5470573
Description
Flashcards by Kizzy Leverton, updated more than 1 year ago
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Created by Kizzy Leverton
almost 8 years ago
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| Question | Answer |
| what is the central nervous system? | - includes the brain and the spinal chord - control behaviour/regulates physiological processes - receives info from senses |
| what is the spinal chord and what is its function? | - a bundle of nerve fibres enclosed within the spinal column and which connects nearly all parts of the body with the brain. - allows brain to monitor/regulate body processes e.g digestion/breathing - contains circuits of nerve cells enabling us to perform simple reflexes without direct Involvement of the brain e.g pulling hand away from something hot |
| what is the function of the brain? | - part of CNS responsible for coordinating sensation, intellectual and nervous activity - 4 areas - cerebrum/ cerebellum/ diencephalon/ brain stem |
| what is the cerebrum and what does it do? | - largest part of brain - 4 different lobes e.g - frontal lobe-thought/speech - occipital lobe - processing of visual images - 2 hemispheres |
| what is the cerebellum and what does it do? | - beneath cerebrum - controls motor skills/balance - coordinates muscles to allow precise movements - abnormalities of this area can result in a number of problems such as speech/motor problems/epilepsy |
| what is the diencephalon and what does it do? | - lies beneath cerebellum/on top of brain stem - thalamus - relay station for nerve impulses coming from senses - routes them to appropriate part of brain - hypothalamus - regulation of body temperature/hunger/thirst - link between endocrine system/NS |
| what is the brain stem and what is its function? | - responsible for regulating the automatic functions essential for life such as breathing, heartbeat and swallowing - motor/sensory neurons travel through the brain stem allowing impulses to pass between the brain and spinal chord |
| what is the Peripheral nervous system? | - the part of the nervous system that is outside of the brain and spinal chord - relay's nerve impulses from CNS to the rest of the body and from the body back to the CNS. - 2 divisions: the somatic nervous system and the autonomic nervous system |
| what is the somatic nervous system? | - responsible for carrying sensory/motor information to and from the CNS - 12 pairs of cranial nerves/31 pairs of spinal nerves (have sensory neurons/motor neurons) - involved in reflex actions without the CNS allowing reflex to occur very quickly |
| what are sensory neurons in the somatic nervous system? | relay messages to the CNS |
| what are motor neurons in the somatic nervous system? | relay info from the CNS to the rest of the body |
| what is the autonomic nervous system? | - Governs the brains involuntary activities e.g stress/ heartbeat - divided into sympathetic branch (F/F) and the parasympathetic branch (rest and digest) |
| what is a sensory neuron? | - carry nerve impulses from sensory receptors to spinal chord/brain - found in eyes/ears/tongue/skin - convert info from these sensory receptors into neural impulses which are translated into sensations like heat, pain etc |
| what is a relay neuron? | - allow sensory and motor neurons to communicate with each other - lie within brain/spinal chord |
| what is a motor neuron? | - project their axons outside the CNS and directly or indirectly control muscles - form synapses with muscles/control their contractions - when stimulated it releases neurotransmitters that bind to receptors on the muscle leading to movement - muscle relaxation caused by inhibition of motor neuron |
| what is a synapse? | the conjunction of the end of the axon of one neuron and the dendrite or cell body of another |
| what are the three types of neuron? | - sensory neuron - motor neuron - relay neuron |
| structure/function of neurons? | -consist of cell body/dendrites/axon - dendrites at one end of neuron receives signal form other neurons/sensory receptors - from cell body the impulse is carried along the axon where it terminates at the axon terminal. |
| what is the Myelin sheath? | - insulating layer around axon - allows nerve impulses to transmit more rapidly along the axon - if it is damaged nerve impulses slow down |
| what is synaptic transmission? | - refers to the process by which a nerve impulse passes across the synaptic cleft from one neuron(the presynaptic neuron) to another (the postsynaptic neuron) |
| what are neurotransmitters? | - the chemical messengers that carry signals across the synaptic gap to the receptor site on the postsynaptic cell. - they can be either excitatory or inhibitory in their action |
