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Page 1: Overview of Nervous Systems

• Major components of the nervous system:

  • Neuroscience terms: Connect, McGraw-Hill, Learn, Succeed

  • Key structures: Brain, radial, cerebral, central nerves, ganglia (nervous and peripheral nervous systems)

  • Types of systems in organisms: Spinal system, nerve cords, nerve nets, nerve rings

Page 2: Learning Objectives

• Compare and contrast:

  • Functional anatomy of the nervous system across diverse organisms

  • Organization of the peripheral nervous system (PNS)

  • Central nervous system (CNS) vs. PNS

• Describe:

  • Anatomical organization of the vertebrate brain

  • Major structures and functions of the human hindbrain, midbrain, and forebrain

• Define learning and memory:

  • Relation to changes in neuronal connections strength

Page 3: Representative Nervous Systems

• Nervous systems in animals:

  • All animals except sponges have a nervous system

  • Nerve net: Simplest form of a nervous system found in cnidarians (jellyfish, hydras)

    • Neurons connected in a network

    • Activation spreads in all directions

    • Stimulates contractile cells

Page 4: Nervous Systems in Echinoderms and Platyhelminths

• Echinoderms:

  • More complex than cnidarians

  • Nerve ring surrounding the mouth, large radial nerves extending to arms

  • Mouth and arms operate independently

• Platyhelminthes:

  • Neurons collected in a cerebral ganglia

  • Integrates sensory input and motor output

  • Nerve cords run along the length of the body, connected by transverse nerves

Page 5: Nervous System of Annelids and Simple Mollusks

• Annelids:

  • Similar structure to flatworms with more neurons

  • Ventral nerve cords have segmental ganglia

• Simple Mollusks:

  • Analogous to annelids but with a pair of anterior ganglia and paired nerve cords

Page 6: Cephalization Trend

• Cephalization:

  • Concentration of sense organs at the anterior end

  • Increasing complexity of the brain

• Insect example (Drosophila):

  • Brain has subdivisions with specific functions

• Advanced mollusks:

  • Well-developed brain coordinates complex behaviors

Page 7: Chordates

• Chordate Nervous System:

  • Central nervous system (CNS) includes brain and spinal cord

  • Peripheral nervous system (PNS) comprises nerves routing information to/from CNS

Page 8: Sensory Detection and Signal Processing

• Peripheral nervous system:

  • Neurons in nose and mouth detect stimuli (odor and taste)

  • Neurons send signals to the brain interpreting those signals as food

• Central nervous system:

  • Processes signals from the PNS.

  • Sends signals for salivation response

Page 9: Somatic Nervous System

• Divisions of the PNS:

  • Somatic Nervous System:

    • Senses external environment controls skeletal muscle movement

    • Sensory neurons receive stimuli (heat, light, smells) and relay to CNS

    • Motor neurons control voluntary responses

Page 10: Autonomic Nervous System

• Autonomic Nervous System:

  • Regulates homeostasis and organ function

  • Predominantly motor neurons, functioning involuntarily

  • Sensory neurons detect internal conditions

Page 11: Efferent Nerves in Autonomic System

• Efferent nerves:

  • Two divisions with opposing actions:

    • Sympathetic Division:

      • Activates fight-or-flight response

      • Increases heart rate and breathing

    • Parasympathetic Division:

      • Activates rest-and-digest response

      • Decreases heart rate and promotes digestion

Page 12: Actions of Autonomic Nerves

• Sympathetic Actions:

  • Dilates pupils, inhibits salivation, increases heart rate

• Parasympathetic Actions:

  • Constricts pupils, stimulates salivation, slows heart rate

  • Involves neurotransmitters like norepinephrine and acetylcholine

Page 13: Vertebrate Brain Divisions

• Three major divisions derived from neural tube:

  • Hindbrain: Metencephalon & Myelencephalon

  • Midbrain: Mesencephalon

  • Forebrain: Telencephalon & Diencephalon

Page 14: Structures of the Brain

• Brain Structure:

  • Forebrain: Cerebrum, thalamus, hypothalamus

  • Midbrain: Mesencephalon

  • Hindbrain: Cerebellum, pons, medulla oblongata

  • Illustrated embryonic and adult brain development

Page 15: Brain Mass and Body Size

• Relationship:

  • Brain mass correlates proportionally with body mass

  • Observations of human and dolphin brains highlight unique exceptions

  • Increased brain size and folding enhances processing capabilities

Page 16: Human Brain Overview

• Forebrain: Contains cortex, basal nuclei, limbic system

• Midbrain: Central processing area

• Hindbrain: Responsible for coordination and reflexes

• Spinal Cord: Connects CNS with peripheral systems

Page 17: Functions of the Hindbrain

• Cerebellum:

  • Maintains balance, coordinates movements

• Pons:

  • Relay center, regulates breathing

• Medulla Oblongata:

  • Homeostatic functions: heart rate, breathing, blood pressure control

Page 18: Functions of the Midbrain

• Processing Functions:

  • Sensory inputs such as vision, smell, and hearing

  • Passes information for further processing to brain regions

Page 19: Brainstem Composition

• Brainstem:

  • Comprised of midbrain, pons, and medulla

  • Contains nuclei for reticular formation regulating alertness and consciousness

  • Involved in respiratory and cardiovascular regulation

Page 20: Organization of the Forebrain

• Diencephalon: Thalamus, hypothalamus, epithalamus

• Cerebrum: More complex structures including the cerebral cortex and system for higher functions

Page 21: Forebrain Structures

• Elaborating on Diencephalon and Cerebral structures

• Cerebral Cortex and its role in higher cognitive function

Page 22: The Diencephalon Components

• Thalamus:

  • Sensory relay station

• Hypothalamus:

  • Maintains homeostasis, controls behavior with hormones

• Epithalamus:

  • Involved in inputs of food/water intake and rhythms

Page 23: The Cerebrum and Basal Nuclei

• Basal Nuclei:

  • Indispensable in planning and fine-tuning movements

  • Disruptions can lead to disorders like Parkinson's

Page 24: The Limbic System

• Structure:

  • Involved in emotion and memory; includes olfactory bulbs, amygdala, and hippocampus

• Amygdala:

  • Emotional understanding

• Hippocampus:

  • Memory formation and spatial navigation

Page 25: Cerebral Cortex Functions

• Cerebral Cortex: Outer layer of brain with varied functions:

  1. Frontal Lobe: Thought, social awareness

  2. Parietal Lobe: Sensory input from visual/somatic pathways

  3. Occipital Lobe: Vision and color recognition

  4. Temporal Lobe: Language, hearing, memory

Page 26: Lobe Functions Summary

• Frontal Lobe: Motor functions, thoughtful control

• Parietal Lobe: Spatial awareness and sensory integration

• Occipital Lobe: Visual processing

• Temporal Lobe: Language and memory functions

Page 27: Body Mapping Structures

• Body Part References:

  • Linkage of brain functions to body parts indicating related areas for sensory input/motor output

Page 28: Cerebral Hemispheres

• Corpus Callosum:

  • Connects cerebral hemispheres

  • Functions independently; lateralization observed in functionality

  • Left hemisphere focuses on language; right hemisphere focuses on nonverbal cues and memories

Page 29: Study of Split-Brain Patients

• Experimental Insights:

  • Procedures for severing corpus callosum as epilepsy treatment

  • Understanding of lateralized processing

Page 30: Body Mapping Continued

• Visualization of connections among body parts similar to prior section

Page 31: Cerebral Functionality

• Overview of independent hemiphere function and specialization in processing differing information

Page 32: Reexamination of Split-Brain Studies

• Cross-sectional observations:

  • Insights on emotional recognition and memory distinctness between hemispheres

Page 33: Nervous System Organization Summary

• Major Divisions:

  • Central and peripheral systems with associated functions and pathways to maintain body regulation

Page 34: Learning and Memory Definition

• Learning: Acquisition of new information

• Memory: Retention and retrieval of information over time

• Long-term potentiation (LTP): Mechanism for strengthening neuronal connections, critical in learning

Page 35: Memory in Sea Slugs

• Model organism: California sea slug (Aplysia californica) studied for learning capabilities

  • Learning through gill-withdrawal reflex observed and assessed

Page 36: Structures of California Sea Slug

• Visual guide to anatomical parts and experimental arrangements of sea slugs

Page 37: Mechanism of Short-term Memory

• Cellular Changes: Activation of presynaptic elements enhances signal transmission temporarily

• Process of phosphorylation substance leading to enhanced neurotransmission

Page 38: Mechanism of Long-term Memory

• Gene Activation: Repeated stimuli promote structural changes leading to synaptic connections' growth

Page 39: Memory Duration and Processes

• Short-term: Lasts minutes/hours influenced by stimuli; Long-term lasts longer and induces structural changes

Page 40: Neurogenesis Insights

• Recent research suggests neurogenesis is possible in adult brains, contributes to memory and learning capabilities.

Overview of Nervous Systems

• Major Components of the Nervous System:

  • Neuroscience Terms: Includes connect, McGraw-Hill resources, and concepts essential for understanding brain function.

  • Key Structures: Major components include the brain, radial and cerebral nerves, central nerves, and ganglia which are integral to both the nervous and peripheral nervous systems.

