bio psychology

cells making up the nervous system are called neurons, they're specialised to conduct electrical impluses. 

The soma or CELL BODY contains the nucleus, this contains genetic material in the form of chromosomes. 

neurons have several extentions called dendrites, it is maily the surface of a dendrite that recieves chemical messages from other nerurons. 

one extension is unique and called the axon, this transmits an electrochemical signal to neurons.

lond axon are typically covered im mylin sheath, a series of fatty cells that are wrapped around the axon. there are gaps in the mylin shealth called nodes of ranvier, where the neruronal cell membrane is exposed. Action potential can jump from gap to gap. this is called saltatory conduction it is faster than standard continuous conduction.

at the end of axon is the terminal buttons,when the electrochemical signal reaches this point it stimulates the release of neurotransmitters into the synaptic gap. 

STEPS:

1. action potential travels down axon and reaches the presynaptic neuron membrane, the vesicles go to the cell membrane and permiate it.

2. the vesicles release neurontransmitters and diffuse over the synaptic space. these are taken in by receptors if they suit it, in the postsynaptic neuron.

3.  the action potential then passes through the postsynaptic neuron.

4. neurontransmitters that are not taken up are either digested by enzymes or return to the presynaptic neuron and packaged back into vesicles to be used again. 

examples of neurontransmitters are dopamine and serotonin which are essential for transmission of nerve impulses across the neuron and are directly responsible for a number of behaviours. 

1.  SENSORY NEURONS carry signals from receptors to the brain and spinal cord; carry info into the CENTRAL NERVOUS SYSTEM, allowing us to experience pain, pressure, and changes in temp. 

2. MOTOR NEURONS  carr info about movement out of the brain. 

3.  RELAY NEURONS carry messages from one area of the central nervous system to another. 

Central Nervous system 

• central control over all activities in body. 
• information is recieved and processed and there is coordination of actions and reactions both concious and unconcious.
• its role is decision making and coordination
• the spinal cord can generate reaction to simple things but when more detailed a response willl be by the brain. 

Peripheral nervous system