1. Chapter 28 Nervous Systems
The central nervous system (CNS) consists of the
brain and spinal cord (vertebrates).
The peripheral nervous system (PNS)
is located outside the CNS and
consists of
nerves (bundles of neurons wrapped in connective tissue)
Neurons are
cells specialized for carrying electrical signals.
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2. 28.12 Vertebrate nervous systems are highly centralized
In the vertebrates, the central nervous system (CNS)
consists of the brain and spinal cord and
The vertebrate peripheral nervous system (PNS) consists of
cranial nerves,
spinal nerves, and
Ganglia (clusters of neurons).
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3. Central nervous system (CNS) Brain Cranial nerves Spinal cord
Figure 28.12A
Central nervous system (CNS)
Brain
Cranial nerves
Spinal cord
Peripheral nervous system (PNS)
Ganglia outside CNS
Spinal nerves
Figure 28.11A A vertebrate nervous system (back view) 3

4. The PNS can be divided into two functional components:
28.12 The peripheral nervous system of vertebrates can be divided into functional components
The PNS can be divided into two functional components:
the motor system, mostly voluntary, and
the autonomic nervous system, mostly involuntary.
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5. The motor nervous system
28.12 The peripheral nervous system of vertebrates can be divided into functional components
The motor nervous system
carries signals to and from skeletal muscles and
mainly responds to external stimuli.
The autonomic nervous system
regulates the internal environment and
controls smooth and cardiac muscle and organs and glands of the digestive, cardiovascular, excretory, and endocrine systems.
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6. (Control of skeletal muscle)
Figure 28.13
CNS
Sensory
neurons
Motor
neurons
Autonomic
nervous system
Motor
system
Sensory
receptors
(Control of skeletal muscle)
Figure Functional divisions of the vertebrate PNS
Parasympathetic
division
Sympathetic
division
Stimuli
(“Rest and digest”)
(“Fight or flight”)
Enteric
division
(Control of digestive system) 6

7. The autonomic nervous system is composed of three divisions.
28.13 The peripheral nervous system of vertebrates can be divided into functional components
The autonomic nervous system is composed of three divisions.
The parasympathetic division primes the body for activities that gain and conserve energy for the body (rest and digest).
The sympathetic division prepares the body for intense, energy-consuming activities (flight and fight).
The enteric division consists of networks of neurons in the digestive tract, pancreas, and gallbladder that control secretion and peristalsis.
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8. 28.14 The vertebrate brain develops from three anterior bulges of the neural tube
The vertebrate brain evolved by the enlargement and subdivision of the
forebrain,
midbrain, and
hindbrain.
In the course of vertebrate evolution, the forebrain and hindbrain gradually became subdivided
structurally and
functionally.
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9. Embryonic Brain Regions Brain Structures Present in Adult
Figure 28.14
Embryonic Brain Regions
Brain Structures Present in Adult
Cerebrum (cerebral hemispheres; includes cerebral cortex, white matter, basal ganglia)
Forebrain
Diencephalon (thalamus, hypothalamus, posterior pituitary, pineal gland)
Midbrain
Midbrain (part of brainstem)
Pons (part of brainstem), cerebellum
Hindbrain
Medulla oblongata (part of brainstem)
Diencephalon
Cerebrum
Midbrain
Midbrain
Figure Embryonic development of the human brain
Hindbrain
Pons
Cerebellum
Medulla oblongata
Spinal cord
Forebrain
Embryo (1 month old)
Fetus (3 months old) 9

10. 28.14 The vertebrate brain develops from three anterior bulges of the neural tube
In birds and mammals the cerebrum
is much larger and
correlates with their sophisticated behavior.
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11. 28.15 The structure of a living supercomputer: The human brain
The human brain is
more powerful than the most sophisticated computer and
composed of five major structures:
Brain stem (medulla oblongata)
Cerebellum
Thalmus
Hypothalmus
Cerebrum
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12. Table 28.15
Table Major Structures of the Human Brain 12

13. Cerebral cortex (outer region of cerebrum)
Figure 28.15A
Cerebral cortex (outer region of cerebrum)
Cerebrum
Forebrain
Thalamus
Hypothalamus
Pituitary gland
Figure 28.15A The main parts of the human brain
Midbrain
Pons
Spinal cord
Medulla oblongata
Hindbrain
Cerebellum 13