Key Concept 5: Neurochemistry Flashcards
What is Neurochemistry?
This looks at the impact of chemical substances in the nervous system. They impact upon the functioning of the brain, thinking, emotions and behaviour. Examples include neurotransmitters such as Dopamine and Serotonin and hormones such as Adrenaline.
Hormones and the stress response
Hormones - chemical messages produced within structures called glands. Several glands work together in a system called the Endocrine system. An example would be the adrenal glands that release Adrenaline into the bloodstream. This travels around the body affecting cells that have adrenaline receptors.
Stress hormones - anything that causes stress is called a stresser. Stress hormones regulate the body’s response to a stresser. Two types of stress: immediate (acute) and long-term (chronic). These phases involve different hormones.
Adrenaline - the body responds to an immediate stress with the fight or flight response. The stress stimulates the sympathetic division of the autonomic nervous system (ANS) and adrenaline is released from the adrenal glands. Adrenaline in the bloodstream triggers the physiological changes needed for fight or flight e.g. speeding up of heart and breathing rate.
Cortisol - Involved in longer-term stress responses. It is also released from the adrenal gland. This can help the body cope with stress for example, restoring energy supplies but over time too much has a harmful effect for example, a weakened immune system. This is a reason why long-term stress is linked with illness.
Neurotransmitters
Neurotransmitters allow communication between nerve cells (neurons) in the brain and the nervous system. Neurons are tiny cells that have gaps between them called synapses. Messages transmit across the neurons in electrical format but when they get to the synapse they transmit chemically, they are carried across the synapse by neurotransmitters.
Serotonin is one of the main neurotransmitters and it is linked to a number of important behaviours and functions (sleep/mood). Low levels of serotonin has been linked to depression. Drug treatments for depression work by increasing the amount of synapses between neurons.
2 types of neurotransmitters: those that reduce the electrical activity of the neuron (inhibitors) and those that increase the activity of the neuron and activate its action potential (excitatory). Some neurons are inhibitory in some areas of the brain but excitatory in others for example, dopamine.
