Chapter Overview Notes BRAIN AND BEHAVIOUR

 1 st : Franz Gall “phrenology” the idea that certain areas of the brain control certain functions and behaviours.  Biological Psychologists: study the links between biology and psychology and in doing so are learning about depression, sleep, dreams and schizophrenia. BRAIN AND BEHAVIOUR

 An electrochemical communication system that enables you to think, feel and act.  It is composed of nerve cells called NEURONS  The Nervous System of animals and humans are very similar and operate similarly. THE NERVOUS SYSTEM

 3 different types of nerve cells called Neurons:  Sensory neuron (send information from sensory organs and tissue to the brain and spinal cord)  Interneuron (processes information in the brain and spinal cord)  Motor neuron (receives instructions from the brain and spinal cord)  The simplest neural response – The REFLEX – touch a hot stove (pain reflex) HOW DOES INFORMATION TRAVEL IN THE NERVOUS SYSTEM?

 Myelin Sheath – insulates to help speed  Axon – passes information to other neurons  Dendrites – receive information from other neurons  For a neural impulse to “FIRE” the combined impulses that reach the dendrite must reach a certain level of intensity or THRESHOLD – this is an all of nothing response to neurons either reaching the threshold or they don’t.  If the Threshold is reached then the neuron transmits an electrical impulse down the axon and this impulse that runs down the axon is called the ACTION POTENTIAL.  Stronger stimuli does not cause a stronger impulse to fire, but, it can cause more neurons to fire and to fire more often. GENERATING A NEURAL IMPULSE

 The axon terminal of one neuron is separated from the receiving neuron by a tiny gap known as the SYNAPSE or SYNAPTIC GAP.  To communicate with one another the neuron releases chemicals called NEUROTRANSMITTERS into the synaptic gap.  The neurotransmitters cross the synaptic gap and bind the receptor sites on the receiving neuron – like a key fitting into a lock.  When these neurotransmitters bind to the receptor sites they either EXCITE or INHIBIT the receptor neurons readiness to fire.  If a neuron receives more excitatory messages, it will fire.  If a neuron receives more inhibitory messages it will not fire. HOW DO NERVE CELLS COMMUNICATE?

 One of the best understood neurotransmitters = acetylcholine (messenger at every junction between a motor neuron and a muscle neuron)  The Endorphins – neurotransmitters that are similar to the drug morphine (which elevates mood and eases pain). They are natural opiates which are released in response to pain and vigorous exercise. HOW DO NEUROTRANSMITTERS INFLUENCE US?

 Central Nervous System: includes all neurons in the brain and spinal cord.  Peripheral Nervous System: links the CNS with the body’s sense receptors, muscles and glands.  Somatic Nervous System: transmits sensory input from the outside world and directs motor input – the voluntary movement of our skeletal muscles. DIVISIONS OF THE NERVOUS SYSTEM

 Autonomic Nervous System: influences the glands and muscles of our internal organs. It can be consciously overridden but usually tends on its own influence.  Sympathetic Nervous System: fight or flight response which accelerates heartbeat, slows digestion.  Parasympathetic Nervous System: this calms you down so the opposite of sympathetic nervous system. DIVISIONS OF THE NERVOUS SYSTEM