Biopsychology Ao1

Question 1

The nervous system

Answer 1

A specialised network of human cells that acts as our primary internal communication system. it uses electrical and chemical signals.

Question 2

The to main functions of the nervous system

Answer 2

• to collect and respond to information in the environment
• to coordinate the working of different organs and cells in the body

Question 3

What are the two subsystems of the nervous system?

Answer 3

-central nervous system
-peripheral nervous system

Question 4

What is the central nervous system split into?

Answer 4

-brain
-spinal chord

Question 5

Describe the brain

Answer 5

The brain is the centre of all conscious awareness. The brains outer layer, the cerebral cortex is inly 3mm thick and is only fund in mammals. The brain is what distinguishes our higher mental functions from those of animals. It is split into two hemispheres.

Question 6

Describe the spinal chord

Answer 6

It passes messages to and from the brain and connects nerves to the PNS. It is responsible for reflex action.

Question 7

What are the subdivisions of the PNS?

Answer 7

-autonomic nervous system: governs vital functions in the body eg breathing, heart rate, sexual arousal and stress responses.
-somatic nervous system- governs muscle movement and receives information from sensory receptors.

Question 8

The endocrine system

Answer 8

Works alongside the nervous system to control vital bodily functions. Acts slower than the nervous system but has widespread and powerful effects .

Question 9

Glands

Answer 9

Various glands in the body produce hormones which are then secrete into the bloodstream and effect target cells with specific receptors. Most hormones effect more than one organ.

Question 10

What is the master gland?

Answer 10

The pituitary gland is located in the brain and controls the release of all other endocrine glands in the body.

Question 11

Fight or flight

Answer 11

The endocrine and autonomic nervous system work in parallel with each other. First a stresses is perceived , then the part of the brain called the hypothalamus activates the pituitary gland which triggers activity of the sympathetic branch of the autonomic nervous system. This changes the body from its normal resting state to a physiologically aroused sympathetic state.

Question 12

Adrenaline

Answer 12

The stress hormone is released from the adrenal medulla into the bloodstream. Adrenaline triggers physiological arousal necessary for the fight or flight response.

Question 13

How quickly is the response?

Answer 13

The response is immediate and automatic as soon as the threat is detected eg increased heart rate. This is an acute response and an automatic reaction from the body.

Question 14

Parasympathetic action

Answer 14

Once the threat has passed the parasympathetic nervous system returns the body to its resting state by working in opposition with the sympathetic nervous system (antagonistic). The parasympathetic nervous system reduced the activities of the body that were previously increased.

Question 15

Neurons

Answer 15

There are 100 billion neurons in the human nervous system, 80% of which are located in the brain. By transmitting signals electrically and chemically they make the nervous system the bodies primary means of communication.

Question 16

Types of neurons

Answer 16

-sensory
-motor
-relay

Question 17

Structure of a neurone

Answer 17

Neurons vary in size from less that a mm to a meter long. They all have a cell body including the nucleus which contains genetic material of the cell. They have an axon which carries impulses away from the cell body. The axon is covered n a fatty layer of myelin sheath that protects the axon and speeds up electrical impulses. Myelin Sheath are segmented by gaps called the nodes of Ranvier. These speed up transmission by forcing impulses to jump across gaps. At the end of the axon there are terminal buttons that communicate with the next neuron across the synapse.

Question 18

Location of neurons

Answer 18

The cell bodies of the motor neuron may be in the CNS but they have long axons which form part of the PNS. Sensory neurons are located outside of the CNS, they are in PNS clusters known as ganglia. Relay neurons make up 97% of all neurons found in the brain and visual system.

Question 19

Electrical transmission

Answer 19

When a neuron is in resting state inside the cell it is negatively charged. When the neuron is activated by the stimulus inside of the cell become positively charges for a split second causing action potential to occur. This creates an electrical impulse.

Question 20

Chemical transmission (synaptic)

Answer 20

Neurons communicate with each other within groups known as neural networks. Each neurone is separated from the next by a tiny gap called a synapse. Signals within neurons are transmitted electrically, signals between neurons are transmitted chemically across a synapse.

Question 21

How are neurotransmitters released?

Answer 21

When the electrical impulse reaches the end of a neuron (presynaptic terminal) it triggers the release of a neurotransmitter from tiny sacs called synaptic vesicles.

Question 22

Neurotransmitters

Answer 22

Chemicals which diffuse across a synapse. When it has crossed the gap it is taken up by the postsynaptic receptor site on the dendrites of the next neuron (axons take signals to the synapse and dendrites take them away). Here chemicals are converted back to an electrical impulse and transmission resumes.

Question 23

What direction do chemical impulses travel?

Answer 23

The can only travel one way because they have to be released by the presynaptic neuron terminal and received by the postsynaptic neuron.

