Anatomy chapter 6

Chondroblasts kon′drō-blast; chondros = grit or gristle, blastos = germ)

are the cells that produce the matrix of cartilage.

Interstitial Growth

1. Chondrocytes housed within lacunae are stimulated to undergo mitotic cell division. 2. Two cells occupy a single lacuna after cell division; they are now called chondroblasts 3. As chondroblasts begin to synthesize and secrete new cartilage matrix, they are pushed apart. These cells now reside in their own lacuna and are called chondrocytes. 4. The cartilage continues to grow in the internal region as chondrocytes continue to produce more matrix.

appositional growth

1. Undifferentiated stem cells at the internal edge of the perichondrium begin to divide. (Note: The perichondrium contains mesenchymal cells as well as these stem cells.) 2. New undifferentiated stem cells and committed cells that differentiate into chondroblasts are formed. These chondro-blasts are located at the periphery of the old cartilage, where they begin to produce and secrete new cartilage matrix 3. chondroblasts push apart as a result of matrix formation, and become chondrocytes, with each occupying its own lacuna. 4. The cartilage continues to grow at the periphery as chondrocytes continue to produce more matrix

Functions of bone Storage of Mineral and Energy Reserves

90% of body reserves of mineral calcium and phosphate stored and released by bone

Phosphate

ATP utilization

bone connective tissue

Also called osseous connective tissue

Functions of bone Movement

Attachment sites for skeletal muscles, bones are levers so when muscles contract bones are pulled

Red bone marrow

Blood cells produces in connective tissue

Support and protection Functions of bone

Bones give structural support and protection Ex rib cage protects heart and lungs

appositional (ap′ō-zish′ŭn-ăl) growth

Growth along the cartilage's outside edge, or periphery

interstitial (in′tĕr-stish′ăl) growth

Growth from within the cartilage itself is termed

Redbone marrow changes from child to adult

In children it in spongy bone and medullary cavity In adults red bone marrow degenerates and becomes yellow bone marrow Only in certain parts of axial skeleton flat bones of the skull, the vertebrae, the ribs, the sternum (breastbone), and the ossa coxae (hip bones). Adults also have red bone marrow in the proximal epiphyses of each humerus and femur

Calcium is important because

Its essential mineral for such body functions as muscle contraction, blood clotting, and nerve impulse transmission.

chondrocytes (kon′drō-sīt; cyte = cell)

Once they become encased within the matrix they have produced and secreted, the cells become this

Cartilage functions

Supports soft tissue *Providing a gliding surface at articulations (joints), where two bones meet. *rought draft for embryo to replace by bone tissue

Functions of bone Hemopoiesis

The process of bone cell production Blood cells are produced in red bone marrow. Red bone marrow contains stem cells that form all of the formed elements in the blood.

calcification

The process that the matrix of bone connective tissue is sturdy and rigid due to deposition of minerals in the matrix

articulations

Where two bones meet

Three types of cartilage

hyaline, elastic, and fibrocartilage

lacunae

occupy small spaces