Biology, Seventh Edition
Solomon • Berg • Martin
Chapter 40
Neural Regulation
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Nerve nets
• Radially symmetrical
invertebrates
• Nerve cells scattered throughout
the body
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Hydra’s
nerve net
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Radial nervous systems
• Radially symmetrical
invertebrates
• Nerve ring and nerves that
extend to various parts of the
body
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Bilateral nervous systems
• Bilaterally symmetrical animals
• Nerve cells form nerves, nerve
cords, ganglia, and brain
• Sense organs concentrated in the
head region
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Bilateral nervous systems
• Wide range of responses
–Increased number of association
neurons
–More complex synaptic contacts
permit a planarian flatworms
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Planarian flatworms
• Cerebral ganglia
• Two solid ventral nerve cords
connected by transverse nerves
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Ladder-type
nervous
system in
flatworms
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Annelids and arthropods
• Ventral nerve cord
• Numerous ganglia
• Cerebral ganglia of arthropods
have specialized regions
• Cephalopod mollusks
• Complex nervous systems
• Neurons in a central region
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Annelid and
arthropod
nervous
systems
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Evolutionary trends
• Increased numbers and
concentration of nerve cells
• Specialization of function
• Increased number of association
neurons
• More complex synaptic contacts
• Formation of a head
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Vertebrate nervous system
• Central nervous system (CNS)
–Brain
–Dorsal, tubular spinal cord
• Peripheral nervous system (PNS)
–Sensory receptors
–Nerves
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Vertebrate brain development
• Brain and spinal cord arise from
the neural tube
• Anterior end of the tube
differentiates into
–Forebrain
–Midbrain
–Hindbrain
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Early development of the vertebrate nervous system
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Section through the human brain
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Hindbrain subdivides into
• Metencephalon
• Myelencephalon
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Myelencephalon develops into
the medulla
• Vital centers
• Other reflex centers
• Fourth ventricle
–Communicates with the central
canal of the spinal cord
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Metencephalon gives rise to the
cerebellum
• Muscle tone
• Posture
• Equilibrium
• Pons
–Connects various parts of the brain
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Midbrain
• Largest part of the brain in fishes
and amphibians
• Main association area, linking
sensory input and motor output
• Center for visual and auditory
reflexes in reptiles, birds, and
mammals
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Brain stem
• Medulla
• Pons
• Midbrain
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Forebrain differentiates to form
the diencephalon and
telencephalon
• Diencephalon develops into the
thalamus and hypothalamus
• Thalamus
• Relay center for motor and
sensory information
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Hypothalamus
• Controls autonomic functions
• Links nervous and endocrine
systems
• Controls temperature, appetite,
and fluid balance
• Emotional and sexual responses
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Telencephalon develops into
the cerebrum and olfactory
bulbs
• Cerebrum
• Divided into right and left
hemispheres
• In fishes and amphibians,
integrates sensory information
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• In birds, the corpus striatum
controls complex behavior
patterns, such as flying and
singing
• In mammals, the neocortex
accounts for a large part of the
cerebral cortex
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Human brain and spinal cord
• Protected by bone and three
meninges
–Dura mater
–Arachnoid
–Pia mater
• Cushioned by cerebrospinal fluid
(CSF)
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Spinal cord
• Transmits impulses to and from
the brain
• Controls many reflex actions
• Gray matter contains nuclei that
serve as reflex centers
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Structure of the spinal cord
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Ascending tracts
• Transmit information to the brain
• Descending tracts
• Transmit information from the
brain
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Withdrawal reflex
• Sensory receptors
• Sensory neurons
• Interneurons
• Motor neurons
• Effectors
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Reflex action
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Human cerebral cortex
• Gray matter
–Forms folds or convolutions
• Fissures
–Deep furrows between the folds
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Cerebrum
• Sensory areas
–Receive incoming sensory
information
• Motor areas
–Control voluntary movement
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Association areas
–Link sensory and motor areas
–Learning
–Language
–Thought
–Judgment
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• The cerebrum consists of lobes
• Frontal lobes
• Parietal lobes
• Temporal lobes
• Occipital lobes
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Human brain
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• White matter of the cerebrum
• Lies beneath the cerebral cortex
• Corpus callosum
–Large band of white matter
–Connects right and left hemispheres
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Basal ganglia
–Cluster of nuclei within the white
matter
–Important centers for motor function
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Sleep–wake pattern
• Regulated by the hypothalamus
and brain stem
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Alpha wave patterns
• Relaxed states
• Beta wave patterns
• Accompany heightened mental
activity
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Theta and delta waves
• Slower frequency
• Higher-amplitude
• Non-REM sleep
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
EEGs showing electrical activity in the brain
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Reticular activating system
(RAS)
• Arousal system
• Neurons filter sensory input
• Selects which information is
transmitted to the cerebrum
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Non-REM sleep
• Electrical activity of the cerebral
cortex slows
• Metabolic rate slows
• REM sleep
• Dreaming
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Suprachiasmatic nucleus
• Main biological clock
• Receives information about light
and dark
• Transmits it to other nuclei that
regulate sleep
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Limbic system
• Emotional aspects of behavior
• Motivation
• Sexual behavior
• Autonomic responses
• Biological rhythms
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Hippocampus
• Categorizes information
• Consolidated memories
• Amygdala
• Evaluates incoming information
• Signals danger
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Learning
• Acquiring information as a result
of experience
• Memory
• Information is encoded, stored,
and retrieved
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Implicit memory
• Unconscious memory for
perceptual and motor skills
• Explicit memory
• Factual memory of people,
places, or objects
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Short-term memory
• Recall information for a few
minutes
• Information can be transferred to
long-term memory
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Synaptic plasticity
• Ability of the nervous system to
modify synapses during learning
and remembering
• Long-term memory storage
• Gene activation
• Long-term functional changes at
synapses
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Long-term potentiation (LTP)
• Increased sensitivity to an action
potential by a postsynaptic
neuron
• Long-term depression (LTD)
• Long-lasting decrease in the
strength of synaptic connections
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Peripheral nervous system
• Somatic division
• Responds to changes in the
external environment
• Autonomic division
• Regulates the internal activities of
the body
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Sympathetic system
• Permits the body to respond to
stressful situations
• Parasympathetic system
• Influences organs to conserve
and restore energy
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Sympathetic and
parasympathetic nerves
• Innervate many organs
• Function in an opposite way
–Sympathetic system increases
heart rate
–Parasympathetic system decreases
heart rate
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
Dual innervation of the heart and stomach
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 40 Neural Regulation
• Drug actions and effects
• Alter mood
• Increase or decrease the
concentrations of specific
neurotransmitters within the brain
Copyright © 2005 Brooks/Cole — Thomson Learning