biopsych Flashcards
1
Q
the nervous system
A
2 main functions:
- to collect, process + respond to info in the environment
- to coordinate the working of different organs + cells in the body
made up of:
- central nervous system
- peripheral nervous system
2
Q
central nervous system
A
made up of the brain + spinal cord:
- the brain = centre of all conscious awareness
- the spinal cord = an extension of the brain + responsible for reflex actions
3
Q
peripheral nervous system
A
made up of neurones that connect the CNS to the rest of the body
further divided into:
- somatic nervous system: controls conscious activities (eg running)
- autonomic nervous system: controls vital functions in body (eg breathing, heart rate, digestion etc)
4
Q
the endocrine system
A
- works alongside the NS to control vital functions in the body through the action of hormones
- acts more slowly but has v widespread + powerful effects
- instructs glands to release hormones directly into the bloodstream to be carried to target organs
5
Q
glands
A
- organs in the body that produce hormones
- pituitary gland (aka master gland) = major endocrine gland located in the brain which controls the release of hormones from all other endocrine glands in the body
6
Q
hormones
A
- secreted into the bloodstream + affect any cell in the body that has a receptor for that particular hormone
7
Q
fight or flight
A
endocrine system + autonomic nervous system work together during stressful events
- when a stressor is perceived, the hypothalamus triggers activity in the sympathetic NS
- stress hormone adrenaline is released from the adrenal medulla into the bloodstream
- adrenaline triggers physiological changes in target organs + causes: increased heart rate, pupil dilation, decreased production of saliva (fight or flight)
- once the threat has passed, the parasympathetic NS returns the body back to its resting state (rest + digest)
8
Q
structure of a neurone
A
- cell body (soma): includes a nucleus which contains the genetic material of the cell
- dendrites: branch-like structures that protrude from the cell body - carry nerve impulses from neighbouring neurons towards the cell body
- axons: carries electrical impulse away from the cell body down the length of the neuron
- myelin sheath: fatty layer that covers the axon + speeds up electric transmission of impulse
- nodes of Ranvier: gaps in the myelin sheath from/to which impulses jump
- terminal buttons: at the end of the axon - communicate w the next neuron in the chain across the synapse
9
Q
firing of a neurone
electric transmission
A
when neurone is at rest:
- inside of cell is more negatively charged compared to the inside
when neurone is stimulated:
- inside of cell becomes positively charged for a split second, causing an AP to occur
- this creates an electrical impulse that travels down the axon toward the end of the neurone
10
Q
types of neurones
A
sensory
- carry messages from the PNS to CNS
- long dendrites and short axons
relay
- connect sensory neurons to motor neurons
- short dendrites and short axons
motor
- connect CNS to effectors e.g. muscles + glands
- short dendrites and long axons
11
Q
synaptic transmission
A
- when the electrical impulse reaches the end of the preSN, it triggers the release of NTs from the synaptic vesicles
- once NT diffuses across synaptic cleft, it’s taken up by the postsynaptic receptor sites (aka dendrites) of the next neurone
- chemical message is converted back into an electrical impulse + process of transmission begins again
12
Q
excitation
A
- when a NT increases the positive charge inside the postsynaptic neurone (depolarisation)
- making it more likely to fire an AP
- eg adrenaline
13
Q
inhibition
A
- when a NT increases the negative charge inside the postSN (hyperpolarisation)
- making it less likely to fire an AP
- eg serotonin
14
Q
summation
A
- accumulation of NTs in the synapse where both excitatory + inhibitory influences are summed
- net effect of NTs on postSN decides whether an AP is fired or not
- is only fired if depolarisation reaches the threshold
15
Q
brain localisation
A
scientists first supported the holistic theory (that all parts of the brain were involved in processing of thought + action
- was replaced by the localisation theory
- Broca & Wernicke discovered specific areas of the brain that are associated w specific functions
- if an area of the brain is damaged, the function associated w that area is also affected
16
Q
lobes
A
- cortex of both hemispheres is subdivided into 4 lobes:
- frontal, parietal, occipital and temporal
- each lobe is associated with different functions
- language, unlike other areas, is restricted to the left hemisphere
17
Q
motor area
A
- found at the back of the frontal lobe
- controls voluntary movement in the opposite side of the body
- damage may result in loss of control over fine motor movements
18
Q
somatosensory area
A
- found at front of parietal lobe
- processes sensory information from the skin (touch, heat, pressure etc)
19
Q
visual area
A
- found at the back of the occipital lobe
- each eye sends info from right visual field to left visual cortex + vice versa
- damage to left hemisphere can produce blindness in the right visual field of both eyes
20
Q
auditory area
A
- found in the temporal lobe
- analyses speech-based info
- damage may produce partial hearing loss
21
Q
Broca’s area
A
- found in left frontal lobe
- responsible for speech production
- damage results in Broca’s aphasia - characterised by slow, laborious speech, lacking in fluency
22
Q
Wernicke’s area
A
- found in the left temporal lobe
- responsible for language comprehension
- damage results in Wernicke’s aphasia - produce neologisms (nonsense words) as part of their speech
23
Q
brain localisation
ao3
A
✔ brain scan evidence
- Peterson used brain scans to demonstrate how Wernicke’s area was active during a listening task + Broca’s area was active during a reading task, showing that these areas of the brain have different functions
- Tulving revealed that semantic + episodic memories reside in different parts of the prefrontal cortex
✔ Phineas Gage case study
- damage to left frontal lobe caused a change in his personality
- calm + reserved –> quick-tempered + rude
- suggests frontal lobe is responsible for regulating mood
- HOWEVER, case studies cannot be generalised
✘ neural plasticity
- suggests that the rest of the brain is able to reorganise itself to recover lost function, following damage
- this poses as a challenge to the localisation theory as it suggests that localisation is not as rigid/permanent as made out to be
- although this doesn’t happen everytime, there are several documented case studies of stroke victims recovering seemingly lost abilities
✘ Lashley’s rats provide counter-evidence
- Lashley removed between 10-50% of the cortex in rats learning a maze
- found that no one area was more important than any other in the rats’ ability to learn the maze
- shows that learning requires every part of the cortex, not just some areas
- suggests learning is too complex to be localised + requires involvement of the whole brain
- HOWEVER, can’t generalise rats to humans
24
Q
hemispheric lateralisation
A
- brain is divided into 2 halves: left + right hemispheres
- generally, left side of body is controlled by right hemisphere + vice versa
lateralisation: idea that 2 halves of the brain are functionally different
- certain mental processes are mainly controlled by a particular hemisphere
- eg language is controlled by the left hemisphere
- suggests language is subject to hemispheric lateralisation
- questions whether other neural processes may be organised this way
- investigated in series of experiments conducted by Sperry via split brain research
25
Q
split brain research
A
- series of studies (began in 60s)
- involving epileptic pxs who had undergone cerebral commissurotomy (surgical lesioning of the corpus callosum) to control epileptic seizures
- where info processed by 1 hemisphere can’t be relayed onto the other
- allowed Sperry to investigate the extent to which brain function is lateralised
