Biopsych Flashcards
(14 cards)
Nervous System
Nervous System and Endocrine System:
Functions:
() Collect, process and respond to information
() Co-ordinate the working of different organs
CNS:
() Brain: Center of concious awareness, cerebral cortex: 3mm thick
() Spinal coord: Connects nerves to PNS, reflex actions
PNS:
() Autonomic nervous system: Vital functions in body
() Parasympathetic: Rest and digest
() Sympathetic: Fight or flight
() Somatic nervous system: Sensory, motor neurons to carry info to CNS. Enables reflex actions.
Endocrine System
Endocrine System:
() Communicates chemical messages to organs of the body
() Regulates activity of organs and cells
Glands:
() Thyroid: Produces thyroxine (increases heart-rate)
() Pituitary gland: Controls release of other glands
Fight or flight:
() Generated by sympathetic
() Hypothalamus stimulates adrenal medulla releases adrenaline / noradrenaline into blood stream
() Adrenaline: Breathing rate, sweating, pupil dilation, inhibits saliva
() Immediate and automatic
() Parasympathetic nervous system: Actions are ANTAGONISTIC, reduces activities of FOF.
Neurons
Types:
() Sensory: PNS to CNS. Long dendrites short axons.
() Relay: Connect sensory to motor. Short dendrites and short axons
() Motor: CNS to effectors. Short dendrites. Long axons.
Structure:
() Cell body: Contains genetic material
() Dendrites: Carry information to cell body and receive from other neurons, “branch like”
() Axon (Myelin sheath surrounds it): Carry messages away from cell body
() Myelin sheath surrounded by nodes of Ranvier (force signals to jump)
() Axon terminals contain neurotransmitter
Location:
Motor: Bodies in CNS, axons in PNS
Relay: Brain, 97% of neurons
Sensory: Outside of CNS, clusters called GANGLIA
Electrical transmission:
() Stimulus
() Cells becomes charged causing an activation potential
() When this reaches presynaptic terminal, neurotransmitter is released from synaptic vesicles
() Neurotransmitter diffuses across the synapse to the postsynaptic receptor site
() Each neurotransmitter has its own structure that fits perfectly into a postsynaptic receptor site
() Excitatory or inhibitory: Determines how likely the post-synaptic is to fire
() Summation: Excitatory and inhibitory influences are summed, acitivation only if threshhold reached.
Example:
ACETYLCHOLINE: Found where motor neuron meets muscle: Causes contraction.
Localisation of function:
Neuroanatomical organisation :
() Hemispheric lateralization: Cerebellum divided
() Contralateral organisation: Left side right side right side left side.
Language (Left side of brain):
() Broca
() Difficulty producing
() Slow laborious speech
() “Tan”
() Wernicke
() Difficulty understanding
() Meaningless speech
() NEOLOGISMS
Other bits:
() Motor area: Back of frontal lobe
() Somatosensory: Separated from motor area by central sulcus
(^) Information from skin
() Visual area: Occipital lobe at back of brain
() Auditory area: Temporal lobes
Hemispheric Lateralization
Hemispheric Lateralization:
() Language is lateralized
() RH can only produce rudimentary words
() LH is analyser
() RH is synthesizer
() Vision, motor, sensory in both areas
() Motor: CONTRALATERAL wiring
() Vision: CONTRALATERAL and IPSILATERAL
Split-Brain research
Sperry:
() Corpus callosum severed to prevent epilepsy
() Normally communicated LHS with RHS
() 11 people
() Image shown to RVF only or LVF only
() RVF: They said something is there
() LVF: They did not say anything was there
() LVF: Could select matching object
() LVF: Emotional reaction at pinup picture
() Conclusion: Certain functions are lateralized in the brain
() Compared to neurotypical control group
() Karen Bryne: Alien hand
Ways of Studying the Brain
fMRI:
() Functional magnetic resonance imaging
() Changes in oxygenation and flow
() HAEMODYNAMIC RESPONSE: Blood flow is in active area
() 3D images
(+) No radiation
(-) Poor temporal resolution
EEG:
() Electroencephalogram
() Measures neural activity (directly below) with electrodes attached to scalp
() Arrhythmic patterns may indicate abnormalities
(+) High temporal resolution
(-) Low spatial resolution, lack of standardization
ERP:
() Event-related potentials:
() More specific than EEG
() Measures neural activity (directly below) with electrodes attached to scalp as a response to a stimulus
() Filters out extraneous brain activity through and averaging technique
(+) Specific: Work out cognitive functions
(-) Noise not easy to eliminate
Post-mortem exams:
() Used for rare disorder
() May compare with neurotypical brains
(+) Built foundation
(-) Informed consent
Plasticity
Brain plasticity:
() SYNAPTIC connection around 15000 per neuron at 2-3 years.
