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16.19: Nervous System - Biology

16.19: Nervous System - Biology



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The central nervous system includes the brain and spinal cord. The brain is held in the cranial cavity of the skull and it consists of the cerebrum, cerebellum, and the brain stem. The nerves involved are cranial nerves and spinal nerves.

Figure 1. The nervous system.

The nervous system has three main functions: sensory input, integration of data and motor output. Sensory input is when the body gathers information or data, by way of neurons, glia and synapses. The nervous system is composed of excitable nerve cells (neurons) and synapses that form between the neurons and connect them to centers throughout the body or to other neurons. These neurons operate on excitation or inhibition, and although nerve cells can vary in size and location, their communication with one another determines their function. These nerves conduct impulses from sensory receptors to the brain and spinal cord. The data is then processed by way of integration of data, which occurs only in the brain. After the brain has processed the information, impulses are then conducted from the brain and spinal cord to muscles and glands, which is called motor output. Glia cells are found within tissues and are not excitable but help with myelination, ionic regulation and extracellular fluid.

The nervous system is comprised of two major parts, or subdivisions, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS includes the brain and spinal cord. The brain is the body’s “control center.” The CNS has various centers located within it that carry out the sensory, motor and integration of data. These centers can be subdivided to Lower Centers (including the spinal cord and brain stem) and Higher centers communicating with the brain via effectors.

The PNS is a vast network of spinal and cranial nerves that are linked to the brain and the spinal cord. It contains sensory receptors which help in processing changes in the internal and external environment. This information is sent to the CNS via afferent sensory nerves. The PNS is then subdivided into the autonomic nervous system and the somatic nervous system. The autonomic has involuntary control of internal organs, blood vessels, smooth and cardiac muscles. The somatic has voluntary control of skin, bones, joints, and skeletal muscle. The two systems function together, by way of nerves from the PNS entering and becoming part of the CNS, and vice versa.

General functions of the CNS

The central nervous system (CNS) represents the largest part of the nervous system, including the brain and the spinal cord. Together with the peripheral nervous system (PNS), it has a fundamental role in the control of behavior.

When the central nervous system becomes damaged or peripheral nerves become trapped, a variety of impacts are possible. It can increase or decrease your internal organs functionality, it can even affect your facial expressions, i.e. make you frown a lot, your smile may become lop sided, your lungs can overwork, or underwork, lung capacity may increase or decrease, your bladder can fill, but you become unable to urinate, your bowels become lapsed and you are unable to completely clear them upon each bowel movement, the muscles in your arms, legs and torso can become weaker and more fatty, not from lack of use, but from the nerves that run from your spine into them being restricted from working properly, you can suffer headaches, earaches, sore throats, blocked sinuses. Even your ability to orgasm can be affected.

The CNS is conceived as a system devoted to information processing, where an appropriate motor output is computed as a response to a sensory input. Many threads of research suggest that motor activity exists well before the maturation of the sensory systems, and senses only influence behavior without dictating it. This has brought the conception of the CNS as an autonomous system.

Neurons

Structure

Neurons are highly specialized for the processing and transmission of cellular signals. Given the diversity of functions performed by neurons in different parts of the nervous system, there is, as expected, a wide variety in the shape, size, and electrochemical properties of neurons. For instance, the soma of a neuron can vary in size from 4 to 100 micrometers in diameter.

The soma (cell body) is the central part of the neuron. It contains the nucleus of the cell, and therefore is where most protein synthesis occurs. The nucleus ranges from 3 to 18 micrometers in diameter. The dendrites of a neuron are cellular extensions with many branches, and metaphorically this overall shape and structure is referred to as a dendritic tree. This is where the majority of input to the neuron occurs. However, information outflow (i.e., from dendrites to other neurons) can also occur—except in chemical synapse in which backflow of impulse is inhibited by the fact that axon do not possess chemoreceptors and dendrites cannot secrete neurotransmitter chemical. This explains one way conduction of nerve impulse.

