chemical signals released into bloodstream and broadcast throughout body.
What effect does hormones have on cells and why?
Different hormones causes specific effects, only in cells with receptors specific to the release hormone.
What is the function of neurons? What are the only other two types of cells that receive nerve impulses?
to transmit info between specific locations. (neurons, muscle cells, endocrine cells)
What two major organ systems specialize in control and coordination? What is their function?
Endocrine-> hormones are released and cast throughout the body. Nervous-> neurons transmit info between specific locations.
What is the purpose of Feedback control loops?
maintain internal environment in many animals
animals maintain a relatively constant internal environment even when external environment changes significantly.
Purpose of having a set point?
like a body temp, sensors detect any stimulus above or below set point, physiological response that helps return the body to its set point.
Difference between negative feedback systems and positive feedback systems? examples.
negative... response reduces stimulus. (opposite) ex. temp control positive... response amplifies the change instead of reversing. (same) ex. childbirth.. pressure of babes head stimulates greater contractions, which cause greater pressure against uterine opening, heightens contractions, ect.
animals maintain internal temp. within a tolerable range
Whats the difference between Endotherms and Ectotherms?
Endotherms-> mammals and birds, heat generated by metabolism. Ectotherms-> invertebrates, fish, reptiles, amphibians, gain most heat from external sources (generate little metabolic heat)
Explain countercurrent exchange.
blood vessels flowing in opposite directions transfer heat so that warm blood from core of animal heading out to the extremities transfers heat to the colder blood returning. Heat that would have been lost to the environment is conserved and returned to core of animal. (relied on for the reduction of heat loss)