What Arctic animals use countercurrent circulation? Where in those animals is it most conspicuous?
What will be an ideal response?
Countercurrent systems in the legs transfer heat from arterial blood that is warm because it is leaving the body core to venous blood that is cold because it is returning from the appendages, especially the legs and feet. Countercurrent circulation is most effective in relatively large animals because their legs are long enough to allow a substantial amount of heat to be transferred.
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Describe the development of reproductive organs in a fetus of each gender. Which genes, gene products, and hormones are involved in the sex differences? Which sex-related hormones are circulating in high concentrations in a pregnant woman compared to a nonpregnant woman? Do these hormones cross the placenta (if you are uncertain, consider hormone chemical class relative to membrane permeability to make an educated guess)? Assuming these hormones do cross the placenta, how do they affect the hormonal environment inside the fetus, and how does this relate to fetal reproductive development?
What will be an ideal response?
Which statements are correct concerning the parasympathetic division of the ANS?
a: Contains preganglionic cell bodies in brainstem nuclei b: Contains preganglionic cell bodies in the lateral horns of the T1-L2 regions c: Participates in the "fight-or-flight" response d: Helps maintain homeostasis e: Contains preganglionic cell bodies in the sacral region of the spinal cord A. a, d, e B. a, c, e C. b, c, d D. b, c E. c, d, e
Cerebrospinal fluid is produced by ________.
Fill in the blank(s) with the appropriate word(s).
What is the function of ependymal cells?
A. They produce the myelin sheath around axons of the peripheral nervous system. B. They are the phagocytes of the brain. C. They support the cell bodies of neurons in peripheral ganglia. D. They produce cerebrospinal fluid, and circulate it around the brain and spinal cord. E. They produce the myelin sheath around axons of the central nervous system.