Biopsych Flashcards
Branches of the Nervous System
- Central Nervous System -> brain and spinal chord
- Peripheral Nervous System -> somatic and autonomic nervous system
- Autonomic nervous system -> sympathetic and parasympathetic nervous system
Two functions of the central nervous system
- control behaviour
- regulates physiological processes
Brain notes
- centre of all conscious awareness
- outerlayer is the cerebral cortex, where higher mental functions occur
- temporal, occipital, frontal and parietal lobes span both hemispheres
- the brain has a cerebellum for primitive functions
Spinal chord notes
- relays info between brain and body
- allows brain to monitor / regulate body processes
- connected to body by spinal nerves
Peripheral nervous system notes
- all nerves outside the CNS
- relays nerve impulses between CNS and body
Somatic nervous system notes
- both sensory and motor neurons receive info from receptors
- controls voluntary movement
- involved in reflex action
Autonomic nervous system
- regulates involuntary actions
- transmits info between organs
Sympathetic nervous system notes
- deals with emergencies
- neurons from CNS travel to every organ and gland under threat
- causes stored energy to be released
Parasympathetic nervous system notes
- relaxes bodily systems once danger has passed
- slows heart rate and blood pressure
- resets digestion
What are neurons
- cells specialised to carry neural info through body
- consist of dendrites, cell body, axons and synapses
What are dendrites, cell bodies, axons and synapses
- Dendrites receive signals from other neurons or sensory bodies and connect to the cell body
- Cell bodies are the control centre, which carry a signal to the axon
- Axons are where the signal terminates, insulated with myelin sheath, then transfers the signal across the synapse
- Synapses transmit the signal between nerves, from pre-synaptic nerve to post-synaptic nerve
Sensory neurons notes
- carry signals from receptors to CNS
- converts info into nerve impulses
- creates circuit for reflex action
Relay neurons notes
- carry messages from part of CNS to another
- situated in spinal chord and brain
Motor neurons notes
- carry signals from CNS to effectors
- release neurotransmitters which bind to muscles and trigger response
Process of synaptic transmission
- action potential moves to axon terminal, needs to transfer to next axon / tissue
- has to cross synapse, synaptic vescicles release neurotransmitters in presence of action potential
- neurotransmitter travels from pre-synaptic nerve to post-synaptic nerve
What is the endocrine system
A network of glands, manufacturing and secreting hormones into the bloodstream.
How does the endocrine system work
- signal stimulated by pituitary gland sends hormones to organs
- regulated by feedback, homeostasis is known as negative feedback
- as bloodstream levels rise , hypothalamus shuts down secretion of hormone til levels are regular again
What is a hormone
A chemical that regulates activity of cells/organs, by stimulating them.
Process of fight or flight
- stressor is detected and assessed for threat by amygdala
- hypothalamus activates the sympathetic branch of the autonomic nervous system
- sends a signal to adrenal medulla to release adrenaline
- lasts 20 minutes til parasympathetic branch takes over, rest and digest
Effect of adrenaline and why
- pupils dilate to help you see
- digestion slows because it is wasted energy
- increased heart rate, blood pressure for more oxygen
- hairs stand on end to help you sweat and keep cool
- decreased blood flow to skin as it is not important
- releases glycogen for energy boost
What is localisation of function
The theory that specific parts of the brain are responsible for specific roles / abilities.
Visual cortex notes
- located in occipital lobe
- contralateral
- light enters retina, strikes photoreceptors, causing nerve impulses to break transmitted to brain via optical nerve
- impulse terminated in the thalamus, passes info onto visual cortex
How does nerve impulse get from eye to visual cortex
- light enters retina, strikes photoreceptors, causing nerve impulses to break transmitted to brain via optical nerve
- impulse terminated in the thalamus, passes info onto visual cortex
Auditory cortex notes
- within temporal lobes on either side of the brain
How does sound travel to audio cortex
- soundwaves converted to impulse in the cochlea, which travel via the auditory nerve
- passes through the brain stem, which decodes info, then to the thalamus which relays the informatiom to the auditory cortex
Motor cortex notes
- voluntary motor movements
- located in frontal lobe, along precentral gynus
- contralateral
- different parts exert control over different body parts
Somatosensory cortex notes
- detects sensory events from different parts of body
- located in parietal lobe, along postcentral gynus, where touch info is processed
- contralateral
- produce sensations of touch, pain, pressure, temperature
Hemispheric lateralisation notes
- left hemisphere dominant for speech and language, right is for visual and motor tasks
What is the corpus callosum
A bundle of nerve fibres that connect the two hemispheres, allowing them to communicate.
