BIO 135

Identification Guide to
Cartilage, Bone & Blood Tissues

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	Hyaline Cartilage Identification: Distinctive lacunae (arrow) distinguish cartilages from other connective tissues. Lacunae often are paired. Note lack of fibrous appearance, instead an overall glassy appearance. Color varies. Features to Know: chondrocyte in lacuna (arrow). Fibers Present: collagen fibers (the thin, evenly dispersed fibers do not appear as fibers, but contribute to an overall glassy appearance). Where Located: articulating ends of long bones, nose, trachea, ends of ribs. Functions: structural support; cushions joints.
	Elastic Cartilage Identification: Distinctive large, often paired lacunae (similar to hyaline cartilage), but note extensive dark elastic fibers (2). Features to Know: chondrocyte in lacuna (1), elastic fibers (2). Fibers Present: elastic fibers (collagen fibers are also present but not visible). Where Located: ear lobe, epiglottis (remember those Es!). Function: flexibility, bendability.
	Fibrocartilage Identification: Distinct, more or less parallel fibers visible. Distinguished from dense regular connective tissue by the distinct lacunae (arrow). Features to Know: chondrocytes in lacunae (arrow). Fibers Present: collagen. Where Located: intervertebral disks, pubic symphysis, menisci of knee joint. Function: resists compressive forces.
	(Compact) Bone Identification: Concentric rings (like tree rings) are unmistakable. Features to Know: lamellae (1), osteocytes in lacunae (2), canaliculi (3), Haversian canal (4). An entire set of concentric rings (lamellae) is called a Haversian System. Fibers Present: collagen fibers present but not visible. Where Located: bones . Functions: support, protection, act as levers, mineral storage.
	Blood Identification: The numerous round, red blood cells in a featureless matrix are unmistakable. Features to Know: the liquid matrix is called the plasma. The numerous round, red cells are erythrocytes (or red blood cells) that lack nuclei (the center of the cell is depressed and thus may appear lighter colored). There are also smaller numbers of larger white cells with large, multi-lobed nuclei called leucocytes (or white blood cells; 1). Fibers Present: none visible. Where Located: within the circulatory system. Functions: transport of nutrients, gasses, wastes, etc.

This page created and maintained by Udo M. Savalli. Maintained by Bill D. Snyder. Last updated July 18, 2012