The axon is a finer, cable-like projection which can extend tens, hundreds, or even tens of thousands of times the diameter of the soma in length. The axon carries nerve signals away from the soma (and also carry some types of information back to it). Many neurons have only one axon, but this axon may—and usually will—undergo extensive branching, enabling communication with many target cells.

The part of the axon where it emerges from the soma is called the axon hillock. Besides being an anatomical structure, the axon hillock is also the part of the neuron that has the greatest density of voltage-dependent sodium channels. This makes it the most easily-excited part of the neuron and the spike initiation zone for the axon: in neurological terms it has the greatest hyperpolarized action potential threshold. While the axon and axon hillock are generally involved in information outflow, this region can also receive input from other neurons as well.

The axon terminal is a specialized structure at the end of the axon that is used to release neurotransmitter chemicals and communicate with target neurons. Although the canonical view of the neuron attributes dedicated functions to its various anatomical components, dendrites and axons often act in ways contrary to their so-called main function.

Axons and dendrites in the central nervous system are typically only about a micrometer thick, while some in the peripheral nervous system are much thicker. The soma is usually about 10–25 micrometers in diameter and often is not much larger than the cell nucleus it contains. The longest axon of a human motor neuron can be over a meter long, reaching from the base of the spine to the toes. Sensory neurons have axons that run from the toes to the dorsal columns, over 1.5 meters in adults. Giraffes have single axons several meters in length running along the entire length of their necks. Much of what is known about axonal function comes from studying the squids giant axon, an ideal experimental preparation because of its relatively immense size (0.5–1 millimeters thick, several centimeters long).

Function

Sensory afferent neurons convey information from tissues and organs into the central nervous system. Efferent neurons transmit signals from the central nervous system to the effector cells and are sometimes called motor neurons. Interneurons connect neurons within specific regions of the central nervous system. Afferent and efferent can also refer generally to neurons which, respectively, bring information to or send information from brain region.

Classification

Excitatory neurons excite their target postsynaptic neurons or target cells causing it to function. Motor neurons and somatic neurons are all excitatory neurons. Excitatory neurons in the brain are often glutamatergic. Spinal motor neurons, which synapse on muscle cells, use acetylcholine as their neurotransmitter. Inhibitory neurons inhibit their target neurons. Inhibitory neurons are also known as short axon neurons, interneurons or microneurons. The output of some brain structures (neostriatum, globus pallidus, cerebellum) are inhibitory. The primary inhibitory neurotransmitters are GABA and glycine. Modulatory neurons evoke more complex effects termed neuromodulation. These neurons use such neurotransmitters as dopamine, acetylcholine, serotonin and others. Each synapses can receive both excitatory and inhibitory signals and the outcome is determined by the adding up of summation.

Learning Objectives

Watch this video for another introduction to the nervous system. This is the first in a series of nine videos. While you may enjoy all the videos in this series, you are only required to watch the first video.

A YouTube element has been excluded from this version of the text. You can view it online here: pb.libretexts.org/biom2/?p=627


16.19: Nervous System - Biology

Resource type:online module series

Publisher: Association for British Pharmaceutical Industry (ABPI)

Price: Free

Introduction

The Association of the British Pharmaceutical Industry (ABPI) has long produced high quality resources to support the teaching of science. Their topics have a focus on biology and medicine, but also cover wider areas of science, as well as PSHE, citizenship and the history of medicine. Topics are allocated to one or more age groups (5- 7, 7-11, 11-14, 14-16, 16+), with most of their resources aimed at older students. For a full list of resources for each age group, please see Table 1 at the end of this review.

Six resources have recently been updated for the 14-16 and 16+ age groups, which focus on recent developments in biotechnology and medicine. It is this series of six resources that is the main subject of this review. A sample of other resources is also described.

