{"id":226,"date":"2025-07-02T20:09:09","date_gmt":"2025-07-02T20:09:09","guid":{"rendered":"https:\/\/press.wpunj.edu\/humanbiologylabmanual\/chapter\/__unknown__\/"},"modified":"2025-07-22T23:50:20","modified_gmt":"2025-07-22T23:50:20","slug":"nervoussystem","status":"publish","type":"chapter","link":"https:\/\/press.wpunj.edu\/humanbiologylabmanual\/chapter\/nervoussystem\/","title":{"raw":"Nervous System","rendered":"Nervous System"},"content":{"raw":"
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Learning Objectives<\/p>\r\n\r\n<\/header>\r\n

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  1. Distinguish between central nervous system and peripheral nervous system.<\/li>\r\n \t
  2. Identify the structures of a neuron and describe their functions.<\/li>\r\n \t
  3. Identify the regions of the brain and their structures.<\/li>\r\n \t
  4. Identify the lobes of the cerebrum.<\/li>\r\n \t
  5. State the general function of each lobe and structure of the brain.<\/li>\r\n \t
  6. Identify the major structures of the sheep brain.<\/li>\r\n \t
  7. Compare and contrast structural differences between the sheep brain and the human brain.<\/li>\r\n \t
  8. Identify white matter and gray matter within a cross-section view of the spinal cord.<\/li>\r\n \t
  9. Distinguish between cranial nerves and spinal nerves based on location.<\/li>\r\n \t
  10. Describe the components of a reflex arc.<\/li>\r\n \t
  11. Perform the knee-jerk reflex.<\/li>\r\n \t
  12. Conduct reaction time experiments and compare undistracted reaction time to distracted reaction time for at least two different types of distractions.<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n

    NERVOUS SYSTEM<\/h1>\r\n

    The nervous system can be separated into two major divisions: the central nervous system and the peripheral nervous system. The central nervous system<\/strong> consists of the brain and spinal cord whereas the peripheral nervous system<\/strong> includes all other nerves that extend throughout the body. (Figure 6.1)<\/p>\r\n

    \"image\"Figure 6.1:<\/strong> The nervous system is divided into two major parts: central nervous system and peripheral nervous system.<\/span><\/p>\r\n

    Nervous tissue is composed of two main types of cells: neurons and neuroglial cells. Neurons<\/strong>, or nerve cells, are the structural and functional units of the nervous system that receive, process, and transmit information through both electrical and chemical signals. They are made up of a cell body, or soma; dendrites; an axon; and synaptic knobs or buttons (Figure 6.2). The cell body<\/strong> can structurally be compared to the basic structure of an animal cell due to housing the nucleus and other essential organelles for the neuron\u2019s function. The dendrites<\/strong> are branched extensions of the cell body that receive signals from other neurons. The axon<\/strong> is a long, cable-like projection that extends from the cell body of the neuron and transmits electrical signals to the other end of the neuron. The synaptic knobs<\/strong> or buttons<\/strong> are specialized ends of the axon that form a synapse with another neuron or cell. They transform the electrical signal into chemical signals, the neurotransmitters, and transmit the signals to receptors in neighboring cells.<\/p>\r\n

    \"image\"<\/p>\r\nFigure 6.2<\/strong>: The basic structure of a neuron. \u00a9 McGraw Hill Education\r\n

    There are three main types of neurons: sensory neurons, interneurons, and motor neurons. Sensory neurons<\/strong> transmit electrical signals from sensory receptors in body tissues and organs to the central nervous system. They detect stimuli or sensations such as touch, heat, cold sound, pain, and light. Motor neurons<\/strong> transmit electrical signals from the central nervous system to muscles and glands and act in response to stimuli. They are involved in both voluntary and involuntary actions. Interneurons<\/strong> transmit electrical signals between sensory and motor neurons within the central nervous system.<\/p>\r\n

