Download 49-1-2 Nervouse systems ppt

LECTURE PRESENTATIONS
For CAMPBELL BIOLOGY, NINTH EDITION
Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
Chapter 49
Nervous Systems
Lectures by
Erin Barley
Kathleen Fitzpatrick
© 2011 Pearson Education, Inc.
Overview: Command and Control Center
• “Brainbow” - method for
expressing combinations of
colored proteins in brain
cells
• may allow researchers to
develop detailed maps of
information transfer
between regions of the
brain
© 2011 Pearson Education, Inc.
Concept 49.1: Nervous systems consist of
circuits of neurons and supporting cells
Nerve net
a series of interconnected
nerve cells
• Nerves are bundles that consist of the
axons of multiple nerve cells
• Sea stars have a nerve net in each arm
connected by radial nerves to a central
nerve ring
© 2011 Pearson Education, Inc.
Figure 49.2a
Radial
nerve
Nerve net
(a) Hydra (cnidarian)
Nerve
ring
(b) Sea star (echinoderm)
• Cephalization - clustering of sensory organs at the
front end of the body
• Bilaterally symmetrical animals
• Relatively simple cephalized animals, such as
flatworms, have a central nervous system
(CNS)
• The CNS consists of a brain and longitudinal
nerve cords
© 2011 Pearson Education, Inc.
• Annelids and arthropods have segmentally
arranged clusters of neurons called ganglia
Brain
Brain
Ventral
nerve cord
Segmental
ganglia
(d) Leech (annelid)
© 2011 Pearson Education, Inc.
Ventral
nerve cord
Segmental
ganglia
(e) Insect (arthropod)
Figure 49.2c
Ganglia
Brain
Ventral
nerve cord
Segmental
ganglia
(e) Insect (arthropod)
Anterior
nerve ring
Longitudinal
nerve cords
(f) Chiton (mollusc)
Figure 49.2d
Brain
Brain
Ganglia
(g) Squid (mollusc)
Spinal
cord
(dorsal
nerve
cord)
Sensory
ganglia
(h) Salamander (vertebrate)
• In vertebrates
– The CNS: composed of brain and spinal cord
– The peripheral nervous system (PNS):
composed of nerves and ganglia
© 2011 Pearson Education, Inc.
Organization of the Vertebrate Nervous System
• The spinal cord also produces reflexes
independently of the brain
• A reflex is the body’s automatic response to a stimulus
– For example, a doctor uses a mallet to trigger a
knee-jerk reflex
© 2011 Pearson Education, Inc.
Figure 49.3
Quadriceps
muscle
Cell body of
sensory neuron in
dorsal root
ganglion
Gray
matter
White
matter
Hamstring
muscle
Spinal cord
(cross section)
Sensory neuron
Motor neuron
Interneuron
Figure 49.4
Central nervous
system (CNS)
Brain
Peripheral nervous
system (PNS)
Cranial nerves
Spinal cord
Ganglia outside
CNS
Spinal nerves
• The spinal cord and brain develop from the
embryonic nerve cord
• The nerve cord gives rise to the central canal
and ventricles of the brain
© 2011 Pearson Education, Inc.
• Ventricles of the brain are hollow, filled with
cerebrospinal fluid
• The cerebrospinal fluid is filtered from blood and
functions to cushion the brain and spinal cord as
well as to provide nutrients and remove wastes
• The brain and spinal cord contain
– Gray matter, which consists of neuron cell
bodies, dendrites, and unmyelinated axons
– White matter, which consists of bundles of
myelinated axons
© 2011 Pearson Education, Inc.
Glia
• have numerous functions to nourish, support,
and regulate neurons
– Embryonic radial glia form tracks along which
newly formed neurons migrate
– Astrocytes induce cells lining capillaries in
the CNS to form tight junctions, resulting in a
blood-brain barrier and restricting the entry
of most substances into the brain
© 2011 Pearson Education, Inc.
Figure 49.6a
CNS
PNS
Neuron
VENTRICLE
Cilia
Astrocyte
Oligodendrocyte
Schwann cell
Microglial cell
Capillary
Ependymal cell
The Peripheral Nervous System
• The PNS transmits information to and from the
CNS and regulates movement and the internal
environment
• In the PNS, afferent neurons transmit information
to the CNS and efferent neurons transmit
information away from the CNS
© 2011 Pearson Education, Inc.
• The PNS has two efferent components: the
motor system and the autonomic nervous system
• The motor system carries signals to skeletal
muscles and is voluntary
• The autonomic nervous system regulates
smooth and cardiac muscles and is generally
involuntary
© 2011 Pearson Education, Inc.
Figure 49.7
Central Nervous
System
(information processing)
Peripheral Nervous
System
Efferent neurons
Afferent neurons
Sensory
receptors
Autonomic
nervous system
Motor
system
Control of
skeletal muscle
Internal
and external
stimuli
Sympathetic Parasympathetic Enteric
division
division
division
Control of smooth muscles,
cardiac muscles, glands
• The autonomic nervous system has
sympathetic, parasympathetic, and enteric
divisions
• The sympathetic division regulates arousal
and energy generation (“fight-or-flight”
response)
• The parasympathetic division has
antagonistic effects on target organs and
promotes calming and a return to “rest and
digest” functions
© 2011 Pearson Education, Inc.
• The enteric division controls activity of the
digestive tract, pancreas, and gallbladder
© 2011 Pearson Education, Inc.
