• There are?two different control systems?in humans that work together to help us?respond?to?stimuli. These are:
  • The?nervous system
  • The?hormonal system?(also known as the?endocrine system)

   

• Changes?in our?external environment?or in the?internal environment?of our bodies act as?stimuli
• The nervous and hormonal systems?coordinate?a?suitable response?to these stimuli
• This allows us to make sense of our surroundings, to respond to the changes that occur in our surroundings and?coordinate and regulate body functions

The nervous system

• Information is sent through the nervous system as?electrical impulses?– these are electrical signals that pass along?nerve cells?known as?neurones
• These impulses travel along neurones at?very high speeds?(up to 100 metres per second)
• This allows?rapid responses?to stimuli (e.g. the?withdrawal reflex?that causes you to move your hand away extremely quickly when it touches a flame)
• The nervous system coordinates?the activities of?sensory?receptors?(eg. those in the eye),?decision-making centres in the?central nervous system?(CNS), and?effectors?such as muscles and glands
• The nervous system is used to control functions that?need instant?(or?very rapid)?responses

The human nervous system

The endocrine system

• Information is sent through the endocrine (hormonal) system as?chemical substances?known as?hormones
• Hormones are carried by the?blood?and can therefore circulate around the whole body
• Hormones transmit information from one part of the organism to another and bring about a?change?(they provide a?signal?that triggers a?response)
• They?alter?the?activity?of one or more specific?target organs
• Hormones are used to control functions that?do not need instant responses
• Hormones are produced by?endocrine glands
• The endocrine glands that produce hormones in animals are known collectively as the?endocrine system
  • A?gland?is a?group of cells?that produces and releases one or more substances (a process known as?secretion)

   

Features of the Nervous System and the Endocrine System Table

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