Nervous System Structures and Functions

Exam 4 Study Guide Chapter 11

Basic Structures & Functions of the Nervous System

  • Knowledge Requirements: Understand the fundamental structures and functions of the nervous system.

Organization of the Nervous System

  • Central Nervous System (CNS) & Peripheral Nervous System (PNS):
    • CNS Components: Brain and spinal cord.
    • PNS Components: Includes many divisions; it is crucial to know all of them.
    • Visual Aids: Reference Table 11.1 and Figures 11.2-3 for detailed illustrations of the CNS and PNS organization.

Structure of Neurons

  • Neurons: The basic functional unit of the nervous system.
  • Classes of Neurons: Detailed knowledge of their structure, location, and classification is essential.
    • Key Locations: Understand where each class of neuron can be found.
  • Visual Aids: Refer to Figures 11.4-5 for structural illustrations of neurons.

Functions of Glial Cells

  • Roles of Glial Cells in CNS & PNS:
    • Oligodendrocytes vs. Schwann Cells: Be able to differentiate their functions and locations in the CNS and PNS, respectively.
  • Visual Aids: See Table 11.2 for comparison of glial cells.

Myelinated vs. Unmyelinated Cells

  • Myelination Types: Understand the differences and the implications for neural conductivity.
  • Grey Matter vs. White Matter:
    • Grey Matter: Characterized by unmyelinated neurons.
    • White Matter: Contains myelinated axons.
  • Visual Aid: Reference Figure 11.7 for a clearer understanding of myelination.

Electrical Properties of Neurons

  • Resting Membrane Potential: Understand how resting membrane potential is established and maintained, detailing involved ions and membrane proteins.
  • Key Concepts:
    • Depolarization vs. Hyperpolarization: Understand the terms and physiological relevance.
    • Graded Potentials: Comprehend how graded potentials influence the propagation of action potentials.
    • Conduction Types: Differentiate between continuous conduction and saltatory conduction.
  • Visual Aids: Refer to Figures 11.6-7 for diagrams of electrical properties.

Chemical Synapse Structure & Function

  • Chemical Synapse: Know the structure and function of the chemical synapse in neurotransmission.
  • Neurotransmitters: Understand that certain neurotransmitters bind to specific receptors, influencing excitatory or inhibitory responses in postsynaptic cells.
  • Summation: Understand how spatial and temporal summation contribute to the overall action potentials at postsynaptic neurons.
  • Visual Aid: See Figure 11.21 for synaptic transmission and integration illustration, and Figure 11.23 for summation processes.

Neuronal Pathways & Circuits

  • Neuronal Pathways: Familiarize with basic neuronal pathways and circuits necessary for understanding reflexes and neural responses. [11.7]

Chapter 12: Spinal Cord Structures

Basic Structures of the Spinal Cord

  • Meningeal Layers: Identify the three meningeal layers protecting the spinal cord.
  • Grey & White Matter Organization: Understand their structural and functional organization in the spinal cord.
  • Nerve Tracts: Learn about ascending and descending nerve tracts and their functions in sensory and motor transmission.
  • Neuronal Locations: Understand where sensory and motor neurons are situated within the spinal cord.
  • Visual Aids: Reference Figures 12.2-4 for structural details of the spinal cord.

Basic Reflex Arc

  • Definition: Reflex arcs serve as the basic functional units of the nervous system, able to respond to stimuli effectively.
  • Components: Roll in receiving stimulus and producing a response; for instance:
    • Stretch Reflexes: Do not involve interneurons, while most reflexes do.
  • Sensory Information: Note that most reflex arcs transmit sensory information to the brain through collateral (divergent) innervation.
  • Visual Aid: Refer to Figure 12.5 for a diagrammatic representation of reflex arcs.

Spinal Nerves Structure & Organization

  • Structure of Spinal Nerves: Familiarize yourself with the spinal nerve structure as discussed in class.
  • Epineurium: Understand that the epineurium is continuous with the dura mater of the spinal cord.
  • Terminal Branches from each Plexus:
    • Cervical Plexus: Including the phrenic nerve (see Fig 12.16).
    • Brachial Plexus: Including all terminal branches (see Fig 12.17).
    • Lumbosacral Plexus: Involving femoral, obturator, and sciatic nerves (see Fig 12.23).

Chapter 13: Brain Structures

Basic Structures, Regions, & Functions of the Brain

  • Knowledge Requirements: Identify and understand the major parts and functions of the brain, including details from later sections.
  • Visual Aids: Refer to Figure 13.1 and Table 13.1 for visual support.

Brainstem Regions

  • Parts of the Brainstem: Understand the functions and significance of key parts:
    • Medulla Oblongata: Controls vital autonomic functions.
    • Pons: Serves as a pathway for signals between the cerebellum and the cerebrum.
    • Midbrain: Involved in vision, hearing, motor control, sleep/wake, arousal, and temperature regulation.
  • Visual Aid: See Figure 13.4 for a detailed diagram of the brainstem.

Structures & Functions of the Cerebellum

  • Cerebellum: Key components include:
    • Purkinje Fibers: The largest neurons in the nervous system, crucial for motor control.
  • Visual Aid: Refer to Figure 13.6 for cerbellar structure.

Diencephalon Components

  • Focus Areas: Key components of the diencephalon include:
    • Thalamus: Relay center for sensory and motor signals.
    • Hypothalamus: Major role in homeostasis and endocrine activities, including regulating hunger, thirst, and circadian rhythms.
  • Visual Aid: Refer to Figure 13.7 for further elucidation.