    Neuroglial cells<\/strong>, or glial cells, serve as support, protection, and insulation for neurons. Glial cells of the central nervous system include oligodendrocytes, astrocytes, ependymal cells, and microglial cells; glial cells of the peripheral nervous system include Schwann cells and satellite cells.<\/p>\r\n\r\n

    CENTRAL NERVOUS SYSTEM<\/h1>\r\n

    BRAIN<\/h3>\r\n

    The brain is composed of gray matter and white matter. Gray matter<\/strong> contains primarily the cell bodies of the neurons, and has its name based on appearing a grayish, pinkish color due to the presence of blood capillaries. White matter<\/strong> consists of the axons of the neurons which are covered in a white fatty structure called the myelin sheath. Gray matter is found mostly in the exterior and white matter is mostly in the interior of the brain.<\/p>\r\n

    The brain has four main regions: the cerebrum, the diencephalon, the cerebellum, and the brainstem (Figure 6.3). Each of these regions can be further subdivided into multiple structures based on their functions.<\/p>\r\n\"image\"The cerebrum<\/strong> is the largest portion of the brain and is associated with higher mental function along with sensory and motor functions. It is divided into left and right cerebral hemispheres, joined at the corpus callosum. The surface area of the human brain is increased due to the folding of the brain tissue into gyri and sulci (folds and grooves), creating more surface area for more neurons to exist within the skull. The cerebrum is subdivided into lobes: frontal lobe, two parietal lobes, two temporal lobes, occipital lobe, and the insular lobe (Figure 6.4). The cerebral lobes contain distinct functional areas made up of sensory, motor, and association areas. The frontal lobe<\/strong> is primarily associated with motor functions (voluntary muscle control); cognitive functions, such as decision-making, problem-solving, and personality; and speech and language. The parietal lobes<\/strong> are associated with somatosensory reception, such as taste and tactile senses of touch, pressure, tickle, pain, and itch. The temporal lobes<\/strong> are associated with hearing and smell. The occipital lobe<\/strong> is responsible for visual perception. The insular lobe<\/strong> is hidden below the other lobes of the brain and plays a role in emotions and self-awareness.\r\n

    \"image\"<\/p>\r\n

    Figure 6.4:<\/strong> Five lobes of the cerebrum along with their functional areas \u00a9 McGraw Hill Education<\/p>\r\n

    Note to students:<\/em><\/span> Write all data and answers to questions on the Lab Report provided.<\/p>\r\n\r\n

    Activity 1: <\/em>Match the <\/em>Functions<\/em> to<\/em> the Cerebral Lobes<\/em><\/h6>\r\n

    Match the cerebral lobe with its function. Record your answers on the Lab Report.<\/p>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
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    Lobe<\/strong><\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    Definition<\/strong><\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n

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    a. Frontal<\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    1. Vision perception<\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n

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    b. Parietal<\/p>\r\n\r\n<\/div><\/td>\r\n

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    2. Hearing and smell<\/p>\r\n<\/td>\r\n<\/tr>\r\n

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    c. Temporal<\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    3. Cognitive function; personality; motor function<\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n

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    d. Occipital<\/p>\r\n\r\n<\/div><\/td>\r\n

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    4. Emotions and self-awareness<\/p>\r\n<\/td>\r\n<\/tr>\r\n

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    e. Insular<\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    5. Somatosensory reception (touch and taste)<\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n

    The diencephalon<\/strong> connects the cerebrum with the rest of the nervous system except for the sense of smell. The olfactory tract has a direct connection from the olfactory epithelium, found at the top of the sinuses, to the cerebrum. The diencephalon includes the thalamus, hypothalamus, epithalamus, and subthalamus. All sensory information, except for the sense of smell, passes through the thalamus<\/strong> before reaching the cerebrum. The thalamus can be considered the Grand Central Station of senses as it also processes that sensory information. The other major region of the diencephalon is the hypothalamus<\/strong>, which is composed of a collection of nuclei that serves as one of the major regulators of homeostasis. It contains control centers for body temperature, blood pressure and heart rate, water and electrolyte balance, appetite and weight control, and the sleep-wake cycle. The epithalamus<\/strong>, which contains the pineal gland, also regulates the sleep-wake cycle by secreting the hormone melatonin. The subthalamus<\/strong> regulates motor activity and has a key role in controlling voluntary movement.<\/p>\r\n\r\n

