HL Paper 3
General anesthetics act on the neurotransmitters in neuron synapses. Explain the effect of anesthetics on patients and how they affect synaptic transmission.
Outline the neural control of the process of swallowing.
Describe an example of learned behaviour.
State the function of the bones in the middle ear.
Explain the role of the hair cells in the cochlea.
D-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), the two main psychoactive ingredients of the Cannabis sativa plant, have distinct symptomatic and behavioural effects. Functional magnetic resonance imaging (f MRI) was used in healthy volunteers to examine their effects on the parahippocampus, an area of the brain related to emotions and on the visual cortex. The effects are as shown.
Outline the benefits of using fMRI in this experiment.
Compare and contrast the effects of THC and CBD on the areas of the brain studied.
State the function of the visual cortex.
Approximately 350 000 people worldwide have received cochlear implants. Outline the use of cochlear implants in patients with hearing problems.
State the part of the ear that is responsible for detecting movement of the head.
Describe the role of bipolar cells in the eye.
Outline the development of axons in immature neurons.
State one activity controlled by the medulla oblongata.
Explain two methods that scientists have used to determine the different functions of the brain.
A study examined the effects of four weeks of intensive training in athletes on vertical jumping performance and neuromuscular learning. The graph shows the results for jumping height.
Outline the effect of training on jumping performance.
List the different types of neurons involved in a reflex arc.
Predict whether an animal such as a laboratory rat could be encouraged to learn a new behaviour pattern.
Using an example, describe how innate behaviour may increase the chances of survival of a species.
The shore crab (Carcinus maenas) preys on mussels (Mytilus edulis). M. edulis vary in size. The frequency distribution of the numbers of each length of M. edulis eaten by a population of C. maenas per day is shown in the graph.
State the most common length of M. edulis eaten by the C. maenas population.
Suggest reasons for the length you stated in (a) being the most common length of M. edulis that C. maenas eat.
The diagram shows the mechanism of action of the psychoactive drug cocaine.
Suggest how cocaine might influence the brain.
Dopamine acts as a slow-acting neurotransmitter. Outline one function of slow-acting neurotransmitters.
Outline the structure of a reflex arc.
State the type of receptor that detects odours.
Graph 1 shows the range of light wavelengths detected by the three types of cone cells in normal colour vision. Graph 2 shows the range of light wavelengths detected by a person with one form of colour blindness. Each line shows a different type of cone cell.
Deduce, with a reason, the difference in colour perception between people with normal colour vision and those with this type of colour blindness.
Explain how sounds of different wavelengths are distinguished by the ear.
The images show the early stages and completed outcome of the process of neurulation.
Label the parts I and II on the images.
Structure Y will eventually elongate to form two structures. State the names of these two structures.
1.
2.
State the condition that arises if the closure of structure X is incomplete during embryonic development.
The diagrams show a rat brain and a human brain. They are not drawn to scale.
Distinguish between the cerebral cortex of the human brain and of the rat brain.
Explain how psychoactive drugs affect the nervous system.
The drawing shows a vertical section through the brain.
[Source: TefiM / istockphoto.com.]
Label the cerebellum on the diagram.
State a function of the cerebellum.
On the diagram, label one named structure that produces hormones.
Outline one method that can be used to investigate the function of different parts of the brain.
The image on the left shows a developing neuron on the first day of culture (day 1). The image on the right shows the same neuron after one day (day 2).
[Source: The establishment of polarity by hippocampal neurons
in culture, CG Dotti, CA Sullivan and GA Banker, Journal of Neuroscience 1 April 1988, 8 (4) 1454–1468;
DOI: https://doi.org/10.1523/JNEUROSCI.08-04-01454.1988, Copyright ©1988 Society for Neuroscience.]
Describe the changes occurring in this neuron from day 1 to day 2.
Suggest other processes that may occur during neural development.
Suggest what can happen to neurons that are unused in the nervous system.
Male eastern bluebirds (Sialia sialis) display brilliant UV-blue feathers on their heads, backs, wings and tails. The brightness index of the male was calculated; the larger the score, the brighter the blue feathers. A brightness value of 0 indicates normal male brightness, so birds with negative scores are less bright than normal.
In an experiment to see the mating behaviour of bluebirds, scientists separated pairs of males and females and then allowed females to choose new partners.
The graph shows the relationship between male brightness index and choice of mate by females in eastern bluebirds.
[Source: Reprinted from Animal Behaviour, 78, Liu, M., Siefferman, L., Mays, H., Steffen, J.E. and Hill, G.E., A field test of
female mate preference for male plumage coloration in eastern bluebirds. pp.879–885. 2009 with permission from Elsevier
and The Association for the Study of Animal Behaviour. https://www.sciencedirect.com/journal/animal-behaviour.]
