Biopsychology Ao1 Only

Question 1

What are the key features of the nervous system?

Answer 1

A specialised network of cells which transport electrical and chemical signals.

1) Collect, process and respond to information in the environment.

2) Co-ordinate working of different organs and cells.

Question 2

Describe the CNS

Answer 2

Central Nervous System (CNS)
- Made up of brain and spinal cord.

The brain is centre of conscious awareness, a highly developed cerebral cortex is what separates humans from other primates and has two hemispheres.

The spinal cord is an extension of the brain and responsible for reflex action. Passes messages to and from the brain and connects nerves to PNS.

Question 3

Describe the PNS

Answer 3

Peripheral Nervous System (PNS)
- Transmits messages via millions of neurons to and from the nervous system.

It divides into:

1) Autonomic Nervous System
- Governs vital (automatic) function of the body.
- Divides into Sympathetic and Parasympathetic.

2) Somatic Nervous System
- Receives information from sensory receptors to govern muscle movement.

Question 4

Describe the endocrine system.

Answer 4

Works alongside the nervous system to control vital functions using hormones. Works slower than electrical signals (seconds instead of milliseconds.

Glands:
- Organs which produce hormones. Pituitary gland is the “master gland” as it controls all other endocrine glands.

Hormones:
- Secreted in the bloodstream and affect any cell that has a receptor for it (lock and key model). E.g thyroxine affects cells in the heart.

Question 5

How do endocrine system and ANS work together?

Answer 5

Example: fight or flight response

• Stressor perceived by hypothalamus which activates pituitary.
• SNS (Sympathetic) is now aroused.
• Adrenaline released to deliver the arousal state which causes symptoms such as increased heart and breathing rate, plus dilated pupils.
• Immediate and automatic response when threat is perceived.
• PNS (Parasympathetic = the rest system) takes over once threat has passed.

Question 6

What are neurons and the 3 types of neuron?

Answer 6

Cells which transmit signals chemically and electrically to provide nervous system with communication. 100 billion neurons 80% located in the brain.

1) Sensory
- Carry messages from PNS to CNS. Long dendrites and short axons. Located in PNS.

2) Relay
- Connect between neurons (e.g sensory to motor). Have short dendrites and short axons. 97% located in brain and visual system.

3) Motor
- Connect CNS to muscles and glands. Short dendrites and long axons. Cell bodies in CNS but long axons in PNS.

Question 7

What is the structure of a neuron?

Answer 7

Cell body:
- Includes nucleus and genetic material.

Dendrites:
- Branch like structure which protrudes from the cell body. Carry nerve impulses from neighbouring cell to neuron.

Axon:
- Carries the electrical signal away from cell body. Covered in fatty myelin sheath for protection. Gaps called “nodes of Ranvier” speed up transmission impulse.

Terminal buttons:
- End of axon communicates with the next neuron across the synapse.

Question 8

What happens when a neuron is activated by a stimulus?

Answer 8

The inside of the cell becomes positively charged for a split second, causing an action potential to occur which creates an electrical impulse that moves down the axon.

Question 9

Describe the basic prosses of synaptic transmission.

Answer 9

Signals within the neuron are always electrical, between neurons they are always chemical.

When electrical impulse is at end of neuron (presynaptic terminal) it triggers the release of neurotransmitter from synaptic vesicles.

Neurotransmitter crosses gap and is taken up by postsynaptic receptor site meaning the signal only ever goes one way.

Question 10

What are neurotransmitters?

Answer 10

Chemicals that diffuse across the synapse and each has its own specific molecular structure it fits into on the receptor site, lock and key model.

Examples:
- Serotonin affects mood and social behaviour.
- Acetylcholine causes muscles to contract.

Question 11

What is inhibition and exhibition?

Answer 11

Neurotransmitters create either an inhibitory or exhibitory effect.

Inhibition:
- Increases the negative charge of the postsynaptic neuron, making it less likely the neuron will fire.
- e.g. Serotonin

Exhibition:
- Increases the positive charge of the postsynaptic neuron, making it more more likely the neuron will fire.
- e.g. Adrenaline.

Impulses are added up and must reach a certain threshold for an action potential to occur. Either the add up is exhibitory or inhibitory.

Question 12

Outline the localisation of function in the brain.

Answer 12

Holistic theory (all parts of brain involved in thought and action) replaced by localisation theory in the 19th century.

The brain is divided into two hemispheres and lateralised (certain functions mainly controlled by one side e.g left controls right side of body).

Outer layer of the brain is the cerebral cortex, its 3mm thick and humans is far more developed than all others. Its also called grey matter.

Cerebral cortex of both hemispheres is divided into four lobes:
1) Frontal lobe = motor area
2) Parietal lobe = Somatosensory area
3) Occipital lobe = visual area
4) Temporal lobe = Auditory area

Question 13

Describe the language centres of the brain.

Answer 13

Broca’s area:
- Speech production, in frontal lobe.
- Broca’s aphasia causes slow, laborious speech which lacks fluency.

Wernicke’s area:
- Language understanding, in temporal lobe.
- Wernicke’s aphasia produce language with ease but is mostly nonsense words with no meaning.

Question 14

Outline hemispheric lateralisation

Answer 14

The brain is lateralised (two hemispheres) with some functions being localised.

Localised and lateralised:
- Some functions are both localised and lateralised.

Contralateral:
- One side of brain controls function on opposite side of body.

Contralateral and ipsilateral:
- Left visual field (LVF) of both eyes is connected to RH and LH, same with the RVF.
- Same arrangement for auditory functions.

Question 15

Describe a procedure and findings into split-brain research.

