Biopsychology - P2 Flashcards
What is the nervous system? - AO1
Consists of the central nervous system and the peripheral nervous system. Communicates using electrical signals.
What are the key features of the nervous system? - AO1
- The nervous system is a specialised network of cells and our primary communication system. It is based on electrical and chemical signals, whereas the endocrine system is based on hormones.
- The nervous system has two main functions:
1. To collect, process, and respond to information in the environment.
2. To coordinate the working of different organs and cells in the body.
What is the central nervous system (CNS)? - AO1
Consists of the brain and spinal cord and is the origin of all complex commands and decisions.
What is the structure and function of the brain in the CNS? - AO1
- The brain is the centre of conscious awareness.
- The outer layer of the brain, the cerebral cortex, 3 mm thick, is highly developed in humans and is what distinguishes our higher mental functions from those of animals.
- The brain is divided into two hemispheres.
What is the structure and function of the spinal cord in the CNS? - AO1
- The spinal cord is an extension of the brain and is responsible for reflex actions.
- It passes messages to and from the brain and connects nerves to the PNS.
What is the peripheral nervous system (PNS)? - AO1
Sends information to the CNS from the outside world and transmits messages from the CNS to muscles and glands in the body.
What is the structure and function of the PNS? - AO1
The PNS transmits messages via millions of neurons to and from the nervous system.
The PNS is further subdivided into:
- Autonomic nervous system (ANS).
- Somatic Nervous System (SNS).
What is the autonomic nervous system (ANS)? - AO1
Transmits information to and from internal bodily organs. Automatic as the system operates involuntarily. It has two main divisions: the sympathetic and parasympathetic nervous system.
- It governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses.
What physiological changes are included in the sympathetic state? - AO1
- Increases heart rate.
- Increases breathing rate.
- Dilates pupils.
- Inhibits digestion.
- saliva production.
- Contracts rectum.
What physiological changes are included in the parasympathetic state? - AO1
- Decreases heart rate.
- Decreases breathing rate
- Constricts pupils.
- Stimulates digestion.
- Stimulates saliva production.
- Relaxes rectum
What is the somatic nervous system (SNS)? - AO1
Information from receptor cells in the sense organs to the CNS. It also receives information from the CNS that directs muscles to act.
- It governs muscle movement and receives information from sensory receptors.
What are the key features of the Endocrine system? - AO1
- The endocrine system works alongside the nervous system to control vital functions in the body through the action of hormones.
- It works more slowly than the nervous system, but has widespread and powerful effects.
What are glands? - AO1
- Glands are organs in the body that produce hormones.
- The key endocrine gland is the pituitary gland located in the brain. It is called the ‘master’ gland because it controls the release of hormones from all the other endocrine glands in the body.
What are hormones? - AO1
- give an example
- Hormones are created in the bloodstream and affect any cell in the body that has a receptor for the particular hormone.
- For example, thyroxine produced by the thyroid gland affects cells in the heart and also cells throughout the body, which increases metabolic rates. This, in turn, affects growth rates.
In what situations does the endocrine system and the ANS work together? - AO1
Often the endocrine system and the ANS work in parallel, for instance during a stressful event.
How do the endocrine system and the ANS work together? - AO1
- Stressors are perceived by the hypothalamus, which activates the pituitary.
- The sympathetic nervous system is now aroused.
- Adrenaline, the stress hormone, is released from the adrenal medulla into the bloodstream. This delivers the aroused state, causing changes in target organs in the body. e.g. increased heart rate, dilation of pupils, decreased production of saliva. This is called the fight or flight response.
- Immediate and automatic - this response happens the instant a threat is perceived.
- Parasympathetic nervous system (rest and digest) takes over once the threat has passed. This returns the body to its resting state. This acts as a break and reduces the activities of the body that were increased by the actions of the sympathetic branch (rest and digest).
What are neurons? - AO1
- how many types are there
There are 100 billion nerve cells (neurons) in the human nervous system, 80% of which are located in the brain.