| what are Excitatory transmitters? | - NS "on switch" - e.g. acetylcholine/noradrenaline - increase the likelihood that a excitatory signal is sent to the postsynaptic cell which is then more likely to fire. |
| what are inhibatory transmitters? | - NS "off switch" - e.g. seretonin/GABA - decrease the likelihood of neuron firing - responsible for calming mind/body, including sleep and filtering out excitatory signals |
| what happens when an excitatory neurotransmitter binds with a postsynaptic receptor? | - causes electrical charge in membrane of that cell causing an ecitatory post synaptic potential (EPSP) meaning that the postsynaptic cell is more likely to fire |
| what happens when an inhibitory neurotransmitter binds with a postsynaptic receptor? | - results in an inhibitory postsynaptic potential (IPSP) making it less likely that the cell will fire |
| synapses... | Where two neurons meet, there is a tiny gap called a synapse. Signals cross this gap using chemicals released by a neuron. The chemical diffuses across the gap makes the next neuron transmit an electrical signal. |
| what is the endocrine system? | - network of glands throughout the body that manufacture and secrete chemical messengers known as hormones |
| what are endocrine glands? | - special groups of cells within the endocrine system, whose function is to secrete and produce hormones - each produce different hormones which regulate the activity of organs and tissues in the body |
| what are the major endocrine glands in the ES? | - pituitary gland, adrenal gland and reproductive organs (ovaries/testes) |
| how is the endocrine system regulated? | - signal sent from hypothalamus to pituitary gland in the form of "releasing hormone" - pituitary gland secretes "stimulating hormone" into the bloodstream - hormone signals the target gland (e.g adrenal gland) to secrete its hormone - as levels of this hormones rise in the bloodstream the hypothalamus shuts down secretion of releasing hormone /pituitary gland shuts down secretion of the stimulating hormone - this slows down secretion of the target glands hormone resulting in stable concentrations of hormones circulating in the bloodstream |
| what are hormones? | - Chemicals that circulate the bloodstream and are carried to target sites around the body - Target cells respond to a particular hormone because they have receptors for that hormone. |
| what happens when enough receptor sites are stimulated by hormones? | - results in a physiological reaction in the target cell - timing of hormone release critical for normal functioning , as are the levels of hormones released - can result in dysfunction of bodily systems - e.g. too much cortisol can lead to Cushing's syndrome characterised by high blood pressure/depression |
| what is the pituitary gland? | - produces hormones (travel in bloodstream) whose primary function is to influence the release of hormones from other glands - regulates many of body functions - controlled by hypothalamus - receives info then uses this info to regulate functions |
| what is negative feedback? | - high levels of hormones produced in other endocrine glands can stop the hypothalamus and pituitary from releasing more of their own hormones - prevents hormone levels from rising too high |
| what is an example of a hormone that the Anterior of the pituitary gland releases? | - releases ACTH as a response to stress - ACTH stimulates the adrenal glands to produce cortisol |
| 2 hormones important in the control of reproductive functioning and sexual characteristics? | - LH/FSH - in females these hormones stimulate the ovaries to produce oestrogen and progesterone, and in males they stimulate the testes to produce testosterone and sperm |
| what does the posterior pituitary release? | - oxytocin - stimulates contraction of the uterus during childbirth and is important for mother infant bonding - recent research using mice has found that oxytocin is indispensable for healthy maintenance and repair and that it declines with age |
| what are the adrenal glands? | - sit on top of kidneys - made up of 2 distinct parts - adrenal cortex/adrenal medulla - hormones released by the adrenal cortex are necessary for life, those released by the medulla are not |
| what does the adrenal cortex produce? | - cortisol - aldosterone |
| what does cortisol do? | - regulates/supports variety of important bodily functions like cardiovascular and anti inflammatory functions - production is increased in response to stress - if Cortisol level is low then the individual has low blood pressure, poor immune function and an inability to cope with stress |
