biopsychology Flashcards
Synaptic transmission
The process by which neighbouring neurons communicate with each other by sending chemical messages across the synaptic cleft that separates them
Neurotransmitters
Brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another. Can be broadly divided into those that perform an inhibitory or an excitory function
Excitation
When a neurotransmitter, such as adrenaline, increases the positive charge of the postsynaptic neuron, increases liklihood that neuron will fire
Inhibition
When a neurotransmitter, serotonin, makes the charge of the postsynaptic neuron more negative, decreases liklihood that neuron will fire
Synapse
The junction between 2 neurons, includes presynaptic, synaptic cleft and postsynaptic receptor site
Synaptic cleft
The space between the post synaptic and presynaptic neuron
Synaptic vesicles
Small sacs on the end of the presynaptic neuron that contains neurotransmitters that will be released into a synapse
Presynaptic neuron
The transmitting neuron, before the synaptic cleft
Post synaptic receptor site
A receptor on the post synaptic neuron site, a neurotransmitter locks into a specific receptor on the post synaptic neuron and this triggers and electrical impulse in the post synaptic neuron
Give 4 examples of neurotransmitters
Serotonin
Adrenaline
Noradrenaline
GABA
Summation
Whether or not a postsynaptic neuron fires as excitation and inhibition added up to get the net effect of positive or negative
2 effects drugs can have on synaptic transmission
Increases the amount of neurotransmitters
Blocks reuptake channels
Decreases amount of neurotransmitters
Blocks the receptors
Brief process of synaptic transmission
Action potential arrives at presynaptic neuron
As a result of action potential, vesicles diffuse towards presynaptic membrane
Vesicles bind to the presynaptic membrane and neurotransmitters are released
Neurotransmitters chemically diffuse across the synapse
Neurotransmitters bind to complementary receptors on the postsynaptic neuron membrane and an electrical impulse is subsequently passed on
Neuron
The basic building blocks of the nervous system, neurons are nerve cells that process and transmit messages through electrical and chemical signals
Sensory neuron
These carry messages from the PNS to the CNS, they have long dendrites and short axons
Relay neuron
These connect the sensory neuron to the motor and other relay neurons, they have short dendrites and short axons
Motor neuron
These connect the CNS to effectors such as the muscles and glands, they have short dendrites and long axons
Cell body
Factory of the neuron, it contains the nucleus and produces all of the necessary proteins that a neuron requires to function
Nucleus
Genetic material within the neuron
Dendrite
Branch like features protrude from the cell body, the carry nerve impulses from neurons towards the cell body
Axon
Carries electrical impulses from the cell body down the length of the neuron covered by the myelin sheath
Myelin sheath
Fatty layer which surrounds and protects the axon, it helps to speed up the electrical transmission of the impulse
Nodes of ranvier
Gaps between the myelin sheath, purpose is to speed up the transmission of the impulse by forcing it to jump across the gaps on the axon
Terminal buttons
Located at the end of the axon, communicate with the next neuron on the other side of the synaptic cleft
Location of sensory neuron
Near body’s surface
Location of relay neuron
Brain and spinal cord
Visual system
Location of motor neuron
Brain (CNS)
linked to muscles
Fight or flight response
- The hypothalamus recognises there is a threat in the environment
- ANS activates sympathetic nervous system
- Sympathetic nervous system tells pituitary gland to release ACTH
- Sends a message to the adrenal gland
- Adrenal gland releases adrenaline
- Adrenaline travels via the bloodstream and targets organs in the body which have adrenaline receptors
- Causes physical changes to occur
- Above process is fight or flight response and allows body to act
- Once threat has passed, body returns to normal
Adrenaline
Hormone produced be adrenal glands which is part of the body’s stress response signal
Direct effect of adrenaline
Increased heart rate
Constricted blood vessels, increased breathing rate and blood flow
Diverts blood away from skin, kidneys and digestive system
Increases blood to brain and skeletal muscles
Increases respiration and sweating
Inhibits saliva production
Indirect effects of adrenaline
Prepare body for action
Increased blood supply to skeletal muscles for physical action
