Homeostasis and response

• What is homeostasis ?

  Maintaining a stable internal environment despite changing conditions 
• Why does the body need to maintain optimal conditions?

  For optimal enzyme action and cell function
• What are the 3 main components of an automatic control system?

  receptors coordination centers (brain and spinal chord) effectors
• What are the two systems which send signals around the body

  Nervous Endocrine
• What is the role of a receptor? 

  Detects changes in the internal or external environment 
• What is the role of a coordination centre? 

  Interprets changes and organises a response 
• Where are the coordination centres located in the body?

  Spinal cord and the brain
• Name the two types of effectors and state what they do.

  The two types of effectors are muscles and glands. 

  Muscles contract when stimulated, whilst glands release hormones. 
• Is the nervous system or the endocrine system faster acting? 

  nervous
• Which system acts more generally across the body, the nervous system or the endocrine system? 

  endocrine
• What is negative feedback?

  whenever the levels of something get too high they're brought back down, and whenever the levels of something get too low, they're brought back up. 
• How does negative feedback work?

  Any change in a system causes an action that reverses the change
• What passes along nerve cells?

  Electrical impulses
• What is the gap between two neurones called?

  Synapse
• What is released across a synapse?

  Chemicals
• What is the role of a receptor?

  Detects the stimulus
• What is the role of a sensory neurone?

  To transfer a signal from a receptor to the CNS
• What is the role of a motor neurone?

  To transfer a signal from the CNS to an effector
• What is the role of a relay neurone?

  To transfer a signal from a sensory neurone to a motor neurone
• What is a reflex?

  An automatic response to a stimulus
• Why are reflexes important? 

  They protect us from harm
• what do glands release ?

  hormones
• What does the pituitary gland do ?

  It releases multiple hormones 

  The hormones it releases control what other glands do
• Which gland releases thyroxine? 

  Thyroid
• What is the role of thyroxine? 

  It regulates metabolism 
• What is the role of adrenaline? 

  Stimulates fight or flight response (higher heart rate etc)
• Which organ is adrenaline released from? 

  Adrenal glands 
• Which organ is insulin released from? 

  Pancreas
• Which of the following are classed as 'sex hormones', and stimulate puberty?

  Testosterone

  Oestrogen
• Which organ is testosterone released from?

  Testes
• Do the effects of the Do the effects of the endocrine system or the nervous system last longer? or the nervous system last longer ?

   endocrine system
• What happens if blood glucose concentrations fall too low? 

  There won't be enough glucose for tissue cells to respire
• Which hormone decreases blood glucose levels? 

  insulin
• What are the two main organs that insulin stimulates to absorb glucose from the blood?

  Liver and muscles
• When glucose is absorbed by the liver for long term storage, what molecule is it converted to?

  Glycogen
• Which type of diabetes more commonly occurs in younger people, such as children and teenagers? 

  Type 1
• What is the underlying issue in type 1 diabetes?

  The pancreas doesn't release enough insulin 
• How is type 1 diabetes managed? 

  People with type 1 diabetes have to inject insulin after meals because they don't produce it themselves. They also have to monitor their diets (for example not have too much sugary food), and also exercise regularly. 
• What is the underlying issue in type 2 diabetes?

  The body's tissues become resistant to insulin
• Which organ is oestrogen released from?

  ovaries