The Nervous SystemChapter 49

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OVERVIEW: COMMAND AND CONTROL CENTER

• The human brain contains about 100 billion neurons, organized into circuits more complex than the most powerful supercomputers

• A recent advance in brain exploration involves a method for expressing combinations of colored proteins in brain cells, a technique called “brainbow”

• This may allow researchers to develop detailed maps of information transfer between regions of the brain

FIGURE 49.1

49.1 VERTEBRATE NERVOUS SYSTEM

AUTONOMIC NERVOUS SYSTEM

Parasympathetic

Sympathetic

Heart rate slows, pupils constrict, blood vessels dilate

Heart rate increases, pupils dilate, blood vessels constrict

Returns body to rest

Regulates arousal and energy generation (“fight-or-flight” response)

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.45 The student is able to describe how nervous systems transmit information.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.45 The student is able to describe how nervous systems transmit information.

CONCEPT 49.2: THE VERTEBRATE BRAIN IS REGIONALLY SPECIALIZED

FIGURE 49.9C

Adult brain viewed from the rear

Cerebellum

Basal nucleiCerebrum

Left cerebralhemisphere

Right cerebralhemisphere

Cerebral cortex

Corpus callosum

SLEEP AND AROUSAL

• The brainstem and cerebrum control arousal and sleep

• The core of the brainstem has a diffuse network of neurons called the reticular formation

• This 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

EMOTIONS IN THE 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

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions.

• 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

EMOTIONS IN THE LIMBIC SYSTEM

BRAINSTEM

• Medulla oblongata• Contains centers that control

visceral (autonomic, homeostatic) functions• Breathing, heart and blood vessel

activity, swallowing, vomiting, and digestion

• Pons • Have nuclei in the medulla that

regulate breathing centers• Midbrain

• Centers for receipt and integration of sensory information

• Coordinates large-scale body movements such as walking

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions.

CEREBELLUM

• Primary function is coordination of movement and balance

• Receives information about position from joints and length of muscles, as well as auditory and visual systems

• Plays role in learning and remembering motor responses (hand-eye coordination)

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.44 The student is able to describe how nervous systems detect external and internal signals. LO 3.45 The student is able to describe how nervous systems transmit information. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.44 The student is able to describe how nervous systems detect external and internal signals. LO 3.45 The student is able to describe how nervous systems transmit information. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

THALAMUS AND HYPOTHALAMUS

• Thalamus• Main input center for sensory

information going to cerebrum• Receives input from cerebrum

to regulate emotion and arousal

• Hypothalamus• Source of posterior pituitary

hormones and releasing hormones that act on anterior pituitary

• Regulates body temp, thirst, hunger, other basic survival mechanisms

• Plays role in sexual response and mating behaviors, fight-or-flight response, and pleasure

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.45 The student is able to describe how nervous systems transmit information. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.45 The student is able to describe how nervous systems transmit information. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

CONCEPT 49.3: THE CEREBRAL CORTEX CONTROLS VOLUNTARY MOVEMENT AND

COGNITIVE FUNCTIONS

• The cerebrum, the largest structure in the human brain• Controls skeletal muscle

contraction• Essential for awareness,

language, cognition, memory, consciousness, and perception

• Four regions, or lobes (frontal, temporal, occipital, and parietal), are landmarks for particular functions

LANGUAGE AND SPEECH

• Studies of brain activity have mapped areas responsible for language and speech

• Broca’s area in the frontal lobe is active when speech is generated

• Wernicke’s area in the temporal lobe is active when speech is heard

• These areas belong to a larger network of regions involved in languageEssential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and

produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

LATERALIZATION OF CORTICAL FUNCTION

• The left hemisphere -- language, math, logic, and processing of serial sequences

• The right hemisphere -- pattern recognition, nonverbal thinking, and emotional processing

• The two hemispheres work together by communicating through the fibers of the corpus callosum

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

LATERALIZATION OF CORTICAL FUNCTION

• Clusters of neurons (basal nuclei) are centers for planning and learning movement sequences

• Damage here during fetal development can result in cerebral palsy, a disorder resulting from a disruption in the transmission of motor commands to the muscles.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

INFORMATION PROCESSING

• The cerebral cortex receives input from sensory organs and somatosensory receptors

• Somatosensory receptors provide information about touch, pain, pressure, temperature, and the position of muscles and limbs

• The thalamus directs different types of input to distinct locations

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. LO 3.44 The student is able to describe how nervous systems detect external and internal signals.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. LO 3.44 The student is able to describe how nervous systems detect external and internal signals.

INFORMATION PROCESSING

• Adjacent areas process features in the sensory input and integrate information from different sensory areas

• Integrated sensory information passes to the prefrontal cortex, which helps plan actions and movements

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. LO 3.44 The student is able to describe how nervous systems detect external and internal signals.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. LO 3.44 The student is able to describe how nervous systems detect external and internal signals.

SOMATOSENSORY CORTEX AND MOTOR CORTEX

• Neurons are arranged according to the part of the body that generates input or receives commands• Motor- surface area

related to neuronal control needed

• Somatosensory- surface area related to number of sensory neuron axons to that partEssential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and

produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

FRONTAL LOBE FUNCTION

• Frontal lobe damage may impair decision making and emotional responses but leave intellect and memory intact

• The frontal lobes have a substantial effect on “executive functions”

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.

Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses. d. Different regions of the vertebrate brain have different functions. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response.