The cerebral hemispheres are the two halves of the largest part of the brain, controlling conscious activities such as vision, hearing, speech, thinking and memory.

The hypothalamus monitors the blood flowing through the brain and, in response, releases hormones or stimulates the pituitary gland , playing a key role in homeostasis (e.g. body temperature and water balance).

The pituitary gland , located below the hypothalamus, produces a range of hormones , some acting directly on the body and others stimulating other endocrine glands to release their hormones.

The cerebellum coordinates movement and balance , controlling muscle activity to produce smooth, coordinated actions.

The medulla oblongata contains coordination centres that control unconscious functions such as heart rate and breathing rate .

Which conscious activities are controlled by the cerebral hemispheres?

Conscious activities including vision , hearing , speech , thinking and memory .

How do the right and left cerebral hemispheres control the body?

The right hemisphere controls the left side of the body and the left hemisphere controls the right side . The two hemispheres are joined by the corpus callosum .

Give two homeostatic processes regulated by the hypothalamus.

Regulation of body temperature (monitoring blood temperature) and water balance (osmoregulation, releasing ADH when the blood becomes too concentrated).

What is the difference between the anterior and posterior pituitary?

The anterior pituitary produces and releases its own hormones, while the posterior pituitary stores and releases hormones made by the hypothalamus (e.g. ADH and oxytocin ).

Which two control centres are found in the medulla oblongata, and what does each control?

The cardiac centre , which controls heart rate , and the respiratory centre , which controls breathing rate .

True or False? The cerebellum controls heart rate and breathing rate.

False. Heart rate and breathing rate are controlled by the medulla oblongata ; the cerebellum coordinates movement and balance.

The two cerebral hemispheres are joined together by a band of nerve fibres called the .

The two cerebral hemispheres are joined together by a band of nerve fibres called the corpus callosum .

Computerised tomography (CT)

A CT scan produces cross-section images of the brain using x-ray radiation , showing physical structures and any tissue damage.

Magnetic resonance imaging (MRI)

MRI uses a magnetic field and radio waves to generate high-resolution images of soft tissue , useful for identifying damaged tissue and tumours .

Functional MRI (fMRI)

fMRI uses a magnetic field and radio waves to show the location of oxygenated blood , allowing brain function to be studied in real time .

Positron emission tomography (PET)

PET uses radioactive tracers that collect in areas of increased blood flow or metabolism, allowing brain structure and function to be studied in real time .

How does a CT scan produce an image of the brain?

A beam of x-rays is aimed at the head from all angles and picked up by detectors. Denser tissue absorbs more radiation and appears lighter on the scan, producing a cross-section image of brain structure .

Why can a CT scan be useful after a patient has had a stroke?

Blood is less dense than brain tissue, so a CT scan can locate damaged blood vessels and areas of bleeding .

Give two advantages of MRI over CT scanning.

MRI produces higher-resolution images of soft tissue and does not use potentially harmful x-rays .

How does an fMRI scan show which regions of the brain are active?

It detects the location of oxygenated blood by measuring the ratio of oxygenated to deoxygenated haemoglobin ; active regions receive more blood and 'light up' in real time .

How does a PET scan reveal active regions of the brain?

A radioactive tracer (e.g. radioactively labelled glucose ) is added to the blood and accumulates in metabolically active regions. The scanner detects areas of high radioactivity , showing which regions are active.

True or False? MRI scans use x-ray radiation to produce images of the brain.

False. MRI uses a magnetic field and radio waves ; it is the CT scan that uses x-ray radiation .

An fMRI scanner works by measuring the ratio of oxygenated to haemoglobin in the brain.

An fMRI scanner works by measuring the ratio of oxygenated to deoxygenated haemoglobin in the brain.

Which scanning techniques allow brain function to be studied in real time?

fMRI and PET scans allow structure and function to be studied in real time , whereas CT and MRI mainly show structure .

A neurotransmitter is a chemical that transmits nerve impulses across a synapse . Imbalances of neurotransmitters in the brain are linked to some diseases.

Parkinson's disease is a brain disorder affecting the co-ordination of movement , caused by the loss of dopamine-producing neurones in parts of the brain.

