Nervous Systems Chapter 48 Vocabulary and Review

Animal Nervous System Development TissueSampleThe development of the nervous system in animals is a complex and fascinating process that begins early in embryonic development and continues throughout the animal's life. Understanding the development of the nervous system is crucial for understanding how it functions and how it can be affected by various factors. Tissue samples are an important tool for studying the development of the nervous system, as they allow researchers to examine the structure and function of the nervous system at a cellular and molecular level. One of the key aspects of nervous system development is the formation of neural stem cells, which give rise to the various cell types that make up the nervous system. Tissue samples can be used to study the development of neural stem cells and the factors that regulate their proliferation and differentiation. This information is important for understanding how the nervous system develops and how it can be repaired or regenerated after injury or disease. In addition to studying neural stem cells, tissue samples can also be used to study the development of specific types of neurons and glial cells, which are the building blocks of the nervous system. By examining the expression of specific genes and proteins in these cells, researchers can gain insight into the molecular mechanisms that govern their development and function. This information is crucial for understanding how the nervous system is wired and how it functions to regulate behavior and physiology. Furthermore, tissue samples can be used to study the development of the nervous system in different animal species, allowing researchers to compare and contrast the mechanisms of nervous system development across evolutionary lineages. This comparative approach can provide valuable insights into the evolution of the nervous system and the factors that have shaped its development over millions of years. By studying the nervous system in a diverse range of animal species, researchers can gain a more comprehensive understanding of its development and function. Moreover, tissue samples can also be used to study the effects of environmental factors on nervous system development. For example, researchers can expose developing nervous system tissue to different chemicals or toxins todetermine how they affect the development of neural stem cells and other cell types. This research is important for understanding how environmental factors can impact nervous system development and how they may contribute to neurodevelopmental disorders and other neurological conditions. In conclusion, tissue samples are a valuable tool for studying the development of the nervous system in animals. By examining the structure and function of nervous systemtissue at a cellular and molecular level, researchers can gain insight into the mechanisms that govern its development and function. This information is crucialfor understanding how the nervous system develops, how it can be affected by various factors, and how it can be repaired or regenerated after injury or disease. Ultimately, studying the development of the nervous system in animals can provide valuable insights into the evolution of the nervous system and the factors that have shaped its development over millions of years.。

Animal Nervous System Development TissueSampleThe development of the nervous system in animals is a complex process that involves the formation and differentiation of various tissues. The nervous system is responsible for controlling and coordinating all the functions of the body, including movement, sensation, and perception. It is therefore essential for the survival of the animal. In this tissue sample, we will explore the different tissues that make up the nervous system and their role in its development. The nervous system is composed of two main types of tissues: the neural tissue and the supporting tissue. Neural tissue consists of neurons, which are specialized cells that transmit signals throughout the body, and glial cells, which provide support and protection to the neurons. Supporting tissue includes connective tissue, blood vessels, and the meninges, which are the protective membranes that surround the brain and spinal cord. During embryonic development, the nervous system begins to form from a group of cells called the neural plate. This plate eventually folds in on itself to form the neural tube, which will give rise to the brain and spinal cord. The neural crest, a group of cells that separate from the neural tube, will form the peripheral nervous system, which includes the nerves that connect the brain and spinal cord to the rest of the body. The differentiation of neural and supporting tissues is a tightly regulated process that involves the activation and repression of various genes. For example, the gene Sox2 is necessary for the maintenance of neural stem cells, which give rise to neurons and glial cells. The gene Pax6 is required for the formation of the optic vesicle, which willeventually give rise to the retina. The development of the nervous system is also influenced by various environmental factors, such as nutrients, growth factors, and hormones. For example, the hormone retinoic acid is essential for the proper development of the spinal cord, while the growth factor FGF8 is required for the formation of the midbrain and hindbrain. Disruptions in the development of the nervous system can lead to various neurological disorders, such as spina bifida, autism, and schizophrenia. These disorders can result from genetic mutations, environmental factors, or a combination of both. Understanding the cellular andmolecular mechanisms that govern nervous system development is therefore crucial for the prevention and treatment of these disorders. In conclusion, the development of the nervous system in animals is a complex process that involves the differentiation of various tissues, including neural and supporting tissues. This process is regulated by a complex interplay of genes and environmental factors, and disruptions can lead to neurological disorders. By understanding the mechanisms that govern nervous system development, we can better prevent and treat these disorders, ultimately improving the quality of life for both animals and humans alike.。

