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.
Describe endochondral ossification.
Takes places within a cartilage template. Bone forms from mesenchyme producing a hyaline cartilage model first which is replaced by bone tissue. Long bones.
How is ossification different for flat and long bones?
Flat; intramembranous.
Long; endochondral.
Describe the factors that affect bone growth.
- nutrition.
- hormones.
- mechanical stress -> causes bone remodelling by an increase in bone mass (density) aligning of trabeculae with stress -> changes are cause by osteoblast activity which increases with stress on bone.
What are the components of the axial skeleton?
- 80 bones.
- bones of the head and trunk; ossicles (inner ear), skull, hyoid bone, rib cage and the vertebral column.
What are the components of appendicular skeleton?
- 126 bones.
- consists of the bones and cartilages that support the appendages.
Trochanter.
Large projection.
Tuberosity.
Rounded projection.
Fossa.
Shallow depression.
Foramen.
Opening.
Crest.
Prominent ridge.
Process.
Projection.
Meatus.
Passageway.
Head.
Rounded projection.
Neck.
Constricted portion.
Condyle.
Large rounded protuberance.
Fissure.
Narrow slit.
General features on a typical vertebrae.
Lamina, spinous process, transverse process, pedicle, body and vertebral foramen.
How do the features differentiate across the various regions of the vertebral column.
Increases in size down the spine to accomodate for weight.
Identify the features found on a typical rib.
Head, neck, body and tubercle.
How do the ribs attach onto the vertebrae.
Articulate posteriorly with the vertebrae- each rib head articulates with the thoracic vertebrae.
How do ribs attach to the sternum.
Ribs articulate anteriorly with the sternum.
What is the difference between the pelvic girdle and the bony pelvis?
- bony pelvis: includes the complete ring around the hip bones including the hip bones, pubic symphysis and sacrum.
- pelvic girdle consists of only the two hip bones.
Explain how joints are classified based on structural and functional differences.
- structural: based on the major connective tissue type that binds bones (fibrous, cartilaginous, synovial).
- functional: based on degree of motion (non-moveable, slightly moveable, freely moveable).
Describe the characteristics of fibrous joints.
- united by fibrous connective tissue.
- have no joint cavity.
- move a little or not at all.
What are the sub classifications of fibrous joints.
- gomphoses e.g. Hold teeth into place.
- sutures e.g. Coronal suture.
- syndesmoses e.g. Radioulnar.
Describe the characteristics of cartilaginous joints.
- unite two bones by means of cartilage.
- little or no movement.
- may be permanent or replaced by other types of joints.
What are the sub classifications of cartilaginous joints.
- hyaline cartilaginous joints e.g. Epiphyseal plates.
- fibrocartilaginous joints e.g. Symphysis pubis.
Describe the characteristics and features of synovial joints.
- contains synovial fluid.
- allows considerable movement.
- complex joints.
- most are joints that unite bones of appendicular skeleton.
- reflect greater mobility of appendicular skeleton compared to axial.
What are the terms of movements that occur at synovial joints?
- gliding.
- angular.
- circular.
- combination of types.
What are the types of angular movements.
- flexion and extension.
- plantarflexion and dorsiflexion.
- abduction and adduction.
What are the types of circular movement?
- rotation.
- pronation and supination.
- circumduction.
List the pairs of special movements.
- Elevation vs. depression.
- Protraction vs. retraction.
- Inversion vs. eversion.
- Opposition vs. reposition.