Question 24

What is the molecular structure of a neuron?

Answer 24

Each neurotransmitter has its own specific molecular structure. That fits perfectly with the postsynaptic receptor site (lock and key). Neurotransmitters also have specialist function eg Acetylcholine- causes muscles to contract.

Question 25

Inhibition

Answer 25

eg the neurotransmitter serotonin causes inhibition in the receiving neuron leaving it negatively charged and less likely to fire.

Question 26

Excitation

Answer 26

eg adrenaline causes excitation of the postsynaptic neurone by increasing its positive charge and making it more likely to charge.

Question 27

Summation

Answer 27

Whether a neuron fires is decided by a process called summation. If the net effect on the postsynaptic neuron is negative, it is less likely to fire. Whereas if the net effect is positive it is more likely to fire. Therefore action potential of the postsynaptic neuron is only triggered if the sum of the excitatory and inhibitory signals reaches the threshold.

Question 28

Holistic theory

Answer 28

Theory that all that all parts of the brain were involved in the processing of thought and action

Question 29

What brought about localisation?

Answer 29

Scientists such as Broca and Wernicke discovered that different areas of the brain were associated with different physical and psychological functions. They argued for localisation of brain function (cortical specialisation).

Question 30

The theory of localisation

Answer 30

The idea that different parts of the brain perform different tasks and are involved with different parts of the body. So if a certain area of the brain gets damaged through illness or injury the function of that part of the brain will be affected.

Question 31

Hemispheres of the brain

Answer 31

The main part of the brain (the cerebrum) is divided into a right and left hemisphere. Some psychological functions are controlled or dominated by one particular hemisphere - this is called lateralisation.

Question 32

General rule of lateralisation

Answer 32

Left-hand side of the brain controls the right side of the body and right-hand side of the brain controls the left hand side of the body. (language is linked to the left hemisphere)

Question 33

Lobes of the brain

Answer 33

The cerebral cortex is the outer layer of both hemispheres. The cortex of both hemispheres is subdivided into 4 lobes.

Question 34

What are the 4 lobes of the brain?

Answer 34

-frontal lobe
-parietal lobe
-occipital lobe
-temporal lobe

Question 35

Functions of the frontal lobe

Answer 35

The motor area which controls voluntary movement in the opposite side of the body. Damage to this area may result in loss of control over five movements.

Question 36

Functions of the parietal lobe

Answer 36

The somatosensory area which is separated from the motor area by a valley called central sulcus. The somatosensory area is where sensory information from the skin is represented. The amount of somatosensory area devoted to a particular body part denotes its sensitivity.

Question 37

Function of the occipital lobe

Answer 37

It is the brains visual area each eye send information to the opposite visual field. This means damage to one hemisphere can can produce partial or full blindness.

Question 38

Function of the temporal lobe

Answer 38

Houses the auditory area, which analyses speech based information. Damage to this area can cause partial or full hearing loss. (the more extensive the damage the more extensive the loss)

Question 39

Language centres in the brain

Answer 39

Language is restricted to the left side o the brain in most people.

Question 40

Broca’s area

Answer 40

Broca identified a small area in the left frontal lobe responsible for speech production. Damage to this area causes aphasia which is characterised by slow speech which lacked fluency, they may also have problems with prepositions and conjunctions.

Question 41

Wernicke’s area

Answer 41

Wernicke identified a region in the left temporal lobe responsible for language understanding. When damaged this would result in Wernicke’s aphasia often fluently produce nonsense words as part of their content of speech.

Question 42

What is lateralisation

Answer 42

The two hemispheres of the brain. For some functions the localised areas appear in both hemispheres.

Question 43

Language lateralisation

Answer 43

Two main language centres are found in the left hemisphere therefore language is lateralised.

Question 44

Can the right hemisphere produce language?

Answer 44

Can only produce rudimentary words and phrases it does however contribute the emotional context to what is being said.

Question 45

What functions are not lateralised?

Answer 45

Vision, motor and somatosensory appear in both hemispheres. Motor area of the brain is cross wired eg right side of the brain controls the left side of the body. The visual area is contralateral and ipsilateral (opposite and same sided). Each eye receives information from both visual fields, this allows us to see slightly different perspectives from each eye. Sound works similarly.

Question 46

Split brain research

Answer 46

Split brain involves severing the connection between the right half and left half of the brain. Mainly the corpus collusum. This is a surgery to reduce epilepsy.

Question 47

Sperry’s research

Answer 47

Devised a system to study how two separated hemispheres deal with things like speech and vision.