By transmitting signals electrically and chemically, these provide the nervous system with its primary means of communication.
There are three types of neuron: Sensory neuron, relay neuron and motor neurons.
What is a sensory neuron? - AO1
Carries messages from the PNS to the CNS. They have long dendrites and short axons. They are located in the PNS in clusters called ganglias.
What is a relay neuron? - AO1
Connect sensory neurons to motor or other relay neurons. Have short dendrites and short axons. Of all neurons, 97% are relay neurons, and most are in the brain and visual system.
What is a motor neuron? - AO1
Connects the CNS to effectors, such as muscles and glands. They have short dendrites and long axons. Cell bodies may be in the CNS, but long axons form part of PNS.
What is the structure of a neuron? - AO1
Neurons vary in size, but all share the same basic structure:
- Cell body (or Soma)
- Dendrites
- Axon
- Terminal buttons at end of axon
What is the cell body of a neuron? - AO1
Includes a nucleus which contains the genetic material of the cell.
What are dendrites of a neuron? - AO1
Branchlike structures that protrude from the cell body. These carry nerve impulses from neighbouring neurons towards the cell body.
What is an axon of a neuron? - AO1
Carries the electrical impulse away from the cell body down the length of the neuron.
- It is covered in a fatty layer of myelin sheath that protects the Axon.
- Gaps in the Axon, called nodes of Ranvier, speed up the transmission of the impulse.
What are the terminal buttons of a neuron? - AO1
Terminal buttons at the end of the Axon communicate with the next neuron in the chain across a gap called the synapse.
What is Electrical transmission? - AO1
- explain the firing of a neuron
- When a neuron is in a resting state, the inside of the cell is negatively charged compared to the outside.
- When a neuron is activated, the inside of the cell becomes positively charged for a split second, causing an action potential to occur.
- This creates an electrical impulse that travels down the Axon towards the end of the neuron.
What is a Synapse? - AO1
Each neuron is separated from the next by an extremely tiny gap, called the synapse.
How are signals transported within neurons and across the synapse? - AO1
Signals within neurons are transmitted electrically, but signals between neurons are transmitted chemically across the synapse.
What is chemical transmission? - AO1
- explain the events that occur at the synapse
1) When the electrical impulse reaches the end of the neuron (the presynaptic terminal) it triggers the release of neurotransmitter from the tiny sacs called synaptic vesicles.
2) Once a neurotransmitter crosses the gap, it is taken up by a postsynaptic receptor site on the next neuron, so the impulse only ever travels in one direction.
3) The chemical message is converted back into an electrical impulse and the process of electrical transmission begins.
what are neurotransmitters? - AO1
Neurotransmitters are chemicals that diffuse across the synapse to the next neuron in the chain.
what is unique about each neurotransmitter? - AO1
- give two examples of neurotransmitters
Many neurotransmitters have been identified. Each has its own specific molecular structure that fits perfectly into a postsynaptic receptor site, like a lock and key.
Each has specific functions. For example:
- Acetylcholine (ACh) found where a motor neuron meets a muscle, causing muscles to contract
- Serotonin affects mood and social behaviour, among other things, which is why it is being implicated as a cause of depression.
What is excitation and inhibition? - AO1
Excitatory and inhibitory influences are summed and must reach a certain threshold in order for the action potential of the postsynaptic neuron to be triggered.
If the net effect of the neurotransmitters is inhibitory, then the postsynaptic neuron is less likely to fire (i.e., no electrical signal is transmitted). It is more likely to fire if the net effect is excitatory.
Do adrenaline, serotonin and dopamine have an excitation or inhibition effect on the neighbouring neuron? - AO1
Adrenaline = Generally excitatory
Serotonin = Really inhibitory
Dopamine = Equally both
What is summation? - AO1
The excitatory and inhibitory influences on the post-synaptic neuron are summed (added together), if the net effect on the post-synaptic is inhibitory, the neuron will be less likely to ‘fire’ and if the net effect is excitatory, the neuron will be more likely to ‘fire.’
