kidney tubules prostate and ductus deferens the muscle cells the fat cells
Beaker 1 contains water at 23 degrees C. Beaker 2 contains water at 5 degrees C. Beaker 3 contains water at 95 degrees C. In which beaker will the rate of diffusion be greatest?
A) beaker 3 B) beaker 2 C) beaker 1 D) There is not enough information given to answer the question.