Animal Nervous System Development TissueSampleThe development of the nervous system in animals is a complex and fascinating process that involves the growth and differentiation of various types of tissues. Tissue samples are crucial for studying the development of the nervous system, as they provide valuable insights into the cellular and molecular mechanisms underlying this process. In this response, I will discuss the importance of tissue samples in studying nervous system development, the different types of tissues involved, and the techniques used to collect and analyze these samples. Tissue samples play a crucial role in understanding the development of the nervous system in animals. By studying these samples, researchers can gain a better understanding of the cellular and molecular processes that govern the formation of the nervous system. This, in turn, can lead to insights into the causes of neurodevelopmental disorders and potential therapeutic targets for treating these conditions. Tissue samples also provide valuable information about the structure and function of the nervous system, helping researchers to unravel its complexities. There areseveral types of tissues involved in the development of the nervous system. These include neural stem cells, which give rise to the various cell types found in the nervous system, such as neurons and glial cells. Additionally, there are specialized tissues such as the neural crest, which gives rise to a wide varietyof cell types including sensory neurons, glial cells, and pigment cells. Studying these different types of tissues is essential for understanding the intricate process of nervous system development. Collecting tissue samples for studying nervous system development requires careful and precise techniques. One common method is to use animal models such as mice or zebrafish, which allow researchers to collect tissue samples at different stages of development. These samples can then be analyzed using a variety of techniques, including histology, immunohistochemistry, and molecular biology methods such as PCR and RNA sequencing. These techniques provide valuable information about the cellular and molecular processes involved in nervous system development. Analyzing tissue samples from the nervous system also involves studying the interactions between different celltypes and the extracellular environment. This can provide insights into how the nervous system develops and functions, as well as how disruptions in these processes can lead to neurodevelopmental disorders. By studying tissue samples, researchers can gain a better understanding of the complex interplay between genetics, environment, and cellular processes that govern nervous system development. In conclusion, tissue samples are invaluable for studying the development of the nervous system in animals. They provide crucial insights into the cellular and molecular processes that govern this complex process, as well as the structure and function of the nervous system. By carefully collecting and analyzing tissue samples, researchers can gain a better understanding of nervous system development and potentially identify new therapeutic targets for neurodevelopmental disorders.。

Animal Nervous System Development TissueSampleThe development of the nervous system in animals is a complex and fascinating process that involves the growth and differentiation of specialized tissues. One way to study this process is through the analysis of tissue samples, which can provide valuable insights into the molecular and cellular mechanisms that drive nervous system development. In this response, we will explore the importance of studying animal nervous system development tissue samples, the techniques used to analyze these samples, and the potential applications of this research. Studying animal nervous system development tissue samples is crucial for understanding the fundamental processes that underlie the formation of the nervous system. The nervous system is responsible for coordinating and controlling the body's activities, and its development is tightly regulated to ensure proper function. By analyzing tissue samples, researchers can identify the specific cell types and molecular signals that drive nervous system development, providing a deeper understanding of the mechanisms involved. One commonly used technique for analyzing animal nervous system development tissue samples is immunohistochemistry, which allows researchers to visualize the distribution of specific proteins within the tissue. This technique involves using antibodies that bind to the target proteins, which are then visualized using a fluorescent or enzymatic signal. By examining the expression patterns of key proteins involved in nervous system development, researchers can gain insights into the spatial and temporalregulation of these processes. In addition to immunohistochemistry, researchers also utilize techniques such as in situ hybridization to study the expression of specific genes within tissue samples. This approach allows for the visualizationof gene expression patterns, providing information about the spatial and temporal regulation of gene activity during nervous system development. By analyzing the expression of key genes, researchers can identify the regulatory networks that control nervous system development and gain a deeper understanding of the underlying mechanisms. The analysis of animal nervous system development tissue samples has numerous potential applications, ranging from basic research to thedevelopment of novel therapies for neurological disorders. By gaining a better understanding of the molecular and cellular mechanisms that drive nervous system development, researchers can identify potential targets for therapeutic intervention. This knowledge can be leveraged to develop new treatments for neurological disorders, ultimately improving the quality of life for individuals affected by these conditions. Furthermore, studying animal nervous system development tissue samples can also provide insights into evolutionary conservation and divergence of developmental processes. By comparing the development of the nervous system across different animal species, researchers can gain a better understanding of the evolutionary changes that have shaped nervous system development. This comparative approach can shed light on the conserved mechanisms that underlie nervous system development, as well as the adaptations that have occurred in different lineages. In conclusion, the analysis of animal nervous system development tissue samples is a powerful approach for studying the fundamental processes that drive nervous system development. Through techniques such as immunohistochemistry and in situ hybridization, researchers can gain insights into the molecular and cellular mechanisms that underlie nervous system development. This knowledge has the potential to inform the development of novel therapies for neurological disorders and provide insights into the evolutionary conservation and divergence of developmental processes. By continuing to study animal nervous system development tissue samples, researchers can further our understanding of this complex and essential biological process.。