“A recommended site for student research or project work. The ease of navigation, quality of content and standard of presentation encourages students to explore topics in depth.”

New Horizons in Medicine series

The series consists of six revised modules, each consisting of a poster, and a set of teaching materials that include information, classroom activities and quizzes. The modules are:

  • Biotechnology
  • Cloning
  • Genetic engineering
  • Polymerase chain reaction
  • Stem cells
  • Unravelling the genome

Suitability

Each resource is well matched to published specifications for GCSE Biology (if labelled 14-16) or A-level Biology, but not AS level biology in England. In Wales, the WJEC GCSE Biology specification has sections on cloning and genetic engineering, whilst in Northern Ireland the CCEA GCSE Biology specification has sections on stem cells and genetic engineering.

Although not specified content for the Scottish Curriculum for Excellence (https://www.education.gov.scot/Documents/sciences-eo.pdf), these resources would support Scottish science students required to consider the moral and ethical implications of controversial biological procedures.

Overseas students studying iGCSE Biology would also benefit from using some of these modules (biotechnology and genetic engineering – Cambridge iGCSE Biology cloning and genetic engineering – Edexcel iGCSE Biology).

Content of each resource provides a full introduction to the topic, as well as sufficient additional information and links to enable the subject matter to be studied in greater depth for those interested, or looking for additional background information.

Style and presentation

“…this resource provides a richness and depth that is not possible in a modern course textbook.”

Each page of information is well written and easy to access – subject matter is presented in short paragraphs, making good use of side headings, images, animations and spaces to break up the text. The language used is accessible to GCSE students, yet contains information that will help teachers maintain their subject knowledge in this rapidly developing field. The site is easy to navigate, with good use being made of tabs, tags and links. Navigation could be further improved by labelling page tabs with page content rather than page number.

How can the resource support teaching and learning?

There is a variety of ways that teachers may choose to use the resource:

  1. A ‘teach yourself’ guide to recent developments in genomics and associated developments in biology, with a specific focus on human health. The end of chapter ‘test your knowledge’ multiple choice quizzes are most useful for individual users working at their own pace through the resource.
  2. A reference resource for teachers to use to update their knowledge of current developments in biology and medicine. Most pages contain links to external sources of further information.
  3. A source of materials and ideas for teaching challenging areas of the curriculum, focusing on benefits and risks of new technology. Good examples include:
  • evaluating the use of stem cells from different sources, including regulations controlling their use (https://www.abpischools.org.uk/topic/stem-cells/13)
  • the ethics of biotechnological developments, which includes video clips expressing different opinions (https://www.abpischools.org.uk/topic/cloning/11)
  • separating fact from opinion or speculation, although this resource demands good subject knowledge. Answers are not provided! (https://www.abpischools.org.uk/topic/biotech/9/1)

These resource ideas could easily be adapted for different contexts.

  1. A recommended site for student research or project work. The ease of navigation, quality of content and standard of presentation encourages students to explore topics in depth. There are links to other topics in the side bar that could easily stimulate further exploration. The search facility provided is effective – searching for ‘sickle cell’ pulled up 154 hits on the site – top hit was the case study, but other hits were displayed clearly making it easy to identify the most useful references.

Free Posters

Poster available for download or in print from the Biotechnology module (https://www.abpischools.org.uk/topic/biotech)

Each module provides a poster that can be downloaded from the web page introducing the module, or ordered free of charge from ABPI (postage charged for overseas orders). Animations and diagrams can be downloaded free for non-commercial educational use, subject to usual terms and conditions.

Biotechnology (14-16 and 16-19)

This poster gives a brief overview of recent biotechnology developments, with a focus on medicine and our understanding of the causes of disease. It would be useful for introducing these ideas at GCSE. It provides a good match to OCR Gateway learning outcomes that cover the medical use of stem cells, use of gene technology and the importance of studying the human genome.

Different types of cloning that can be used in medicine, explained clearly through a series of diagrams.

