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AIM SWBAT describe the structures and functions of the divisions of the nervous system.

Criteria for Success [ ] I can take organized notes. [ ] I can describe the cell types in neural tissue. [ ] I can compare the divisions in the nervous system. [ ] I can describe the divisions in the peripheral nervous system.

Introduction Cell types in neural tissue: Neurons Dendrites Cell body Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell types in neural tissue: Neurons Dendrites Cell body Nuclei of neuroglia Axon © Ed Reschke

Introduction Cell types in neural tissue: Neurons: nerve cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell types in neural tissue: Neurons: nerve cells Dendrites Cell body Nuclei of neuroglia Axon © Ed Reschke

Introduction Cell types in neural tissue: Neurons Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell types in neural tissue: Neurons Neuroglial cells (also known as neuroglia, glia, and glial cells) Dendrites Cell body Nuclei of neuroglia Axon © Ed Reschke

Introduction Cell types in neural tissue: Neurons Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell types in neural tissue: Neurons Neuroglial cells (also known as neuroglia, glia, and glial cells): specialized nervous system cells that: Produce myelin Maintain ionic environment Provide growth factors Provide structural support Dendrites Cell body Nuclei of neuroglia Axon © Ed Reschke

Divisions of the Nervous System Central Nervous System (CNS)

Divisions of the Nervous System Central Nervous System (CNS) Brain Spinal cord

Divisions of the Nervous System Central Nervous System (CNS) Brain Spinal cord Peripheral Nervous System (PNS)

Divisions of the Nervous System Central Nervous System (CNS) Brain Spinal cord Peripheral Nervous System (PNS) Cranial nerves Spinal nerves

Divisions of the Nervous System Central (CNS) Peripheral (PNS) http://www.morphonix.com

Divisions of Peripheral Nervous System Sensory Division

Divisions of Peripheral Nervous System Sensory Division Picks up sensory information and delivers it to the CNS

Divisions of Peripheral Nervous System Sensory Division Picks up sensory information and delivers it to the CNS Motor Division

Divisions of Peripheral Nervous System Sensory Division Picks up sensory information and delivers it to the CNS Motor Division Carries information to muscles and glands

Divisions of Peripheral Nervous System Sensory Division Picks up sensory information and delivers it to the CNS Motor Division Carries information to muscles and glands Divisions of the Motor Division:

Divisions of Peripheral Nervous System Sensory Division Picks up sensory information and delivers it to the CNS Motor Division Carries information to muscles and glands Divisions of the Motor Division: Somatic – carries information to skeletal muscle

Divisions of Peripheral Nervous System Sensory Division Picks up sensory information and delivers it to the CNS Motor Division Carries information to muscles and glands Divisions of the Motor Division: Somatic – carries information to skeletal muscle Autonomic – carries information to smooth muscle, cardiac muscle, and glands

Divisions Nervous System Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central Nervous System (brain and spinal cord) Peripheral Nervous System (cranial and spinal nerves) Brain Cranial nerves Sensory division Sensory receptors Spinal cord Spinal nerves Motor division Somatic Nervous System Skeletal muscle Autonomic Nervous System Smooth muscle Cardiac muscle Glands (a) (b)

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AIM SWBAT describe the functions of the nervous system and the structure and function of neurons and their components.

Criteria for Success [ ] I can compare and contrast the three functions of the nervous system. [ ] I can describe the structure of a neuron. [ ] I can describe the structure of a Schwann cell. [ ] I can differentiate between white and gray matter.

General Functions of the Nervous System The three general functions of the nervous system:

General Functions of the Nervous System The three general functions of the nervous system: Receiving stimuli = sensory function

General Functions of the Nervous System The three general functions of the nervous system: Receiving stimuli = sensory function Deciding about stimuli = integrative function

General Functions of the Nervous System The three general functions of the nervous system: Receiving stimuli = sensory function Deciding about stimuli = integrative function Reacting to stimuli = motor function

Functions of Nervous System Sensory Function Sensory receptors gather information Information is carried to the CNS

Functions of Nervous System Sensory Function Sensory receptors gather information Information is carried to the CNS Integrative Function Sensory information used to create: Sensations Memory Thoughts Decisions

Functions of Nervous System Sensory Function Sensory receptors gather information Information is carried to the CNS Integrative Function Sensory information used to create: Sensations Memory Thoughts Decisions Motor Function Decisions are acted upon Impulses are carried to effectors

Description of Cells of the Nervous System Neurons vary in size and shape

Description of Cells of the Nervous System Neurons vary in size and shape They may differ in length and size of their axons and dendrites

