Understanding the Central Nervous System: Brain and Spinal Cord
School
The University of Sydney**We aren't endorsed by this school
Course
BIOL 1007
Subject
Psychology
Date
Dec 10, 2024
Pages
28
Uploaded by MateStingray1817
219 Our next chapter in the nervous system series covers the division known as the central nervous system (CNS). Here we explore the structure and functions of the two main organs of the CNS: the brain and the spinal cord. What Do You Already Know? Try to answer the following questions before proceeding to the next section. If you’re unsure of the correct answers, give it your best attempt based on previous courses, previous chapters, or just your general knowledge. • What percentage of our brains do we use? • What protects the brain and spinal cord? • Can people be “right-brained” or “left-brained?” Module 12.1: Overview of the Central Nervous System Module 12.1 in your text introduces you to the structural and functional features of the brain and the spinal cord and looks at the process of nervous system development. By the end of the module, you should be able to do the following: 1. Describe the structure and function of each major area of the brain. 2. Describe the five developmental regions of the brain, and identify the major areas of the adult brain that arise from each region. Build Your Own Glossary Following is a table listing key terms from Module 12.1. Before you read the module, use the glossary at the back of your book or look through the module to define the following terms. The Central Nervous System
220Active-Learning Workbook Key Terms for Module 12.1 Term Definition Brain Cerebrum Diencephalon Cerebellum Brainstem Spinal cord White matter Gray matter Tract Nuclei Survey It: Form Questions Before you read the module, survey it and form at least two questions for yourself. When you have finished reading the module, return to these questions and answer them. Question 1:Answer:Question 2:Answer:
Chapter 12The Central Nervous System221Identify It: Divisions of the Brain Identify and color-code each division of the brain in Figure 12.1. Then, in the boxes on the right, list the main functions of each division. Figure 12.1 Divisions of the brain. Key Concept:How do gray matter and white matter differ? Why are they different colors? Key Concept:What are the early nervous system structures called, and how do they change as development takes place?
222Active-Learning Workbook Module 12.2: The Brain Now we take a closer look at the structure of the brain. When you finish this module, you should be able to do the following: 1. Describe and identify the five lobes of the cerebral cortex, and explain how motor and sensory functions are distributed among the lobes. 2. Describe the structure, components, and general functions of the regions of the diencephalon, cerebellum, and brainstem. 3. Describe the location and functions of the limbic system and the reticular formation. Build Your Own Glossary Below is a table listing key terms from Module 12.2. Before you read the module, use the glossary at the back of your book or look through the module to define the following terms. Key Terms for Module 12.2 Term Definition Sulcus Fissure Gyrus Cerebral cortex Association area Basal nuclei Corpus callosum Limbic system Thalamus Hypothalamus Midbrain Pons Medulla oblongata Reticular formation
Chapter 12The Central Nervous System223Survey It: Form Questions Before you read the module, survey it and form at least two questions for yourself. When you have finished reading the module, return to these questions and answer them. Question 1:Answer:Question 2:Answer:Key Concept:What is the advantage of having the surface of the brain folded into gyri and sulci? Identify It: Lobes and Area of the Cerebrum Identify and color-code each lobe and area of the cerebrum in Figure 12.2. Also, add your own leaders and label the following: gyrus, sulcus, central sulcus, lateral fissure, precentral gyrus, and postcentral gyrus. Then, identify the main function(s) of each. Figure 12.2 The cerebrum.
224Active-Learning Workbook Figure 12.2 (continued) Build Your Own Summary Table: The Brain There are a lotof structures in the brain, and that makes it easy to get overwhelmed. To help yourself see the big picture and focus on the main points, fill in this summary table as you read. In the first column, label the brain structure and, in the second, list its functions. A completed table (text Figure 12.17) can be seen at the end of the module. When you finish, compare your table to Figure 12.17 to ensure that you didn’t leave out any important details.
Chapter 12The Central Nervous System225Summary of Brain Structures and Functions
226Active-Learning Workbook Key Concept:Why is the thalamus often called the “gateway” to the cerebrum? Key Concept:What are the main types of structures housed in the brainstem? Why does this make the brainstem so critical to our survival? Identify It: Structures of the Brain Label and color-code the structures of the brain illustrated in Figure 12.3. Figure 12.3 Anatomy of the brain.
