Complete Text (Part 2)

The suitable care, nursing and treatment of the patients is also one of the aims of the science of Hygiene, besides the prevention of sicknesses. A quick restoration of health may be attained in the shortest time and in the surest way by proper treatment. In this connection the clubs and other similar institutions are of great importance. They alleviate the lot of the patient and of his family; they contribute to diminish the number of days of illness and thus restrict in the most efficacious manner the lenght of time, during which the work of the patient and his earnings are interrupted: Some knowledge of the nature and of the functions of the human body is necessary for the purpose of enabling us to appreciate fully the value and the demands of Hygiene. The human body forms after all the principal aim of the science of Hygiene. 1* A. The structure of the human body; the action and the uses of its organs. The constituent parts of the human body. §1. Description of the parts of the body. We have to distinguish between the hard portions of the body, its soft and the liquid constituents parts. The hard are the bones, the cartilage and the teeth. The bones are united by strong liga- ments; the totality of the bones of the human body is called the skeleton, To the soft parts of the body belong the skin, the adipose tissues, the muscles, the entrails (viscera) the bloodvessels and the nerves. The boodvessels and the nerves are spread through all parts of the human body; the fatty tissue is found princi- pally immediately under the skin, but it also passes through the muscles and the viscera. Among the liquid constituents the blood has the greatest importance. § 2. Bones and cartilage. The bones, of which we know over 200 in the human body are partly hollow tubes, which contain in their interior a soft mass, rich in blood, called the bone marrow. Besides these rced-bones there are also flat bones, for instance the external bones of the skull and spongy bones, like the vertebre. Every bone is surrounded by a thin fine membrane, called the Periosteum. Many bones change at their ends into cartilage, which is an elastic mass, similar to the substance of the bone, but less hard. Independent cartilages unconnected with a bone are to be found in the larynx and in the auricle. § 3. Ligaments, Joints. Bones are ordinarily connected together by strong ligaments; such a connection is called a joint, if it permits a movement of one bone towards the other. The constituent parts of the human body. 5 Each joint represents a hermetically (air tight) closed capsule, formed of masses of ligaments, in which rest the ends of several bones, covered by a flat cartilaginous mass; it contains a small portion of a mucous thread-like fluid, the joint grease (synovia) which facilitates the gliding of the ends of the bones over one another. While some joints, for instance the middle finger-joint permit movement in one plane only, other joints for instance the shoulder joint (the capular) permit much more extended movements in various directions. § 4. Muscles, sinews. The muscles bring about the movements in the body and in its component parts. They constitute the principal mass of the flesh, they are composed of bundles of fibre and possess the property of shortening themselves by contraction and of reverting again to their longer form from the contracted state by relaxation. The muscles ordinarily lie between the skin and the bones, and are joined to the latter by means of ribbon-like bands, the sinews. By its contraction the muscle, like a stretched band of india rubber gets shorter and thereby causes those parts of the body to come nearer to one another, to which its ends are fastened. If (for example) in the out- stretched arm the fore-muscle of the upper arm contracts, the lower arm thereby is brought nearer to the upper arm; that means, that a bending of the arm at the elbow-joint follows. If the same muscle then relaxes, it gets lengthened again and the arm returns from the bent into the outstretched position, as soon as the hind muscle of the upper arm contracts. $5. Glands. Some of the organs, which belong to the soft parts of the body secrete fluids from their tissues or from the blood which flows through them; these fluids are either used during the different functions of the body, as for instance the gastric juice in the process of digestion, or they leave the body and remove matter which can no longer be used in the body, as the urine, secreted in the kidneys. These organs are called glands. They generally possess one or more excretory ducts, through which is discharged the secreted fluid. Besides the large glands, to which for instance the liver be- longs, there are minutely small glands, which are hardly visible without the aid of a magnifying-glass, like the perspiratory glands. The secretion from the glands may be a thin fluid like the urine, or slimy like the saliva or viscous like the car-wax. 6 A. The structure of the human body. Some other organs, which secrete nothing externally, are also called glands; for instance the lymphatic glands (cf. § 17). § 6. The skin; the mucous membranes. Our skin forms the outer (external) covering of our body; it consists of two layers, the more tender epidermis and the corium under it. The epidermis is covered with fine hair, which in some parts of the body, as for instance on the head attain considerable length and thickness. The back of the ends of the fingers and of the toes is specially protected by horny, non sensi- tive substances, called nails. In the