Description of Cells of the Nervous System Neurons vary in size and shape They may differ in length and size of their axons and dendrites Neurons share certain features:

Description of Cells of the Nervous System Neurons vary in size and shape They may differ in length and size of their axons and dendrites Neurons share certain features: Dendrites: small cellular processes that receive the input

Description of Cells of the Nervous System Neurons vary in size and shape They may differ in length and size of their axons and dendrites Neurons share certain features: Dendrites Axon: (also called nerve fiber) a longer process that carries the information away from the cell in the form of bioelectric signals called nerve impulses

Description of Cells of the Nervous System Neurons vary in size and shape They may differ in length and size of their axons and dendrites Neurons share certain features: Dendrites Axon Cell Body

Neuron Structure Chromatophilic substance (Nissl bodies) Dendrites Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chromatophilic substance (Nissl bodies) Dendrites Cell body Nucleus Nucleolus Neurofibrils Axonal hillock Impulse Axon Synaptic knob of axon terminal Nodes of Ranvier Myelin (cut) Schwann cell Nucleus of Schwann cell Axon Portion of a collateral

Schwann Cells PNS Dendrite Unmyelinated region of axon Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrite Unmyelinated region of axon Myelinated region of axon Node of Ranvier Axon Neuron cell body Neuron nucleus (a) Enveloping Schwann cell Schwann cell nucleus Longitudinal groove Unmyelinated axon (c)

Schwann Cells PNS Encase large axons in lipid-rich sheaths Dendrite Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrite Unmyelinated region of axon Myelinated region of axon Node of Ranvier Axon Neuron cell body Neuron nucleus (a) Enveloping Schwann cell Schwann cell nucleus Longitudinal groove Unmyelinated axon (c)

Schwann Cells PNS Encase large axons in lipid-rich sheaths Layers composed of myelin Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrite Unmyelinated region of axon Myelinated region of axon Node of Ranvier Axon Neuron cell body Neuron nucleus (a) Enveloping Schwann cell Schwann cell nucleus Longitudinal groove Unmyelinated axon (c)

Schwann Cells PNS Encase large axons in lipid-rich sheaths Layers composed of myelin Neurilemma contains cytoplasm and nuclei Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrite Unmyelinated region of axon Myelinated region of axon Node of Ranvier Axon Neuron cell body Neuron nucleus (a) Enveloping Schwann cell Schwann cell nucleus Longitudinal groove Unmyelinated axon (c)

Schwann Cells PNS Encase large axons in lipid-rich sheaths Layers composed of myelin Neurilemma contains cytoplasm and nuclei Gaps in myelin sheath between Schwann cells called nodes of Ranvier Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrite Unmyelinated region of axon Myelinated region of axon Node of Ranvier Axon Neuron cell body Neuron nucleus (a) Enveloping Schwann cell Schwann cell nucleus Longitudinal groove Unmyelinated axon (c)

Myelination of Axons White Matter Contains myelinated axons Considered fiber tracts Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrite Unmyelinated region of axon Myelinated region of axon Node of Ranvier Axon Neuron cell body Neuron nucleus (a) Enveloping Schwann cell Schwann cell nucleus Longitudinal groove Unmyelinated axon (c)

Myelination of Axons White Matter Contains myelinated axons in groups Considered fiber tracts PNS Gray Matter Contains unmyelinated structures Cell bodies, dendrites CNS Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrite Unmyelinated region of axon Myelinated region of axon Node of Ranvier Axon Neuron cell body Neuron nucleus (a) Enveloping Schwann cell Schwann cell nucleus Longitudinal groove Unmyelinated axon (c)

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Catalyst 1. The cells in the nervous system that fill spaces and support neurons both physically and nutritionally are called ________________________. 2. Schwann cells are composed of layers of ____________. 3. Sheaths of ________________________ cells often enclose the larger axons outside of the brain and spinal cord. 4. A(n) _____________________ is the junction between neurons.

Homework Tissue Review WS Force Resistance Resistance Resistance Force Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Force Resistance Resistance Resistance Force Resistance Fulcrum Fulcrum Fulcrum Fulcrum Force Force (a) First-class lever (b) Second-class lever Resistance Force Resistance Fulcrum (c) Third-class lever Fulcrum Force

AIM SWBAT classify neuroglia and neurons according to both structure and function.

Criteria for Success [ ] I can classify neurons according to structure: unipolar, bipolar and multipolar. [ ] I can classify neurons according to function: sensory, integrative motor. [ ] I can define ganglia. [ ] I can differentiate between glial cells in the CNS and the PNS. [ ] I can explain the process of regeneration of a nerve.