    Activity 2: Match the Functions to the <\/em>Structures of the Diencephalon<\/em><\/h6>\r\n

    Match the structure of the diencephalon with its function. Record your answers on the Lab Report.<\/p>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
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    Structure<\/strong><\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    Definition<\/strong><\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n

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    a. Hypothalamus<\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    1. Regulates sleep-wake cycle through the hormone melatonin<\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n

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    b. Epithalamus<\/p>\r\n\r\n<\/div><\/td>\r\n

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    2. Regulates motor activity and controls voluntary movement<\/p>\r\n<\/td>\r\n<\/tr>\r\n

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    c. Subthalamus<\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    3. Processes all sensory information except the sense of smell<\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n

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    d. Thalamus<\/p>\r\n\r\n<\/div><\/td>\r\n

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    4. Regulates homeostasis<\/p>\r\n<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n


    The cerebellum<\/strong> is located posterior to the cerebrum. It has the function of coordinating and fine-tuning voluntary muscle movements; helping to maintain balance and equilibrium; and plays a role in motor learning, such as walking and riding a bicycle.<\/p>\r\nThe brain stem<\/strong> is the part of the brain that connects it with the spinal cord. It serves as a relay station for nerve impulses passing from the spinal cord to the brain. It consists of 3 components: midbrain, pons, and medulla oblongata (Figure 6.5). The midbrain<\/strong> plays an important role in processing visual, auditory, and somatosensory perception. The pons<\/strong> connects the brain stem to the cerebellum and acts as a bridge to relay nerve impulses between the two structures. The medulla oblongata<\/strong> regulates breathing, heart rate, and blood pressure. It also plays a role in reflexes such as swallowing, vomiting, coughing, and sneezing. It is the main connection between the brain and the spinal cord.\r\n

    \"image\"<\/p>\r\n\r\n

    Activity 3: Match the Functions to the Structures of the Brain Stem<\/em><\/h6>\r\n

    Match the structure of the brain stem with its function. Record your answers on the Lab Report.<\/p>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
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    Structure<\/strong><\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    Definition<\/strong><\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n

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    a. Midbrain<\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    1. Serves as the control center for breathing, heart rate, and blood pressure<\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n

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    b. Pons<\/p>\r\n\r\n<\/div><\/td>\r\n

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    2. Connects the brain to the cerebellum to relay the nerve impulses<\/p>\r\n<\/td>\r\n<\/tr>\r\n

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    c. Medulla oblongata<\/p>\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n

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    3. Processes visual, auditory, and somatosensory perception<\/p>\r\n\r\n<\/div><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n


    Activity 4: Dissection of the Sheep Brain<\/em><\/h6>\r\n

    The sheep brain is similar to the human brain as both organisms are mammals. However, some regions of the sheep brain are proportionally smaller compared to the human brain. For example, the sheep cerebrum is considerably smaller in proportion to total brain size than the human cerebrum. The orientation of the brain stem and spinal cord is also different because humans are bipedal (walk upright on two legs) and sheep are quadrupedal (walk on four legs). The sheep brain stem and spinal cord emerge and run horizontally from the back of the brain whereas the human brain stem and spinal cord emerge and run vertically below the cerebrum.<\/p>\r\n\r\n

    EXTERNAL BRAIN ANATOMY<\/h3>\r\n
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    1. One student from each lab bench may obtain safety glasses, a pair of nitrile gloves, one preserved sheep brain, one scalpel, one pair of scissors, one probe, and one dissecting tray.<\/li>\r\n \t
    2. Remove the sheep brain from its packaging and throw away the packaging in the regular garbage near the lab bench. Place the sheep brain dorsal side (top side) up onto the dissecting tray.<\/li>\r\n \t
    3. Observe the external anatomy:<\/li>\r\n<\/ol>\r\n