| what is aldosterone? | - responsible for maintaining blood volume and blood pressure |
| what does the adrenal medulla release? | - adrenaline and noradrenaline (hormones that prepare the body for fight or flight) - adrenaline - helps body respond to stressful situations (increased heartrate/bloodflow to muscles/brain) - noradrenaline - constricts blood vessels causing blood pressure to increase. |
| what are ovaries? | - responsible for the production of eggs and for the hormones oestrogen and progesterone |
| what are the testes? | - male reproductive glands that produce the hormone testosterone - causes the development of male characteristics such as growth of facial hair, deepening of the voice etc |
| what is testosterone controlled by? | - hypothalamus/ pituitary gland - hypothalamus instructs the pituitary gland on how much testosterone to produce - pituitary gland passes this message onto the testes |
| what is the fight or flight response? | - a sequence of activity within the body that is triggered when the body prepares itself for defending or attacking (fight) or running away to safety (flight). this activity involves changes in the NS and the secretion of hormones that are necessary to sustain arousal |
| what is the Amygdala? | - when an individual is faced with threat the amygdala is mobilised - associates sensory signals with emotions associated with fight or flight (fear/anger) - sends distress signal to hypothalamus |
| what does the hypothalamus do? | - functions like a command centre in the brain, communicating with the rest of the body through the SNS |
| what happens when the SNS is triggered?(acute stressors) | - prepares body for rapid action necessary for fight or flight - sends signal to adrenal medulla which releases adrenaline into the bloodstream |
| what does adrenaline do? | - as it circulates through the body it: > makes the heart beat faster pushing blood to heart/vital organs > blood pressure increases > breathing becomes more rapid > release of blood sugar (glucose) with fats which flood into bloodstream supplying energy to parts of body associated with fight or flight |
| what does the parasympathetic nervous system do after the threat has passed? | - dampens down stress response - slows down heartbeat - reduces blood pressure - digestion begins again |
| what is the response to chronic (ongoing) stressors? | - if the brain continues to perceive something as threatening the hypothalamus activates a stress response system called the HPA axis - consisting of the hypothalamus/ pituitary gland/ adrenal glands |
| what happens in the HPA axis? | - H - hypothalamus releases chemical messenger (CRH) which is released into bloodstream - P - CRH causes the pituitary gland to produce/release ACTH which is transported in the bloodstream to its target sight in the adrenal glands - A - ACTH stimulates adrenal cortex to release stress related hormones like cortisol - this system is efficient at regulating itself (H/PG have receptors monitoring cortisol levels |
| what are the negative consequences of the fight or flight? | - stressors of modern everyday life rarely require high levels of physical activity and the stress response is repeatedly activated e.g increased blood pressure that is a charcteristic of SNS activation can lead to physical damage in blood vessels and eventually heart disease - e.g too much cortisol can supress the immune response shutting down th process that fights infection |
| what did Gray (1988) suggest about fight or flight? | - that the first stage of reaction to threat is not to fight or flee but to avoid confrontation - prior to reponding with attacking or running away most animals/human display the freeze response where the animal is hyper vigilant, alert to the slightest sign of danger - this is an advantage because "freezing" focuses attention and makes you look for more information in order to make the best response for that particular threat |
| sex differences in fight or flight? | - Lee and Harley (2012) found evidence of gender differences - the SRY gene found in male Y chromosome directs male development promoting aggression. - SRY gene may prime males to respond to stress in this way by release of adrenaline/increased blood flow to organs. - females do not have SRY gene/having oestrogen and oxytocin may prevent this response to stress |
| what did Taylor et al (2000) suggest? | - suggested that for females behavioral response to stress are more characterized by pattern of tend and befriend - involves protecting their young through nurturing (tend) and forming protective alliances with other women (befriend) |
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