Chapter 12The Central Nervous System227Figure 12.3 (continued) Module 12.3: Homeostasis Part I: Role of the Brain in Maintenance of Homeostasis The nervous system is one of the major regulatory systems in the body and is tasked with maintaining homeostasis of other organ systems. We take a look at the role of the CNS in these regulatory processes in this module. The discussion of homeostasis continues in the chapter on the autonomic nervous system. At the end of this module, you should be able to do the following: 1. Describe the differences between the endocrine system and the nervous system in terms of how they maintain homeostasis. 2. Provide specific examples demonstrating how the nervous system responds to maintain homeostasis in the body. Build Your Own Glossary Following is a table listing key terms from Module 12.3. Before you read the module, use the glossary at the back of your book or look through the module to define the following terms.
228Active-Learning Workbook Key Terms of Module 12.3 Term Definition Autonomic nervous system Vasopressor center Vasodepressor center Sleep Circadian rhythm Beta waves Theta waves Delta waves REM sleep Survey It: Form Questions Before you read the module, survey it and form at least three questions for yourself. When you have finished reading the module, return to these questions and answer them. Question 1:Answer:Question 2:Answer:Question 3:Answer:Key Concept:Which two components of the CNS are largely responsible for homeostatic regulation?
Chapter 12The Central Nervous System229Describe It: CNS Control of Homeostasis Write a paragraph describing the mechanisms of control of homeostasis by the CNS as if you were teaching the topic to a group of your fellow students. Key Concept:Which parts of the brain are involved in sleep and circadian rhythms? How is regulation of sleep and circadian rhythms connected to the level of light? Identify It: Stages of Wakefulness and Sleep Identify and color-code each component of the graph of the stages of wakefulness and sleep in Figure 12.4. Figure 12.4 The stages of wakefulness and sleep. Module 12.4: Higher Mental Functions We now explore the higher brain functions, including cognition, language, learning, memory, and emotions. At the end of this module, you should be able to do the following: 1. Describe the areas of the cortex responsible for cognition and language. 2. Discuss the concept of cerebral hemispheric specialization. 3. Describe the parts of the brain involved in storage of long-term memory, and discuss possible mechanisms of memory consolidation. Build Your Own Glossary Below is a table listing key terms from Module 12.4. Before you read the module, use the glossary at the back of your book or look through the module to define the following terms.
230Active-Learning Workbook Key Terms of Module 12.4 Term Definition Cognition Cerebral lateralization Language Declarative memory Nondeclarative memory Consolidation Long-term potentiation Survey It: Form Questions Before you read the module, survey it and form at least two questions for yourself. When you have finished reading the module, return to these questions and answer them. Question 1:Answer:Question 2:Answer:Key Concept:What are cognitive functions, and which parts of the brain are responsible for executing these functions? Key Concept:What is cerebral lateralization? Can people be “right-brained” or “left-brained?”
Chapter 12The Central Nervous System231Complete It: Language, Learning, Memory, and Emotion Fill in the blanks to complete the following paragraphs that describe the role of the brain in language, learning, memory, and emotion. Language functions tend to be lateralized to the ____________ ____________. The two language areas are ____________ ____________ and ____________ ____________. The first area is responsible for the ____________ ____________ ____________, whereas the second is responsible for the ____________ ____________ ____________. Memories that are fact-based are called ____________ ____________. These memories are stored in the brain via the ____________ and a process called ____________ ____________ ____________. Memories that are procedure-based are called ____________ ____________. The storage of these memories seems to involve the ____________ ____________, the ____________, and the ____________ ____________. The visceral response to emotion seems to involve the ____________, whereas the somatic response is mediated by this part of the brain and the ____________ ____________. The “feeling” component of emotion involves the part of the brain known as the ____________. Module 12.5: Protection of the Brain The delicate tissues of the brain are protected in several ways, which we examine in this module. When you complete it, you should be able to do the following: 1. Describe the functions of cerebrospinal fluid as well as the details of its production, its circulation within the CNS, and its ultimate reabsorption into the bloodstream. 2. Describe the structural basis for and the importance of the blood brain barrier. 3. Identify and describe the cranial meninges, and explain their functional relationship to the brain. Build Your Own Glossary Following is a table listing key terms from Module 12.5. Before you read the module, use the glossary at the back of your book or look through the module to define the following terms.