Structure & Functions of the Cerebrum

  • Cerebrum: Understand the cerebral structure and associated functions, including:
    • Basal Nuclei: Important for motor control and regulation.
    • Limbic System: Involved in emotion, memory, and behavior regulation.
  • Visual Aid: Reference Figures 13.8, 13.10-11 for in-depth structure-function relationships.

Meningeal Layers of the Brain

  • Meningeal Structures: Understand the meningeal layers in the brain:
    • Analyze the functional importance of dural venous sinuses and structures formed from dural folds.
  • Visual Aid: Consult Figure 13.12 for a detailed view.

Ventricular Structures & Cerebrospinal Fluid (CSF) Production

  • Ventricles in the Brain: Understand the structure and function of the brain's ventricles.
    • Choroid Plexus: Location of CSF production.
    • CSF Pathway: Trace the complete circulation of CSF through the CNS (see Fig 13.14).

Cerebral Blood Supply & Barriers

  • Blood Supply: Identify the arteries supplying blood to the brain and assess the significance of the blood-brain barrier.
  • Cerebral Arterial Circle (Circle of Willis): Understand its relevance for collateral circulation in the brain.
  • Visual Aid: Reference Figures 13.7 for blood supply visuals.

Cranial Nerves

  • Anatomy of Cranial Nerves: Learn the names and numbers of all cranial nerves.
    • Functional Organization: Understand the organization of these nerves and specific sensory and motor functions, with emphasis on the vagus nerve, which plays a vital role in autonomic functions.
  • Visual Aids: Review Figure 13.15 for anatomical and functional details, along with Table 13.4 and 13.5 for functional summaries.

Chapter 14: Sensation & Perception

Sensation vs. Perception

  • Definitions: Differentiate clearly between the two concepts in the context of neuroscience.

Classification of Senses

  • General vs. Special Senses: Understand the distinctions and examples of each.
    • Cutaneous Receptors: Relating to touch.
    • Proprioception: Information about body position and joint movement awareness.
  • Pain Sensation: Recognize the variability in pain sensations based on factors such as location and duration.

Sensory & Motor Information Processing in the Cerebral Cortex

  • Cerebral Cortex Areas: Know how different areas process sensory and motor information; use Figure 14.2 for assistance.
  • Homunculus Representation: Compare spatial organization for primary somatosensory and primary motor cortices based on sensitivity and fine motor control regions.

Contralateral Innervation/Processing

  • Definition: Understand the cross-lateral processing whereby each hemisphere of the brain interprets sensory information from and coordinates motor activity for the opposite side of the body.

Pathways of Sensory Information

  • Flow of Sensory Information: Track sensory information flow from entry point to processing locations:
    • Ascends from various body parts via ascending nerve tracts to the brainstem, cerebellum, thalamus, and onto the primary somatosensory cortex.
    • If more processing is required, use the somatosensory association areas, located posterior to the primary somatosensory cortex.
    • Note that most sensory information decussates entering the spinal cord.

Pathways of Motor Information

  • Motor Information Processing & Exit: Sensory information processed primarily in anterior sections of the cortex:
    • Steps include: from sensory cortex to prefrontal area, then to premotor area, primary motor cortex, and projecting fibers into descending nerve tracts.
    • Direct pathways leading to medullary pyramids (where decussation occurs) versus indirect pathways routed through thalamus and basal nuclei.
  • Movements: Recognize various movements corresponding to the direct and indirect motor pathways.
  • Cerebellar Comparator Function: Understand this function in movement coordination and error correction, see Figure 14.19 for representation.

Speech Processing Basics

  • Identify Key Areas: Recognize Wernicke’s area, Broca’s area, and arcuate fasciculus.
    • Processes Involved: Be familiar with event sequences concerning reading aloud and repeating heard phrases.
  • Visual Aid: Refer to Figure 14.21 for a comprehensive overview of speech areas.

Chapter 16: Autonomic Nervous System

Somatic vs. Autonomic Nervous Systems

  • Contrasts: Explore key differences between these two systems in functioning and anatomical structure (see Fig 16.1 and Table 16.1).

Divisions of the Autonomic Nervous System

  • Three Divisions:
    • Sympathetic Division:
    • Function: Manages “fight or flight” responses.
    • Anatomical Origin: Extends from T1 to L2 regions, termed “thoracolumbar.”
    • Parasympathetic Division:
    • Function: Controls “rest and digest” activities.
    • Anatomical Origin: Arises from brainstem and S2-S4, termed “craniosacral.”
    • Location of Terminal Ganglia: Familiarize with termi- nal ganglia placement.
    • Enteric Division:
    • Characteristics: Situated within the walls of the digestive system, regulated independently but often alongside the CNS; comprises sensory, motor, and interneurons.

Comparison Between Sympathetic & Parasympathetic Divisions

  • Differentiation Factors: Understand the contrast of preganglionic and postganglionic neurons in terms of:
    • Myelination: Levels of myelination of neurons in each division.
    • Lengths: Differences in lengths of fibers in sympathetic and parasympathetic systems.
  • Nerve Plexus Distributions: Reference Figure 16.5 for visual information on distribution.
  • Organ Innervation Patterns: Understand dual innervation effects including stimulatory vs. inhibitory, and opposing vs. cooperative interactions.

Regulation of the Autonomic Nervous System

  • Regulatory Mechanisms: Primarily through autonomic reflexes (see Fig 16.8), influenced by the CNS, notably the hypothalamus as the main control center for autonomic functions (Table 16.4).