Without regular supplies of some hormones our capacity to behave would be seriously impaired; without others we would soon die. Tiny amounts of some hormones can modify moods and actions, our inclination to eat or drink, our aggressiveness or submissiveness, and our reproductive and parental behavior. And hormones do more than influence adult behavior; early in life they help to determine the development of bodily form and may even determine an individuals behavioral capacities. Later in life the changing outputs of some endocrine glands and the bodys changing sensitivity to some hormones are essential aspects of the phenomena of aging.
Communication within the body and the consequent integration of behavior were considered the exclusive province of the nervous system up to the beginning of the present century. The emergence of endocrinology as a separate discipline can probably be traced to the experiments of Bayliss and Starling on the hormone secretion. This substance is secreted from cells in the intestinal walls when food enters the stomach; it travels through the bloodstream and stimulates the pancreas to liberate pancreatic juice, which aids in digestion. By showing that special cells secret chemical agents that are conveyed by the bloodstream and regulate distant target organs or tissues. Bayliss and starling demonstrated that chemical integration could occur without participation of the nervous system.
The term hormone was first used with reference to secretion. Starling derived the term from the Greek hormone,meaning to excite or set in motion. The term endocrine was introduced shortly thereafter Endocrine is used to refer to glands that secret products into the bloodstream. The term endocrine contrasts with exocrine, which is applied to glands that secret their products though ducts to the site of action. Examples of exocrine glands are the tear glands,the sweat glands,and the pancreas,which secrets pancreatic juice through a duct into the intestine. Exocrine glands are also called duct glands,while endocrine glands are called ductless.
河北省2016届高考英语一轮复习学案(新人教版) Unit 4《Body language》必修4
2016届高考英语人教版一轮复习:课时作业10
2016届高考英语人教版一轮复习:课时作业12
2016届高考英语人教版一轮复习:课时作业1
山西省2016届高考英语一轮复习学案(新人教版) Uint 3《Under the sea》选修7
山西省2016届高考英语一轮复习学案(新人教版) Uint 4《Body language》必修4
山西省2016届高考英语一轮复习学案(新人教版) Uint 5《First aid》必修5
山西省2016届高考英语一轮复习学案(新人教版) Uint 4《Making the news》必修5
河北省2016届高考英语一轮复习学案(新人教版) Unit 3《The Million Pound Bank Note》必修3
山西省2016届高考英语一轮复习学案(新人教版) Uint 4《Sharing》选修7
2016届高考英语人教版一轮复习:课时作业16
山西省2016届高考英语一轮复习学案(新人教版) Uint 5《Meeting your ancestors》选修8
山西省2016届高考英语一轮复习学案(新人教版) Uint 5《Canada—“The True North”》必修3
河北省2016届高考英语一轮复习学案(新人教版) Unit 1《Friendship》必修1
2016届高考英语人教版一轮复习:课时作业9
山西省2016届高考英语一轮复习学案(新人教版) Uint 4《Pygmalion》选修8
河北省2016届高考英语一轮复习学案(新人教版) Unit 2《Healthy eating》必修3
山西省2016届高考英语一轮复习学案(新人教版) Uint 5《Theme parks》必修4
河北省2016届高考英语一轮复习学案(新人教版) Unit 3《Travel journal》必修1
2016届高考英语人教版一轮复习:课时作业3
山西省2016届高考英语一轮复习学案(新人教版) Uint 4《Earthquake》必修1
2016届高考英语人教版一轮复习:课时作业2
山西省2016届高考英语一轮复习学案(新人教版) Uint 5《Travelling abroad》选修7
河北省2016届高考英语一轮复习学案(新人教版) Unit 3《A taste of English humour》必修4
山西省2016届高考英语一轮复习学案(新人教版) Uint 4《Wildlife Protection》必修2
2016届高考英语人教版一轮复习:课时作业7
2016届高考英语人教版一轮复习:课时作业4
河北省2016届高考英语一轮复习学案(新人教版) Unit 2《English around the world 》必修1
河北省2016届高考英语一轮复习学案(新人教版) Unit 1《Great Scientists》必修5
河北省2016届高考英语一轮复习学案(新人教版) Unit 2《The Unit ed Kingdom》必修5
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