What is localisation of function in the brain? - AO1
- who argued this
The theory that different areas of the brain are responsible for specific behaviours, processes or activities
- theory argued + created by Broca and Wernicke
What is the holistic in the brain? - AO1
- who argued this
the theory that all parts of the brain were involved in the processing of thought and action
- believed by scientists before Broca + Wernicke’s research and before Phineas Gage research
What is lateralisation? - AO1
Part of the brain, the cerebrum, is divided into two symmetrical halves called the right and left hemisphere. Some of our physical and psychological functions are controlled or dominated by a particular hemisphere. This is called lateralisation.
What parts of our body are controlled by what halves of the brain? -AO1
As a general rule, activity on the left hand side of the body is controlled by the right hemisphere, and activity on the right hand side of the body by the left. Language is linked to the left hemisphere.
What is the cerebral cortex? - AO1
- What are both hemispheres divided into
- The cerebral cortex, or cortex, is the outer layer of both hemispheres.
- The cortex of both hemispheres is subdivided into four centres called the lobes of the brain: the frontal lobe, the parietal lobe, the occipital lobe and the temporal lobe.
What is a lobe? - AO1
A lobe is a part of an organ that is separate in some way from the rest. Each lobe in the brain is associated with different functions.
What is the motor area? - AO1
- what is the effect of damage
- At the back of the frontal lobe in both hemispheres is the motor area, which controls voluntary movement in the opposite side of the body.
- Damage to this area of the brain may result in a loss of control over fine movements.
What is the somatosensory area? - AO1
- what is the effect of damage
- At the front of both parietal lobes is the somatosensory area, which is separated from the motor area by a valley called the Central Sulcus.
- The somatosensory area is where sensory information from the skin, e.g. related to touch, heat, pressure, etc. Is represented.
- The amount of somatosensory area devoted to a particular body part donates its sensitivity. For instance, receptors for our face and hands occupy over half of the somatosensory area.
What is the visual area? - AO1
- what is the effect of damage
- In the occipital lobe, at the back of the brain is the visual area, or visual cortex. Each eye sends information from the right visual field to the left visual cortex and from the left visual field to the right visual cortex.
- This means that damage to the left hemisphere, for example, can produce blindness in part of the right visual field of both eyes.
What is the auditory area? - AO1
- what is the effect of damage
- The temporal lobes house the auditory area which analyses speech based information.
- Damage may produce partial hearing loss. The more extensive the damage, the more extensive the loss.
What is Broca’s area? - AO1
- Is an area of the frontal lobe in the left hemisphere (in most people) responsible for speech production.
- Damage to Broca’s area causes broca’s aphasia, which is characterised by a speech that is slow, laborious, and lacking in fluency.
Describe the research into localisation of brain function. - AO1
- What did Broca find
- Broca carried out a post mortem on the brain of a patient known as ‘Tan’
- This patient was only able to say ‘Tan’
- Broca found that he had part of his left frontal lobe missing, leading to a language function being associated with this area of the brain.
What is Wernicke’s area? - AO1
- Is an area of the temporal lobe (encirculating the auditory cortex) in the left hemisphere (in most people) responsible for language comprehension.
- Damage to Wernicke’s area will result in Wernicke’s aphasia, often producing nonsense words, neologism as part of content of their speech.
What is one strength of localisation theory? - AO3
One strength is that damage to areas of the brain have been linked to mental disorders.
- Neurosurgery is a last resort method for treating some mental disorders, targeting specific areas of the brain which may be involved.
- Darin Dougherty et. al (2002) reported on 44 people with OCD who had undergone a cingulotomy. A post-surgical follow up after 32 weeks, about 30% had met the criteria for successful response to the surgery and 14% for partial response.
- The success of these procedures suggest that behaviours associated with serious mental disorders may be localised.
What is another strength of localisation theory? - AO3
Another strength is evidenced from brain scans that support the idea that many everyday brain functions are localised.
- For instance, Stephen Peterson et. al (1988) used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task.
