CARTILAGE HISTOLOGY LAB ©David B. Fankhauser, Ph.D., Professor of Biology and Chemistry University of Cincinnati Clermont College, Batavia OH 45103
Elastic cartilage from the ear	This page has been accessed  times since 12 October 2001.  14 October 1991, rvsd 18 Oct 94, 12 Sept 95, 23 Sept 96, 10 Oct 96, 24 Sept 97, 11 Sept 99, 13 Oct 99, 28 Sept 01	Hyaline Cartilage from the trachea

Cartilage is a connective tissue in which the cells are relatively sparse and embedded in a large amount of firm characteristic matrix. The matrix is composed of ground substance bound together with characteristic fibers which vary in composition and orientation according to the type of cartilage. Note the distinguishing characteristics in each of the following types of cartilage:

1. arrangement of cells
2. unusual details of the matrix
3. its staining characteristics

Click on the  image to enlarge:	Type of cartilage	Features to learn and label in your illustration
	1. (slide 11) Hyaline cartilage (VE: fig 3-3, p 41) (trachea):  Forms models for immature bones. Forms epiphyseal cartilage on long bones by which they grow. Gives shape to nose, trachea, etc. Connects bones as with ribs to stermum. Covers the mating surfaces of bones in sinovial joints. It is resilient and shock absorbing. Collagen is the primary fiber, chondroitin the major component of ground substance. Here is a labeled view of hyaline cartilage and associated tissue.	chondrocytes cells which maintain cartilage                         lacunae chambers (houses chondrocytes)                             matrix material which fills space between lacunae perichondrium fibrous layer nourishes the cartilage (dense irregular connective tissue )  chondroblasts at boundary of perichondrium and cartilage proper Glands in surrounding connective tissue: mucus acinar gland (tracheal gland) makes mucus which "floats" on top of cilia. serous gland with darker shallow cuboid makes thin serous fluid which bathes the cilia, allowing free movement of cilia
	2. (slide 12) Elastic cartilage (VE: fig 3-5, p 43) (ear):  Similar to hyaline cartilage, but elastin is the predominant fiber, giving the tissue great elasticity. It is prominent in cartilage which give the external ear and the eustachian tubes their structures. The Verhoeff stain specifically stains elastin blue, making it visible in this slide as blue fibers surrounding lacunae. Here is a labeled view of elastic cartilage.	perichondrium elastin fibers in matrix (anastomosing) lacunae chondrocytes
with H & E stain: with aniline blue stain:	3. (slide 13) Fibrocartilage (VE: 3-4, p 43) (intervertebral disc): View this slide first at low power to see the loosely organized pulp in the center of the disc. Multiple organized layers of collagen give this cartilage strength and allow it to absorb shock. It ties bones together as in the pubic symphysis and intervertebral discs and serves as a shock absorber as in the menisci of the knee. Note in the cortex that the chondrocytes are characteristically lined up in rows embedded in a matrix composed mostly of collagen fibers (little ground substance). Collagen fibers stain pink with H&E, and dark blue with aniline blue Here is a labeled version of fibrocartilage. (Some slides are stained with hematoxylin and eosin , others with aniline blue .)	lacunae chondrocytes in train-like rows collagenous fibers, wavy and parallel  in arrangement

Other images related to these specimens:
 
 

	a cross section through an intervertebral disc.  The outer cortex consists of fibrocartilage, the inner pulp is gel-like making the disc a tough, resilient shock absorber between the vertebra.  When the cortex weakens, as when a great weight is lifted incorrectly, the pulp can cause the disc to bulge out, causing a so-called "slipped disc."
	The trachea, viewed in this exercise for its hyaline cartilage, contains interesting features:
	tracheal glands (acinar mucous glands) which produce mucus.  Note that the appearance is similar in consistency to goblet cells
	serous glands, embedded in the lamina propria.  .
	And, as we saw in the exercise on epithelial tissues, the superficial most tissue in the trachea is pseudostratified ciliated columnar epithelium