biological questions last set before exam Flashcards
Split brain patients show unusual behaviour when tested in experiments. Briefly explain how unusual behaviour in split brain patients could be tested in an experiment.
plausible experimental situation / set-up – eg split visual field, dichotic listening
*plausible stimulus – visual, faces, words, auditory, digits, music etc
*plausible task for patient – verbal or visuospatial response, eg drawing, matching etc.
Briefly evaluate the use of EEGs as a way of identifying cortical specialisation in the brain.
Likely points: safe way of measuring brain activity; there is no surgery or invasive process; helps to identify activity in various regions of brain; its use as a diagnostic tool eg epilepsy; lacks precision in measuring individual action potential of neurons / electrodes not sensitive enough, etc.
Briefly outline the process of synaptic transmission.
the release of neurotransmitter into the synapse. to neurotransmitter binding with receptors on the dendrite or next neuron to binding another impulse.
Raoul has recently been prescribed a drug for a mental illness. He looks on the internet to find out more about the drug but he does not understand the phrase ‘synaptic transmission’.
Write a brief explanation of synaptic transmission in the brain to help Raoul understand how his drug might work.
Transmission involves impulses crossing a space or gap between an axon terminus and the adjacent neuron (the synapse/synaptic cleft)
* Neurotransmitters are chemicals released from vesicles on the presynaptic neuron
* They travel/diffuse across the synapse and lock onto receptor sites on receiving/postsynaptic neuron
* Some neurotransmitters increase the rate of firing in the receiving neurons and others decrease the rate of firing
* Psychoactive drugs work by affecting (increasing or inhibiting) the transmission of neurotransmitters across the synapse
Explain the function of the endocrine system.
to regulate cell or organ activity within the body and control vital physiological processes in the body
* to release hormones/chemical messengers from glands into the bloodstream which then bind with specific receptors in order to regulate the activity of cells or organs in the body
* examples of specific hormones to illustrate effects such as adrenaline and fight or flight response
* reference to how imbalance in hormones might lead to dysfunction for example, high levels of cortisol causing Cushing’s disease.
What doe the romantic nervous system connect?
connects the central nervous system and the senses.
Jeremy is digging in the garden. He feels the spade hit a rock and stops digging immediately.
Explain how sensory, relay and motor neurons would function in this situation.
Sensory neurons send information from the senses to the brain – here receptors in Jeremy’s hand would sense the jolt of the spade hitting the rock and send that information via the peripheral nervous system to his brain/CNS.
* Relay neurons connect with other neurons, mostly found in the brain/CNS - here they would be involved in analysis of the sensation, what it means, deciding about how to respond to it, thus acting between the sensory and motor neurons.
* Motor neurons send messages via long axons from the brain to the muscles or effectors – here the message from the brain instructs Jeremy’s arm muscles to stop working and stop the digging action.
Outline the role of adrenaline in the fight or flight response.
Adrenaline is released from the adrenal medulla in response to activation of the sympathomedullary pathway.
*Adrenaline has a range of effects on the body
*Direct effects of adrenaline
– increase heart rate
– constricts blood vessels, increasing rate of blood flow and raising blood pressure
– diverts blood away from the skin, kidneys and digestive system
– increases blood to brain and skeletal muscle
– increases respiration and sweating
*The general effects of adrenaline
– prepare the body for action, fight or flight,
– increase blood supply/oxygen, to skeletal muscle for physical action
– increase oxygen to brain for rapid response planning
roblems. She used random sampling to form two groups each of 20 students.
She tested one group on one set of maths problems at 3 am in the morning. The other group were tested on another set of maths problems at 3 pm in the afternoon. She found that performance of the group tested at 3 pm was significantly better than the group tested at 3 am.
When submitted for peer review the paper was rejected because of serious design problems.
Explain one problem with the design of this study and suggest ways of dealing with this problem.
Problem – random sampling; the 3 pm group might simply have been better at maths than the 3 am group. The solution would be a matched pairs (matched on maths ability) or repeated measures design.
*Problem – use of different maths tests, with no evidence that they were matched for difficulty. The solution would be to use the same set of maths problems if a matched pairs design was used.
*Individual differences due to independent groups design so use repeated measures but would need different but equivalent tests and counterbalancing.
*Other issues, such as individual differences in biological rhythms (‘owls’ versus ‘larks’) confounding results. Such answers should be marked on their merits – is the problem plausible and is the solution sensible?
Briefly outline how excitation and inhibition are involved in synaptic transmission?
Neurotransmitters can be excitatory or inhibitory (most can be both but GABA is purely inhibitory).
*If the neurotransmitter is excitatory then the post synaptic neuron is more likely to fire an impulse.
*If the neurotransmitter is inhibitory then the post synaptic neuron is less likely to fire an impulse.
*The excitatory and inhibitory influences are summed, if the net effect on the post synaptic neuron 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.
Outline the fight or flight response.
hypothalamus prepares the body for action/emergency response
*involves the release of adrenaline (from the adrenal gland/medulla).
*Triggers/activates/switches from parasympathetic to sympathetic activity and back again.
*direct effects of adrenaline, eg increase heart rate – constricts blood vessels, increasing rate of blood flow and raising blood pressure – diverts blood away from the skin, kidneys and digestive system – increases blood to brain and skeletal muscle – increases respiration and sweating.
Information can only travel in one direction at a synapse.
Explain why neurons can only transmit information in one direction at a synapse.
the synaptic vesicles containing the neurotransmitter are only present on / released from the presynaptic membrane
* the receptors for the neurotransmitters are only present on the postsynaptic membrane
* it is the binding of the neurotransmitter to the receptor which enables the signal / information to be passed / transmitted on (to the next neuron)
* diffusion of the neurotransmitters mean they can only go from high to low concentration, so can only travel from the presynaptic to the postsynaptic membrane.
Give one difference between the autonomic nervous system and the somatic nervous system.
the autonomic nervous system is involuntary whereas the somatic nervous system is under conscious control.
A survey of hospital patients has found that a new drug, Zapurpain, is as effective as other pain medication.
Zapurpain acts like an inhibitory neurotransmitter at the synapse.
Explain how Zapurpain might affect the process of synaptic transmission through inhibition.
* Zapurpain mimics the effect of inhibitory neurotransmitters, stimulation of postsynaptic receptors by an inhibitory neurotransmitter result in inhibition (hyperpolarisation) of the postsynaptic membrane
* when an inhibitory neurotransmitter binds to the post-synaptic receptors it makes the post-synaptic cell less likely to fire (IPSP)
* Summation – if inhibitory inputs are higher than excitatory they can cancel out excitation and inhibit an action potential occurring/Zapurpain would decrease the overall activity
* Zapurpain would make the post-synaptic cell less likely to fire
* reducing brain activity may lead to reduced pain.