Genetic engineering (14-16 and 16-19)

The poster provides a simple explanation of the steps involved in genetically modifying a bacterium cell and then outlines different possible uses of the technique in medicine, including the use of CRISPR-Cas9 as a gene editing tool.

An outline of the basic principles involved in the polymerase chain reaction and a brief overview of five uses of this technology in medicine and forensics. It would be particularly useful to those teaching AQA A-level biology.

The poster distinguishes different types of stem cells, outlining possible uses, but also mentions technical and ethical issues that have slowed their progress as a medical tool.

Unravelling the genome (16-19)

A summary diagram outlines key stages in eliciting the sequence of bases in a strand of DNA, and an overview of some of the big data-gathering projects associated with the human genome is provided. Of all the posters in this series, this one needs most support from the additional resources provided.

Other sources of posters that may be of use for use in teaching biology at this level include:

The modules

Each module has a consistent layout, although the number and variety of pages in each module varies. In the summary of the modules that follows, the page titles are listed and key features of the module are described.

Page layout of the New Horizons in Medicine resource

Module pages

Gene therapy - hope for the future?

SCID and sickle cell disease – case studies in gene editing

Muscular dystrophy – the importance of animal models

The ‘What is Biotechnology’ page introduces many of the ideas that are covered in subsequent modules (genetic engineering, DNA sequencing, cloning, stem cell use, the diagnosis and treatment of disease). Key words are highlighted and they link to a useful glossary that uses current terminology that may not be familiar to some teachers. An example is gene editing - A relatively new alternative term for genetic engineering, also known as genome editing’.

Further pages cover case studies of diseases such as sickle cell, muscular dystrophy, and use of animal models, all of which are relevant especially to GCSE biology, but also GCSE combined science.

Module pages

Adult cell or reproductive cloning

Activity: Cloning – what do you know?

Activity: Should artificial twinning remain banned?

Different types of cloning are covered in some detail, with good use of diagrams being used to distinguish key features. The resources are not shy of raising ethical and political concerns. I particularly liked the link to a parliamentary briefing paper on mitochondrial disease, which will help reinforce the contemporary and controversial nature of this science. Much of the content is accessible to 14-16 year-old pupils, but some (such as the page on technical problems, which introduces epigenetics and the importance of telomeres) are more appropriate to post-16 classes. The resource provides a balanced view of the implications and uses of cloning, including a useful table of the advantages and disadvantages of different techniques.

Module pages

What is genetic engineering?

How does genetic engineering work?

Genetic engineering: hopes and fears

Transgenic plants – food for the future

Gene therapy – case studies

Minimising the risks of genetic engineering

Activity: genetic engineering in the media

Activity: genetic engineering in commercial agriculture

The first few pages provide a clear and informative guide on genetic modification that would be a useful resource for teaching GCSE biology and combined science. Other content (such as CRISPR-Cas9) is more appropriate for post-16 studies, although it is also a useful primer for teachers. The resource contains several detailed case studies that could be modified for different audiences if necessary. A strength of this resource is the highlighting of ethical and religious considerations in the application of new technologies. There are classroom activities provided around this aspect, but I preferred the activities in other resources that involved evaluating statements, as they will be more engaging for most students. The resource includes several Flash animations.

Module pages

What is the polymerase chain reaction?

Impact of PCR on medicine

This resource is appropriate for post-16 study. It outlines the process of PCR and gives details of historical and current cases (such as Ebola) where the technique has contributed to the fight against disease or to the solving of crime. Current developments are explained that allow the rapid diagnosis of disease, including cases of avian flu that affected parts of the UK in 2017. Classroom activities are provided around the impact of PCR in medicine, the development of flu vaccines and whether there should be a national DNA database. These activities challenge students to write opinion pieces for an imaginary audience. I would also like to see activities promoting debate within a class, perhaps by providing some video stimulus material.

