ANATOMY

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ANATOMY

• NERVOUS SYSTEM
• OVERVIEW

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Nervous System

• The nervous system of the human is the most
  highly organized system of the body.
• The overall function of the nervous system is to
  control and coordinate the human body.

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NERVOUS SYSTEM

• The nervous system consists of the brain, the
  spinal cord and the nerves.
• The functional, structural unit of the nervous
  system is the nerve cell called the neuron.

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Neurons

• The neuron has extensions of various lengths from
  its cell body called Dendrites and Axons.
• Each cell body may have many dendrites, but only
  one axon.

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Neurons

• The Dendrites receive an impulse, pass it to the
  cell body, then to the axon where it is passed on
  to muscle, glands or another neuron.

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Neurons

• There are three types of neurons
• Sensory
• Motor or connecting
• Associative
• Neurons do not connect with each other but send
  impulses over spaces called synapses.

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Divisions of the nervous system

• The central nervous system includes the brain and
  the spinal cord. The nerves of the spinal cord
  and brain do not have the special coating called
  neurilemma which allows nerve cells to repair.
  (paralysis or death may occur)

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Nervous system divisions

• The peripheral nervous system is composed of all
  the nerves extending from the brain (cranial
  nerves) and spinal cord. (spinal nerves)

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Peripheral system

• The peripheral nervous system connects the
  central nervous system to various body
  structures. Cranial nerves carry impulses to and
  from the brain, spinal nerves carry impulses to
  and from the spinal cord.

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Autonomic system

• The autonomic system controls the involuntary or
  automatic activities of vital internal organs,
  such as the heart, blood vessels and organs of
  digestion.

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The brain

• The brain is a complex mass of tissue protected
  by the bony structure of the cranium. The brain
  is further protected by membrane coverings called
  the meninges and cerebrospinal fluid.

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The brain

• There are three major parts of the brain.
• The cerebrum
• The cerebellum
• The brain stem

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The Cerebrum

• The cerebrum is the largest part of the brain,
  divided into two hemispheres. Each hemisphere is
  divided into four lobes.
• The frontal
• The parietal
• The occipital
• The temporal

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Lobes of the brain

• Each lobe of the cerebral hemispheres control
  specific functions .
• 1 The frontal lobe
• The cells in the right half control the voluntary
  motor movements of the left side of the body, and
  the left side controls the right side. The
  frontal lobe also controls speech.

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Lobes of the brain

• 2 The parietal lobe
• This area receives and interprets nerve impulses
  from the sensory receptors for pain, touch, heat
  and cold. The parietal lobe also helps determine
  distance, size and shape.
• 3 The occipital lobe
• Located over the back of the brain over the
  cerebellum contains the visual area controlling
  eyesight.

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Lobes of the brain

• 4 The temporal
• Located on the sides of the brain, the temporal
  lobe contains areas which control auditory
  hearing and olfactory smell.

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The Cerebrum

• The outer layer of the cerebrum is gray nerve
  tissue called the cerebral cortex. It is formed
  with deep folds causing elevated portions called
  convolutions and furrows and groves called
  fissures.

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The cerebrum

• This folding (convolutions and fissures) increase
  the surface area of the cerebral cortex. The
  cerebral cortex controls thoughts, judgment,
  memory, reasoning, and will power.

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Under the gray matter

• Beneath the gray matter of the cerebral cortex
  lies the thalamus, and hypothalamus. The thalamus
  acts as a relay center for sensory impulses to
  the cerebral cortex. The hypothalamus controls
  temperature, sleep, water balance and chemical
  activities.

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The cerebellum

• This part of the brain located at the back and
  lower part of the brain coordinates the muscular
  movements of the body, such as balance in walking
  and sitting.

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The brain stem

• The brain stem is made up of three parts. The
  midbrain, the pons and the medulla. This part of
  the brain controls respiration, heart and blood
  vessels.

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The Spinal cord

• The spinal cord is made up of nerve fibers
  protected by the bony structure of the vertebra
  and spinal fluid. The function of the spinal
  cord is to serve as a pathway to and from the
  brain.

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Diseases

• Nerve cells often do not repair themselves so
  damage can cause permanent loss of function.
  Damage to the brain and spinal cord by force and
  injury may result in death or paralysis.

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Diseases

• Other disease include
• Parkinson's
• Seizures
• Multiple sclerosis
• Cerebral vascular accident (CVA or stroke)
• Infections and tumors also may affect the nervous
  system.

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Vocabulary Words