Animal Nervous System Development TissueSampleThe development of the nervous system in animals is a fascinating and complex process that involves the formation of specialized tissues and structures. Understanding the development of the nervous system is crucial for gaininginsights into various neurological disorders and for developing potential treatments. One way to study the development of the nervous system is by analyzing tissue samples from different stages of development. These tissue samples can provide valuable information about the cellular and molecular processes involvedin nervous system development. Studying the nervous system development in animals is not only scientifically intriguing but also has significant implications for human health. Many aspects of nervous system development are conserved across different species, making animal models an essential tool for understanding human neurodevelopmental disorders. By analyzing tissue samples from animal models, researchers can gain insights into the genetic and environmental factors that influence nervous system development. This knowledge can potentially lead to the development of new therapeutic strategies for treating neurological disorders. Obtaining tissue samples for studying nervous system development in animals requires careful consideration of ethical and practical considerations. Researchers must ensure that the animals are treated ethically and that the tissue collection process minimizes any potential harm or distress to the animals. Additionally, the collection and storage of tissue samples must be conducted in a manner that preserves the integrity of the samples for subsequent analysis. This may involve using specialized techniques for tissue collection and preservation, as well as maintaining strict protocols for sample handling and storage. Analyzing tissue samples from different stages of nervous system development can provide valuable insights into the cellular and molecular processes that drive neurogenesis, axon guidance, synaptogenesis, and other critical events in nervous system development. By examining the expression patterns of key genes and proteins in these tissue samples, researchers can gain a better understanding of the molecular mechanisms that regulate nervous system development. This knowledge canhelp identify potential targets for therapeutic intervention in neurological disorders and may ultimately lead to the development of new treatment strategies. In addition to providing insights into the molecular mechanisms of nervous system development, tissue samples from animal models can also be used to study the effects of genetic and environmental factors on neurodevelopment. By comparing tissue samples from normal and genetically modified animals, researchers can identify the specific genes and pathways that are involved in nervous system development. Similarly, by exposing animals to different environmental conditions during development, researchers can assess the impact of environmental factors on nervous system development. This information is crucial for understanding the etiology of neurodevelopmental disorders and for developing targeted interventions to mitigate their effects. In conclusion, the analysis of tissue samples from animal models is a valuable approach for studying the development of the nervous system. By examining the cellular and molecular processes involved in nervous system development, researchers can gain insights into the etiology of neurodevelopmental disorders and identify potential targets for therapeutic intervention. However, it is essential to consider ethical and practical considerations when obtaining and analyzing tissue samples, ensuring that the process is conducted in a manner that is both scientifically rigorous andethically sound. Ultimately, the study of animal nervous system development holds great promise for advancing our understanding of neurodevelopmental disorders and for developing new strategies to improve human health.。

Animal Nervous System Development TissueSampleThe development of the nervous system in animals is a fascinating and complex process that begins early in embryonic development. This process involves the differentiation and organization of cells to form the intricate network of neurons and glial cells that make up the nervous system. Tissue samples taken from developing animal embryos provide valuable insights into the molecular andcellular mechanisms that regulate nervous system development. One of the key events in nervous system development is the formation of the neural tube, which gives rise to the brain and spinal cord. This process is highly regulated and involves the coordinated actions of various signaling molecules and transcription factors. Tissue samples taken from embryos at different stages of development can help researchers understand the temporal and spatial dynamics of neural tube formation. In addition to the neural tube, tissue samples can also provide information about the development of peripheral nerves and sensory organs. For example, the development of sensory neurons in the peripheral nervous system is guided by a complex interplay of growth factors and guidance cues. Tissue samples taken from developing sensory organs, such as the retina or inner ear, can shed light on the mechanisms that regulate the differentiation and connectivity of sensory neurons. Studying tissue samples from developing animal embryos can also provide insights into the role of stem cells in nervous system development. Stem cells have the remarkable ability to differentiate into various cell types, including neurons and glial cells. By analyzing the gene expression profiles of stem cells in tissue