Biopsychology Flashcards
(19 cards)
1
Q
The Nervous System
A
- Is our primary internal communication system; its a specialised network of nerve cells in our body
- It consists of the CNS and the PNS; each are further divided
2
Q
The Central Nervous System
A
- Receives info from the senses and controls the behaviour + regulation of the bodies psychological processes
- The brain recieves info from sensory receptors and sends messages to muscles and glands
- Consists of the brain and spinal cord (spinal cord is an extension of the brain responsible for reflex actions.
3
Q
The Peripheral Nervous System
A
- Consists of the somatics nervous system + autonomous nervous system
- The PNS is made up of spinal nerves containing the sensory (afferent) and motor (efferent) pathways which connect the CNS with receptors, organs, muscles in the body.
4
Q
Somatic Nervous System
Is in the PNS
A
- The SNS is made up of sensory pathways from the sensory receptors (eg touch, pain, pressure) and motor pathways. The sensory pathways send information from the environment to the brain. The motor pathways control skeletal muscles as a result from sensory stimulus from the environment. The SNS maintains communication between CNS and outside world.
5
Q
Autonomous Nervous System
Is in the PNS
A
- The ANS regulates glands, blood vessels and internal organs by homeostasis the ANS is involuntary
- The ANS is made up of motor pathways which control the activity of the internal body systems, eg heart and circulatory system.
- The ANS consists of the sympathetic nervous system (mobilises body for action, outputs energy) + parasympathetic nervous system (conserves energy, maintains quiet state). Nerve fibres from both branches connect with internal structures such as various glands
- If a dangerous or threatening situation is perceived, higher brain centres signal the hypothalamus, a key structure buried deep in the brain, to activate the sympathetic branch of the ANS.
6
Q
The Endocrine System
A
- The endocrine system is a network of glands throughout the body whose function is to control the activity of particular cells or organs in the body.
- Glands secrete hormones directly into the bloodstream or circulatory system.
- Hormones released by these glands are vital to most of the physiological functions of the body.
- The ‘master gland’ is the pituitary - rather than having a direct effect on tissues of the body the function of this gland is to control other endocrine glands.
- The hypothalamus controls the release of hormones from the pituitary gland and is thus considered to have general control of the endocrine system.
7
Q
Examples of some endocrine glands
A
- Examples of other key glands, their associated hormones and their functions include:
- thyroid, releases the hormone thyroxine, function - regulates metabolic rate
- testes, release androgens, function - development of male characteristics at puberty
- ovaries, release oestrogens, function - regulate female reproductive system etc
- pineal, releases melatonin, function - regulates biological rhythms etc
- adrenal medulla, releases adrenaline and noradrenaline, function - fight or flight response
- adrenal cortex, (i) releases glucocorticoids eg cortisone, function - release glucose, suppress immune response etc i releases mineralcorticoids, function - regulates water balance of the body.
8
Q
Fight or Flight Response
A
- Higher brain centres (cortex and limbic system) carry out an appraisal of a situation and identify it as potentially dangerous.
- This activates the sympathetic nervous system of the ANS.
- Hypothalamus is instructed to stimulate the release of adrenocorticotrophic hormones (ACTH) from the pituitary gland.
- ACTH stimulates the release of corticosteroids (cortisol and corticosterone) from the adrenal cortex into the bloodstream.
- Sympathetic nervous system sends a neural message to the adrenal medulla to instruct it to increase the release of adrenaline and noradrenaline into the bloodstream.
- Adrenaline speeds up heart rate, constricts blood vessels and raises blood pressure.
- Energy reserves are released, leading to raised levels of glucose and fatty acids.
- A negative feedback loop via the hypothalamus monitors the hormone levels.
