Alveolar glands may be either simple, simple branched, or compound branched.
Some alveolar glands would be the sebaceous glands, pancreas, mammary gland, ovary and thyroid.
Tubulo-alveolar Glands.—In these, there is a combination of the tubular and the alveolar type. They may also be simple, simple branched or compound branched.
Some of this type would be certain of the pyloric glands, certain of the sweat glands, some mucous glands, the prostate and the lungs.
The most important glands will be discussed under the tissue or the organ in which they are situated.
Cartilage.
—Cartilage is a transition stage between connective tissue and bone; when it is boiled it yields condrin. It is found in various parts of the body, in the adults being found chiefly in the joints, in the sides of the thorax, and in various tubes which are not kept permanently open, such as the air passages, nostrils, ears, etc. In the foetus, the greater part of the framework is cartilaginous and as the foetus matures this cartilage is finally replaced by bone. Cartilage is divided into hyaline cartilage, elastic cartilage, and fibro cartilage.
Hyaline cartilage is found in the nose, larynx, trachea, and bronchi.
Elastic cartilage is found in the epiglottis and the cartilages of the larynx.
Fibro cartilage is found at the point of insertion of the ligaments, into the body of the bone, such as the cartilage which helps to hold the femur or long bone of the thigh into the hip.