• Types of Systems in Organisms:

  • Various arrangements exist, such as spinal systems which coordinate reflexes, nerve cords found in organisms like worms which facilitate movement, nerve nets prevalent in cnidarians (e.g., jellyfish), and nerve rings that are present in some echinoderms.

Learning Objectives

• Compare and Contrast:

  • Examine functional anatomy of the nervous system across diverse organisms such as vertebrates, invertebrates, and others.

  • Distinguish the organization of the Peripheral Nervous System (PNS) from the Central Nervous System (CNS), highlighting key functional differences and structures.

• Describe:

  • The anatomical organization of the vertebrate brain, including the role of various structures such as the cortex and nuclei.

  • Key structures and functions within the human brain, emphasizing details of the hindbrain (including the medulla and cerebellum), midbrain, and forebrain roles in behavior and physiological regulation.

• Define Learning and Memory:

  • Explore how learning involves changes in the strength of neuronal connections leading to memory formation, encompassing concepts like long-term potentiation (LTP) crucial for retaining information.

Representative Nervous Systems

• Nervous Systems in Animals:

  • All animals except sponges possess some form of nervous system for processing information.

  • Nerve Net: This is the simplest form of a nervous system found in cnidarians characterized by a decentralized network of interconnected neurons that activate contractile cells for basic motor function.

Nervous Systems in Echinoderms and Platyhelminths

• Echinoderms:

  • More complex than cnidarians with a nerve ring surrounding the mouth and large radial nerves extending to the limbs, allowing for independent operation of the mouth and arms, facilitating coordinated movement.

• Platyhelminthes:

  • Contains a concentration of neurons in cerebral ganglia that processes sensory input and coordinates motor output. Nerve cords run the body’s length, interconnected by transverse nerves contributing to movement and response to stimuli.

Nervous System of Annelids and Simple Mollusks

• Annelids:

  • Possess a more intricate structure compared to flatworms, with ventral nerve cords that feature segmental ganglia allowing for greater motor control and processing of sensory data.

• Simple Mollusks:

  • Similar to annelids but characterized by a pair of anterior ganglia and paired nerve cords that enhance motor and sensory functions.

Cephalization Trend

• Cephalization:

  • This refers to the evolutionary trend where sensory organs become concentrated at the anterior end of the organism, enhancing its ability to process environmental stimuli and increasing the complexity of the brain.

  • Insect Example (Drosophila):

    • The brain exhibits subdivisions with specific functions that enhance sensory processing and behavioral responses.

  • Advanced Mollusks:

    • Feature a well-developed brain that enables coordination of complex behaviors and responses to stimuli.

Chordates

• Chordate Nervous System:

  • The Central Nervous System (CNS) comprises the brain and spinal cord, while the Peripheral Nervous System (PNS) connects sensory and motor neurons for information relay between the CNS and the rest of the body, crucial for maintaining homeostasis and responsiveness to environmental changes.

Sensory Detection and Signal Processing

• Peripheral Nervous System:

  • Specialized neurons in the nose and mouth detect external stimuli such as odor and taste. Signals transmitted to the central nervous system are interpreted as important information like food sources.

• Central Nervous System:

  • Processes signals received from the PNS and orchestrates necessary responses, such as initiating salivation in response to food detection.

Somatic and Autonomic Nervous Systems

• Somatic Nervous System:

  • This division of the PNS manages the conscious control of skeletal muscle movements and senses the external environment through sensory neurons that relay stimuli (heat, light, smell) to the CNS, enabling voluntary responses.

• Autonomic Nervous System:

  • Regulates homeostasis and organ function involuntarily through predominantly motor neurons. It includes sensory neurons that detect internal conditions and regulate bodily responses unconsciously.

Efferent Nerves in the Autonomic System

• Efferent Nerves:

  • Divided into two opposing divisions, the sympathetic and parasympathetic systems.

  • Sympathetic Division:

    • Activates the fight-or-flight response, which includes physiological changes such as increased heart rate and respiration to prepare the body for rapid activity.

  • Parasympathetic Division:

    • Promotes the rest-and-digest response that conserves energy by slowing the heart rate and facilitating digestion.

Functions of the Brain

• Vertebrate Brain Divisions:

  • The major divisions derived from the neural tube include the hindbrain (Metencephalon & Myelencephalon), midbrain (Mesencephalon), and forebrain (Telencephalon & Diencephalon), each with distinct functions supporting essential biological processes.

• Brain Structure:

  • The Forebrain contains critical structures such as the cerebrum, thalamus, and hypothalamus, while the Midbrain and Hindbrain comprise structures like the mesencephalon, cerebellum, pons, and medulla oblongata which are integral to processing sensory input and executing motor control.