- The fight or flight response is a reflex response and the body’s physiological reactions to stressful situations
- Perception of threat switches control from parasympathetic to sympathetic nervous system
- The response is generated from the sympathetic branch of the ANS and allows the individual to react quickly so that they can fight or escape the threat
- The hypothalamus recognizes the threat and sends a message to the adrenal gland (adrenal medulla)
- This triggers the release of adrenaline (to the endocrine system) and noradrenaline in the brain
- This prompts physical changes to help deal with the threat OR to escape. Changes include: increased heart and breathing rate; muscle tension, sweating; reduction in digestion etc
- Once the threat has passed, the parasympathetic nervous system is activated and the physiological arousal associates with the fight or flight response decreases and the body switches back to the resting parasympathetic state.
- Heart rate and blood pressure are reduced and digestion begins again, this is sometimes called the rest and digest
9
Q
Whats a neuron?
A
- They’re the cells that make up the nervous system
- There’re motor, relay and sensory neurons
10
Q
Motor neurons
A
- The nerve cells responsible for carrying signals away from the CNS towards muscles to cause movement
- They release neurotransmitters to trigger responses leading to bodily movement
- Motor neurons are located in the brainstem or spinal cord (parts of the CNS) and connect to muscles glands and organs throughout the body
11
Q
Relay neurons
A
- Allows SENSORY and MOTOR neurons to communicate with each other and alsodifferent parts of the CNS
- Relay neurons lie entirely within the CNS, and much of the brain is made up of relay neurons.
12
Q
Sensory neurons
A
- Sensory receptors carry info by a sensory neuron into the spinal cord and then on to the brain
- Sensory neurons are nerve cells which carry nerve impulses from sensory receptors towards the CNS and brain. When these nerve impulses reach the brain, they are translated into ‘sensations’, such as vision, hearing, taste and touch
13
Q
Synapse
A
- A synapse is a tiny gap between two neurons, across which nerve impulses are passed
- A synapse is a combination of PRESYNAPTIC ENDINGS; which contain the neurotransmitters (chemical messengers), SYNAPTIC CLEFTS; which is the gap between 2 neurons and POSTSYNAPTIC ENDINGS; which contain the sites for receptors (particular structure that matches the structure of the neurotransmitter molecule)
14
Q
Synaptic transmissions
A
- Synaptic transmissions is a process through which one neuron communicates with another, crosses the synaptic cleft between pre + post synaptic neurons
- Electrical nerve impulses (aka action potential) travel down the axon and when they reach the axon terminal they stimulate the release of neurotransmitter molecules (from the synaptic vesicles) into the synaptic gap
- Synaptic vesicles are found at the end of the neuron (terminal buttons)
- The signal is then carried across the synaptic gap by neurotransmitters. They bind to synaptic receptors, causing an excitatory or inhibitory response.
- The post-synaptic neuron converts the neurotransmitters to an electrical impulse to travel down to the next pre-synaptic terminal.
- Excitation is an increase in the neural activity in the post-synaptic neuron.
- It increases the likelihood of an action potential to be triggered.
- Some neurotransmitters have an excitatory effect making the receiving
neuron more likely to fire. - Examples of excitatory neurotransmitters include dopamine, serotonin and acetylcholine.
15
Q
Localisation of functions in the brain
A
LANGUAGE CENTRES -
* Language is usually based in the left hemisphere and there are two specific language areas known as Broca’s and Wernicke’s
* From a case study Broca identified an area at the base of the left frontal lobe that seemed to be responsible for putting words together and the production of speech. This area is now known as Broca’s area
* Broca’s aphasia (expressive) is when speech production is lost but comprehension is intact
* Wernicke noticed that patients with damage in the left hemisphere at the top of the temporal lobe (close to the auditory cortex) had specific language impairments such as the inability to comprehend language. This is now known as Wernicke’s area
* Wernicke’s areas is responsible for language comprehension
* Wernicke’s aphasia (receptive) is when the individual appears to speak fluently but has lost speech comprehension.