Increased oxygen to brain for rapid response planning
Evaluation F or F
Humans engage in initial freeze response
Females adopt a tend and befriend
Early research typically conducted on males
Stresses of modern day life effect fight or flight
Biologically reductionist
Pituitary gland
Lots of hormones
Known as master gland because hormones released stimulate the release of hormones from other glands in the endocrine system
Pineal gland
Melatonin
Responsible for important biological rhythm such as sleep-wake cycle
Thyroid gland
Thyroxine
Responsible for regulating metabolism
Testes
Testosterone
Responsible for development of male sex characteristics during puberty while promoting muscle growth
Ovaries
Oestrogen
Controls the regulation of the female reproductive system, including menstrual cycle and pregnancy
Adrenal gland
Adrenaline
Responsible for fight or flight response
Pancreas
Insulin
Allows body to use glucose from carbohydrates in food for energy or to store glucose for future use, helps keep blood sugar levels stable
CNS
consists of brain and spinal cord, passes messages to and from the brain and connects nerves to PNS
PNS
Sends information to the cns from the outside world and transmits messages from cns to muscles and glands in the body
Somatic nervous system
Transmits information from receptor cells in the sense organs to the cns, also receives information from cns that directs muscles to contract, receives information from sensory receptors
Autonomic nervous system
Transmits information to and from bodily organs, operates involuntarily, governs vital functions of the body
Parasympathetic nervous system
Division of the ANS which controls relaxed state conserving resources and promotes digestion and metabolism
Sympathetic nervous system
Activates internal organs for vigorous activities and emergencies, decreased digestive activity
Nervous system
Human nervous system
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PNS CNS
ANS SNS B SC
SNS PSNS
Sympathetic nervous system effects
Increased heart rate
Increased breathing rate
Inhibits digestion
Contracts rectum
Inhibits saliva production
Dilates pupils
Parasympathetic nervous system effects
Stimulates digestion
Stimulates saliva production
Decreases heart rate
Decreases breathing rate
Stimulates rectum
Constructs pupils
fMRI description
Measures blood flow to the brain when a person performs a task
Uses mri technology which detects radiowaves from magnetic fields
fMRI strengths
High spacial resolution allows for a detailed picture of the brain
Non invasive technique
No radiation so safe
fMRI limitations
Expensive method less opportunities to take part in research
Participant needs to be still
Poor temporal resolution
EEG description
Records tiny electrical signals produced by brain activity
Different wave patterns are measured and used to diagnose certain conditions
EEG strengths
High temporal resolution- moment to moment picture of what is happening
Inexpensive so more studies
EEG limitations
Low spacial resolution- only outer layers
ERP description
Brains electrophysical response to specific sensory cognitive of motor events
Can be statistically analysed through EEG data
Activity related to stimulus
ERP strengths
High temporal resolution
ERP limitations
Needs to completely eliminate background noise
Lack of standardisation makes it difficult to confirm reliability
PME description
Brain analysed after death to determine whether certain observed behaviours in life can be linked to abnormalities in the brain
PME strength
In depth study of parts of the brain
BROCA AND WERNICKE
PME limitations
Damage to the brain may be due to decay not deficient - causation
Ethical issue of informed consent
Localisation
The theory that specific areas of the brain are associated with specific functions such as physical and psychological
Holistic theory
All parts of the brain are involved in processing that of thought and action
18th century
Phrenology
Detailed study of the size abd shape of the cranium as a supposed indicator of character and mental ability
Central core
Brain stem
Includes hypothalamus
Regulates primitive functions such as breathing or sneezing
Limbic system
Controls emotion
Hippocampus
Key role in memory
Cerebrum
Two hemispheres
Cortex about 3mm
Human cotrex more developed than animals
Cortex
Divided into four lobes
Frontal
Parental
Occipital
Temporal
Different function
Motor cortex location
Back of frontal
Somatosensory cortex location
Front of parental lobe
Visual cortex location
Occupatal lobe
Auditory cortex location
Temporal lobe
Wernicke’s area location
