Transcript 1. Intro to Bones - WEB

Introduction to the Skeletal
System – Bone Tissue
(Chapter 6)
In addition to
bones, the
skeletal system
includes
cartilage,
tendons
(connect bones
to muscles), &
ligaments
(connect bones
to bones)
Functions of the Skeletal System
• SUPPORT
• PROTECTION
• MOVEMENT
• STORAGE OF MINERALS
• BLOOD CELL FORMATION
Classification of Bones
Features of a Long Bone
• Epiphysis (head) - end of the
bone
• Diaphysis (shaft) - surrounds
the marrow cavity
• Epiphyseal plate - layer of
cartilage allowing bone to grow
in length; when bone stops
growing, cartilage is replaced
by bone - epiphyseal line
• Articular Cartilage - reduces
friction, absorbs shock, and
allows for smooth movement
Bone Histology
• Connective tissue
• Dense matrix – primarily made of collagen and
hydroxyapatite - Ca10(PO4)6(OH)2
• Matrix contains bone cells:
Osteogenic cells – undergo cell division and
become osteoblasts
Osteoblasts – form new bone
Osteocytes – mature osteoblasts; maintain
bone
Osteoclasts – break bone down
Osteoblasts, Osteocytes, Osteoclasts
Types of Bone Tissue
• Spongy
– Irregular lattice of thin columns
= trabeculae
– Trabeculae reduce weight,
protect red bone marrow
– Trabeculae are oriented along
lines of stress
• Compact
– very dense & strong
– most of the bone mass in the
body
More about the Compact Bone
Osteon: basic
functioning unit of
compact bone
Central canal:
contains blood
vessels & nerve
Lacunae: spaces
that house
osteocytes
Osteon (Haversian System)