samples, researchers can identify the molecular pathways that drive neural differentiation and maturation. Furthermore, tissue samples can be used to study the effects of genetic mutations or environmental factors on nervous system development. For example, researchers can compare the gene expression profiles of normal tissue samples with those from embryos carrying mutations in key developmental genes. This comparative analysis can reveal how specific genetic mutations disrupt normal neural development and lead to neurological disorders. Overall, tissue samples from developing animal embryos are invaluable tools forstudying the molecular and cellular mechanisms that regulate nervous system development. By analyzing these samples, researchers can gain a deeper understanding of how the nervous system forms and functions, as well as identify potential targets for therapeutic interventions in neurological disorders. The insights gained from studying tissue samples have the potential to revolutionize our understanding of the nervous system and pave the way for new treatments for neurological diseases.。

Mammalian Nervous System Tissue Sample The mammalian nervous system is a complex network of tissues that plays a crucial role in transmitting signals throughout the body. One of the key components of the nervous system is nervous tissue, which is made up of neurons and glial cells. Neurons are specialized cells that transmit electrical and chemical signals, while glial cells provide support and protection for neurons. When examining a mammalian nervous system tissue sample, one of the first things that may stand out is the intricate network of neurons and glial cells. Neurons are the primary functional unit of the nervous system, responsible fortransmitting signals from one part of the body to another. These cells have a unique structure, with a cell body, dendrites that receive signals, and an axon that transmits signals to other neurons or cells. In addition to neurons, glial cells play a crucial role in supporting the function of the nervous system. These cells provide structural support for neurons, regulate the chemical environment around neurons, and help to repair damage to the nervous system. Without glial cells, neurons would not be able to function properly, highlighting the importance of these cells in maintaining the health of the nervous system. Examining a mammalian nervous system tissue sample can also provide insights into the organization of the nervous system. The nervous system is divided into the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which includes nerves that extend throughout the body. By examining the tissue sample, researchers can gain a better understanding of how neurons and glial cells are organized within these different regions of the nervous system. Furthermore, studying a mammalian nervous system tissue sample can provide valuable information about the development and function of the nervous system. During development, neurons form connections with other neurons to create neural circuits that are essential for transmitting signals. By examining tissue samples from different stages of development, researchers can gain insights into how these neural circuits form and function. In addition to studying thestructure and organization of the nervous system, researchers may also use tissue samples to investigate neurological disorders and injuries. Conditions such as Alzheimer's disease, Parkinson's disease, and spinal cord injuries can have aprofound impact on the nervous system, leading to impaired function and communication between neurons. By studying tissue samples from individuals with these conditions, researchers can gain a better understanding of the underlying mechanisms and potentially develop new treatments. Overall, examining a mammalian nervous system tissue sample can provide valuable insights into the structure, organization, development, and function of the nervous system. By studying neurons and glial cells, researchers can gain a better understanding of how signals are transmitted throughout the body and how the nervous system responds to different stimuli. Additionally, tissue samples can be used to investigate neurological disorders and injuries, leading to new discoveries and potential treatments for these conditions.。

Chapter 9Nervous SystemObjectivesI．Nervous System-Basic Structure and FunctionAfter completing this chapter, you should be able to: name the two major divisions of the nervous system and list the organs within each; fully discuss the three general functions of the nervous system, and draw a figure that summarizes them; construct a flow chart illustrating the relationship between the divisions of the nervous system; distinguish between sensory receptors and effectors; describe the structure of a neuron; compare the histological characteristics of neuroglia and neurons; describe grey matter and white matter, and give examples of each; describe the cellular properties that permit communication among neurons and effectors; describe the various types of neural circuits in the nervous system; define the terms ventricles and central canal (in the CNS); classify neurons according to their function; classify neurons according to their structure, drawing an illustration of each. II. The Spinal Cord and BrainAfter completing this chapter, you should be able to: outline the major divisions of the nervous system; discuss how the organs of the central nervous system (CNS) are protected in terms of bones, membranes and fluid; discuss the external structure of the spinal cord in terms of its length, start, end, number of segments, and enlarged areas; name the terminal point of the spinal cord, the term used for how the remaining spinal nerves appear, and the point at which they terminate; fully discuss the cross-sectional anatomy of the spinal cord; distinguish between a "horn" and a "column" in the spinal cord; explain which portion of the spinal cord is the location for the major nerve tracts, and discuss their significance; compare and contrast ascending and descending tracts; discuss the general characteristics of nerve tracts; discuss the features located on the periphery of the spinal cord in cross-section; define the term ganglion and discuss the specificities of a dorsal root ganglion.You should be able to: name and locate the three major regions of the brain and describe how the brain is protected; discuss