232Active-Learning Workbook Key Terms of Module 12.5 Term Definition Cranial meninges Dura mater Arachnoid mater Pia mater Dural sinuses Lateral ventricles Third ventricle Fourth ventricle Cerebrospinal fluid Choroid plexuses Blood brain barrier Survey It: Form Questions Before you read the module, survey it and form at least four questions for yourself. When you have finished reading the module, return to these questions and answer them. Question 1:Answer:Question 2: Answer: Question 3:Answer:Question 4:Answer:
Chapter 12The Central Nervous System233Identify It: Cranial Meninges Identify and color-code the structures associated with the cranial meninges illustrated in Figure 12.5. Figure 12.5 The cranial meninges and dural sinuses. Key Concept:Why is there no true epidural space around the brain? What is located in the subdural and subarachnoid spaces?
234Active-Learning Workbook Identify It: Ventricles of the Brain Identify and color-code the ventricles of the brain illustrated in Figure 12.6. Figure 12.6 Ventricles of the brain. Key Concept:What is the function of CSF and how is it produced?
Chapter 12The Central Nervous System235Draw It: CSF Circulation Draw arrows to trace the pathway of CSF circulation through the brain illustrated in Figure 12.7. Then, label the structures and describe the steps of CSF formation, circulation, and reabsorption. Figure 12.7 Formation and flow of cerebrospinal fluid.
236Active-Learning Workbook Module 12.6: The Spinal Cord Module 12.6 in your text explores the structure of the spinal cord. At the end of this module, you should be able to do the following: 1. Describe the gross anatomy and location of the spinal cord. 2. Identify and describe the anatomical features seen in a cross-sectional view of the spinal cord. 3. Identify and describe the spinal meninges and the spaces between and around them. 4. Describe the differences between ascending and descending tracts in the spinal cord. Build Your Own Glossary Below is a table listing key terms from Module 12.6. Before you read the module, use the glossary at the back of your book or look through the module to define the following terms. Key Terms of Module 12.6 Term Definition Spinal meninges Epidural space Conus medullaris Filum terminale Cauda equina Central canal Anterior horn Lateral horn Posterior horn Funiculus Survey It: Form Questions Before you read the module, survey it and form at least three questions for yourself. When you have finished reading the module, return to these questions and answer them.
Chapter 12The Central Nervous System237Question 1: Answer: Question 2: Answer: Question 3: Answer: Identify It: Structure of the Spinal Meninges Identify and color-code each component of the spinal meninges illustrated in Figure 12.8. Then, write the function of each part under its label. Figure 12.8 Structure of the spinal meninges. Key Concept:What are the key differences between the cranial and spinal meninges?
238Active-Learning Workbook Draw It: Internal Anatomy of the Spinal Cord In the space below, draw an outline of a spinal cord transverse section, as shown in text Figures 12.28 and 12.29. Then, draw in the gray matter, central canal, nerve roots, and ascending and descending tracts. After you have drawn each part, color-code and label them. Key Concept:What types of stimuli do the spinal cord’s ascending tracts carry? What do the spinal cord’s descending tracts carry? Module 12.7: Sensation Part I: Role of the CNS in Sensation Sensation is the process of detecting stimuli in the internal and external environments. In this module, we look at the role that the central nervous system plays in sensation; our discussion of sensation continues in the peripheral nervous system (PNS) chapter. At the end of this module, you should be able to do the following: 1. Describe the roles of the central and peripheral nervous systems in processing sensory stimuli. 2. Describe the locations and functions of first-, second-, and third-order neurons in a sensory pathway. 3. Explain the ways in which special sensory stimuli are processed by the CNS.