What is plasticity
The brains ability to modify its own structure and functioning through experience.
How can plasticity be affected by various events
Life experience - new experiences strengthen neural pathways, rarely used pathways die out (Boyke juggling)
Video games - improvements in spatial navigation, strategic planning, working memory and motor performance (Kühn)
Meditation - tibetan monks have a larger increase in gamma activity when meditating (Davison et al)
What is functional recovery
The brains ability to recover abilities and mental processes damaged by brain injury and disease
What is neuronal unmasking
Dormant synapses open connections of the brain that are not normally activated, creating a lateral spread of activation, replacing damaged synapses
What is axonal sprouting
Undamaged axons can grow new axons and nerve endings to reconnect the neurons, thus regaining neural activity
What are stem cells
- unspecialised cells with the potential to differentiate into cells with different functions, including nerve cells.
- can be transplanted in and directly replace dead / dying cells
What is a post mortem
Studying the brain after death
What are fMRI scans
- functional magnetic resonance imaging
- measures change of blood flow in particular areas of the brain, as areas that are in use require oxygen
What is an EEG
- electroencephalogram
- measures electrical activity in the brain, electrodes are placed on the scalp and measure tiny electrical changes
What is an ERP
- event related potential
- uses an EEG but while performing a task
What is a biorhythm
An internal process that happens around a specific clock or time period
What are endogenous pacemakers
Any internal mechanism that regulates internal biorhythms
What are exogenous zeitgebers
Any external mechanism that regulates internal biorhythms
What is the superchiasmatic nucleus
- tiny cluster of cells in the hypothalamus responsible for circadian rhythms
- SCN neurons synchronise with eachother, keeping target neurons coordinated
- works in correlation with light: light enters eye, travels along optic nerve to the SCN, the light readjusts the clock, putting us in sync with the outside world
What is the pineal gland
- secretes melatonin, which is the hormone for sleep
- kept informed by the SCN, when light hits eye in the morning it tells the pineal gland to slow production of melatonin, works inversely at night
Importance of social cues in biorhythms
- e.g meal times, social activities, siestas
- klein & wagmann found that jet lag time reduces the more travellers adjust to social cues of their destination
- for example, eating at correct times links to digestive system, which helps reset pacemakers
What is a circadian rhythm
A biological rhythm that occurs roughly every 24 hours
Sleep wake cycle notes
- circadian
- controlled by light which triggers pineal gland to secrete melatonin
- affected by homeostasis, the longer we are awake, the more energy we use, the more our body tells us to sleep
- circadian rhythm tells us to sleep when dark, homeostasis tells us to sleep when tired
- in absence of external cues, circadian rhythm can free run at 24-25 hours
What is an infradian rhythm
Cycle that takes longer than 24 hours to complete
Menstrual cycle notes
- cycle regulates ovulation
- pituitary gland releases hormones which stimulate release of egg and oestrogen
- once egg ripens, progesterone secretes snd builds up blood supply in womb
- 2 weeks after if no pregnancy, the womb lining breaks down
2 refinetti found fluctuation of 23 - 36 day cycles
Exogenous zeitgebers that affect menstrual cycle
- stress
- extreme calorie reduction
- extreme exercise
What is an ultradian rhythm
Happens more than once every 24 hours
Stages of sleep
1) alpha waves, light sleep, slowing of muscles, heart rate and breathing, occasional hypnagogic twitch
2) theta waves, functions slow further, temp decreases
3) core / SWS sleep begins, delta waves begin
4) deepest sleep, all functions very slow, little body movement, long slow delta waves, growth hormone released
5) back to stage 2 where you enter REM
What is rapid eye movement
Brainwaves return to beta waves, HR + BP increase, all near to waking levels, but muscles are relaxed and cannot move, dreaming state.
