![]() For example, serotonin has an inhibitory effect, and adrenaline an excitatory effect. They have different effects, either excitation (increasing the post-synaptic neuron’s positive charge and the likelihood of the message being passed on) or inhibition (increasing the post-synaptic neuron’s negative charge and decreasing the likelihood of the message being passed on). ![]() Each neurotransmitter has a particular structure, and fits perfectly into particular receptors on the post-synaptic cell. The process of transmission from one neuron to another is known as a neural network. The chemical message is converted into an electrical one, and is sent along the dendrites towards the soma of the neuron. Excess neurotransmitter is reabsorbed by the pre-synaptic cell. These chemicals are released into the synapse, and are taken up by the next neuron (the post-synaptic cell). A message reaches the end of one neuron (the pre-synaptic cell), triggering the release of neurotransmitters from vesicles (sacs) located at the terminal button. The communication between neurons takes place across synapses. Synaptic transmission: Messages are transmitted electrically within neurons, and chemically between them. When activated by a stimulus, the neuron gets a short positive charge that creates an electrical impulse (‘action potential’), which then travels down the axon. When in an inactive, resting state, neurons have a negative electrical charge. At the end of the neuron are terminal buttons which allow for communication with adjacent neurons- the gap between them is called the synapse. This effect is achieved by making the impulse ‘jump’ between gaps in the myelin sheath- these gaps are known as the nodes of Ranvier. The axon is covered in a protective layer known as the myelin sheath, which speeds up transmission. The axon carries impulses away from the soma. They have a cell body (soma), containing genetic material, and branches (dendrites) which carry nerve impulses to the soma. Neurons vary in size, but have the same structure. Relay: Connect sensory neurons to motor and other relay neurons.Sensory: Carry messages from the PNS to the CNS.Motor: Connect the central nervous system to muscles and glands.Neurons: These are nerve cells which transmit messages chemically and electrically. Once the perceived stressor passes, the ‘parasympathetic’ branch of the ANS returns the body to normal, reducing the effects and activity of the sympathetic branch. This state of arousal in the system is known as the ‘sympathetic’ state. The stress hormone adrenaline is released in response, leading to physiological changes (increased heart rate, sweating, and so on- the ‘fight or flight’ response). For example, when a person perceives a situation as stressful, the sympathetic branch of the ANS is triggered. The pituitary gland is the most important gland, as it controls the release of hormones from other glands in the body.įight or Flight Response: The endocrine system and the ANS often work together. Thyroxine, produced by the thyroid gland, has various effects, including increasing heart rate and raising metabolic rate. Hormones are chemical messengers which travel to particular organs and have powerful effects. The Endocrine System: This instructs various glands (for example, the thyroid gland) to release various hormones which travel round the body. The PNS can also be sub-divided into the autonomic nervous system (ANS), governing functions such as heart rate and the stress response, and the somatic nervous system (SNS), controlling muscle movement. There are two sub-systems, which are the central nervous system (CNS), consisting of the brain and spinal cord, which are involved with complex commands and decisions, and the peripheral nervous system (PNS), which is responsible for transmitting messages to and from the CNS through neurons (nerve cells). It responds to environmental stimuli and co-ordinates the work of the body’s various organs and cells. The Nervous System: This is the body’s primary internal communication system, made up of cells. Dealing with Offending Behaviour: Custodial Sentencingīiopsychology Nervous System & Endocrine System.Psychological Explanations of Offending Behaviour.The Ethological Explanation of Aggression.Research Methods: Scientific Method & Techniques.Explanations of Attachment: Learning Theory.
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