Chapter 12The Central Nervous System239Build Your Own Glossary Following is a table listing key terms from Module 12.7. Before you read the module, use the glossary at the back of your book or look through the module to define the following terms. Key Terms of Module 12.7 Term Definition Sensory stimuli Perception Tactile senses Nondiscriminative touch Posterior columns/ medial lemniscus tracts Anterolateral system Spinothalamic tracts Somatotopy Nociception Survey It: Form Questions Before you read the module, survey it and form at least three questions for yourself. When you have finished reading the module, return to these questions and answer them. Question 1:Answer:Question 2:Answer:Question 3:Answer:
240Active-Learning Workbook Key Concept:What are discriminative touch and nondiscriminative touch? Which tract(s) carry these stimuli? Describe It: The Posterior Columns Label and color-code the main structures involved in the posterior columns/medial lemniscal system in Figure 12.9. Then, write out each step of information transfer from the initial stimulus to its delivery to the cerebral cortex. Figure 12.9 The posterior columns/medial lemniscal system.
Chapter 12The Central Nervous System241Describe It: The Spinothalamic Tract (Anterolateral System) Label and color-code the main structures involved in the spinothalamic tract (anterolateral system) in Figure 12.10. Then, write out each step of information transfer from the initial stimulus to its delivery to the cerebral cortex. Figure 12.10 The spinothalamic tract (part of the anterolateral system). Key Concept:What are the key structural and functional differences between the posterior columns and anterolateral system?
242Active-Learning Workbook Module 12.8: Movement Part I: Role of the CNS in Voluntary Movement Like sensation, movement involves both the PNS and CNS. We examine the role of the CNS in movement in this module and will continue this discussion in the PNS chapter. At the end of this module, you should be able to do the following: 1. Describe the locations and functions of the upper and lower motor neurons in a motor pathway. 2. Explain the roles of the cerebral cortex, basal nuclei, and cerebellum in movement. 3. Describe the overall pathway from the decision to move to the execution and monitoring of a motor program. 4. Explain how decussation occurs in sensory and motor pathways, and predict how brain and spinal cord injuries affect these pathways. Build Your Own Glossary Below is a table listing key terms from Module 12.8. Before you read the module, use the glossary at the back of your book or look through the module to define the following terms. Key Terms of Module 12.8 Term Definition Corticospinal tracts Motor program Upper motor neurons Globus pallidus Caudate nucleus Putamen Motor learning Survey It: Form Questions Before you read the module, survey it and form at least three questions for yourself. When you have finished reading the module, return to these questions and answer them. Question 1:Answer:Question 2:Answer:
Chapter 12The Central Nervous System243Question 3:Answer:Key Concept:How do upper motor neurons and lower motor neurons differ? Describe It: The Corticospinal Tract Label and color-code the main structures involved in the corticospinal tract in Figure 12.11. Then, write out each step of information transfer from the initial stimulus to its delivery to the lower motor neuron. Figure 12.11 The corticospinal tract.
244Active-Learning Workbook Complete It: The Brain and Movement Fill in the blanks to complete the following paragraph that describes the role of the brain in movement. Like the primary somatosensory cortex, the primary motor cortex is organized ____________ and can be represented by the ____________ ____________. Smooth, fluid movement requires the activity of the ____________ ____________, including the putamen, caudate nucleus, and putamen, and the ____________ ____________ of the midbrain. The basal nuclei modify the activity of ____________ ____________ ____________. The cerebellum is also required for smooth movement, as it determines ____________ ____________. The process of correcting this error over time is called ____________ ____________. Key Concept:What are the two key roles of the basal nuclei in movement? Team Up Make a handout to teach the overall pathway of the initiation and control of movement by the CNS. You can use Figure 12.37 in your text on page 469 as a guide, but the handout should be in your own words and with your own diagrams. At the end of the handout, write a few quiz questions. Once you have completed your handout, team up with one or more study partners and trade handouts. Study your partners’ diagrams, and when you have finished, take the quiz at the end. When you and your group have finished taking all the quizzes, discuss the answers to determine places where you need additional study. After you’ve finished, combine the best elements of each handout to make one “master” diagram for the control of movement by the CNS. Key Concept:How does the control of movement by the cerebellum differ from that of the basal nuclei?
Chapter 12The Central Nervous System245What Do You Know Now? Let’s now revisit the questions you answered in the beginning of this chapter. How have your answers changed now that you’ve worked through the material? • What percentage of our brains do we use? • What protects the brain and spinal cord? • Can people be “right-brained” or “left-brained?”