The Nervous System

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The Nervous System

• And Brain Organization

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Central Nervous System

• Consists of the brain and spinal cord
• The brain is the central computer of the
  nervous system
• The spinal cord is the cable that is used to
  communicate to the rest of the body

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Peripheral Nervous System

• All the parts of the nervous system outside of
  the brain and spinal cord
• Two major divisions
• Somatic system the muscles and sense organs
  (voluntary behavior)
• Autonomic system the internal organs and glands
  (involuntary behavior)

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Autonomic Nervous System

• Two divisions
• Sympathetic branch arouses the body
• Prepares the body for fight or flight
• Parasympathetic branch quiets the body or
  brings it back to normal

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Nervous System
Central Nervous System
Peripheral Nervous System
Brain
Spinal Cord
Autonomic System
Somatic System
Sympathetic System
Parasympathetic System
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Brain Organization

• Cerebrum two large hemispheres that cover the
  upper part of the brain
• Cerebral cortex the outer layer of the cerebrum
• made up of wrinkled gray matter that contains
  nerve cell bodies

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Brain Organization contd

• Cerebral hemispheres right and left halves of
  the cerebrum
• Corpus callosum bundle of fibers connecting the
  hemispheres
• Cut in a split-brain operation
• Spatial neglect when a person pays no attention
  to the left side of visual space after damage to
  the right hemisphere

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Lobes of the Cerebral Cortex

• Lobes areas on the cortex defined by major
  fissures or functions
• Occipital lobe vision
• Parietal lobe bodily sensations (touch,
  temperature, pressure)

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Lobes of the Cerebral Cortex

• Temporal lobes language (on the left only) and
  hearing
• Frontal lobes motor control, speech, abstract
  thought
• Association cortex all areas of the cerebral
  cortex not primarily sensory or motor in function
  complex skills like language, memory,
  recognition, and problem solving

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Parietal lobe
Frontal lobe
Occipital lobe
Temporal lobe
Cerebellum
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Association Cortex

• Brocas area language area grammar and
  pronunciation left frontal lobe
• Aphasia speech disturbance related to brain
  damage
• Wernickes area language comprehension left
  temporal lobe
• Agnosia inability to identify seen objects

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Subcortex

• Subcortex - all brain structures below the
  cerebral hemispheres
• Divided into three parts
• Brainstem (or hindbrain)
• Midbrain
• Forebrain

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The Brainstem

• Also known as the hindbrain
• Lowest portions of the brain
• Contains the cerebellum, medulla and pons

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• Cerebellum controls posture, muscle tone and
  coordination stores memories related to skills
  and habits
• Medulla connects brain to spinal cord
  controls vital life functions such as heart rate,
  breathing, swallowing, etc.
• Pons bridge between medulla and other
  structures influences sleep and arousal

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The Midbrain

• Small region, located above spinal cord, but
  below the forebrain
• Coordinates simple muscle movements with sensory
  information
• Reticular formation network of fibers and cell
  bodies throughout the hindbrain associated with
  attention, alertness and some reflexes

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The Forebrain

• Contains the thalamus and hypothalamus
• Thalamus located on top of brain stem relays
  sensory information to the cerebral cortex
• Hypothalamus controls metabolic functions
  including body temp, libido, hunger, thirst, and
  the endocrine system

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The Limbic System

• Contains hypothalamus, parts of the thalamus,
  amygdala, and hippocampus
• Large role in producing emotion and motivated
  behavior
• Amygdala associated with fear responses
• Hippocampus associated with storing memories
  (lies in the temporal lobe)

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