Evaluate the hypothesis that females prefer to mate with males whose feathers are a brighter blue.
Explain how natural selection can cause mate selection behaviour patterns to develop in a species such as eastern bluebirds.
Another type of behaviour is altruistic behaviour. Outline an example of altruistic behaviour.
Outline how the human brain can reorganize itself following a stroke.
State the area of the human brain that may have been damaged when the following symptom is present:
A lack of muscle control on the left side of the body
State the area of the human brain that may have been damaged when the following
symptom is present.
Difficulty in swallowing
The graph shows the correlation between the cerebral cortex mass and the number of neurons in the cerebral cortex of three groups of mammals (rodents, primates and insectivores). Each point indicates the mean number from different research studies for the species.
[Source: S Herculano-Houzel (2009) Frontiers in Human Neuroscience, 3, p 31, Frontiers Research Foundation
http://journal.frontiersin.org/article/10.3389/neuro.09.031.2009/full]
State which group has the lowest percentage of cerebral cortex mass.
Suggest advantages of the cerebral cortex containing a high percentage of the brain’s neurons.
Suggest a role for the cerebral cortex in rodents such as rats and mice.
Explain how the cerebral cortex in humans differs from other mammals.
Noise from ships has the capacity to disrupt the foraging behaviour of shore crabs (Carcinus maenas). In this study, C. maenas were collected from Newquay Harbour in the UK and held for a maximum of 48 hours in salt-water tanks located at a neighbouring aquarium. The graph shows the effect of simulated ship noise on the time spent foraging for food by C. maenas.
[Source: Republished with permission of Elsevier Science and Technology Journals, from ‘Noise negatively affects foraging and antipredator behaviour in shore crabs’, Matthew A. Wale, Stephen D. Simpson, Andrew N. Radford, Animal Behaviour 86, 2013; permission conveyed through Copyright Clearance Center, Inc]
State the effect of simulated ship noise on foraging behaviour.
Predict the consequences on C. maenas of increasing noise related to human activity.
A cataract is a clouding of the lens in the eye, resulting in blurred vision.
[Source: Cataract in Human Eye, Rakesh Ahuja, MD (https://en.wikipedia.org/wiki/Cataract#/media/File:Cataract_in_human_eye.png)]
Explain the use of a local anesthetic during surgery to remove the cataract.
Describe red-green colour blindness.
A patient was asked to trace a line between two guidelines of a star shape, starting at point S (see star image) while viewing the star in a mirror. The graph shows the number of times the patient strayed outside the boundaries while drawing the star in each trial for both hands.
[Reprinted from Neuron, 20(3), Brenda Milner, Larry R. Squire and Eric R. Kande, 'Cognitive neuroscience and the study of memory',
pp. 445–468, Copyright (1998), with permission from Elsevier. https://www.sciencedirect.com/journal/neuron]
Outline how this experiment shows learned behaviour.
Deduce, with a reason, whether the patient is left-handed or right-handed.
Define, with an example, operant conditioning.
Define, with an example, imprinting.
Outline the effects of slow-acting neurotransmitters.
Defects in the formation of synapses could be the cause of neurological disorders such as Alzheimer’s disease that affects the ability to think and remember clearly. It is more frequent in people older than 65 years of age. The graph shows the changes in synapse number over time. The diagram shows activity-related neural development.
State what happens to unused neurons.
Predict how mental activity might delay the onset of Alzheimer’s disease.
Autism appears early in life and affects how a person communicates and relates to others. There is evidence that autism could be caused by a surplus of synapses. Using all of the information provided, suggest two possible causes of a surplus of synapses in people with autism.
The diagram (not to scale) represents the average brain volume of six species of mammal. The mammals are arranged in rank order of body mass.
Compare and contrast the rank order of body mass and brain volume in the six species of mammals.
Predict the difference that would be seen if the cerebral cortex of a human and a gorilla were compared.
State one function of each of the following areas of the brain.
Broca’s area
State one function of each of the following areas of the brain.
Nucleus accumbens
State one function of each of the following areas of the brain.
Medulla oblongata
The images show differences in structure between the brain of a person without Alzheimer’s disease (image I) and the brain of a patient with Alzheimer’s disease (image II).
[Source: Reprinted by permission from Springer Nature: Nature, Pathways towards and away from Alzheimer’s disease,
Mark P. Mattson, © 2004]
Label the cerebellum on image I.
State one function of the cerebellum.
State the difference in the cerebral cortex between the two images of the brain.
A person with Alzheimer’s disease typically has a reduced nucleus accumbens. Predict how this will affect the person.
The images show the differences in glucose uptake between the brain of a person without Alzheimer’s disease (image I) and the brain of a patient with Alzheimer’s disease (image II). The key indicates the levels of glucose uptake.