derma (corium, harder skin) we find the skin-glands, small tube-like structures, the aperture of which, opening on the surface are called the pores of the skin. Some skin-glands secrete a fatty mass, the skin grease, which gives to the skin its flexibility and lustre; by other skin-glands is secreted the sweat, the well-known watery and salty fluid. The skin changes at the natural openings of the body into a similar covering, which is called the mucous membrane. This transition can be plainly seen at the lips and also at the eyelids, where the boundary line between the skin and the mucous membrane is specially marked by the eyelashes. The mucous membrane covers the cavities which are con- nected with the natural apertures of the body (nostrils, larynx, mouth, esophagus, stomach, intestines); it is of a more tender construction than the external skin, has a reddish appearance as it allows the bloodvessels to be seen through, which are filled with red blood. The surface of the mucous membranes is moist and slippery, owing to a mucus which is secreted by microscopically small glands. Some parts of the Body and their Functions. § 7. General division of the body. The human body is divided into the head, the trunk and the limbs. (Fig. 1.) In the head we distinguish between the skull and the face. The skull, approaching in shape that of a hemisphere encloses the cranial cavity, in which is situated the brain. In the skull we distinguish in front the forehead, on the top the crown of the head, on both sides the temples and at the back the occiput. The crown, the occiput and parts of the temples are Some parts of the Body and their Functions. 7 covered with hair. In the face we notice the eyes, the nose, the mouth, the cheeks and the between the skull and the face are the ears. The Trunk is divided into the neck, the backpart of which is called the nape; the breast, the belly, the back, the loins, and the pelvis, the sides of which are the hips. The furrow which se- parates the trunk in front from the upper thigh is called bend of the groin. The trunk contains two large cavities, which are filled with entrails, the thorax and the abdomen. Among the limbs we distinguish the upper limbs or arms from the lower limbs or legs. § 8. The Head, the Face, the facial cavities. (Fig. 2.) The head is composed of the bones of the skull and of the facial bones, which are covered with soft tissues; these bones are nearly all joined together immovably firm. The lower jaw alone, which belongs to the facial bones possesses moveable- ness; the ends of its joints are situated in front of the ears; their movements, in chewing for instance can be felt by placing the finger on that spot. Other facial bones are the On the boundary line Fig. 1. Skeleton. two bones of the nose, which join to form the osseous bridge of the nose, the Zygoma or cheekbones and the two bones of the upper jaw. The facial bones form partly by themselves partly with the skull as well as with the cartilages and tissues the two orbits (cavities of the eyes) the cavity of the nose and the oral cavity. 8 A. The structure of the human body. The cavities of the eyes, which are formed only by bones are widely opened in front, extend back deeply into the head and become narrower, as they recede inwards and backwards. From their hindmost part a small, round opening, through which I-¥. Bones of the skull, (7 Frontal Bone. 17 Parietal Bone, 117 Occipital Bove. 1¥ Sphe- nold Bone. V Optic Bone) V7 Nasal Bone. V1! Upper Jaw. VIII Lower Jaw. 1X Breast- bone. X—XII Vertebne. XIII Hyold Bone. 1—8. Turbinated Bones. 4, Soft Palate with Uvula. 6, Opening of the Eustachian Tube. 6. Mouth. 7. Tongue, 8. Larynx. 9, Windpipe. 10, @sophngus. 11, Thyroid gland, 12. Epiglottis, 18. 14, Muscles of the Neck. 15. Skin. the optic nerve passes into the brain leads into the cavity of the skull. In front, in the inner corner the cavity of the eye is connected with the nasal cavity by the thin lacrymal duct. The cavity of the nose is divided by a partition, partly bony, partly cartilaginous into a right half and into a left Some parts of the Body and their Functions. 9 half; both halves are open in front and behind. The con- tinuation of the nasal cavity behind is the choanae, (pharynx.) into which the oral cavity also leads. The oral cavity (fig. 3) is above divided from the nasal cavity by the palate, of which the anterior bony part, the hard palate is distinguished from the posterior moveable portion, ealled the soft palate. The floor of the oral cavity is formed of tissues, which enclose the hyoid bone. The teeth project from the upper jaw and from the lower jaw; an adult person has sixteen teeth above and sixteen below, making thirty two altogether. There are in each jaw in front four incisors, on each side of which we find an eyetooth and five jaw-teeth. The hind- most jaw-teeth, which usually appear only af- ter the sixteenth year are called wisdom teeth. Inevery tooth we distin- guish the visible crown of the tooth, whose most important part is the hard enamel, from the root of the tooth, which is firmly fixed in thejaw. The connection between Vig. 3. Structure of the Mouth, a, Uvula, 1b. Anterior palatine Arch, ¢, Posterior Pala- the root and the crown tine Arch, d. Tonails, e. Tongue. f. Pharynx, is called the neck of the tooth. The tooth contains in its interior the soft tooth-pulp, which is traversed by bloodvessels and sensitive nerves. Behind the teeth isthe tongue whose hindmost part with the soft palate bounds the narrowest spot in the cavity of the mouth. We notice at the back of the