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Friday, October 2, 2009

How is body heat regulated?

How is body heat regulated?
The thermoregulatory center is composed of two parts. The rostral part is a heat loss center
that is parasympathetic. The caudal part is a heat production center that is sympathetic.
Peripheral thermoreceptors in the skin and internal receptors in the abdomen and central nervous system (eNS) along with the thermoregulatory centers help to maintain a delicate balance between heat loss and production.

What is fever?

What is fever?
Fever is an increased core body temperature due to resetting of the hypothalamic thermoregulatory center to a higher temperature. The thermoregulatory center is located in the preoptic region of the rostral hypothalamus.

Tuesday, August 18, 2009

The Meller's chameleon

is the largest of the chameleons not native to Madagascar. Their stout bodies can grow to be up to two feet (two-thirds of a meter) long and weigh more than a pound (one-half kilogram).
Meller's distinguish themselves from their universally bizarre-looking cousins with a single small horn protruding from the front of their snouts. This and their size earn them the common name "giant one-horned chameleon."
They are fairly common in the savanna of East Africa, including Malawi, northern Mozambique, and Tanzania. Almost one-half of the world’s chameleons live on the island of Madagascar.
As with all chameleons, Meller's will change colors in response to stress and to communicate with other chameleons. Their normal appearance is deep green with yellow stripes and random black spots. Females are slightly smaller, but are otherwise indistinguishable from males.