Central Nervous System Brain

During development, the central nervous system forms from a long tube. As the anterior part of the tube, which becomes the brain, folds during its continuing formation, four different regions become apparent. These regions become the four subdivisions of the brain: cerebrum, diencephalon, brainstem, and cerebellum (Figure 8-38). The cerebrum and diencephalon together constitute the forebrain. The brainstem consists of the midbrain, pons, and medulla oblongata. The brain also contains four interconnected cavities, the cerebral ventricles, which are filled with circulating cerebrospinal fluid (Figure 8-39), to be discussed more fully later in this chapter.

Vander et al.: Human Physiology: The Mechanism of Body Function, Eighth Edition

Neural Control Mechanisms CHAPTER EIGHT

Neural Control Mechanisms CHAPTER EIGHT

Forebrain

-Skull

Cerebrum Diencephalon

Dorsal root ganglion

C8 T1

Scapula

Brainstem

Cerebrum Diencephalon

Brainstem

Medulla oblongata

Cerebellum

Medulla oblongata

Ribs

Spinal cord

FIGURE 8-38

The spinal cord and divisions of the brain. %

T12-

L1 12th rib vertebra vertebra

L5 S1

Pelvis

Sacrum

Coccyx (tailbone)

Sciatic nerve

FIGURE 8-37

Dorsal view of the spinal cord. Parts of the skull and vertebrae have been cut away. In general, the eight cervical nerves (C) control the muscles and glands and receive sensory input from the neck, shoulder, arm, and hand. The 12 thoracic nerves (T) are associated with the chest and abdominal walls. The five lumbar nerves (L) are associated with the hip and leg, and the five sacral nerves (S) are associated with the genitals and lower digestive tract.

Redrawn from FUNDAMENTAL NEUROANATOMY by Walle J. H. Nauta and Michael Fiertag. Copyright © 1986 by W. H. Freeman and Company. Reprinted by permission.

PART TWO Biological Control Systems

Vander et al.: Human Physiology: The Mechanism of Body Function, Eighth Edition

PART TWO Biological Control Systems

Right lateral ventricle

Left lateral ventricle

Third ventricle

Fourth ventricle

Left lateral ventricle

Third ventricle

Body Systems And Functions

FIGURE 8-39

The four interconnected ventricles of the brain.

FIGURE 8-39

The four interconnected ventricles of the brain.

Overviews of the brain subdivisions are included here and later in Table 8-9, but their functions are discussed more fully in remaining chapters of the book, particularly Chapters 9, 12, and 13.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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