Figure 49.8
Sympathetic division
Parasympathetic division
Action on target organs:
Action on target organs:
Constricts pupil
of eye
Dilates pupil of eye
Stimulates salivary
gland secretion
Inhibits salivary
gland secretion
Constricts
bronchi in lungs
Cervical
Sympathetic
ganglia
Relaxes bronchi
in lungs
Slows heart
Accelerates heart
Stimulates activity
of stomach and
intestines
Inhibits activity of
stomach and intestines
Thoracic
Stimulates activity
of pancreas
Inhibits activity
of pancreas
Stimulates
gallbladder
Stimulates glucose
release from liver;
inhibits gallbladder
Lumbar
Stimulates
adrenal medulla
Promotes emptying
of bladder
Promotes erection
of genitalia
Inhibits emptying
of bladder
Sacral
Synapse
Promotes ejaculation
and vaginal contractions
Figure 49.8a
Parasympathetic division
Sympathetic division
Action on target organs:
Action on target organs:
Constricts pupil
of eye
Dilates pupil of eye
Stimulates salivary
gland secretion
Inhibits salivary
gland secretion
Constricts
bronchi in lungs
Slows heart
Stimulates activity
of stomach and
intestines
Stimulates activity
of pancreas
Stimulates
gallbladder
Cervical
Sympathetic
ganglia
Figure 49.8b
Parasympathetic division
Sympathetic division
Relaxes bronchi
in lungs
Accelerates heart
Inhibits activity of
stomach and intestines
Thoracic
Inhibits activity
of pancreas
Stimulates glucose
release from liver;
inhibits gallbladder
Lumbar
Stimulates
adrenal medulla
Promotes emptying
of bladder
Promotes erection
of genitalia
Inhibits emptying
of bladder
Sacral
Synapse
Promotes ejaculation
and vaginal contractions
Concept 49.2: The vertebrate brain is
regionally specialized
• Specific brain
structures are
particularly specialized
for diverse functions
• These structures arise
during embryonic
development
© 2011 Pearson Education, Inc.
Figure 49.9b
Brain structures in child and adult
Embryonic brain regions
Telencephalon
Cerebrum (includes cerebral cortex, white
matter, basal nuclei)
Diencephalon
Diencephalon (thalamus, hypothalamus,
epithalamus)
Forebrain
Midbrain
Mesencephalon
Midbrain (part of brainstem)
Metencephalon
Pons (part of brainstem), cerebellum
Myelencephalon
Medulla oblongata (part of brainstem)
Hindbrain
Cerebrum
Mesencephalon
Midbrain
Hindbrain
Metencephalon
Diencephalon
Diencephalon
Midbrain
Myelencephalon
Forebrain
Telencephalon
Embryo at 1 month
Embryo at 5 weeks
Pons
Medulla
oblongata
Spinal
cord
Cerebellum
Spinal cord
Child
Figure 49.9c
Left cerebral
hemisphere
Right cerebral
hemisphere
Cerebral cortex
Corpus callosum
Cerebrum
Basal nuclei
Cerebellum
Adult brain viewed from the rear
Figure 49.9d
Diencephalon
Thalamus
Pineal gland
Hypothalamus
Brainstem
Midbrain
Pituitary gland
Pons
Medulla
oblongata
Spinal cord
Arousal and Sleep
• The brainstem and cerebrum control arousal
and sleep
• The core of the brainstem has a diffuse network
of neurons called the reticular formation
• regulates the amount and type of information
that reaches the cerebral cortex and affects
alertness
• The hormone melatonin is released by the
pineal gland and plays a role in bird and
mammal sleep cycles
© 2011 Pearson Education, Inc.
Figure 49.10
Eye
Reticular formation
Input from touch,
pain, and temperature
receptors
Input from nerves
of ears
Key
• Sleep is essential and may play a role in the
consolidation of learning and memory
• Dolphins sleep with one brain hemisphere at a time and
are therefore able to swim while “asleep”
Low-frequency waves characteristic of sleep
High-frequency waves characteristic of wakefulness
Location
Left
hemisphere
Right
hemisphere
Time: 0 hours
Time: 1 hour
Biological Clock Regulation
• Cycles of sleep and wakefulness are examples
of circadian rhythms, daily cycles of biological
activity
• Mammalian circadian rhythms rely on a
biological clock, molecular mechanism that
directs periodic gene expression
• Biological clocks are typically synchronized to
light and dark cycles
© 2011 Pearson Education, Inc.
• In mammals, circadian rhythms are coordinated
by a group of neurons in the hypothalamus
called the suprachiasmatic nucleus (SCN)
• The SCN acts as a pacemaker, synchronizing
the biological clock
© 2011 Pearson Education, Inc.
Emotions
• Limbic System
• Generation and experience of emotions involve
many brain structures including the amygdala,
hippocampus, and parts of the thalamus
• The limbic system also functions in motivation,
olfaction, behavior, and memory
Thalamus
Hypothalamus
Olfactory
bulb
Amygdala
© 2011 Pearson Education, Inc.
Hippocampus
• Generation and experience of emotion also
require interaction between the limbic system
and sensory areas of the cerebrum
• The structure most important to the storage of
emotion in the memory is the amygdala, a mass
of nuclei near the base of the cerebrum
Nucleus accumbens
Happy music
© 2011 Pearson Education, Inc.
Amygdala
Sad music