Module pages

Induced pluripotent stem cells (iPSCs)

Therapeutic stem cell cloning

Using stem cells: the cardiovascular system

Using stem cells: repairing the nervous system

Using stem cells: repairing skeletal tissues

Using stem cells: replacement tissues and organs

The resource provides a very useful reminder of cell differentiation and protein synthesis before going on to explain the different types of stem cell. Good use is made of diagrams to distinguish the development of stem cells from different sources. The second part of the resource looks at different uses of stem cells in medicine, before going on to look at legal and ethical aspects of obtaining stem cells from embryos in the UK, Europe and US. The resource would be entirely appropriate for use with a GCSE combined science class, either as presented, or for use as a source of information for a teacher producing their own teaching resources.

Module pages

The secrets of the genome

Try sequencing DNA yourself

Progress in DNA sequencing

Genomics and the pharmaceutical industry

Ethical issues arising from genome sequencing

Who should know about your genes?

Quiz – unravelling the genome

The material in this resource is intended for post-16 students, as it involves a complex simulation activity to identify the sequence of bases on a strand of DNA from electrophoresis results. A sense of the speed of developments in this field is made clear as new technologies are described, giving rise to increasing numbers of applications, and new sciences such as computational biology and bioinformatics. Several classroom activities are provided that address different ethical concerns about the use and potential misuse of genomics data. The quiz is a good check on whether the information provided has been assimilated and provides user feedback on their responses.

Summary

The New Horizons in Medicine series from ABPI is a very useful resource for secondary science teachers – whether subject specialists teaching 16-19 biology, or non-specialists teaching 14-16 combined science and biology.

The content covers the medical use of new technologies in biology, providing useful updates for teachers, resource material for student research and ideas for classroom activities. Information is current, well presented and easy to navigate. Classroom activities are provided that address difficult-to-teach topics such as ethical, societal or legal concerns. A glossary provides support for technical terms, and good use is made of diagrams, illustrations and animations.

Each module includes a poster summarising key aspects of the content, useful both as an introduction to the topic and as a revision aid.

Current textbooks such as Twenty First Century Science GCSE Biology (Oxford) do an admirable job of introducing genomics and biotechnology (including ethical concerns), but this resource provides a richness and depth that is not possible in a modern course textbook. The resource is highly recommended, and well worth any investment made in exploring the range of content in each module.

Examples of other ABPI resources

The New Horizons in Medicine modules form part of a large bank of resources that have been published over several years. The following review looks at a sample of those resources targeting different age groups. Other resource materials on the ABPI site cover topics such as virtual tours of industrial laboratories and the history of medicine. A full list of the ABPI modules is provided in Table 1 after this section.

Example of a Flash animation used in an existing resource (Body Builder)

Where do medicines come from (5-7)

This is a PowerPoint activity for whole class use, telling the story of Ellie who goes on a voyage of discovery to find out about the development of new medicines. It is accompanied by a sequencing activity (with or without text) and is also available in the Welsh language. There is an accompanying poster and teacher notes.

The activity is age-appropriate and would be a useful resource when the need arises to teach the class where their medicines come from, and about the range of individuals employed in this field.

Solids, liquids and gases (5-7, 7-11, 11-14)

The activity includes a Flash animation, with 12 pages explaining the particulate nature of matter, changes of state and dissolving, reversible and irreversible changes. These can be downloaded, shown full-screen and have multiple controls to allow specific parts of the animation to be played. The intended audience covers three age ranges, but has some content relevant to each of these groups. The teacher’s information page contains links to further pupil activity sheets and teacher guidance, which has been produced in collaboration with RSC. There is an interactive quiz provided.

This is an interactive quiz to encourage pupils to find out more about animals and their habitats. On-screen questions and answers are read aloud, but the introduction and information are quite text-heavy and challenging for children with developing reading skills. A series of worksheets are available in different formats involving anagrams, and cloze sentences.