Question 48

Sperry’s procedure

Answer 48

11 people who had undergone split brain surgery were studied. The set up allowed an image to be projected in the RVF (processed by the left side of the brain) and a different photo is shown to the other visual field. In a ‘normal brain’ the callosum would share the photo giving the whole photo or word. Presenting it to one hemisphere of a split brain participant meant that the information couldn’t be conveyed to the other hemisphere.

Question 49

Sperry’s finding

Answer 49

When picture of an object was shown to a participants RFV (linked to LH) participants could describe what was seen. When they were shown it in their LFV (RH) they said nothing was there this is because messages from the RH are transmitted to the language system in the LH but this is not possible in split brain patients. Although participants couldn’t give verbal cues for thing in the LFV (RH) they could select a matching object using their right hand or a closely associated object.

Question 50

Sperry’s conclusions

Answer 50

Prove that certain functions are lateralized.
And support that the LH is verbal and the RH is emotional.

Question 51

Brain plasticity

Answer 51

The brain has the ability to change throughout life. In infancy the brain experiences rapid growth an the number of synaptic connections peaks at 15000 between age 2-3. (twice as many as the adult brain). As we age the connections that we rarely use deleted and frequently used ones are strengthened (process known as sympathetic pruning). This process allows lifelong plasticity.

Question 52

Research into plasticity

Answer 52

Maguire et al studied the brains of London taxi drivers and found significantly more volume of grey matter in the posterior hippocampus than the control group. The part of their brain associated with spatial and navigational skills structural difference showed positive correlation with their time on the job.

Draganski et al imaged brains of med student and found that their studying before their exam induced changes as a result of their learning.

Question 53

Functional recovery of the brain after trauma

Answer 53

Following injury the brain can often adapt and compensate for the areas which are damaged and is an example of neutral plasticity. Healthy parts of the brain quickly take over after trauma and then this slows down after months. At this point methods of rehabilitation are necessary for further improvement.

Question 54

What happens to the brain during recovery

Answer 54

The brain reorganizes itself be forming new synaptic connections close to the damaged area. Neutral pathways which would not usually be used then carry out functions and are activated which enables functioning to continue similarly to before. This can alter the brains structure.

Question 55

What can alter in the brains structure?

Answer 55

-axonal spouting- growth of new nerve endings which connect with undamaged nerve cells to create a new pathway
-denervation supersensitivity- occurs when axons which so similar jobs become aroused to a higher level to compensate for the ones which are lost, this can have an oversensitivity to messages such as pain.
-recruitment of homologues areas on the opposite side of the brain- eg if Brocas area was damaged the RH of the brain may carry out the function (it can shift back to the left in time)

Question 56

Functional magnetic resonance imaging

Answer 56

Works by detecting the changes in blood oxygenation and flow which occurs as a result of neural activity in specific parts of the brain. When a brain area is more active it consumes more oxygen and to meet this demand blood flow is directed to the active area (haemodynamic response). fMRI produces 3 dimensional images showing parts of the brain involved with mental processes. This is key in our understanding of brain function.

Question 57

Electroencephalogram

Answer 57

Measures electrical activity in the brain via electrodes fitted to an individuals scalp using a skull cap. The scan recording represents brainwave patterns that are generated from the action of thousands of neurons providing an overall account of brain activity. It is often used as a diagnostic tool for unusual patterns of activity.

Question 58

event related potentials

Answer 58

Shows an overall general measure of brain activity and researchers have developed a way of isolating certain responses using statistical average technique and therefore only leaving the related response. This is usually a brainwave triggered by a specific event.

Question 59

Post-mortem examinations

Answer 59

Analysis of a persons brain following their death. This is most likely to be a person with a rare disorder or unusual cognitive processes throughout their life. Areas of damage can be helpful in recognizing the reason for a persons affliction. It can be compared with a neurotypical brain.

Question 60

Biological rhythms

Answer 60

Influence the way in which the body behaves, they are effected by two things, the bodies endogenous pacemakers and exogenous zeitgebers.

Question 61

The sleep/wake cycle

Answer 61

Daylight is an exogenous zeitgeber in the sleep/wake cycle however the endogenous pacemaker of the superchiasmatic nucleus is also relevant. It lies just above the optic chiasm (light can reset the SCN)

Question 62

Siffre’s case study

Answer 62

Siffe spent several extended periods underground, he resurfaced mid September believing it was mid august. He later did a similar experiment and found that his natural body clock ran at about 25 hours but he still had a regular sleep wake cycle.

Question 63

Other research

Answer 63

Aschoff and Wever - group of participants spent four weeks in a ww2 bunker all but one displayed a circadian rhythm between 24 and 25 hours. This shows our natural rhythm is longer than 24 hours but exogenous zeitgebers entrain it to a 24 hour cycle.

Folkard et al - when participants clock slowly sped up from a 24 hour day to a 22 hour day only one participant could comfortably adjust.