Integration and Control: Nervous Systems

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Integration and Control Nervous Systems

• Starr/Taggarts
• Biology
• The Unity and Diversity of Life, 9e
• Chapter 35

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Key Concepts

• Nervous systems are composed of neurons and
  neuroglia which support them
• Neurons integrate information and command muscles
  and glands
• Radial animals have the simplest nervous systems

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Key Concepts

• Most animals show cephalization and bilateral
  symmetry
• Vertebrate nervous systems are divided into
  central and peripheral regions
• Somatic nerves innervate skeletal muscles
• Autonomic nerves deal with internal organs

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Key Concepts

• The vertebrate brain has three regions the
  hindbrain, midbrain, and forebrain
• Birds and mammals have forebrains called a
  cerebrum that contains complex centers
• The hypothalamus is the homeostatic control
  center of the internal environment

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Vertebrate Nervous Systems
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Divisions of the Vertebrate Nervous System

• Central Nervous System (CNS)
• Spinal cord
• Brain
• Peripheral Nervous System (PNS)
• Cranial Spinal Nerves

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Human Nervous System
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Central Nervous System

• Spinal Cord
• Tracts
• White Matter
• Axons
• Gray Matter
• Nerve cell bodies
• Dendrites
• Unmyelinated axons
• Neuroglia

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Peripheral Nervous System

• Spinal Nerves
• 31 pairs
• Cranial Nerves
• 12 pairs
• Somatic Nerves
• Motor neurons
• Sensory

• Autonomic
• To
• Viscera
• Cardiac Muscle
• Smooth Muscle
• Glands
• Sympathetic
• Fight or Flight
• Parasympathetic
• Housekeeping

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Sympathetic and Parasympathetic Nerves
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spinal cord
(posterior)
ganglion
nerve
meninges (protective coverings)
vertebra
(anterior)
gray matter
central canal
white matter
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The Spinal Cord

• Functions
• Signals between the PNS and Brain
• Reflex connections
• Coverings
• Meninges
• Nerve tracts
• Ascend and descend

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Functional Division of the Vertebrate Brain

• Hindbrain
• Medulla oblongata
• Respiration
• Cardiac
• Cerebellum
• Sensory input
• Motor dexterity

• Midbrain
• Reflex responses
• Sight and sound
• Tectum
• Forebrain
• Cerebrum
• Thalamus

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Functional Division of the Vertebrate Brain

• Pons
• Information between cerebellum and forebrain
• Hypothalamus
• Sensory Input
• Homeostatic Control

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Reticular Formation

• Network of interneurons
• Input to cerebral centers

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Brain Cavities and Canals

• Cavities
• Ventricles
• Canals
• Cerebrospinal Fluid
• Blood Brain Barrier

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The Human Cerebrum

• Cerebral Hemispheres
• Cortex
• Interneurons
• Left Hemisphere
• Analytical
• Speech
• Right Hemisphere
• Spatial
• Artistic

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The Human Cerebrum

• Lobes
• Occipital
• Vision
• Temporal
• Hearing Vision associations
• Memory
• Parietal
• Somatosensory
• Frontal
• Motor Cortex
• Planning

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Control by the Primary Motor Cortex
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Connections with the Limbic System

• Emotions
• Memory
• Olfaction
• Cerebral cortical connections

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Sperrys Split-Brain Experiments

• Pathway
• Sensory input
• Visual stimuli reaches visual cortex

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Sperrys Experiment

• Epilepsy
• Corpus callosum cut
• Test responses to visual stimuli
• Hemispheres function independently
• Conclusion
• Signals across corpus callosum coordinate the
  functioning of the 2 hemispheres

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Response of Split-Brain Patients
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Memory

• Short-term
• Few seconds - hours
• Few bits of information
• Long-term
• Unlimited amount of information

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Circuits Involved in Fact Memory and Skill Memory

• (a) Facts
• (b) Skills

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hypothalamus
thalamus
pineal gland location
corpus callosum
part of an optic nerve
midbrain
cerebellum
pons
medulla oblongata
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States of Consciousness

• Sleeping
• Slow waves
• REM
• Alert
• Fast waves
• Relaxed
• Alpha waves

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Drugs and the Brain

• Stimulants
• Caffeine Nicotine Amphetamines Cocaine
• Analgesics
• Endorphins Enkephalins
• Narcotics
• Codeine, Heroin

• Depressants
• Alcohol
• Psychedelics
• LSD
• Marijuana

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In Conclusion

• Nervous systems detect, interpret, and respond to
  stimuli
• The simplest nervous systems are nerve nets see
  in radial animals
• The vertebrate CNS consists of the brain and
  spinal cord

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In Conclusion

• The PNS consists of nerves that carry signals to
  and from the spinal cord
• Somatic nerves deal with skeletal muscles
• Autonomic nerves deal with visceral organs
• Autonomic nerves are Parasympathetic or
  Sympathetic

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In Conclusion

• Reflex connections are made in the spinal cord
• An extension of the embryonic neural tube gives
  rise to the brain
• The reticular formation is a low-level route to
  centers of motor activity
• The Brain has 3 main divisions the Hindbrain,
  Midbrain, and Forebrain which govern different
  functions
• developed by M. Roig