Ch 40

Food moves along the digestive tract as the result of contractions by _____.

smooth muscle

Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers?

Fluffing creates a pocket of air near the bird that acts as insulation.

What would be an advantage for an animal that conforms to a changing environmental condition, such as temperature?

The animal would spend less energy regulating its internal temperature.

In many animals, fat is stored in specialized cells in the ________.

adipose tissue

Much of the coordination of vertebrate body functions via chemical signals is accomplished by the _____.

endocrine system

Most of the exchange surfaces of multicellular animals are lined with _____.

epithelial tissue

All types of muscle tissue have _____.

interactions between actin and myosin

When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of _____.

negative feedback

Connective tissues typically have _____.

relatively few cells and a large amount of extracellular matrix

Which of the following would increase the rate of heat exchange between an animal and its environment?

wind blowing across the body surface