Communication .................................................................................................................................... 3-4
The Nervous System ......................................................................................................................................................................................... 3
The Endocrine System ..................................................................................................................................................................................... 4
The Brain ........................................................................................................................................... 18-27
Brain Structure .......................................................................................................................................................................................... 18-19
Brain Imaging Techniques.................................................................................................................................................................... 20-21
The Visual Cortex ............................................................................................................................................................................................ 22
Evidence for the Critical Period of Visual Development ................................................................................................................ 23
Studying Brain Development .............................................................................................................................................................. 24-25
Drugs and Disease ............................................................................................................................. 27-31
Use of Drugs to Treat Brain Disorders ................................................................................................................................................... 27
Parkinson’s Disease ........................................................................................................................................................................................ 28
Depression ......................................................................................................................................................................................................... 29
Genome Sequencing ....................................................................................................................................................................................... 30
Producing Drugs with Genetically Modified Organisms (GMOs) ............................................................................................... 31
1
,Specification
8.1 Know the structure and function of sensory, relay and motor neurones including the role of Schwann cells and
myelination. (P5)
8.2 i) Understand how the nervous systems of organisms can cause effectors to respond to a stimulus. (P3)
ii) Understand how the pupil dilates and contracts. (P13)
8.3 Understand how a nerve impulse (action potential) is conducted along an axon including changes in
membrane permeability to sodium and potassium ions and the role of the myelination in saltatory conduction.
(P6-7)
8.4 Know the structure and function of synapses in nerve impulse transmission, including the role of
neurotransmitters, including acetylcholine. (P10-12)
8.5 Understand how the nervous systems of organisms can detect stimuli with reference to rods in the retina of
mammals, the roles of rhodopsin, opsin, retinal, sodium ions, cation channels and hyperpolarisation of rod
cells in forming action potentials in the optic neurones. (P14)
8.6 Understand how phytochrome and IAA bring about responses in plants to environmental cues, including their
effects on transcription. (P15-17)
8.7 Understand how co-ordination is brought about through nervous and hormonal control in animals. (P3-4)
8.8 Know the location and functions of the cerebral hemispheres, hypothalamus, cerebellum and medulla
oblongata in the human brain. (P18-19)
8.9 Understand how magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), positron
emission tomography (PET) and computed tomography (CT) scans are used in medical diagnosis and the
investigation of brain structure and function. (P20-21)
8.10 Understand what happens during the critical period so that mammals can develop their visual capacities to the
full. (P22)
8.11 Understand the role animal models have played in the research into human brain development and function,
including Hubel and Wiesel’s experiments with monkeys and kittens. (P23)
8.12 Be able to discuss moral and ethical issues relating to the use of animals in medical research from two ethical
standpoints. (P23)
8.13 Understand how animals, including humans, can learn by habituation. (P26)
8.14 Understand how imbalances in certain, naturally occurring brain chemicals can contribute to ill health,
including dopamine in Parkinson’s disease and serotonin in depression, and to the development of new drugs.
(P27-29)
8.15 Understand the effects of drugs on synaptic transmissions, including the use of L-Dopa in the treatment of
Parkinson’s disease and the action of MDMA in Ecstasy. (P27-29)
8.16 Understand how the outcomes of genome sequencing projects are being used in the development of
personalised medicine and the social, moral and ethical issues this raises. (P30)
8.17 Know how drugs can be produced using genetically modified organisms (plants, animals and
microorganisms). (P31)
8.18 Understand the risks and benefits associated with the use of genetically modified organisms. (P31)
8.19 Understand the methods used to investigate the contributions of nature and nurture to brain development,
including evidence from the abilities of new-born babies, animal experiments, studies of individuals with
damaged brain areas, twin studies and cross-cultural studies. (P24-25)
CORE PRACTICAL 18: Investigate habituation to a stimulus. (P26)
2
,The Nervous System
8.2 i) Understand how the nervous systems of organisms can cause effectors to respond to a stimulus.
8.7 Understand how co-ordination is brought about through nervous and hormonal control in animals
Nervous System Organisation
Pathway of Response
• Plants and animals respond to changes in their external environments to increase their chances of
survival.
• Plants and animals respond to changes in their internal environments to ensure conditions are always
optimal for their metabolism.
• Receptors communicate with effectors via the nervous or hormonal system.
Nervous System Communication:
1. Stimulus Change in external / internal environment
2. Receptor Detects stimulus
3. Sensory Neuron Nerve cell that carries sensory info from receptor ! CNS
4. Co-ordinator Brain / spinal chord; response is co-ordinated
5. Motor Neuron Nerve cell that carries motor command from CNS ! effector
6. Effector Muscles / glands respond to stimulus
7. Response The action the stimulus brings
3
, The Endocrine System
8.7 Understand how co-ordination is brought about through nervous and hormonal control in animals
The Endocrine System
Made up of glands and hormones:
• Glands: groups of cells that are specialised to secrete useful substances, such as hormones.
• Hormones: ‘chemical messengers’, e.g. proteins/peptides (e.g. insulin) or steroids (e.g.
progesterone).
Endocrine System Communication:
1. Glands stimulated by electrical impulses or changes in concentration of a specific substance.
2. Gland secretes hormones.
3. Hormones diffuse directly into the blood.
4. Hormones travel around the body via circulatory system.
5. Each hormone binds to specific receptors for that hormone, found on the membrane of target cells.
6. Target cell responds to stimulus.
Example:
• Stimulus: Low blood glucose concentration.
• Receptor: Receptors on pancreas cells detect low blood glucose concentration.
• Hormone: Pancreas releases glucagon into the blood.
• Effector: Target cells in liver detect glucagon and convert glycogen into glucose.
• Response: Glucose released into the blood and glucose concentration increases.
Nervous Communication Vs. Endocrine Communication
Nervous Communication Endocrine Communication
Communication by nerve impulses Communication by hormones
Nerve impulse travels to specific parts of the Hormones travel to all parts of the body but only
body target organs respond
Transmission by neurons Transmission by blood
Very rapid transmission Usually relatively slow transmission
Rapid response Slow response
Short-lived response Long-lasting response
Localised response Widespread response
Effect is temporary and reversible Effect may be permanent and irreversible
4
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