free ebooks

A Handbook of Health by Woods Hutchinson

Those from the brain and spinal cord outward


Res

pi ra'tion. Breathing; the action of the body by which carbon dioxid is given off from the blood and a corresponding amount of oxygen is absorbed into the blood.

Skin. The continuous outer covering of the body, in the deeper layer (der'ma) of which are located the sweat glands, which secrete sweat (a watery, oily substance containing impurities from the blood) and excrete it through the sweat ducts and their openings (pores) in the surface of the skin.

Tra'che a (or tr[=a] ch[=e]' [.a]). The windpipe between the larynx and the bronchi.

U'ri na ry system. The organs concerned in the secretion and discharge of urine: the kid'neys (two glands in the abdominal cavity, back of the peritoneum, which receive wastes from the blood, and excrete them as urine), the u re'ters (ducts through which the urine flows from the kidneys to the bladder), the blad'der (an elastic muscle-sac in which the urine is retained until discharged from the body).

VI. RELATING TO THE NERVOUS AND MOTOR SYSTEMS

Brain. The soft mass of nerve tissue filling the upper cavity of the skull. Its cellular tissue is gray, and its fibrous tissue white. With the spinal cord it controls all the sensory and motor activities of the body.

Cer e bel'lum. The part of the brain lying below the hind part of the cerebrum.

style="text-align: justify;">Cer'e brum. The upper or fore part of the brain; it is divided by a deep fissure into two hemispheres, its cor'tex (surface) lies in many con vo lu'tions (folds), and its fibres run down into the spinal cord. In this part of the brain are the centres, or controlling nerve cells, of the senses and most of our conscious activities.

Gang'li a (g[)a]ng'l[)i] [.a]). (Plural of _ganglion_). Nerve knots, or groupings of nerve cells, forming an enlargement in the course of a nerve.

Me dul'la. A portion of the brain forming an enlargement at the top of the spinal cord and being continuous with it; the channel between the brain and the other parts of the nervous system.

Muscle (mus'l). A kind of animal tissue that consists of fibres that have the power of contracting when properly stimulated. A bundle of muscle fibres, called a muscle, is usually attached to the part to be moved by a ten'don, or sinew. Muscles causing bones to bend are termed flex'ors; those causing them to straighten, ex ten'sors. The movements of muscles may be voluntary (controlled by the will), or involuntary (made without conscious exercise of the will).

Nerve. A fibre of nerve tissue, or a bundle of such fibres, connecting nerve ganglia with each other or with some terminal nerve organ. Nerves running inward toward the spinal cord and the brain are called sen'so ry nerves; those from the brain and spinal cord outward, mo'tor nerves.

Nerv'ous system. The nerve centres with the sensory and motor nerves and the organs of sense.

Neu'rons. The cells of the spinal cord and the brain.

Re'flex. A simple action of the nervous system, in which a stimulus is carried along sensory nerves to a nerve centre, and from which an answering stimulus is sent along motor nerves to call into play the activity of some organ, without consciousness, or without direct effort of the will.


eBook Search
Social Sharing
Share Button
About us

freefictionbooks.org is a collection of free ebooks that can be read online. Ebooks are split into pages for easier reading and better bookmarking.

We have more than 35,000 free books in our collection and are adding new books daily.

We invite you to link to us, so as many people as possible can enjoy this wonderful free website.

© 2010-2013 freefictionbooks.org - All Rights Reserved.

Terms of Use | Privacy Policy | Contact Us