the structure of the cerebrum in terms of its size, two major divisions, surface appearance, major grooves, and lobal divisions; identify the composition of the bulk of the cerebrum; define the term cerebral cortex, gyri, fissures and sulci of the cerebrum; and discuss its composition and significance; compare the major functional areas (sensory and motor) of the cerebral cortex in terms of location and function (a diagram may help here); explain what is meant by an association area of the cerebral cortex and name a few association traits; explain what is meant by hemisphere dominance, and name the hemisphere that is dominant in most people; define the term basal ganglia and explain their location and function; discuss the two important areas of gray matter within the diencephalon, in terms of location and function; identify the three major parts of the brain stem; discuss the midbrain in terms of its location, composition and function; discuss the importance of the medulla (oblongata); briefly explain the significance of the limbic system and reticular formation; locate the cerebellum on a diagram, and discuss its structure and function.III. The Spinal Nerves and Cranial NervesAfter completing this chapter, you should be able to: describe how spinal nerves are connected to the spinal cord; discuss the characteristics of spinal nerves in terms of number, coverings, and composition; discuss how a spinal nerve is distributed; define the term nerve plexus and describe the anatomical importance of a plexus; name the four major nerve plexuses and briefly discuss the areas that each innervates.You should be able to: define the term “cranial nerve,” and identify the twelve pairs of cranial nerves by name, number, and functions; discuss the general structure of a nerve; distinguish between a mixed, sensory, and motor nerve; name the twelve pairs of cranial nerves, designate them by roman numeral, discuss their function, and designate them as sensory, motor, or mixed.You should be able to: compare the structural and functional characteristics of the somatic and autonomic nervous systems; compare the length of a preganglionic and postganglionic neuron in the sympathetic and parasympathetic division of the ANS; define the term ganglion, and compare the location of sympathetic and parasympathetic ganglia; explain why sympathetic ganglia are called chain ganglia; compare the origin of a sympathetic preganglionic neuron with a parasympathetic preganglionic neuron; describe the structures around the spinal cord (i.e. dorsal root, ventral root, spinal nerve, white ramus communicans, gray ramus communicans, paravertebral (chain) ganglia, and prevertebral ganglia.).IV. Nervous Pathway and Meninges of Brain and Spinal Cord, and the Cerebrospinal FluidAfter completing this chapter, you should be able to: define the term nerve pathway; list and discuss the components in a reflex arc; discuss the significance of reflex arcs; describe the major characteristics of the somatic sensory pathways and somatic motor pathways; fully discuss the three-fold function of the nervous system; in the first sentence, name the three functions of the nervous system; then write a paragraph discussing how and where a nerve impulse begins and name the components of a nerve pathway; then draw a simple nerve pathway that involves three neurons (with cell parts labeled), finally fully discuss how the nerve impulse begins, how it travels through each neuron, how it is transmitted between neurons, and finally, how it transmitted to the effector; compare the locations and functions of the direct and indirect motor pathways.You should be able to: name the three meninges and discuss the differences between how they are structured around the brain and spinal cord; name the space that lies between two of the meninges surrounding both the brain and spinal cord, and name the fluid that fills this space; name the additional space that is found around the spinal cord, and name the fluid that fills this space; name the cells that line the central canal and identify the fluid that fills the central canal; explain the formation, circulation, and functions of cerebrospinal fluid (CSF); name the interconnected cavities within the cerebrum and brain stem and identify the fluid that fills these spaces and name the cells that line these spaces; name the specialized capillaries that secrete CSF and denote their location on a diagram; trace a drop of CSF from where itis secreted to where it is reabsorbed back into the blood stream; define the terms arachnoid granulations and dural sinuses; discuss the functions of CSF.Key Words and TopicsI．Nervous System-Basic Structure and FunctionMake certain that you can define, and use in context, each of the terms listed below, and that you understand the significance of each of the concepts, structures and functions of the nervous systemBrain; Cranial nerves; Nerve; Spinal cord; Spinal nerves; Ganglion (plural is ganglia); Sensory receptor; Sensory or afferent neuron; Interneuron (also called association neuron); Motor neuron or efferent neuron; Effector.Organization:A. central nervous system (CNS): brain and spinal cordB. peripheral nervous system (PNS): somatic nervous system, autonomic nervous system (PNS)-sympathetic division, parasympathetic divisionHistology:A. parts of a neuron: cell body, dendrite, axon, synapse, synaptic vesicle, neurotransmitter.B. structural diversity: multipolar neuron, bipolar neuron, unipolar neuron.C. neuroglia or glia: astrocytes, oligodendrocytes, myelin sheath, myelinated, microglia, ependymal cells, Schwann cells, satellite cells, nodes of Ranvier.D. white matterE. gray matter: nucleusElectrical signalsA. signal transmission at synapses: presynaptic neuron, postsynaptic neuron, chemical synapse-synaptic cleft, transmission of signals at a chemical synapse.Neural circuitsII. The Spinal Cord and BrainMake certain that you can define, and use in context, each of the terms listed below, and that you understand the significance of each of the concepts.Part OneSpinal cord anatomyA. external anatomy of the spinal cord: conus medullaris, filum terminale, cauda equine, spinal nerve (posterior or dorsal root-posterior or dorsal root ganglion and anterior or ventral root).B. internal anatomy of the spinal cord: anterior median fissure, posterior median sulcus, grey commissure (central canal), nuclei, anterior (ventral) gray horn, posterior (dorsal) gray horn, lateral