Integumentary and Skeletal Systems Test Notes

Skeletal System The skeletal system consists of: Bones Cartilage Tendons Ligaments Bone maintains the shape of the body, protects internal organs, is a lever system for muscles to act upon, and is a site of mineral storage and blood-cell formation. Cartilage forms a fetal model of bone, covers the ends of bones, and provides a firm, flexible support. Tendons attach muscle to bone. Ligaments attach bone to bone. To help you remember: LLL, TTT (ligaments are like to like, tendons are two types)

Skeletal System (Tendons and Ligaments) extracellular matrix of tendons and ligaments is made up of primarily collagen fibers which makes them very tough like ropes or cables. ligament

Skeletal System (Cartilage) Three types of cartilage: Hyaline Elastic Fibrocartilage Hyaline cartilage is most intimately associated with bone function and development hyaline elastic fibrocartilage

Skeletal System (Bone) Bone Tissue Types: Cancellous (Spongy) Compact Cancellous Bone: Located mainly in the epiphyses of long bones & the interior of all other bones. Consists of a lacy network of bone with many small, marrow-filled spaces. Compact Bone: Mostly solid matrix and cells. Forms most of the diaphysis of long bones & the thinner surfaces of all other bones. cancellous compact

Skeletal System (Bone) Bone is composed of an organic matrix (mostly collagen) that provides flexible strength and an inorganic matrix (hydroxyapatite) that provides compressional strength (weight bearing). Hydroxyapatite are calcium phosphate crystals Bone is formed in thin sheets of extracellular matrix called lamellae Compact bone consists of cells called osteocytes located within spaces in the matrix called lacunae

Skeletal System (Bone) Ossification is the formation of bone by osteoblasts Intramembranous ossification occurs when osteoblasts begin to produce bone in connective tissue membranes (primarily in bones of the skull) Endochondral ossification is the process that produces most of the skeleton, occurs when bones develop from cartilage models, and occurs when osteoblasts invade the spaces left by dying cartilage cells

Skeletal System (Bone) Four types of bone, based on their shape: Long Short Flat Irregular

Skeletal System (Bone Shapes) Long bones are longer than they are wide (bones of upper & lower limbs). Short bones are approximately as broad as they are long (bones of ankle & wrist). Flat bones have a relatively thin flattened shape (some skull bones, ribs, & sternum). Irregular bones do not fit in the other shape categories (vertebrae & facial bones). Long bones Short bones Flat bones Irregular bones

BONE STRUCTURE - Long Bone Epiphysis Diaphysis Hyaline (Articular) Cartilage Periosteum

Skeletal System (Bone) a long bone has a diaphysis (shaft) and an epiphysis (each end) the epiphyseal plate (growth plate), is the site of growth in length of a long bone, and is found between each epiphysis and the diaphysis a long bone has a medullary cavity (filled with yellow marrow) in the diaphysis, has cancellous bone at the ends (filled with red marrow) has an endosteum lining the medullary cavity outer surface covered by a connective tissue layer- periosteum

Structure of a Long Bone Figure 6.3a-c

Medullary Cavity – hollow chamber filled with bone marrow Inside the Long Bone Medullary Cavity – hollow chamber filled with bone marrow Red Marrow (blood) Yellow Marrow (fat) Endosteum – lining of the medullary

Compact (wall of the diaphysis) Spongy (cancellous, epiphysis) Types of Bone Tissue Compact (wall of the diaphysis) Spongy (cancellous, epiphysis)

Review the Structure of a Long Bone Matching quiz at http://www.mhhe.com/biosci/ap/holehaap/student/olc2/chap07matching01.html

Microscopic Structure MATRIX - where the bone cells live   OSTEOCYTES  - mature bone cells, enclosed in tiny chambers called LACUNAE OSTEOCYTES form rings (LAMELLAE) around a HAVERSIAN CANAL which houses blood vessels Osteocytes are linked by CANALICULI Haversian Canals are linked by VOLKMAN's CANALS

Compact Bone

BONE DEVELOPMENT & GROWTH Intramembranous bones – flat, skull  Endochondral bones – all other   ALL BONES START AS HYALINE CARTILAGE, areas graduallly turn to bone           PRIMARY OSSIFICATION CENTER (shaft)          SECONDARY OSSIFICATION CENTER (ends)

Bone Development & Growth EPIPHYSEAL DISK  (growth plate) is a band of cartilage between the epiphysis and diaphysis   These areas increase bone length as the cells ossify Cartilage becomes OSTEOBLASTS become OSTEOCYTES

RESORPTION OSTEOCLASTS - dissolve bone tissue to release minerals,  process is called RESORPTION

Bone Growth

Bone Growth