Classification of Neurons and Neuroglia Neurons vary in function They can be sensory, motor, or integrative neurons Neurons vary in size and shape, and in the number of axons and dendrites that they may have Due to structural differences, neurons can be classified into three (3) major groups: Unipolar neurons Bipolar neurons Multipolar neurons

Classification of Neurons: Structural Differences Unipolar neurons One process Divides into 2 branches Peripheral Central Ganglia (specialized masses of nerve tissue)of PNS Sensory Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrites Peripheral process Axon Direction of impulse Central process Axon Axon (a) Multipolar (b) Bipolar (c) Unipolar

Classification of Neurons: Structural Differences Bipolar neurons Two processes One process from each end Axon Dendrite Eyes, ears, nose Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrites Peripheral process Axon Direction of impulse Central process Axon Axon (a) Multipolar (b) Bipolar (c) Unipolar

Classification of Neurons: Structural Differences Multipolar neurons 99% of neurons Many processes One axon Many dendrites Most neurons of CNS Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dendrites Peripheral process Axon Direction of impulse Central process Axon Axon (a) Multipolar (b) Bipolar (c) Unipolar

Classification of Neurons: Functional Differences Sensory (afferent) Neurons Most unipolar

Classification of Neurons: Functional Differences Sensory (afferent) Neurons Most unipolar Carry nerve impulses from peripheral body parts

Classification of Neurons: Functional Differences Sensory (afferent) Neurons Most unipolar Carry nerve impulses from peripheral body parts Distal ends act as sensory receptors Changes in outside world Changes in body

Classification of Neurons: Functional Differences Interneurons Multipolar

Classification of Neurons: Functional Differences Interneurons Multipolar Form links between other neurons

Classification of Neurons: Functional Differences Interneurons Multipolar Form links between other neurons Direct incoming sensory impulses to appropriate regions for processing and interpreting

Classification of Neurons: Functional Differences Motor (efferent) Neurons Multipolar

Classification of Neurons: Functional Differences Motor (efferent) Neurons Multipolar Carry impulses out of CNS to effectors

Classification of Neurons: Functional Differences Motor (efferent) Neurons Multipolar Carry impulses out of CNS to effectors Somatic nervous system

Classification of Neurons: Functional Differences Motor (efferent) Neurons Multipolar Carry impulses out of CNS to effectors Somatic nervous system Cardiac and smooth muscle and glands

Types of Neuroglial Cells in the CNS 1) Microglia CNS Small, few process Phagocytic cell

Types of Neuroglial Cells in the CNS 1) Microglia CNS Small, few processes Phagocytic cell 2) Astrocytes CNS Star-shaped Scar tissue in brain tissue Mop up excess ions, etc. Connect neurons to blood vessels Part of Blood Brain Barrier

Types of Neuroglial Cells in the CNS 1) Microglia CNS Small, few processes Phagocytic cell 3) Oligodendrocytes CNS Resemble astrocytes Myelinating cell Many processes 2) Astrocytes CNS Star-shaped Scar tissue Mop up excess ions, etc. Induce synapse formation Connect neurons to blood vessels Part of Blood Brain Barrier

Types of Neuroglial Cells in the CNS 1) Microglia CNS Small, few processes Phagocytic cell 3) Oligodendrocytes CNS Resemble astrocytes Myelinating cell Many processes 2) Astrocytes CNS Scar tissue Mop up excess ions, etc. Induce synapse formation Connect neurons to blood vessels Part of Blood Brain Barrier 4) Ependyma or ependymal CNS Ciliated Line central canal of spinal cord Line ventricles of brain

Types of Neuroglial Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fluid-filled cavity of the brain or spinal cord Neuron Ependymal cell Oligodendrocyte Astrocyte Microglial cell Axon Myelin sheath (cut) Capillary Node of Ranvier

Types of Neuroglial Cells in the PNS 1) Schwann Cells Produce myelin found on peripheral myelinated neurons Speed up neurotransmission

Types of Neuroglial Cells in the PNS 1) Schwann Cells Produce myelin found on peripheral myelinated neurons Speed up neurotransmission 2) Satellite Cells Support clusters of neuron cell bodies (ganglia)

Neuroglial Cells Comprise more than half of brain volume Outnumber neurons 10 to 1 Cause most brain tumors Damage to cell body kills cell; however axons may regenerate

Regeneration of A Nerve Axon Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Motor neuron cell body Skeletal muscle fiber Changes over time Site of injury Schwann cells Axon (a) Distal portion of axon degenerates (b) Proximal end of injured axon regenerates into tube of sheath cells (c) Schwann cells degenerate (d) Schwann cells proliferate (e) Former connection reestablished