Periodic table (11-14, 14-16, 16-19)

The main activity is another Flash animation that appears a little dated in terms of technology and the approach to learning. ABPI are aware of issues with the use of Flash and are taking steps to address them. It is an interactive game format that is relevant to the curriculum, and could be used as extension of revision material which students may find useful in preparation for a test or exam. The worksheets (finding missing names or symbols) support students to interact with the Flash animation and may help them to memorise key elements and symbols.

A brief introductory page describes seven essential food types and introduces the main activity. This is an interactive animation using Flash technology. Students choose meals for a selected character, and find out the contribution of each meal to an ideal daily amount for a range of nutrients. The animation allows the user to explore the effect of changes in lifestyle and diet.

Further information is provided for teachers about the animation and there are a number of worksheets in editable and presentation format. The worksheets involve word searches, anagrams of words and word matching.

The animation was easy to use, but rather text- and graph-heavy. Teachers could use it as a short exploration activity for students in presentation mode or use it in a project-based activity to do some extended work on diets for different population groups. The animation was detailed and factual, and one of the better digital resources that have been produced for schools on this topic. The worksheets are rather basic and undemanding and, although entertaining, would not contribute greatly to the understanding of the importance of diet on human wellbeing.

Eight pages of information, ranging from types, causes and treatment of diabetes to the ethical implications of using gene therapy. Explanations are interspersed with animations, quizzes and voice recordings. This is a useful resource for anyone teaching GCSE. It is well matched to examination specifications and, thanks to the range of interactive features, should be engaging for most students.

Infectious diseases - immunity (14-16)

Well matched to current English examination specifications, this series of six pages explains immunity, how vaccination programmes can be used to prevent disease in individuals and populations and about the use of monoclonal antibodies in diagnosis and treatment. Explanations are illustrated by animations and there are several graphs provided to develop skills of analysis.

Some very useful GCSE content (neurones, reflexes and eye), plus content suitable for more advanced study (impulse transmission, synapses, brain disorders), presented in a concise and clear text, and illustrated by photos, animations and diagrams. There are useful quizzes to check understanding at different points in the resource.

History of medicine (14-16, 16-19)

The period 8000 BC – 21 st century is covered in a series of 14 pages of detailed information on landmark events in medicine, including the contribution of Arabic medicine. Each page includes relevant images and comprehension quizzes. There is a useful page of biographies that includes several women and non-Europeans. This is a valuable research resource and parts (such as vaccination) would be appropriate for younger audiences or their teachers.

Laboratory and pilot plant tours (14-16, 16-19)

This collection of five virtual tours (using Flash animation) could be used to supplement science teaching in several different areas:

  • Synthetic chemistry laboratory tour – explaining safe working practices
  • Analytic chemistry laboratory tour – explaining the use of complex techniques such as NMR and gas chromatography
  • Chemistry pilot plant tour – the challenges of developing products from initial laboratory findings
  • Automated chemistry laboratory tour – automating the production of new compounds
  • Safety signs tour – finding out more about the hazard signs used in industrial laboratories

Each tour is supported by teacher notes, and some have accompanying presentations and hand outs for students

A relatively recent module that has good coverage of A level biology specification content including properties, structure, inhibition, sensitivity and uses of enzymes in medicine. Fewer animations or teacher resources are provided than in other modules, making this more appropriate either for student self-study or as a source of material for a teacher to adapt for use in a lesson.