gray horn, anterior (ventral) white column, posterior (dorsal) white column, lateral white column, tract, sensory (ascending) tract, motor (descending) tract.Reflex: spinal reflex, cranial reflex, somatic reflex, autonomic reflex or visceral reflex.Reflex arc: sensory receptor (stimulus), sensory neuron, integrating centre (monosynaptic reflex arc, polysynaptic reflex arc), motor neuron (effector).Part TwoPrincipal parts of the brain: brain stem, cerebellum, diencephalons, cerebrum.Brain stemA. medulla oblongata: pyramids, decussation of pyramids, cardiovascular centre, medullary rhythmicity area of the respiratory centre.B. pons:C. midbrain or mesencephalonCerebellum: transverse fissure, vermis, cerebellar hemispheres, cerebellar cortex, folia.Diencephalon: thalamus, hypothalamus, pineal gland-melatonin.Cerebrum: cerebral cortex, gyrus or convolution (plural is gyri), fissure (sulcus or plural is sulci, longitudinal fissure, cerebral hemispheres, corpus callosum, central sulcus, frontal lobe, parietal lobe, precentral gyrus, postcentral gyrus, lateral cerebral sulcus, temporal lobe, parieto-occipital sulcus, occipital lobe, insula, cerebral white matter-association tracts, commissural tracts, projection tracts, basal ganglia, limbic system).Functional organization of the cerebral cortex:A. sensory areas: primary somatosensory area, primary visual area, primary auditory area, primary gustatory area, primary olfactory area.B. motor areas: primary motor area, Broca’s speech area.C. association areas: somatosensory association area, prefrontal cortex (frontal association area), visual association area, auditory association area, Wernicke’s area or posterior language area, language area.D. hemispheric lateralizationIII. The Spinal Nerves and Cranial NervesMake certain that you can define, and use in context, each of the terms listed below, and that you understand the significance of each of the concepts.Part OneSpinal nervesA. mixed nerveB. connective tissue coverings: endoneurium (fascicle), perineurium, epineurium.C. distribution of spinal nerves: ramus (plural is rami), plexus (cervical plexus, brachial plexus, lumbar plexus and sacral plexus), intercostal or thoracic nerves.Part TwoCranial nerves: sensory nerves, mixed nerves.Note: There are 12 pairs of cranial nerves (originating from the brain) in the PNS; their names indicate their distribution or function. The table below provides a brief summary of the numbers, names, and major functions of the cranial nerves.Although they are not described in your textbook, scientists have recently confirmed the presence of a thirteenth pair of cranial nerves in the human body. This pair is currently numbered “zero” because th ey are located anterior to the olfactory (first) nerves. These nerves innervate a newly discovered pair of sensory organs called the vomeronasal organs (located in the anterior nasal cavity). The function of the human vomeronasal organs is not yet known; however, there is some evidence thatthey might detect pheromones, chemical signals passed subconsciously from one individual to another (in other animals, pheromones are known to have effects on reproductive and social behaviors).Number Name Major FunctionI Olfactory SmellII Optic VisionIII Oculomotor Control some of the muscles moving the eyeballs,changes in size of pupil and shape of lensIV Trochlear Control some of the muscles moving the eyeballsV Trigeminal Carry nerve impulses associated with head sensationsand chewing musclesVI Abducens Control some of the muscles moving the eyeballsVII Facial Carry nerve impulses associated with taste, salivationand muscles of facial expressionVIII Vestibulocochlear Carry nerve impulses associated with hearing andequilibriumIX Glossopharyngeal Carry nerve impulses associated with swallowing,salivation and tasteX Vagus Carry nerve impulses to and from many organs in thethoracic and abdominal cavitiesXI Accessory Control head and shoulder musclesXII Hypoglossal Control tongue musclesPart ThreeComparison of somatic and autonomic nervous systems: autonomic sensory neurons, autonomic motor neurons, autonomic ganglion, sympathetic division, parasympathetic division.Anatomy of autonomic motor pathways:A. preganglionic neurons: thoracolumbar division, thoracolumbar outflow, craniosacral division, craniosacral outflow.B. autonomic ganglia: sympathetic ganglia (sympathetic trunk ganglia or vertebral chain ganglia or paravertebral ganglia and prevertebral ganglia or collateral ganglia), parasympathetic ganglia (terminal ganglia or intramural ganglia).C. postganglionic neurons:D. autonomic plexusesIV. Nervous Pathway and Meninges of Brain and Spinal Cord, and the Cerebrospinal FluidMake certain that you can define, and use in context, each of the terms listed below, and that you understand the significance of each of the concepts.Part OneSomatic sensory pathwaysA. sets of three neurons: first-order neurons, second-order neurons, third-order neurons.B. posterior column-medial lemniscus pathway to the cortexC. anterolateral or spinothalamic pathways to the cortex: lateral spinothalamic tract.D. mapping of the somatosensory area (located in the postcentral gyrus)E. somatic sensory pathways to the cerebellumSomatic motor pathwaysA. primary motor area (located in the precentral gyrus)B. direct motor pathways or pyramidal pathways: upper motor neuron (UMN), lower motor neuron (LMN)-final common pathway.C. indirect motor pathways or extrapyramidal pathwaysSpinal cord physiologyA. sensory and motor tracts: lateral and anterior spinothalamic tracts, direct pathways, indirect pathways.Gustatory pathwayVisual pathway: processing of visual input in the retina, brain pathway and visual fields, optic chiasm, optic tract, optic radiations, visual field, binocular visual field (nasal or central half and temporal or peripheral half).Auditory pathwayEquilibrium pathwaysOlfactory pathway: olfactory (I) nerves, olfactory bulbs, olfactory tracts.Part TwoSpinal meninx (plural is meninges)A. dura mater: epidural spaceB. arachnoid mater: subdural spaceC. pia mater: subarachnoid spaceCranial meninx (plural is meninges): dura mater, arachnoid, pia mater.Blood-brain barrier (BBB)Cerebrospinal fluid (CSF)A. subarachnoid spaceB. ventricle: lateral ventricles (2), third ventricle, fourth ventricle.C. functions of CSFD. choroid plexusEssentialsPart OneI. Nervous System IntroductionThe general function of the nervous system is to coordinate all body