Starting with A for "ACE inhibitor" and continuing through to Y for "Yolk Sac Tumour", we give you succinct explanations for scientific and medical terms in clear and simple words.
- Bone tissueApart from the teeth, the hardest structural component of the body (resistance to tension 10 kg/mm2, resistance to pressure 15 kg/mm2). Bone formation occurs as the result of so-called ossification.
The skeleton is the scaffolding for the body and consists of long, short and flat bones. The joints function as levers for the connected muscles. Bones, ligaments and skeletal musculature together form the so-called locomotor apparatus. In addition, the bones provide mechanical protection for the brain, spinal chord, sensory organs and bone marrow.
1. On the outside of the bone lies the periosteum ("bone skin"); 2. The bone substance consists of a solid outer zone (Substantia corticalis, Substantia compacta or Os compactum) and a spongy internal scaffolding of fine bars of bone, known as trabeculae. This spongy layer is known as the Substantia spongiosa or Os spongiosum; 3. The bone marrow (Medulla ossium) lies in the marrow cavity between the trabeculae. At birth, only bone marrow which forms red blood is present. In the course of life, this is gradually replaced by yellow fatty marrow and is only kept in a few bones, such as the ribs, breastbone, vertebral bodies, wrist and elbow bones, the flat bones in the skull and the ileal crest.
The intracellular substance lies between the bone cells (osteocytes) and consists of collagen fibres and calcified ground substance. The intracellular substance is either arranged in lamellae (plates) (lamellar bone tissue) or is disordered (woven bone).
Glossary entries: Roche and Walter de Gruyter, Berlin