oral cavity, when the tongue is pressed down the uvula hanging down from the centre of the soft palate; at the two sides the anterior and posterior arches of the pa- late and the tonsils between the arches of the palate on each side. Under the tonsils lie two bluish transparent salivary glands; two other salivary glands are on each side of the lower edge of the lower jaw and in front of the exterior portion 10 A. The structure of the human body. of this bone near the ear. The clear saliva, which is secre- ted by these six glands is mixed with the phlegm to be found on the mucous membrane of the cavity of the mouth. § 9. The Trunk; the cavities of the Trunk. The trunk finds its principal support in the spinal column; (also called back bone.) this runs from the head to the pelvis and is com- posed of 24 separate vertebrae; namely: seven cervical, twelve dorsal and five lumbar vertebrae. At its lower end the spinal column merges in the back of the bony pelvis, which is called the ,Os sacrum“. In each vertebra we distinguish in front the vertebral aperture, enclosed by the vertebral arch; and several bony projections; those projecting back- wards may be externally felt in the middle line of the neck and of the back. The vertebral cavities of the vertebrae lie close above one another and form together with the cavity of the ,sacrum“ the tubelike vertebral canal, which is con- nected through the occipital aperture with the cavity of the skull and encloses the spinal cord. From the twelve dorsal vertebrae twelve ribs, curved like a bow branch off on each side; there are therefore 24 ribs altogether; they run in a more or less sloping direction from back to front. The seven upper ribs on each side are called the true ribs, the five lower the false ribs. The ten upper rips are connected in front by cartilaginous continuations (costal cartilage) with the breastbone. This is a flat bone which runs downwards from the neck in front the middleline of the body. At its upper end are joined on both sides the two collarbones, which run to the shoulders. The pit of the stomach or cardiac region is bounded up- wards by the lower end of the breast bone and by the car- tilage of the lower ribs which tend upwards to meet it. The so called 2horax which is formed by the 24 ribs, the spinal column and the breast-bone enclose the cavity of the chest; (§§ 12—16). Below this lies the abdominal cavity (§ 18 sqq.) bounded underneath by the pelvis, behind by the lumbar vertebrae and elsewhere by tissues and separated from the thorax by a moveable partition, which consists o fa thin layer of muscles, called the Diaphragm. The pelvis is formed by the ,Sacrum“ and the two hip-bones; the latterare joined in front by a cartilage. On the exterior side of the hip-bones is a semi-circular hollow for the upper end of the Some parts of the Body and their Functions. i upper femoral bone which is called the joint-pan; the part of the thigh-bone below that hollow is called the sitting-bone. The lowest part of the abdominal cavity enclosed by the pelvis is called the pelvic cavity. g 10. The Upper Limbs. In the upper limbs, the arms we distinguish the upper arm, the lower (or fore-arm) and the hand. They are connected with the trunk by the shoulders. The bony frame of each shoulder is formed at the back by the shoulder- blade, a flat triangular bone lying in the back plane of the trunk; in front by the collar-bone, a ~ like spiral tube-like bone, which runs on the lower edge of the neck almost horizontally to the breast-bone and at the sides the upper end of the upper arm-bone. This is called the upper-armhead and it posseses a hemi-spheroidal arched joint plane which with a glenoid cavity placed at the outer side of the shoulder-blade forms the shoulder-joint. Below this we find the armpit between the trunk and the upper arm. The bony frame of the lower arm consists of the radius, situated on the same side as the thumb and the ulna placed on the same side as the little finger; the hookshaped upper end of the ulna projects at the back of the elbow-joint. The radius can be moved round the ulna and thus makes possible the rotations of the hand, which follow its movements. In the hand we distinguish the wrist, the middle hand and the fingers. The bony portion of the wrist is formed by two rows of small bones, the eight bones of the wrist, the upper row of which combines with the lower end of the radius and of the ulna to form the joint of the hand. In the middle hand we distingulsh the back of the hand from the hollow of the hand; the latter is bounded on its side by the ball of the thumb and the ball of the little finger. The mobility of the fingers is effected partly by small handmuscles situated in the middle hand, partly by the muscles of the lower arm, whose long string-shaped sinews stretch through the wrist and middle-hand as far as the finger-bones. § 11. The Lower Limbs. The lower limbs or legs begin at the hips and divide into upper and lower thigh and foot, The bony portion of each upper thigh is the thigh-bone, the Strongest and longest bone in the human body. Its ball- shaped enlargement at the upper end forms with the glenoid 12 ‘A. The structure of the human body. cavity (§ 9) in the hip-bone the thigh-joint. The lower thigh, (leg) the fleshy backpart of which is called the calf of the leg possesses two bones, viz.: the shin-bone on the inner side and the thinner fibula on the outer side. The upper end of the shin-bone joins with the lower end of the upper thigh in the kneejoint, in the formation of which the flat kneecap, lying in front