Biopsychology Flashcards
Explain the full process of synaptic transmission
The nerve impulse arrives at the pre-synaptic terminal, causing synaptic vesicles to travel down to the pre-synaptic membrane. The pre-synaptic membrane and synaptic vesicle fuse, causing the release of neurotransmitters into the synaptic cleft. The neurotransmitters then bind to post-synaptic receptors.
As a result, the receptors allow positively charged particles to enter the post-synaptic terminal, creating small, positive changes in voltage in the neuron. Once there is a large enough change in voltage, a nerve impulse is triggered. Meanwhile, the neurotransmitters are released back into the synaptic cleft, where they are sucked back into the pre-synaptic membrane by re-uptake proteins.
Summarise how nerve impulses are passed from one neuron to the next.
First, a nerve impulse arrives at the pre-synaptic terminal of the first neuron. This triggers the release of neurotransmitters from the pre-synaptic terminal to the synaptic cleft. The neurotransmitters diffuse across the cleft and bind to post-synaptic receptors. This causes charged particles to enter the post-synaptic neuron. A nerve impulse occurs in the post-synaptic neuron if there is a large enough, positive, change in voltage.
define summation
summation occurs when multiple nerve impulses occur in the pre-synaptic neuron in close succession or if multiple occur at the same time
excitatory neurotransmitters(EPSPS)
-Create excitatory post synaptic potentials
-cause positively charged particles to enter
-therefore making nerve impulses more likely to happen
inhibitory neurotransmitters(IPSPS)
-lead to inhibitory post synaptic potentials
-cause negatively charged particles to enter
-make nerve impulses less likely to occur
Types of neurotransmitters : Acetylcholine
-released by neurons controlling our muscles
-makes nerve impulses more likely to happen meaning it is an excitatory neurotransmitter
Types of neurotransmitters: GABA
-main inhibitory neurotransmitter used in the brain
-makes nerve impulses less likely to happen
Types of neurotransmitters: Dopamine
-can be both a excitatory and inhibitory in neurotransmitter
-controls our response to rewards
Types of neurotransmitters: Serotonin
-can be both an excitatory or inhibitory neurotransmitter
-controls our response to mood
Sensory neurons
-neurons that pick up sensory information from sensory receptors and transmit information(5 senses) towards the brain
-are present in both CNS and PNS
motor neurons
-neurons that carry information away from the brain, and tell our muscles to move
-are present in both CNS and PNS
relay neuron
-relay neurons are neurons that process and transform sensory information
-they sit in between the sensory and motor neurons and can communicate with both
-are only present in CNS
divisions of the neuron system: Spinal chord
-the spinal chord is a long branch of axons
-its protected by the spinal column
-information that is sent to the brain goes up the spinal chord whilst information that is sent from the brain travels down the spinal chord
the nervous system: 2 divisions
-the nervous system refers to he network of all the neurons in our body
-the 2 divisions are the central nervous system(CNS) and peripheral nervous system(PNS)
Central nervous system(CNS)
-CNS consists of all the neurons within the brain and spinal chord
Peripheral nervous system(PNS)
-PNS consists of all the parts of the nervous system that are outside the brain and spinal chord
-has 2 parts which are:
-the somatic nervous system that deals with the outside world by communicating with sensory receptors and with muscles, the activities in the somatic NS are usually conscious
-Autonomic nervous system which is the part of the PNS that deals with our internal organs by communicating with the muscles of the organs, activities in the autonomic NS are usually unconscious
Autonomic nervous system: 2 divisions
sympathetic:
-increases bodily activity
-keeps our body active and alert
parasympathetic:
-decreases bodily activity
-keeps our body rested and saving energy
the endocrine system
-the cells in the endocrine system cluster into glands
-these glands communicate by releasing hormones into the bloodstream
-there are glands all over the body including the brain, glands in the brain receive electrical signals but do not send them, they send hormones into the blood stream instead
Adrenal glands
-adrenal glands release hormones in response to stress and are located above the kidneys
-the adrenal gland consists of two components which are the adrenal medulla which is the inner part of the adrenal gland and releases adrenaline in response to stress, And the adrenal cortex which is the outer part of the adrenal gland and releases cortisol in response to stress
outline the role pituitary glands
pituitary glands is known as the queen of glands that controls the release of hormones from all other glands in the body by releasing a hormone called ACTH which acts as a messenger and activates other glands in the body, causing the glands to release hormones to.
Describe communication in the endocrine system
- A stimulus triggers a gland to release hormones into the bloodstream. the hormones then travel around the blood stream until they reach their target cells, then they bind to the receptors of the target cells which causes a response in the target cells
the fight or flight response
-the fight or flight response is a bodily reaction that occurs in response to stress and potential danger. This causes bodily reactions such as pupil dilation, increased sweat, increased heart rate, decreased salivation and food digestion etc.
-the fight or flight response is controlled by 2 mechanisms/ systems which are the endocrine system which is the network of cells which communicate by releasing hormones into the blood stream, and the sympathetic branch of the autonomic nervous system which increases bodily activity and alertness.
outline how the hypothalamus is involved in the fight or flight response
The hypothalamus is apart of the endocrine system and the central nervous system and is located just above the pituitary gland. The hypothalamus communicated with the autonomic nervous system and endocrine system to produce the fight or flight response when your in immediate danger. This occurs by the hypothalamus receiving signals from the CNS and PNS about potential threats. if there is a threat the hypothalamus sends electrical signals to the sympathetic nervous system. this in turn activated the adrenal medulla which releases adrenaline into the bloodstream. Adrenaline then binds to receptors in target cells causing bodily reactions of the fight or flight response to occur such as pupil dilation, increased heart rate etc.