BIO 130: Human Biology with Lab

This course will focus on the structure and function of the human organism and the issues facing humans in today's world. It is intended to give students a better understanding of our place in nature. Emphasis will be placed on the biochemical, cellular, tissue, organ, and organ-system levels of development. The online lab emphasizes the application of scientific method, basic laboratory methods, and principles of human anatomy and physiology. This lab component will parallel the lecture content and use cooperative learning and technology in laboratory activities. Cannot be used towards the Biology concentration. (4 credits)


Stage Information for Childhood CNS Germ Cell Tumors

There is no universally accepted clinical staging system for germ cell tumors (GCTs), but a modified Chang staging system has been traditionally used.[1] Staging evaluation of central nervous system (CNS) GCTs includes the following:

  • Magnetic resonance imaging (MRI). In addition to whole-brain MRI, MRI of the spine is required.
  • Lumbar cerebrospinal fluid (CSF). When medically permissible, lumbar CSF should be obtained for the measurement of tumor markers (alpha-fetoprotein [AFP] and beta subunit human chorionic gonadotropin [beta-HCG]) and for cytopathologic review.

Ventricular tumor markers are obtained for AFP and beta-HCG in the presence of obstructive hydrocephalus and a necessary CSF diversion however, ventricular CSF does not serve as a substitute for CSF tumor staging and cytopathologic review. Both serum and CSF tumor markers should be obtained for a thorough staging and diagnostic evaluation.[2]

Patients with localized disease and negative CSF cytology are considered to be M0 (metastatic negative) patients with positive CSF cytology or patients with drop metastasis (spinal or cranial subarachnoid metastases) are considered to be M+ (metastatic positive). Appropriate staging is crucial because patients with metastatic disease require extended radiation fields.

GCTs may be disseminated throughout the neuraxis at the time of diagnosis or at any disease stage. Several patterns of spread may occur in germinomas, such as subependymal dissemination in the lateral or third ventricles and parenchymal infiltration. Rarely, extracranial spread to lung and bone has also been reported.[3,4]

Patients with bifocal intracranial GCTs limited to the suprasellar and pineal region were treated in the same manner as were patients with localized, nonmetastatic tumors in studies in North America and Europe.

References
  1. Calaminus G, Kortmann R, Worch J, et al.: SIOP CNS GCT 96: final report of outcome of a prospective, multinational nonrandomized trial for children and adults with intracranial germinoma, comparing craniospinal irradiation alone with chemotherapy followed by focal primary site irradiation for patients with localized disease. Neuro Oncol 15 (6): 788-96, 2013. [PUBMED Abstract]
  2. Fujimaki T, Mishima K, Asai A, et al.: Levels of beta-human chorionic gonadotropin in cerebrospinal fluid of patients with malignant germ cell tumor can be used to detect early recurrence and monitor the response to treatment. Jpn J Clin Oncol 30 (7): 291-4, 2000. [PUBMED Abstract]
  3. Jennings MT, Gelman R, Hochberg F: Intracranial germ-cell tumors: natural history and pathogenesis. J Neurosurg 63 (2): 155-67, 1985. [PUBMED Abstract]
  4. Gay JC, Janco RL, Lukens JN: Systemic metastases in primary intracranial germinoma. Case report and literature review. Cancer 55 (11): 2688-90, 1985. [PUBMED Abstract]

Conclusions

The assessment of different α-synucleinopathies focuses on a variety of mechanisms that affect the pathogenesis of Lewy body diseases. While all α-synucleinopathies are characterized by α-synuclein aggregates with similar posttranslational modifications and lipid associations, the cell type involved, their location and their association with other protein depositions vary substantially, and recent data suggest that perhaps the strain of α-synucleininvolved may also differ. An increase in α-synuclein is hypothesized to precipitate the protein's aggregation, and this is evident in some familial forms of PD, but the precipitating events for most of the α-synucleinopathies remain to be determined. It is clear for Lewy body disorders that the neuronal propagation can be slow or rapid, and is impacted on by AD pathology however, Lewy bodies in AD are focused in the amygdala, suggesting that the initiating region of α-synuclein aggregation in the brain can be diverse. Importantly, the concept of propagation of α-synuclein pathology between neurons has resulted in the development of new therapies that target this mechanism with the potential to halt or slow this aspect of Lewy body diseases.


Watch the video: Die Interaktion des Mikrobioms mit dem Nervensystem (August 2022).