1. The nervous system and the endocrine system
Pages
Biopsychology
Specification details
The divisions of the nervous system: central and peripheral (somatic and autonomic).
The function of the endocrine system: glands and hormones.
The fight or flight response including the role of adrenaline.

2. The nervous system
Biopsychologists assume that behaviour and experiences are caused by activity in the nervous system
The nervous system is a specialised network of cells in the human body and is our primary internal communication system
It has two main functions:
To collect, process and respond to information in the environment
To co-ordinate the working of different organs and cells

3. The major sub-divisions of the human nervous system
Peripheral nervous system (PNS)
Central nervous system (CNS)
Autonomic nervous system
Somatic nervous system
Brain
Spinal cord
Sympathetic nervous system
Parasympathetic nervous system
Print this sheet for students to complete
The major sub-divisions of the human nervous system

4. The major sub-divisions of the human nervous system
Peripheral nervous system (PNS)
Central nervous system (CNS)
Autonomic nervous system
Somatic nervous system
Brain
Spinal cord
Sympathetic nervous system
Parasympathetic nervous system
The major sub-divisions of the human nervous system

5. The central nervous system (CNS)
The CNS is made up of the brain and the spinal cord
The brain is the centre of all conscious awareness. The brain’s outer layer, the cerebral cortex, is highly developed in humans
The brain is divided in two hemispheres
The spinal cord is an extension of the brain. It is responsible for reflex actions
The CNS passes messages to and from the brain and connects nerves to the PNS

6. The peripheral nervous system (PNS)
The PNS transmits messages via millions of neurons (nerve cells), to and from the central nervous system
The PNS is further sub-divided into:
the somatic nervous system (SNS)
the autonomic nervous system (ANS)

7. The somatic nervous system
This is the part of the PNS that is responsible for carrying sensory and motor information to and from the spinal cord

8. The autonomic nervous system (ANS)
This governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses

9. The two main divisions of the ANS
The two main divisions of the autonomic nervous system are:
The sympathetic nervous system
The parasympathetic nervous system
Their actions are mostly antagonistic - that is they usefully work in opposition to each other

10. The opposing actions of the sympathetic and the parasympathetic nervous system
Organ
Sympathetic nervous system
Parasympathetic nervous system
Gut
Slows digestion
Increases digestion
Salivary glands
Inhibits saliva production
Increases saliva production
Heart
Increases heart rate
Decreases heart rate
Liver
Stimulates glucose production
Stimulates bile production
Bladder
Stimulates urination (relaxes the bladder)
Inhibits urination (contracting bladder)
Eye
Dilates pupils
Constricts pupils
Lungs
Dilates bronchi
Constricts bronchi

11. Generally, maintains and conserves body energy and functions
Generally prepares the body to expend energy for fight or flight

12. Fight or flight response
Anxiety and fear are actually important for survival because they act as a mechanism to protect the body against stress and danger.
The sympathetic nervous system controls what has been called the "Fight or Flight" phenomenon because of its control over the necessary bodily changes needed when we are faced with a situation where we may need to defend ourselves or escape. 

13. Imagine…
You are walking down a dark street at night by yourself.  Suddenly you hear what you suspect are footsteps approaching you rapidly. 
What happens?  
Your sympathetic nervous system kicks in and in an instant, your body is prepares itself for either defence or escape.

14. Fight or flight?
These changes enable the body to take action and protect itself in dangerous situations, either by running away or fighting – hence, the fight or flight response.

15. When the ‘threat’ has passed…
Now imagine that the footsteps belong to a good friend who catches up to you and offers to walk you home.  You feel relief instantly, but your body takes longer to adjust. 
In order to return everything to normal, the parasympathetic nervous system kicks in. 
This system is slow acting, unlike its counterpart, and may take several minutes or even longer to get your body back to where it was before the scare.

16. These two subsystems are at work constantly shifting your body to more prepared states and more relaxed states. 
Every time a potentially threatening experience occurs (e.g., someone slams on their breaks in front of you, you hear a noise in your house at night, you hear a loud bang, a stranger taps you on the shoulder unexpectedly), your body reacts. 

17. The constant shifting between these two systems keeps your body ready for your current situation.

18. The Endocrine System
The endocrine system is in charge of body processes that happen slowly, such as cell growth.
Faster processes like breathing and body movement are controlled by the nervous system.
However, even though the nervous system and endocrine system are separate systems, they often work together to help the body function properly.

19. This controls the release of hormones from all other endocrine glands
These release adrenalin directly into the bloodstream which prepares the body for fight or flight by constricting blood vessels in the stomach. This inhibits digestion and gives you that sick feeling as well as increasing your heart rate
This facilitates the release of the female hormones – oestrogen and progesterone
This facilitates the release of the male hormones – testosterone

20. Summary questions
Using an example, explain what is meant by the fight or flight response
If you hear a noise that makes you jump, your body immediately diverts blood away from your stomach to your muscles in order for you to stay and confront a potential attacker (fight), or run away (flight)

21. Summary questions
Give two actions of the sympathetic nervous system and two actions of the parasympathetic nervous system
Sympathetic nervous system – dilates pupils, inhibits saliva production, dilates bronchi, speeds up heart rate, inhibits digestion, stimulates glucose production, inhibits urination
Parasympathetic nervous system – constricts pupils, stimulates saliva production, constricts bronchi, slows down heart rate, stimulates digestion, stimulates bile production, stimulates urination

22. Summary questions
Billy is an A level student. He has been asked by his teacher to give a short presentation to the other psychology students in his class. Just before his presentation, Billy feels his mouth go dry and he starts to sweat. After the presentation has ended, Billy feels his breathing slow down and he begins to feel thirsty.
Use your knowledge of the autonomic nervous system to explain Billy’s behaviour before and after the presentation.

23. Possible answer
Billy feels stressed about giving a presentation to the class and this activates sympathetic responses in his autonomic nervous system. Blood is diverted to the muscles for energy and as a result, Billy sweats to allow heat energy to be lost from the surface of the skin. It is the body’s cooling mechanism. His salivary glands have inhibited saliva production making his mouth go dry. Once the presentation is over, Billy’s stress is no longer present and his parasympathetic nervous system is now acting to restore his bodily functions to a normal state; this is why his breathing is slowing down. He feels thirsty as his previously inhibited saliva production has dried his mouth out and now he is aware of this and this needs rectifying

24. Can you? Outline the role of the central nervous system (4 marks)
Identify two divisions of the autonomic nervous system (2 marks)
Identify the two components of the central nervous system (2 marks)
Outline the role of the somatic nervous system (4 marks each)
Outline the role of the autonomic nervous system (4 marks each)
Using an example, outline the function of the endocrine system inn the human body (4 marks)
Answer the ‘Check it’ questions on page 115

25. Ensure you have written up your class notes to include the following:
Homework
Ensure you have written up your class notes to include the following:
The divisions of the nervous system including:
central and peripheral (somatic and autonomic).
The function of the endocrine system: glands and hormones.
The fight or flight response including the role of adrenaline.