Answer 15

Sperry

Procedure:
- Corpus callosum can be severe (separates the Hs) for those with sever epilepsy.
- 11 split-brain participants were studied. Shown image or word projected to RVF (LH) or LFV (RH). Presenting image to one hemisphere only meant information could not be shared across the two.

Findings:
- Object shown to RVF could be described (language is LH).
- Object shown to LVF could not be described or named, but participants could select a matching or closely associated object.
- Demonstrates how certain functions are lateralised.

Question 16

Outline plasticity

Answer 16

The brain is “plastic” with synaptic connection form and are pruned.
- Growth of synaptic connections peak at 2-3 years of age, at around 15,000.
- Rarely used connections are deleted, frequently used ones are strengthened.
- Neural connections can be formed at any time during your life (learning).

Question 17

Outline functional recovery of the brain after trauma.

Answer 17

Following trauma, unaffected areas of the brain take over “lost functions”.

The brain “rewires” itself by forming new synaptic connections. Secondary neural pathways (like a backup power generator) carry out “lost” functions.

Structural changes in the brain occur:

1) Axonal sprouting:
Nerve ending growth connects with undamaged areas to form new “pathways”.

2) Denervation super-sensitivity:
- Axons that do a similar job are put on higher levels of arousal to compensate for ones that are lost.

3) Recruitment of homologous area:
- Opposite side of brain takes over different tasks.

Question 18

Outline ways of studying the brain and four techniques.

Answer 18

Psychologists use medical techniques to investigate brain localisation.

1) fMRI
- Highlights active areas of the brain by detecting changes in blood and oxygen flow.

2) EEG
- Shows overall electrical activity via electrodes on a skull cap.

3) ERP
- Brainwaves related to particular events.

4) Post-mortems
- Examinations of dead brains.

Question 19

Outline circadian rhythms.

Answer 19

Biological rhythms are patterns of changes in body activity that conform to a cyclical time period and are governed by:
- Endogenous Pacemakers (Internal clock/ EP)
- Exogenous Zeitgebers (External cues/ EZ)

The circadian rhythm lasts about 24 hours and there are several important circadian rhythms/ cycles.

Sleep/wake cycle is governed by internal and external mechanisms.
- Endogenous Pacemakers = A free running biological clock when there’s no sunlight.
- Exogenous Zeitgebers = Tired when dark, alert when sunny. Effect of daylight. EZs reset the SCN.

Superchiasmatic nucleus (SCN) governs basic rhythm by providing information from the eyes about light.

Question 20

Outline three studies into circadian rhythms.

Answer 20

1) Siffre cave studies
- Conducted studies where he lived in caves without light to examine the effect of free-running biological rhythms. Both times, his free-running rhythm settled at 25 hours.

2) Aschoff and Wever
- Had a group of participants do the same study as Siffre, but in a WW2 bunker. All but one participant had rhythms settle between 24 and 25 hours.

3) Folkard et al.
- 12 people in the cave when researchers slowly shortened their days to 22 hours by telling them when to sleep and wake. Only one participant comfortably adjusted. EPs are stronger than EZs.

Question 21

Outline Infradian rhythms.

Answer 21

Biological rhythms with a duration of over 24 hours.

Exogenous Zeitgebers synchronise cycles:
Stern and McClintock
- Menstrual cycles synchronised using pheromones from armpits on cotton swabs. 68% of women had cycles closer to pheromone donor.

Seasonal Affective Disorder (SAD) is an infradian rhythm. Depression in winter due to low sunlight.
- SAD caused by over-secretion of melatonin due to lack of light which reduces serotonin levels.

Question 22

Outline Ultradian rhythms.

Answer 22

Biological rhythms with a duration of under 24 hours.

Sleep is an example of an Ultradian rhythm with multiple 90 minute cycles during sleep, each cycle has five stages:

• 1&2: Light sleep, brain produces alpha waves. In stage two, sleep spindles (random changes in pattern) occur. Easy to wake from.
• 3&4: Deep sleep, brain produces deep waves with lower frequency and higher amplitude (opposite to alpha waves). Hard to wake from.
• 5: REM (Rapid Eye Movement/ dream stage), the body is paralysed and the brain produces theta waves.

Question 23

Outline endogenous pacemakers and the sleep/ wake cycle.

Answer 23

Internal body clocks.

The suprachiasmatic nucleus (SCN) is a tiny bundle of nerves in the hypothalamus. It receives information about light from the optic chiasm where nerve fibres from the eyes cross.

Research into influence of SCN:

1) DeCoursey et al.
- SCN connections in chipmunks brains destroyed and they lost their sleep/wake cycle completely. Many were killed by predators when released.

2) Raph et al.
- SCN from bred “mutant” hamsters to have 20 hour sleep cycle transplanted into normal hamsters. 20 hour sleep cycle was developed.

SCN indicates day length to pineal gland which secretes melatonin when dark. They are both endogenous mechanisms.

Question 24

Outline exogenous zeitgebers and the sleep/wake cycle.

Answer 24

External environmental factors that reset biological clocks. Without external cues, free-running biological clock continues to click in a cyclical pattern.

Light is the main key EZ and can reset the EP.

Campbell and Murphy
- Woke up participants at various time, shone light at back of knees. Sleep/ wake cycle deviated by three hours. Light does not rely on eyes to influence the SCN.

Social cues have effect on sleep/ wake cycle. Sleep-wake cycle is random in human new-borns until about 16 weeks. Schedules imposed by parents e.g regular meal times and bedtimes have great effect.

Research shows adapting to local times for eating and sleeping reduces jet lag quicker by entraining circadian rhythms.