Which neurotransmitter is deficient in Parkinson's disease, and what is its role?

Dopamine , which is involved in muscle control . In Parkinson's disease, dopamine-producing neurones are lost, so insufficient dopamine is produced.

Explain how a lack of dopamine leads to the symptoms of Parkinson's disease.

Less dopamine is released into the synaptic cleft, so less binds to receptors on the postsynaptic membrane. Fewer sodium channels open , so depolarisation does not occur, giving fewer action potentials and symptoms such as tremors and slow movement.

How do dopamine agonists treat Parkinson's disease?

They bind to and activate dopamine receptors on the postsynaptic membrane, producing the same effect as dopamine .

A dopamine precursor (e.g. L-dopa ) is a chemical that can be converted into dopamine in neurones, used as a drug to treat Parkinson's disease.

Which neurotransmitter is linked to depression, and what does it do?

Serotonin , which transmits nerve impulses through areas of the brain that control mood . Low levels of serotonin are linked to depression.

How do SSRIs treat depression?

SSRIs (selective serotonin reuptake inhibitors) prevent the reuptake of serotonin at synapses, increasing the overall level of serotonin in the brain.

How do MAOB inhibitors help treat brain disease?

They inhibit enzymes that would otherwise break down neurotransmitters (such as dopamine or serotonin) in the synaptic cleft, raising their levels in the brain.

True or False? Parkinson's disease is caused by producing too much dopamine.

False. Parkinson's disease is caused by producing too little dopamine , due to the loss of dopamine-producing neurones.

Low levels of the neurotransmitter have been linked to depression.

Low levels of the neurotransmitter serotonin have been linked to depression.

Besides drugs, name two future therapies being researched to treat Parkinson's disease.

Gene therapy (adding genes to increase dopamine production or protect dopamine-producing cells) and stem cell therapy (replacing lost dopamine-producing cells).

International A Level (IAL)BiologyEdexcelFlashcards8. Coordination, Response & Gene TechnologyThe Brain

The Brain (Edexcel International A Level (IAL) Biology): Flashcards

Exam code: YBI11

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FrontHuman Brain Structures & Functions
Cerebral hemispheres

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Cards in this collection (36)

