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Nervous System. Ms. Bowman. Nervous System. Master controlling and communicating system of the body 1-Information that is gathered and sent to the brain is sensory 2-The brain processes and interprets the information and decides what action should be taken

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Nervous system

Nervous System

Ms. Bowman

Nervous system1
Nervous System

  • Master controlling and communicating system of the body

  • 1-Information that is gathered and sent to the brain is sensory

  • 2-The brain processes and interprets the information and decides what action should be taken

  • 3-Brain sends a response called a motor output

Central nervous system cns
Central Nervous System (CNS)

  • Consists of brain and spinal cord

  • The integrating and command center of the nervous system

  • Interprets sensory input and dictates motor responses based on past experience, reflexes, and current conditions

Peripheral nervous system pns
Peripheral Nervous System (PNS)

  • The part of the nervous system outside of the CNS

  • Consists mainly of nerves that extend from the brain (cranial nerves) and spinal cord (spinal nerves)

  • These nerves serve as the communicating lines that link all parts of the body to the CNS

  • 2 divisions-Sensory and Motor

Sensory division of pns
Sensory Division of PNS

  • “carrying toward”

  • Consists of nerve fibers that convey impulses to the CNS from sensory receptors located throughout the body

  • Keeps the CNS constantly informed of events going on inside and outside the body

Motor division of pns
Motor Division of PNS

  • “carrying away”

  • Transmits impulses from the CNS to effector organs (muscles and glands)

  • Impulses activate muscles to contract and glands to secrete

  • They bring about a motor response

  • 2 parts: Somatic and Autonomic

Somatic nervous system
Somatic Nervous System

  • Voluntary nervous system

  • Composed of nerve fibers that conduct impulses from CNS to skeletal muscles

  • Allows us to consciously control our skeletal muscles

Autonomic nervous system
Autonomic Nervous System

  • Involuntary nervous system

  • Consists of visceral (pertaining to your gut) motor fibers that regulate the activity of smooth muscles, cardiac muscles, and glands

  • 2 subdivisions: Sympathetic and Parasympathetic

Sympathetic division of ans
Sympathetic Division of ANS

  • Mobilizes involuntary body systems during activity

Parasympathetic division of ans
Parasympathetic Division of ANS

  • Conserves energy

  • Promotes housekeeping functions during rest


  • Nerve cells

  • The structural units of the nervous system

  • Highly specialized cells that conduct messages in the form of nerve impulses from one part of the body to another

  • Special characteristics

    • Extreme longevity-can function for a lifetime

    • Amitotic-lose ability to divide; most cannot be replaced if they are damaged or destroyed

    • High metabolic rate-require continuous and abundant supplies of oxygen and glucose


  • Typically large, complex cells

  • Vary in structure, but all have a nucleus and one or more processes that project

  • Processes

    • Axons-conducting region; generate nerve impulses and transmit them

    • Dendrites-receptive or input region; information collector

Classification of neurons
Classification of Neurons

  • Multipolar-3 or more processes; most common neuron type in humans and major type in CNS

  • Bipolar-2 processes; one axon and dendrite; rare neurons found in some special sense organs

  • Unipolar-1 single short process that divides T-like


  • Protected by the meninges

    • Comprised of 3 layers of connective membranes

      • Dura Mater-strongest; outermost

      • Arachnoid Mater- middle; forms a loose brain covering; web-like projections anchor it to pia mater

      • Pia Mater-composed of delicate connective tissue; lots of blood vessels; innermost; clings tightly to brain

  • Cerebrospinal Fluid (CSF)-watery “broth” that forms a liquid cushion and protects the brain and spinal cord; helps to nourish the brain

  • Ventricles-canals that carry the CSF within brain and brain stem


  • Divided into 3 components

    • Cerebrum

    • Cerebellum

    • Brain Stem

Cerebral hemispheres
Cerebral Hemispheres

  • Form the superior part of the brain

  • Entire surface marked by gyri (elevated ridges of tissue) that are separated by sulci (shallow grooves)

  • Fissures (deep grooves) separate large regions of the brain

  • Where our conscious mind is found; enables us to be aware of ourselves and sensations, to communicate, remember, understand, and initiate voluntary movements


  • Processes inputs received from the cerebrum, brain stem, and sensory receptors

  • Provides the precise timing and appropriate patterns of skeletal muscle contraction for smooth, coordinated movements and agility needed for our daily living

  • Activity occurs subconsciously so we are not aware of it

Brain stem
Brain Stem

  • Produce the rigidly programmed, automatic behaviors necessary for survival

  • Origin of 10 of the 12 pairs of cranial nerves