MOTOR + SOMATOSENSORY AREA -
* The motor centre controls voluntary movements, both hemispheres contain motor cortex with each side controlling muscles on the opposite side of the body (eg motor cortex in left hemisphere controls muscles on right side of body)
VISUAL CENTRES-
* The right hemispheres visual cortex processes visual information recieved by the left eye and vice versa. The visual cortex contains different regions with colour, shape, movement etc
AUDITORY CENTRES-
* Processing of auditory information (sound) begins in the inner ear, where sound waves are converted into nerve impulses which travel along auditory nerve to the brain stem (which decoded duration + intensity of sound), then to the auditory cortex, which recognises the sound and may form an appropriate response to that sound
16
Q
Split Brain Research
A
- Carried out with epilepsy patients whose left and right side (hemispheres) are surgically separated (by cutting the corpus callosum), which stops communication between left and right sides of brain.
- Sperry (1968) showed patients separate images to their left and right visual field.
- Information from left visual field is normally processed by the right side of the brain and information from the right visual field is normally processed by the left side of the brain.
- Sperry found patients could not use language (normally processed in the left brain) to name an object shown to the left visual field.
- Even though patients could not name objects presented to left visual field they could identify them by touch (eg he flashed a word such as ‘glass’ to the right hemisphere, and found that the left hand would select the glass from the range of objects)
- words or objects displayed to left visual field could be drawn; words or images displayed to right visual field could be named.
- In most other ways patients’ behaviour appeared normal.
- Sperry showed the effects of disrupting the normal sharing of information between left and right hemispheres.
17
Q
AO3 of Split Brain Research
A
- A limitation is an issue with generalisation. Many researchers said these findings aren’t widely accepted as split-brain patients are such a rare sample of people, and only 11 patients took part in all the variations. All had a history of seizures, which may have caused many changes in he brain that influenced the findings. This limits the extent to which results can be generalised to normal brains, reducing the validity of the conclusions
- A strength of split-brain research by Sperry is his careful standardising of the procedure of presenting visual information to one hemisphere at a time. One limitation to the procedure was the natural tendency for the participant to move their eyes towards the stimulus. If the eyes move too much the stimulus is likely to be picked up by both hemispheres. To prevent this happening, Participants stared at a fixed point with one eve, and an image flashed for 0.l seconds, so the patient didn t have time to move their eyes over to the image. This allowed Sperry to ensure only one hemisphere received information at a time, making it a beneficial and well-controlled procedure.
18
Q
Plasticity and Functional Recovery
A
- Plasticity refers to the brain’s ability to change and adapt structure and function in response to learning and experience. The brain creates new neural pathways and alters existing ones in response to the evolving experiences. As we get older, cognitive pruning occurs, which is when unnecessary or unused synaptic connections are removed and used synaptic connections are strengthened to allow more space for learning and experience.
- McGuire et al. (2000) studied the brains of London taxi drivers. As part of their training, they have to take a test called ‘The Knowledge’, which assessed their recall of city streets and possible routes. There was significantly more volume of grey matter in the posterior hippocampus of the taxi drivers compared to match controls. This part of the brain is associated with the development of spatial and navigational skills in humans and other animals. The longer they had been in the job, the more pronounced the structural difference (a positive correlation).
- The brain shows evidence of functional recovery, which is when functions transfer from the damaged areas of the brain after trauma or physical damage to the entire region. This process is when the brain rewires and reorganises Itself by forming new synaptic connections (Neural generation) and neural reorganisation where functions are transferred to undamaged areas to recover damage. This can occur quickly and eventually slows down after months.
19
Q
AO3 of Plasticity and Functional Recovery
A
- A strength of functional recovery is that it is supported by a case study. Gabby Giftards was shot in the left hemisphere and placed in a coma so her brain could recover. Within months and with the help of rehabilitation, she could walk, read, understand, and speak short phrases. Additionally, she regained control even in her right arm, which implies that functional recovery is possible. Therefore, supporting the theory of functional recovery.
- However, this can’t be generalised to the general population as it’s an isolated case study because what happened in their case is a unique circumstance that not everyone goes through. Thus, reducing the external validity of functional recovery.