Deduce the implications of reduced glucose uptake in the brain of a patient with Alzheimer’s disease.
The table shows the typical sound intensity of different sources.
State the type of sensory receptors that detect sound.
Suggest one reason for hearing loss caused by extended exposure to high intensity sound.
Outline the role of the ear in balance perception.
Modification of neurons starts in the earliest stages of embryo development and continues to the final years of life. The image shows changes occurring in mice brain neurons at an early stage in life.
Outline how an immature neuron develops an axon.
Explain neuroplasticity in terms of the developing neurons.
The diagram shows one of the stages in neurulation.
Describe what happens next in neurulation.
Explain the causes of spina bifida in vertebrates.
Explain the process of neural pruning.
Drug misuse and abuse are major health problems in the world. The diagram shows the correlation between physical harm and dependence for various psychoactive drugs.
Identify an example of inhibitory drug shown in the diagram.
Addiction may be affected by social environment. Outline one other named factor that can affect addiction to drugs.
Distinguish between innate behaviour and learned behaviour in the development of birdsong.
Outline an example of a change in animal behaviour as a result of natural selection.
The brain requires a large energy input. Suggest one reason for this.
Outline the functional magnetic resonance imaging (fMRI) technique for brain research.
Explain, using examples, the neurological effects of inhibitory psychoactive drugs.
An organism’s diminished response to a repeated stimulus is referred to as habituation. The diagrams show the experiments performed on habituation to a stimulus in a sea slug (Aplysia californica). The sea slug is a mollusc that has an external gill for gas exchange. If the siphon of the sea slug is stimulated mechanically, it withdraws the gill in a simple reflex action.
State the effector in this reflex arc.
With reference to the experiments on habituation, state the effect of repeated stimulation on the level of neurotransmitter in the synapses.
With reference to the withdrawal of the siphon in Aplysia californica, explain the concept of summation.
Amphetamines act on synapses that use dopamine as a neurotransmitter by increasing the release of dopamine into the synaptic cleft. Outline the effect this would have on human synaptic transmission.
The large tree finch (Camarhynchus psittacula) communicates through singing. The frequency (pitch) of a finch’s song was recorded. The results for a short period of the song are shown.
[Source: Reproduced / adapted with permission. Podos, J., Southall, J.A. and Rossi-Santos, M.,
2004. Vocal mechanics in Darwin’s finches: correlation of beak gape and song frequency. Journal of Experimental
Biology, 207(4), pp.607–619. Published by The Company of Biologists 2004. doi:10.1242/jeb.00770. Permission
conveyed through Copyright Clearance Center, Inc. https://jeb.biologists.org/content/207/4/607.]
Outline the trend in large tree finch song frequency.
Describe the role of inheritance and learning in birdsongs.
Compare and contrast innate behaviour and learned behaviour.
A dog owner wants to teach a dog to stop jumping up on people.
[Source: © Nevit Dilmen]
Explain how operant conditioning could be used to train the dog.
The diagram shows a section through the human brain.
[Source: https://pixabay.com/vectors/brain-anatomy-human-medicine-150935/]
Label the diagram to show part of the visual cortex of the brain.
Outline how the diagram can be identified as a human brain and not the brain of a monkey.
Explain how studies of lesions have helped to identify the functions of different parts of the brain.
Outline innate and learned behaviour.
The diagram shows part of the embryonic development in a clawed toad of the genus Xenopus.
[Source: © International Baccalaureate Organization 2019]
Describe the process occurring in the diagram.
State what would occur in the embryo immediately after stage IV.
Outline the consequences of incomplete closure of the neural tube in humans.
The drawing shows male and female Emperor birds of paradise (Paradisaea guilielmi ) found in Papua New Guinea.
Suggest how the external features and courtship behaviour of these birds of paradise affect reproductive success.
To investigate the effects of the drug MDMA (ecstasy) on impulsive behaviour, investigators carried out a test on former users, current users and those who had never taken the drug. Impulsive behaviours were defined by the researchers as those done quickly, without fully considering the consequences. The participants in the study were asked which of the images (1 to 6) was identical to the original image on the left.
The time and accuracy of their responses were recorded. The results are based on 15 participants per group.
[Source: National Institute on Drug Abuse; National Institutes of Health; U.S. Department of Health and Human Services]
Calculate the difference in the number of former users of MDMA and those who have never used the drug making an error before a correct response.
Outline the evidence that MDMA leads to impulsive behaviour.
Explain the effect MDMA has on the metabolism in the brain.
Discuss the effect of endorphins on the central nervous system (CNS) and in pain relief.
Hearing loss can range from mild to severe. Cochlear implants have been used in those with profound hearing loss such as children who are born deaf. The image shows a cross section of the ear with a cochlear implant.