- A study for long-term memory by Endel Tulving et. al (1944), revealed that semantic and episodic memories reside in different parts of the prefrontal cortex.
- These studies confirm localised areas for everyday behaviours. Therefore, objective methods for measuring brain activity have provided sound scientific evidence that many brain functions are localised.
What is a counterpoint of the other strength of localisation theory? - AO3
- A challenge to localisation theory comes from the work of Karl Lashley (1950). Lashley removed areas of the cortex between 10% and 50% in rats that were learning the route through a maze. No area was proven to be more important than any other area in terms of the rats’ ability to learn the route.
- The process of learning seemed to require every part of the cortex, rather than being confined to a particular area. Suggests that higher cognitive processes such as learning or not localised but distributed in a more holistic way in the brain.
What is one limitation of localisation theory? - AO3
A limitation is that language may not be localised just to Broca’s and Wernicke’s areas.
- A recent review by Anthony Dick and Pascal Tremblay (2016) found that only 2% of modern researchers think that language in the brain is completely controlled by Broca’s and Wernicke’s areas.
- Advances in brain imaging techniques such as fMRI mean that neural processes in the brain can be studied with more clarity than ever before. It seems that language function is distributed far more holistically in the brain than was first thought. So-called language streams have been identified across the cortex and including brain regions in the right hemisphere as well as subcortical regions such as the thalamus.
- This suggests rather than being confined to a couple of key areas, language may be organised more holistically in the brain, which contradicts localisation theory.
What is Hemisphere Lateralisation? - AO1
The idea that the two hemispheres of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by 1 hemisphere rather than the other as in the example of language.
What is Split-Brain Research? - AO1
A series of studies which began in the 1960s forward, involving people with epilepsy who had experienced a surgical separation of the hemispheres of the brain to reduce the severity of their epilepsy. This enabled researchers to test lateral functions of the brain in isolation.
Explain the difference between localisation and lateralisation in context of the brain. - AO1
- Localisation refers to the fact that some functions, e.g., vision and language are governed by very specific areas in the brain.
- Lateralisation refers to the fact that there are two sides called hemispheres of the brain and some functions appear in both hemispheres.
What is the function of the left hemisphere? - AO1
- Known as the analyser.
- Controls the right side of the body.
- Viewed objects are visible in the right visual field.
- The finer image details are seen
Has two main centres, Broca’s area which is the frontal lobe and Wernicke’s area which is in the temporal lobe, therefore showing the brain is lateralized. - understanding of language.
What is the function of the right hemisphere? - AO1
- Known as the synthesiser.
- Controls the left side of the body.
- Viewed objects are visible in the left visual field.
- Used for drawing due to motor area.
- The wider visual picture.
- Emotional context of language.
Explain and describe Sperrys (1968) Split-Brain Research. - AO1
- Sperry’s participants had undergone the splitting of the corpus callosum.
- Sperry devised a general procedure in which an image or word could be projected to a patient’s right visual field, which is processed by the left hemisphere, and the same or different image could be projected to the left visual field, which is processed by the right hemisphere.
- In the ‘normal’ brain, the corpus callosum would immediately share the information between both hemispheres, giving a complete picture of the visual word.
- However, presenting the image to one hemisphere of a split-brain patient meant that the information could not be conveyed from that hemisphere to the other.
What is one strength of Hemispheric lateralisation? - AO3
Strength is research showing that even in normal brains, the two hemispheres process information differently.
- Fink et al. (1996) used PET scans to investigate visual processing.
- They found that different sides were more active.
- This suggests that, at least as far as visual processing is concerned, hemispheric lateralisation is a feature of the normal brain as well as the split-brain.
What is one limitation of hemispheric lateralisation? - AO3
One limitation is the idea that the LH as analyzer and RH as synthesiser may be wrong.
- There may be different functions in the RH and LH, but research suggests people do not have a dominant side of their brain, which creates a different personality.
- Nielsen et al. (1996) found that people used certain hemispheres for different tasks, but there was no evidence of a dominant side.
- This suggests that the notion of right-or-left-brained people is wrong.