() Twice as many as in adult brain
() SYNAPTIC PRUNING: Strengthened and deleted neurons
() Synaptic pruning gives lifelong plasticity
() Maguire: Found more grey matter in posterior hippocampus of London drivers than a CONTROL GROUP
() POSITIVE CORRELATION between time spent at the job and size
() Draganski: Larger posterior hippocampus and parietal cortex in size of med students
Functional Recovery
() Other parts of the brain adapt
() SPONTANEOUS RECOVERY – instant
() Then slow down after weeks
() Doidge: NEURAL UNMASKING, activation of dormant synapses
() AXONAL SPROUTING – Growth of new nerve endings
() Denervation super sensitivity – Axon becomes more aroused to compensate
() Recruitment of homologous areas: Similar areas on opposite side of the brain are recruited
Circadian Rhythms
Sleep wake cycle:
() Endogenous pacemaker: Suprachiasmatic nucleus
() SCN: Just above the optic chasm
() SCN can be “reset” by exogenous zeitgebers: Entrainment
Sifre’s cave:
() Michael Siffre: Self-styled caveman
() Went in cave in 1962 for 2 months but believed 1
() Free-running rhythm was 25 hours
Other Research:
() Aschoff and Wever
() 4 weeks in bunker, 24h-25h apart from a 29h
() ENTRAINED by exogenous zeitgebers
() Folkhard
() 12 participants in cave for 3 weeks
() Only 1 able to adjust to speeding up of clock to 22 hours
Infradian
Menstrual Cycle
() Menstrual cycle (28 days)
() Levels of oestrogen rise: Cause egg to develop
() Progesterone helps womb to grow thicker
() Stern and McClintock
() Pheromones given to 29 women in pads for 8h per day
() 9 women donors at different stage menstrual cycle
() New pad each day
() 68% experienced closer to odour donor
SAD:
() Seasonal affective disorder
() Low mood, loss of activity
() When daylight is shorter
() Classed as circannual
() Could be circadian due to it being due to the disruption of sleep-wake
() More MELATONIN produced by PINEAL GLAND has knock on effect on SERETONIN
Ultradian
() Stages of sleep
() All together 90 minutes
(HFSA) Stage 1 and 2: Alpha waves
Stage 2: pattern changes called SLEEP SPINDLES
(LFHA) Stage 3 and 4: Delta waves, Slow waves sleep, difficult to wake somebody
() Stage 5: Theta waves, REM Sleep, body paralysed
Endogenous pacemakers
Endogenous pacemakers:
() SCN: In the hypothalamus of each hemisphere.
() Nerve fibres cross on their way to each hemisphere (VISUAL CORTEX) (optic chasm)
() SCN just above optic chasm
() Received information about light
() Passes to pineal gland, which produced melatonin
Animal Studies:
() DeCoursey
() 30 SCNless chipmunks all gone at end of 80 days
() Ralph
() Bred 20h hamsters
() Changed hamsters when SCN cells implanted into other
Exogenous zeitgebers
Light:
() Campbell and Murphy
() Light shone on back of knee when sleeping
() 15 participants woken at various times
() Disrupt by up to 3h
Social Cues:
() Babies: Circadian rhythms begin at 6 weeks
() Entrained by age 16 weeks
() Research shows eating and sleeping is good to entrain jetlag