[Source: NIDCD (www.nidcd.nih.gov/health/cochlear-implants)]
People who are deaf often learn to communicate using sign language. In a study, brain imaging was carried out using functional magnetic resonance imaging (fMRI) of profoundly deaf and hearing people who were processing the same aspects of language. The deaf individuals in the study used either an English sign language or a French sign language.
[Source: Copyright 2000 National Academy of Sciences, U.S.A.]
Identify the parts of the ear labelled X and Y.
X:
Y:
Describe the use of cochlear implants in deaf patients.
Identify the area of the brain which is labelled with the white arrow in the fMRI.
Compare the general patterns of activation in the brain shown when all of the individuals in the study processed language.
Suggest one reason for two different language groups being used in the study.
Outline how fMRI is used in brain studies.
Suggest what might result if a deaf individual who uses sign language has a lesion in the Broca’s area of the brain.
An investigation was carried out to examine whether honeybees (Apis mellifera) can learn “rules” to deal with complex tasks and then apply them to new situations. To train bees, they were rewarded each time they followed a cue to make a correct turn at the start of a training maze. They were then allowed to find their way through the entire training maze.
This was followed by attempts to navigate two unfamiliar mazes (maze 1 and maze 2) to see whether the bees could apply the rules to follow a path through different mazes. Untrained control bees were also put into mazes. Only one bee was tested in each maze at a time.
The bees were classified according to how successful they were in making their way through each maze. The results are shown in the bar chart.
[Source: reprinted from Neurobiology of Learning and Memory, 72, S.W. Zhang et al, Honeybee Memory: Navigation by
Associative Grouping and Recall of Visual Stimuli, 180–201, Copyright 1999, with permission from Elsevier]
Distinguish between learned behaviour and innate behaviour.
Evaluate how the data supports the hypothesis that honeybees are able to learn to use cues to find the path through new mazes.
Suggest an advantage of such behaviour.
The shore crab (Carcinus maenas) forages for food in the intertidal zone on rocky seashores. An experiment was carried out to assess predation at specified levels of food abundance. An area of shore was enclosed in a wire cage. All other food was removed from the encaged area except the mussels provided by the investigators. The number of mussels consumed was measured while the crabs foraged at densities of one, two or four crabs per cage.
[Source: reprinted from B D Griffen and D G Delaney, Ecology, 88 (12), pages 3012–3021,
copyright 2007, with permission, the Ecological Society of America]
Suggest a reason for the plateau in the graph when only one crab is present in the cage.
Determine whether foraging by crabs is dependent on number of prey (mussels) or number of predators (crabs).
Outline the role of natural selection in animal behaviour.
Prior to the 1840s, doctors and dentists did not routinely use anesthesia when operating on patients. However, advances in the knowledge of neurotransmitters have assisted the use of anesthesia.
Define neurotransmitter.
Describe how local anesthetics act on the nervous system.
Describe the main role of slow-acting neurotransmitters in memory and learning.
Many animals have a unique technique for courting their mate. The male peacocks (Pavo cristatus) spread their brightly-coloured tails to impress the females (peahens).
[Source: cocoparisienne/Pixabay]
Courtship behaviour leads to mate selection. Describe innate behaviour.
Explain the implications of courtship behaviour in natural selection.
Outline operant conditioning, giving an example.
Explain how the human eye is able to distinguish between different colours of light.
The diagram shows part of a human retina.
On the diagram, draw an arrow showing the direction of the light.
Identify the cells labelled A and B.
A:
B:
Photoreceptors in the retina sense light. State the name of another type of receptor with an example of the stimulus it detects.
Explain, using the diagram, how the visual stimuli from the right eye reach the visual cortex of the brain.
The figures below show a human and a sheep brain.
[Source: Pearson Scott Foresman, donated to the Wikimedia Foundation,
https://commons.wikimedia.org/wiki/File:Convolution_he_-_sheep_and_human_brain.png]
The human brain is larger than the brain of many animals. Identify one other difference between the human brain and the brain of a sheep.
Outline the main feature of neural pruning.
State the name of the part of the brain that controls breathing rate.
Explain the need for the adult human brain to be supplied continuously with a relatively large supply of blood.
The diagram shows the human ear.
[Source: Didier Descouens, https://commons.wikimedia.org/wiki/Category:Human_middle_ear#/media/File:Place-desosselets-
Schema.jpg, licensed under CC BY-SA 3.0]
Identify the structures labelled X and Y in the diagram.
Identify the structure in the inner ear that is in contact with the stapes.
Explain the function of the semicircular canals.
Explain the effect of a named stimulant drug on the nervous system.
Outline the process that could result in spina bifida during neural tube development.
Explain how the eye detects stimuli and sends information to the brain.