Cerebral hemispheres
The cerebral hemispheres are the two halves of the largest part of the brain, controlling conscious activities such as vision, hearing, speech, thinking and memory.
Hypothalamus
The hypothalamus monitors the blood flowing through the brain and, in response, releases hormones or stimulates the pituitary gland, playing a key role in homeostasis (e.g. body temperature and water balance).
Pituitary gland
The pituitary gland, located below the hypothalamus, produces a range of hormones, some acting directly on the body and others stimulating other endocrine glands to release their hormones.
Cerebellum
The cerebellum coordinates movement and balance, controlling muscle activity to produce smooth, coordinated actions.
Medulla oblongata
The medulla oblongata contains coordination centres that control unconscious functions such as heart rate and breathing rate.
Which conscious activities are controlled by the cerebral hemispheres?
Conscious activities including vision, hearing, speech, thinking and memory.
How do the right and left cerebral hemispheres control the body?
The right hemisphere controls the left side of the body and the left hemisphere controls the right side. The two hemispheres are joined by the corpus callosum.
Give two homeostatic processes regulated by the hypothalamus.
Regulation of body temperature (monitoring blood temperature) and water balance (osmoregulation, releasing ADH when the blood becomes too concentrated).
What is the difference between the anterior and posterior pituitary?
The anterior pituitary produces and releases its own hormones, while the posterior pituitary stores and releases hormones made by the hypothalamus (e.g. ADH and oxytocin).
Which two control centres are found in the medulla oblongata, and what does each control?
The cardiac centre, which controls heart rate, and the respiratory centre, which controls breathing rate.
True or False?
The cerebellum controls heart rate and breathing rate.
False.
Heart rate and breathing rate are controlled by the medulla oblongata; the cerebellum coordinates movement and balance.
The two cerebral hemispheres are joined together by a band of nerve fibres called the .
The two cerebral hemispheres are joined together by a band of nerve fibres called the corpus callosum.
Computerised tomography (CT)
A CT scan produces cross-section images of the brain using x-ray radiation, showing physical structures and any tissue damage.
Magnetic resonance imaging (MRI)
MRI uses a magnetic field and radio waves to generate high-resolution images of soft tissue, useful for identifying damaged tissue and tumours.
Functional MRI (fMRI)
fMRI uses a magnetic field and radio waves to show the location of oxygenated blood, allowing brain function to be studied in real time.
Positron emission tomography (PET)
PET uses radioactive tracers that collect in areas of increased blood flow or metabolism, allowing brain structure and function to be studied in real time.
How does a CT scan produce an image of the brain?
A beam of x-rays is aimed at the head from all angles and picked up by detectors. Denser tissue absorbs more radiation and appears lighter on the scan, producing a cross-section image of brain structure.
Why can a CT scan be useful after a patient has had a stroke?
Blood is less dense than brain tissue, so a CT scan can locate damaged blood vessels and areas of bleeding.
Give two advantages of MRI over CT scanning.
MRI produces higher-resolution images of soft tissue and does not use potentially harmful x-rays.
How does an fMRI scan show which regions of the brain are active?
It detects the location of oxygenated blood by measuring the ratio of oxygenated to deoxygenated haemoglobin; active regions receive more blood and 'light up' in real time.
How does a PET scan reveal active regions of the brain?
A radioactive tracer (e.g. radioactively labelled glucose) is added to the blood and accumulates in metabolically active regions. The scanner detects areas of high radioactivity, showing which regions are active.
True or False?
MRI scans use x-ray radiation to produce images of the brain.
False.
MRI uses a magnetic field and radio waves; it is the CT scan that uses x-ray radiation.
An fMRI scanner works by measuring the ratio of oxygenated to haemoglobin in the brain.
An fMRI scanner works by measuring the ratio of oxygenated to deoxygenated haemoglobin in the brain.
Which scanning techniques allow brain function to be studied in real time?
fMRI and PET scans allow structure and function to be studied in real time, whereas CT and MRI mainly show structure.
Neurotransmitter
A neurotransmitter is a chemical that transmits nerve impulses across a synapse. Imbalances of neurotransmitters in the brain are linked to some diseases.
Parkinson's disease
Parkinson's disease is a brain disorder affecting the co-ordination of movement, caused by the loss of dopamine-producing neurones in parts of the brain.
Which neurotransmitter is deficient in Parkinson's disease, and what is its role?
Dopamine, which is involved in muscle control. In Parkinson's disease, dopamine-producing neurones are lost, so insufficient dopamine is produced.
Explain how a lack of dopamine leads to the symptoms of Parkinson's disease.
Less dopamine is released into the synaptic cleft, so less binds to receptors on the postsynaptic membrane. Fewer sodium channels open, so depolarisation does not occur, giving fewer action potentials and symptoms such as tremors and slow movement.
How do dopamine agonists treat Parkinson's disease?
They bind to and activate dopamine receptors on the postsynaptic membrane, producing the same effect as dopamine.
Dopamine precursor
A dopamine precursor (e.g. L-dopa) is a chemical that can be converted into dopamine in neurones, used as a drug to treat Parkinson's disease.
Which neurotransmitter is linked to depression, and what does it do?
Serotonin, which transmits nerve impulses through areas of the brain that control mood. Low levels of serotonin are linked to depression.
How do SSRIs treat depression?
SSRIs (selective serotonin reuptake inhibitors) prevent the reuptake of serotonin at synapses, increasing the overall level of serotonin in the brain.
How do MAOB inhibitors help treat brain disease?
They inhibit enzymes that would otherwise break down neurotransmitters (such as dopamine or serotonin) in the synaptic cleft, raising their levels in the brain.
True or False?
Parkinson's disease is caused by producing too much dopamine.
False.
Parkinson's disease is caused by producing too little dopamine, due to the loss of dopamine-producing neurones.
Low levels of the neurotransmitter have been linked to depression.
Low levels of the neurotransmitter serotonin have been linked to depression.
Besides drugs, name two future therapies being researched to treat Parkinson's disease.
Gene therapy (adding genes to increase dopamine production or protect dopamine-producing cells) and stem cell therapy (replacing lost dopamine-producing cells).

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