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Biopsychology - Coggle Diagram
Biopsychology
Nervous system
2 parts: peripheral and central. Peripheral is split into autonomic and somatic. Autonomic is responsible for self-regulated actions of organs & glands (involuntary). It is split into sympathetic, which is arousing acts as an accelerant to bodily functions (reflexes) and parasympathetic which is a calming response, 'rest and digest'.
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The CNS involves the brain & spinal cord. Spinal cord transmits messages to & from the brain to the peripheral NS using neurons. The brain's main job is to maintain life, involves breathing & heartbeat as well as planning/problem solving.
Arc reflex: receptor detects the stimulus e.g hot surface, sensory neuron sends impulses to the relay neuron which are in the spinal cord. Relay neutron connects sensory neuron to motor neuron. Motor neuron sends impulses to effector and effector produces a response.
Neurons transmit chemical and electrical signals to allow communication. Electrical impulses travel through the neuron and release a neurotransmitter.
Neuron structure: cell body (contains a nucleus), dendrites which project from the body & carry impulses from other neurons to cell body. Axon carries impulses away down the length of the neuron. Myelin sheath covers the axon to protect it & speeds up the electrical impulse. Myelin sheath is segmented by gaps (nodes of Ranvier), speeds up transmission as it 'jumps' across the gaps. End of the axon is 'terminal buttons' which communicate with next neuron across a synaptic gap using neurotransmitters.
Sensory neuron: are unipolar &go to the brain. Nerve cells are activated by sensory input (environment) and they send signals to the CNS. Inputs can be physical or chemical (smell or taste).
Relay neuron: have no myelin sheath and are very short. Connect the sensory to the motor (mainly in the spinal cord), also known as interneurons. They can communicate with each other to form circuits.
Motor neuron: are multipolar. Part of the CNS, transmit signals from spinal cord to muscles. Lower motor neurons travel from the spinal cord to muscles. Upper motor neurons travel between the brain & spinal cord.
Synaptic transmission: Soma fires an action potential (impulse) down axon to pre-synaptic membrane. Electrical impulse converted to a chemical message (neurotransmitter) in order to move over the synapse. Vesicles which contain the neurotransmitter move towards the membrane wall. Vesicles fuse into the wall, neurotransmitter fired across synapse to post-synaptic membrane. Neurotransmitter binds to a receptor (lock & key). Projects the message. Not all of the chemical finds a receptor and that remains in synapse will be re-uptaken.
Neurotransmitter will elicit an exitationary response (glutamate) when it makes it across the synapse or an inhibitory response (GABA). Exitationary means that it will increase the chance of the neuron firing (positive charge), inhibitory means it will decrease the chance (negative charge).
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Brain plasticity: how the brain changes to what you do as a result of experiences (experience dependant) and learning. Used to believe that changes only happened in childhood (experience expectant).
Involves synaptic pruning: neural connections are strengthened but some are eliminated, those which aren't used.
Synaptogenesis: formation of new synapses between neurons as axons & dendrites grow.
Neurogenesis: process in which new neurons form.
2 types of plasticity: structural & functional.
Structural refers to everyday events which alter our brain's development.
Functional refers to the brain's ability to move functions from damaged areas to undamaged areas, usually occurs in stroke patients.
Functional recovery: how your brain recovers after trauma.
The brain will need to replace axon functioning afterwards & it does this by: increased brain stimulation, axon sprouting & denervation supersensitivity.
Axon sprouting means that new axons are grown to reconnect with damaged neurons. 2 types: compensatory sprouting and regeneration. Regeneration is where new nerve endings grow & connect with damaged areas, this can compensate & enable recovery.
Neural reorganisation: brain transfers functions from damaged areas to undamaged sections. E.g Broca's area damaged on left side then an area on the right hemisphere may take over.
Neuronal unmasking: this is where 'dormant' synapses which haven't received enough input to be active, open connections to compensate for a damaged area of the brain.
Factors that affect the rate & success of recovery: perserverance, physical exhaustion, stress, age & gender.
Biological Rhythms: ultradian, infradian, circadian.
Infradian rhythms last longer than 24 hours e.g human menstrual cycle or seasonal affective disorder. Menstrual: 28 day rhythm influenced by endocrine system.
Ultradian rhythms lasts less than 24 hours e.g human feeding patterns & sleep which moves through different stages.
Circadian rhythms last approx 24 hours e.g sleep/waking, body temperature, metabolic activity & hormones. They have an affect on observable behaviour. Influenced by internal & external environments - endogenous & exogenous zeitgebers/pacemakers.
Endogenous pacemakers: rhythms that are from are internal bodily systems. Suprachiasmatic nucleus (SCN) dictates the release of certain hormones. SCN is regulated by external factors e.g light.
Exogenous Zeitgebers: external influences that affect the SCN. Cues from the environment which help regulate our timings for sleep. Can become confused because of jet lag.
Endocrine & f or f
Functions to secrete hormones into the blood stream in order to regulate bodily functions e.g melatonin is released from the pineal gland to aid sleep.
Most influence comes from the pituitary gland which can influence all the other glands. It is in the hypothalamus. It releases the adrenocortical trophic hormone (ACTH) which releases glucocorticoids and is a key component in stress response. Also releases the growth hormone.
The adrenal gland - adrenal medulla releases adrenaline which is used in flight or fight.
The pineal gland produces melatonin.
Thyroid produces thyroxin which is linked to metabolism & energy.
Flight or fight response is a combination of the nervous system & endocrine system. It will occur if something is perceived as a threat.
It results in a surge of adrenaline - improves likelihood of survival. It is an evolutionary response. The response comes from the autonomic nervous system specifically from the sympathetic branch as it is a reflex response.
Stress response can be 1 of 2 types based on the appraisal of the threat/stressor. Short term stressors mean that f or f is activated (emergency). In long term stress diff systems are activated (pituitary adrenal system).
Appraisal of stressor: body appraises the situation using sensory systems and stored memories. Hippocampus & amygdala can try to recognise emotional reactions to it. If is is deemed to be stressful the hypothalamus which recognises threats is alerted and triggers the SAM system = f or f.
when the SAM pathway is activated it stimulates the adrenal gland (above kidneys) and the adrenal medulla secretes adrenaline which prepare the body for f or f. This causes: increase sweat, increased heart rate, increase in respiration, increase blood flow in muscles, pupil dilation & reduction of activity in digestive system.
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