systems! This is accomplished by the transmission of (electrochemical) signals from body parts to the brain and back to the body parts.A. The organs of the nervous system are divided into two major groups:1. Central Nervous System (CNS) = brain & spinal cord2. Peripheral Nervous System (PNS) = nerves that extend from the brain (cranial nerves) and spinal cord (spinal nerves)B. General Functions of Nervous System (3 fold function):1. Sensory Input Functiona. PNS;b. Sensory receptors (located at the ends of peripheral neurons) detect changes (i.e. are stimulated) occurring in their surroundings;c. Once stimulated, sensory receptors transmit a sensory impulse to the CNS.d. A sensory impulse is carried on a sensory neuron.2. Integrative Functiona. CNS (brain and/or spinal cord);b. involves interpretation of an incoming sensory impulse (i.e. decision is made concerning what's going to happen next, based on sensory impulse).c. Integration occurs in interneurons.d. A motor impulse begins...3. Motor Functiona. PNS;b. involves the response of a body part;c. Motor impulses are carried from CNS to responsive body parts called effectors;d. A motor impulse is carried on a motor neuron;e. Effectors = 2 types: muscles (that contract); glands (that secrete a hormone).. Levels of Organization of Nervous SystemNERVOUS SYSTEM||_________________________________________| |CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM(BRAIN & SPINAL CORD) (CRANIAL NERVES & SPINAL NERVES) (INTERNEURONS)||____________________________________| |SENSORY MOTOR(INPUT INTO CNS) (OUTPUT FROM CNS)(AFFERENT NEURONS) (EFFERENT NEURONS)||_________________________________________| |SOMATIC AUTONOMIC(EFFECTORS: SKELETAL MUSCLE) (EFFECTORS: SMOOTH MUSCLE;(CONSCIOUS CONTROL) CARDIAC MUSCLE; GLANDS)(UNCONSCIOUS CONTROL)||___________________________________| |PARASYMPATHETIC SYMPATHETIC(HOMEOSTASIS) (FIGHT-OR-FLIGHT)II. Histology/Structure of the Nervous SystemA. Neuron = the structural & functional unit of the nervous system; anerve cell.1. Neuron StructureEach neuron is composed of a cell body and many extensions from the cell body called neuron processes or nerve fibers.a. Cell Body = central portion of neuron; contains usual organelles, except centrioles;b. Neuron Processes/ Nerve Fibers = extensions from cell body; two types:●Dendrites:1. many per neuron;2. short and branched;3. receptive portion of a neuron;4. carry impulses toward cell body.●Axon s:1. one per neuron;2. long, thin process;3. carry impulses away from cell body4. Note terminations of axon branch = axonal terminals; synaptic knobs.5. Axons in PNS:a. Large axons are surrounded by a myelin sheath produced by many layers of Schwann Cells (neuroglial cell).●"myelinated nerve fiber";●myelin = lipoprotein;●Interruptions in the myelin sheath between Schwann cells = Nodes of Ranvier.b.Small axons do not have a myelin sheath.●"unmyelinated nerve fibers";●however all axons (in PNS) are associated with Schwann cells.a. Myelin is produced by an oligodendrocyte rather than Schwann Cells;b. A bundle of myelinated nerve fibers = "White Matter";c. This is in contrast to CNS "Gray Matter" = A bundle of cell bodies (or unmyelinated nerve fibers).B. Neuroglial Cells = accessory cells of nervous system form supportingnetwork for neurons; "nerve glue".1. PNS = Schwann cells produces myelin.2. CNS =4 types; provide bulk of brain and spinal cord tissue:a. Oligodendrocyteb. Astrocytec. Microgliad. Ependymal cellsIII. Classification of Neurons:A. Functional Classification:1. Sensory neuronsa. PNS;b. afferent neurons;c. carry sensory impulses from sensory receptors to CNS;d. input information to CNS;e. Location of receptors = skin & sense organs.2. Interneurons (Association)a. CNS;b. link other neurons together (i.e. sensory neuron to interneuron to motor neuron);3. Motor Neuronsa. PNS;b. efferent neurons;c. carry motor impulses away from CNS and to effectors;d. output information from CNS;e. Effectors = muscles & glands.B. Structural Classification:1. Multipolar Neuronsa. many extensions;b. Many dendrites lead toward cell body, one axon leads away from cell body.2. Bipolar Neuronsa. two extensions;b. one fused dendrite leads toward cell body, one axon leads away from cell body;3. Unipolar Neuronsa. one process from cell body;b. forms central and peripheral processes;c. only distal ends are dendrites.IV. Synaptic (Chemical) TransmissionNerve impulses are transferred from one neuron to the next through synaptic transmission.A. Synapse =the junction between two neurons where a nerve impulse istransmitted;1. occurs between the axon of one neuron and dendrite or cell body of a second neuron.2. Note that the two neurons do not touch. There is a gap between them = synaptic cleft.Part TwoI. THE SPINAL CORDThe spinal cord is a nerve column that passes downward from brain into the vertebral canal. Recall that it is part of the CNS. Spinal nerves extend to/from the spinal cord and are part of the PNS.A. Gross Structure of Spinal Cord:1. Length = about 17 inches;a. Start = foramen magnum;b. End = tapers to point (conus medullaris) and terminates near the intervertebral disc that separates the 1st - 2nd lumbar (L1-L2) vertebra.2. Contains 31 segments (and therefore gives rise to 31 pairs of spinal nerves).3. Note cervical and lumbar enlargements.4. Note cauda equina ("horse's tail) in which the lower lumbar and sacral nerves travel downward (i.e. lower spinal nerves must "chase" their points of exit).5. Note filum terminale that represents distal portion of the tail (pia mater).B. Cross-Sectional Anatomy of Spinal CordA cross-section of the spinal cord resembles a butterfly with its wings outspread (gray matter) surrounded by white matter.1. Gray matter or "butterfly" = bundles of (interneuron) cell bodies:a. posterior (dorsal) horns,b. lateral horns, andc. anterior (ventral) horns.2. Note location of:a. central canal (lined by ependymal cells),b. gray commissure,c. anterior median fissure,d. posterior median sulcus.3. White matter = myelinated (interneuron) axons:a. Locations:●posterior (dorsal) funiculi or white column,●lateral funiculi or white column,●and anterior (ventral) funiculi or white column.b.The white matter of the spinal cord represents the location of our major nervepathways called "nerve tracts".