limitation of fight or flight response
-one limitation of the fight or flight response is that most research that has been carried out has only used male participants, this is a problem as we cannot generalise these findings to women, meaning the research lacks population validity
-another limitation of the fight or flight response is that it assumes that people always respond to stress by fighting or fleeing. this may not be the case because of individual differences as some people react by freezing up which is not explained by the fight or flight response
outline the slow response of the hypothalamus
-the hypothalamus releases hormones that target the pituitary gland, which releases ACTH into the blood stream therefore activating the adrenal cortex which releases cortisol which binds to target cells, telling the body to stay active and alert
outline the rest and digest response
-when stress is removed, the hypothalamus activates the parasympathetic nervous system which decreases bodily activity. this is called the rest and digest response
evaluation of fight or flight
-fight or flight might not be very useful as we deal with small, frequent and non life threatening stress in our everyday life. due to these, our fight or flight response can become over active which can be harmful to our health
define localisation of function
localisation of function is the idea that different parts of the brain perform different actions
left hemisphere
-the left hemisphere is responsible for language and the body movement, vision and touch of the right side of the body
right hemisphere
-the right hemisphere is responsible for spatial skills and the body movement, vision and touch of the left side of the body for
Define hemispheric laterlisation
hemispheric laterlisation is the idea that two hemispheres perform different functions
how do the hemispheres communicate
-the two hemispheres communicate by sending nerve impulses to each other
-the corpus callosum is a bundle of nerve axons that enables communication between the two hemispheres
Evidence for hemispheric laterlisation: split brain research
-method
-split brain patients are patients whos corpus callosum have been cut meaning the two hemispheres can no longer communicate with each other
method:
1)present stimulus to left or right hemisphere
2) ask patients to respond to stimulus
split brain research: results
-results showed if a function isn’t hemispherically lateralised, the patient should be able to perform the function no matter whether it was presented to left or right hemisphere
-if a function is hemispherically laterlised to the right hemisphere, the patient would only be able to perform the function if the stimulus is presented to the right hemisphere and if a function is hemipherically laterlised to the left, the patient would only be able to perform the function if the stimulus is presented to the left hemisphere
split brain research: findings
Sperry:
-presented images to patients left and right hemisphere
-Sperry’s first study found that if patients were asked to point to one of the four pictures to identify which match the image, they could perform the task whether the image was presented to their left or right hemisphere
-however, in Sperry’s second study, if patients were asked to verbally describe the image, they could only perform the task if the image was presented to their left hemisphere
-therefore, sperry concluded thatlanguage is hemispherically laterlised to the left hemishpere
split brain research: limitations
- one limitation of split brain research is that the findings may lack generalisability as we cant be sure other peoples brains are organized in the same way
-also, a split brain patients brain may have brain abnormalities which could act as confounding variables
-not all findings have been replicated, and more recent studies have shown not all aspects of language are controlled by the left hemisphere
exceptions to the theory of hemispheric lateralisation: EB
-EB had a tumour on his left hemisphere when he was 2.5 years old which meant the doctors had to remove nearly all of his left hemisphere.
-although this caused EB to lose all his language skills, he regained them completely after rehabilitation
EB case study
Danelli(2014)
-aimed to investigate how EB regained all his language skills
-conducted a case study on EB, using verbal testing and MRI
-she compared images from EB’s brain to images from a control group of people with normal brain
-she found that hemispherically lateralised functions can be taken over by the other hemisphere
-which therefore means there are exceptions to the theory of hemispheric lateralisation
motor cortex
-controls our movement
- organised contralaterally as there’s a motor cortex in the left hemisphere which controls the right side of the body and a motor cortex in the right hemisphere which controls the left side of the body
somatosensory cortex
-located just behind the motor cortex
-part of the brain that processes our feeling of touch
- organised contralaterally as the somatosensory cortex in the left hemisphere controls the right side of the body and the somatosensory cortex in the right hemisphere which controls the left side of the body
auditory cortex
-sits behind and slightly below the somatosensory cortex
-the part of the brain that allows us to hear thigs by receiving nerve impulses from sensory neurons that tall to sensory receptors in the ears
-there is a auditory cortex in both hemispheres but it isn’t organised contralaterally
visual cortex
-located at the back of the brain
-part of the brain that processes vision
-there is a visual cortex in both hemispheres and these are organised contralaterally
Brocas area
-the part of the brain that enables us to produce language
-broca’s area is hemispherically lateralised to the left hemisphere
wernickes area
-the part of the brain that allows us to understand language
-hemispherically lateralised to the left hemisphere
Aphasia
-aphasia is when people lose the ability to understand language
brocas aphasia
-brocas area damaged which leads to the inability to produce language
wernickes aphasia
-wernickes area damaged which leads to the inability understand language
support for brain localisation:
-localisation of function in the brain is supported by case studies of patients with unusual symptoms like patient TAN
-when the patients died, researchers performed post-mortem examinations to see which parts of the brain were damaged
-researchers found that damage to specific brain areas consistently lead to the same symptoms
limitation of localisation of the brain
-might be oversimplified because a complex function often requires more than one brain region:
-this is supported by Dronkers study which showed that patient TAN had damage to brain regions other than brocas area
-Ignores the importance of communication between brain regions:
-damage to the connection between brain regions prevents communication between the two regions, this can therefore impair function
-Dejerne:
-described a patient who struggled to understand written words because he had damaged the connection between wernickes area and the visual cortex
limitation of localisation of function: individual differences
-ignores the individual differences of brain organisation:
Bevelier(1997)
-conducted a study where she got people to to read silently while the brain was imaged in a brain scanner
-bevelier looked at the parts of the brain that were active whilst the participants read
-she found that different people use slightly different parts of the brain and some people used more parts of their brain than others