Left temporal lobe
Broca’s area location
Left frontal lobe
Role of motor cortex
Sends nerve impulses to the muscles
Damage to motor cortex
Loss of movement on opposite side of which it controls
Somatosensory cortex role
Processes sensory information from the skin
Pressure, heat, pain
Damage to somatosensory cortex
Loss of senses
Not sight or hearing
Role of visual cortex
Receives and processes information from the optic nerve
Damage to visual cortex
Loss of visual cortex
Auditory cortex role
Analyse speech based information
Auditory complex damage
Loss of hearing
Wernickes area role
Comprehension of language
Wernickes area damage
Wernickes aphasia
Difficulty in comprehending
Brocas area role
Speech production
Brocas area damage
Brocas aphasia
Damage results in slow speech that lacks frequency
phineas gage 1848
meter long pole through left cheek, behind left eye out of skull taking most of left frontal lobe
goes against hollistic theory
frontal lobe responsible for regulating mood
contra-lateral
the opposite side of the body to the brain hemisphere that controls it
corpus callousum
broad band of fibres that joins the two hemispheres of the brain, this allows communication to occur
cutting of the corpus callousum means information cannot be passed between hemispheres
plasticity
the brains tendancy to change and adapt (functionally and physically) as a result of experience and new learning
functional recovery
a form of plasticity, the brains ability to redistribute or transfer functions following damage or trauma
synaptic pruning
as we age, rarely used connections are deleted and frequently used connections are strengthened
axonal sprouting
undamaged axons grow new nerve endings to reconnect neurons whose links are injured and severed
bridging
where new connections are strengthened due to use or new stimulus
the law of equipotentiality
secondary neural circuits surrounding the damaged area become activated. the brain rewires and reorganises itself by forming new synaptic connections close to the area of damage
neural unmasking
neural activation of dormant synapses to compensate for damaged areas in the brain
reformation of blood vessels
part of the haemodynamic response, where activated areas experience a higher blood deoxygenation level
neural reorganisation
the transfer of functions to undamaged areas
recruitment of homologous areas
the use of similar areas on the opposite side of the brain to perform certain tasks
endogenous pacemakers
internal body clocks that regulate many of our biological rhythms such as SCN on sleep-wake cycle
exogenous zeitgebers
external cues that may effect or entrain our biological rhythms, such as the influence of light on the sleep-wake cycle
circadian rhythms
sleep-wake cycle
melatonin production
regulation of body temperature
sleep-wake cycle
strongest sleep drive- 2-4am and 1-3pm
sleepiness less intense with circadian dips
homeostasis controls our need to sleep-if we need more energy, our body tells us to sleep
light-exogenous zeitgeber
hormone production
melatonin is produced and released from the pineal gland
levels peak during hours of darkness
by activating synapses in the brain, melatonin encourages feelings of sleep
body temperature
lowest at 4am highest at 6pm
36-38 degrees c
temp rises during last few hours of sleep
the warmer we are, the better our cognitive performance
SCN
ball of nerve cells in the hypothalamus of each hemisphere which sends messages to the pineal gland
role of SCN
optic chaism detects light
SCN sends message to pineal gland
light sensitive cells
melatonin production
light falls- melatonin increases
increases drowsiness and biological conditions needed for sleep
inhibits mechanisms that promote awake state
what social cues can effect sleep-wake cycle
times to eat/ go to bed
jet lag
infraradian rhythms
more than a day
menstrual cycles
can vary between 23-36 days, most commonly 28
rising levels of oestrogen cause ovary to develop an egg and release at day 14
ovulation- oestrogen peak at 16-32 hours
after ovulation, progesterone levels increase and uterus lining gets thicker to prepare for pregnancy
if pregnancy does not occur, the egg is absorbed into the body and the womb lining leaves the body-menstrual flow
SAD
depressive disorder
seasonal pattern
persistant low mood and general lack of activity and interest in life
symptoms triggered during winter months when number of daylight hours is shorter
circoannual rhythms is a subjective yearly cycle
lack of light means melatonin secretion process continues for longer which leads to knock on effect of seratonin production