●provide a 2-way system of communication:1. In general, ascending tracts are located in the posterior (dorsal) columns and conduct sensory (afferent) impulses from body parts to brain;2. In general, descending tracts are located in the anterior (ventral) columns and conduct motor (efferent) impulses from brain to effectors.a. General characteristics of nerve tracts:●Most cross over;●Most consist of 2-3 successive neurons;●Most exhibit somatotropy (i.e. tracts from/to upper body are located on outside,tracts from/to lower body on inside);●All pathways are paired (right and left).4. Other Important Features:a. ventral root;b. dorsal root;●dorsal root ganglion (DRG).1. Ganglion = a bundle of cell bodies outside the CNS;2. DRG contains the cells bodies of sensory (afferent) neurons bringing impulses to the CNS.c. The fusion of the dorsal and ventral roots designates the beginning of the spinal nerve which then passes through its intervertebral foramen.II. THE BRAINThe brain is the largest and most complex portion of the nervous system. It occupies the cranial cavity and is composed of one hundred billion multipolar neurons. The brain oversees the function of the entire body and also provides characteristics like personality.A. Regions of BrainThe brain is composed of 4 major portions, including the cerebrum, cerebellum, diencephalon and brain stem.1. Cerebrum = the largest portion of the brain, which is divided into two cerebral hemispheres.a. Hemispheres are connected by a deep bridge of nerve fibers called the corpus callosum;b. Surface ridges are called convolutions* (gyri);c. Each hemisphere is divided into lobes which are named for the bones that cover them including frontal, parietal, temporal, and occipital lobes.d. Convolutions are separated by two types of grooves:●sulci = shallow groove;1.central sulcus (frontal/parietal)teral sulcus (temporal/others)●fissure = deep groove;1. longitudinal fissure separates the two cerebral hemispheres.2. transverse fissure (cerebrum/cerebellum)e. Composition:●Bulk of cerebrum is white matter.* bundles of myelinated nerve fibers (by oligodendrocyte);●Cerebral cortex or the outer portion of cerebrum is composed of gray matter.* bundles of neuron cell bodies.f. Cerebral cortex●responsible for all conscious behavior by containing three kinds of functionalareas, which include motor, sensory and association areas:1. Motor Areas are located in the frontal cortex:a. Primary motor cortex●initiates all voluntary muscle movements;●located in the gyrus just anterior to the central sulcus (precentral gyrus).b. Broca's area●motor speech area;●located in left frontal lobe, above temporal lobe;2. Sensory Areas are concerned with conscious awareness of sensations and are located in the parietal, occipital, and temporal cortex.a. Primary somatosensory cortex●receives information from general receptors (i.e. temperature, touch, pressure, &pain).●located in postcentral gyrus of parietal cortex;b.Visual (Cortex) Area●receives incoming information from vision receptors (in eye);●located in occipital cortex.c. Auditory (Cortex) Area●receives incoming information from hearing receptors (in ear);●located in temporal cortex.d. Gustatory cortex●receives incoming information from taste receptors in taste buds;●located in parietal cortex just above the temporal lobe.3. Association Areas of cerebral cortexa. General:●include areas that are not directly involved in motor or sensory function.●are involved in many traits.●are usually interconnected.●involve all four lobes.b.Association traits include:●analyzing & interpreting sensory experiences;●help provide memory, reasoning, verbalizing, judgement and emotions.g.Hemisphere Dominance (Brain Lateralization)●Most basic functions (sensory & motor) are equally controlled by both left &right hemispheres (remember communication exists through corpuscallosum).●However, for some association functions, one hemisphere has greater controlover language-related activities including speech, writing, reading,mathematics and logic.1. This hemisphere is considered the "dominant hemisphere".a. In most people, the left hemisphere is dominant.b. The other hemisphere (non-dominant) controls orientation in space, art and musical appreciation and emotions.i. Basal Nuclei●masses of gray matter located deep within the white matter of the cerebralhemispheres.●serve as relay stations for outgoing motor impulses from the brain. (i.e. fromprimary motor cortex in frontal cortex to basal ganglia and then through brain stem, down spinal cord, etc.)2. The Diencephalon:a. includes two important areas of gray matter:●Thalamuscentral relay station for incoming sensory impulses (except smell), that directs the impulse to the appropriate are of the cerebral cortex for interpretation;●Hypothalamus1. main visceral control center of the body (i.e. regulates homeostasis).a. heart rate & blood pressure;b. body temperature;c. water & electrolyte balance;d. control of hunger & body weight;e. control of digestive movements & secretions;f. regulation of sleep-wake cycles;g. control of endocrine system functioning.b. Involved in Emotional response: Limbic System●also includes structures in the frontal and temporal cortex, basal nuclei, and deepnuclei;●controls emotional experience and expression;●can modify the way a person acts;●produces feelings of fear, anger, pleasure, and sorrow;●recognizes life-threatening upsets in a person's physical or psychologicalcondition and counters them;●involved in sense of smell.3. The Brain Stem:The brain stem is composed of three major parts that include the midbrain, pons, and medulla oblongata. The brain stem serves as a pathway for fiber tracts running to (sensory impulses) and from (motor impulses) the cerebrum and houses many cranial nerves (PNS).a. Midbrain1. located between diencephalon and pons2. Corpora quadrigemina = 4 dome-like protrusions on the dorsal midbrain surface (remember you saw these in lab when you separated the cerebrum from cerebellum!);3. gray matter within white matter;4. acts in reflex actions (visual and auditory);5. also contains areas associated with reticular formation.b. Pons1. bulging portion of brain stem;2. "bridge" or pathway of conduction tracts;3. location of pneumotaxic area (regulation of breathing rate) of respiratory center;4. also contains areas associated with reticular formation.c. Medulla (Oblongata)1. inferior portion of brain stem which blends into the spinal cord at its base;2. contains an autonomic reflex center involved in maintaining homeostasis of important visceral organs.●Cardiac center adjusts force and rate of heart contraction;。