The aims are to study interactions among organs and systems,and interaction between animal body and environment. 2 Purpose of Resreach To garsp the rule of vital activities in animal body,to prevent and treat disease in livestock and poultry effectively,and promote the development ofstockbreeding. 3 Resreach Methods 3.1 acute experiments Experiment performed on animals under anesthesia or with transection of the brain is called acute experiment: (1)in vitro:Experiments performed on an isolated tissue or organ (2)in vivo:Experiments performed on the whole body. 3.2 chronicexperiments Chronic experiments shoud be performed on a conscious subject for a long period oftime. Seaction2 Regulation of body functions Regulation:the ability of an organism to maintain a stable internal condition in a constantly changing environment Three types: 1)Chemical (hormonal)Regulation:a regulatory process performed by hormone or active chemical substance in blood or tissue. It response slowly,acts extensively and lasts for a long time. 2)Nervous Regulation:a process in which body functions are controlled byThe aims are to study interactions among organs and systems, and interaction between animal body and environment. 2 Purpose of Resreach To garsp the rule of vital activities in animal body, to prevent and treat disease in livestock and poultry effectively, and promote the development of stockbreeding. 3 Resreach Methods 3.1 acute experiments Experiment performed on animals under anesthesia or with transection of the brain is called acute experiment: （1）in vitro : Experiments performed on an isolated tissue or organ （2）in vivo : Experiments performed on the whole body. 3.2 chronic experiments Chronic experiments shoud be performed on a conscious subject for a long period of time. Seaction2 Regulation of body functions Regulation: the ability of an organism to maintain a stable internal condition in a constantly changing environment Three types: 1) Chemical (hormonal) Regulation: a regulatory process performed by hormone or active chemical substance in blood or tissue. It response slowly, acts extensively and lasts for a long time. 2) Nervous Regulation: a process in which body functions are controlled by