How Is The Body Supported? Flashcards
What are the major functions of the skeletal system.
- Support.
- Protection.
- Assistance with movement.
- Mineral homeostasis.
- Blood cell production.
- Triglyceride storage.
Describe cartilage.
- made of matrix.
- avascular.
- no nerves.
Describe the make up of bone.
- 35% organic.
- 65% inorganic.
List the main types of cartilage.
- hyaline.
- fibrocartilage.
- elastic.
Explain the structure of hyaline cartilage.
- collagen fibres are small and evenly dispersed in the matrix therefore matrix appears transparent and is firm but flexible. Chondrocytes are found in lacunae.
- allows the growth of long bones.
- contain chondroblasts that produce the matrix.
Describe the structure of fibrocartilage.
-more collagen bundles than hyaline and are arranged in thick bundles.
Describe the structure of elastic cartilage.
Matrix collagen similar to hyaline but also contains elastic fibres.
What are the organic components of bone and how does it relate to its properties?
Collagen fibres and proteoglycans -> stops bone from being too brittle.
What are the inorganic components of bone and how do they relate to its properties?
Hydroxyapatite -> stops bone from being too bendable.
State the function of osteoblasts.
Bone forming cells; produce the chemicals and structures that make up the matrix (lay down the matrix).
State the function of osteocytes.
Maintain the matrix.
State the function of osteoclasts.
Bone destroying cells; breaks down the matrix.
What is the role of collagen in bone tissue?
Bone strength -> stops it from being brittle.
Describe spongy bone structure.
Appears porous and contains columns of bone called trabeculae. It usually surrounded by a sleeve of compact bone.
State the function of spongy bone and its location.
- provides strength and support without the greater weight of compact bone.
- in the interior of the bones of the skull, vertebrae, sternum and pelvis; in the ends of the long bones.
Describe the structure of compact bone.
- very organised.
- has a hard bong matrix with many osteocytes.
- basic unit: osteon/harvesian system.
State the function of compact bone and its location.
- great strength and support; prevents breaks and punctures.
- located in the outer portions of all bones and the shafts of long bone.
Classify bones according to their shape, give examples.
- long: upper and lower limbs e.g. femur, tibia.
- short: carpals and tarsals.
- flat: ribs, sternum, skull, scapulae.
- irregular: vertebrae, facial.
List the components of the general structure of long bone.
- diaphysis.
- epiphysis.
- epiphyseal plate.
- epiphyseal line.
- medullary cavity.
How does an epiphyseal plate become a line?
Cartilage is replaced by bone and the bone stops growing in length (adult).
Describe in detail the arrangement of bone tissue in compact bone.
Layers of bone (lamellae) form around the central canal form the osteon. Osteocytes sit in the spaces between the lamellae (called lacunae). Periosteum is a dense, irregular CT sheath surrounding the bone. Endosteum is the thin membrane lining the medullary cavity.
What is the embryonic precursor tissue and cell of bone?
Mesoderm and mesenchymal tissue.
How does bone ossify?
- intramembranous.
- endochondral.
Describe intramembranous ossification.
Bone forms directly from mesenchyme. Takes place within connective tissue membranes. Flat bones.
