skeletal system-Bone Flashcards
components of the skeletal system
Bone
Cartilage(Hyaline, Fibrocartilage, Elastic)
Tendons and ligaments
functions of the skeletal system
support(bone=hard and rigid, cartilage=flexible and strong)
protection(e.g. skull around brain)
movement(tendons=bone to muscle)
storage(Ca+ and P stored in bones. adipose in marrow)
blood cell production(haemopoietic tissue/red bone marrow in marrow)
what are the 4 categories of bone?
long(femur)
short(tarsals)
flat(scapula)
irregular(pelvis)
what is the structure of a long bone?
Diaphysis(shaft) Epiphysis(end) Epiphyseal plate(growth plate) epiphyseal line(bone stops growing in length) Medullary cavity(inner cavity)
What is the Diaphysis?
. the shaft of the bone
. exterior is compact bone
What is the Epiphysis?
. the end of the bone
. contains spongy bone
What is the Epiphyseal plate?
Hyaline cartilage; present until growth stops(only juveniles)
What is the Epiphyseal line?
bone stops growing in length(narrowed Epiphyseal plate)
What is the Medullary cavity?
In children medullary cavity is red marrow,
gradually changes to yellow in limb bones and skull
what is the inner structure of a long bone?
Periosteum
Sharpey’s fibers
Endosteum
what is the Periosteum?
Outer is fibrous
Double-layered connective tissue membrane covering the outer surface of bone except where articular cartilage is present.
what is are Sharpey’s fibers?
some periosteal fibers penetrate
through the periosteum and
into the bone. Strengthen
attachment of tendon to bone
what is the Endosteum
Similar to periosteum, but more cellular. Lines all internal spaces including spaces in spongy bone
what is Articular cartilage?
thin layer of hyaline cartilage covering a bone where it forms a joint with another bone.
structure of Flat bone?
No diaphysis, epiphysis
sandwich of spongy between compact bone
structure of short and irregular bone?
. compact bone that surrounds spongy bone
similar structure of epiphysis of long bones
. no diaphysis and not elongated
what do some flat and irregular bones have?
Some flat and irregular bones of skull have sinuses
lined by mucous membranes
where does bone growth in length occur?
Growth in length occurs at the epiphyseal plate
What does bone growth in length involve?
Involves the formation of new cartilage by
◦ Interstitial cartilage growth
◦ Appositional growth on the surface of the cartilage
closure of epiphyseal plate
epiphyseal plate is ossified becoming the epiphyseal line. Between 12 and 25 years of age
what is the process of bone growth in length?
- new cartilage is produced on the epiphyseal side of the plate as the chondrocytes divide and form stacks of cells.
- chondrocytes mature and enlarge
- Matrix is calcified and chondrocytes die
- the cartilage on the diaphyseal side of the plate is replaced by bone
Growth at articular cartilage
Increases size of bones with no epiphyses(short bones)
Growth in bone width stage 1
- Osteoblasts beneath the periosteum lay down bone to form ridges separated by grooves. Blood vessels of the periosteum lie in the grooves.
Growth in bone width stage 2
The groove is transformed into a tunnel when the
bone built on adjacent ridges meets. The periosteum of the
groove becomes the endosteum of the tunnel.
Growth in bone width stage 3
Appositional growth by osteoblasts
from the endosteum results in the
formation of a new concentric
lamella.
Growth in bone width stage 4
The production of additional concentric lamellae fills in the tunnel and completes the formation of the osteon.
factors affecting bone growth?
Size and shape of a bone determined genetically but can be modified and influenced by nutrition and hormones
factors affecting bone growth-Hormone
◦ Growth hormone from anterior pituitary. Stimulates
interstitial cartilage growth and appositional bone
growth
◦ Thyroid hormone required for growth of all tissues
◦ Sex hormones such as oestrogen and testosterone
- Cause growth at puberty, but also cause closure of the
epiphyseal plates and the cessation of growth
Mechanical stress and bone strength
Stress causes bone remodelling to:
◦ Increase bone mass (density)
◦ Align trabeculae with stress
What causes changes in bone strength?
Changes caused by:
◦ Osteoblast activity
- Increases with stress
Bone repair stage 1
Hematoma formation:
Blood released from damaged blood vessels forms a hematoma
Bone repair stage 2
Callus formation:
the internal callus forms between the ends of the bones, and the external callus forms a collar around the break
Bone repair stage 3
Callus ossification:
woven, spongy bone replaces the internal and external calluses.
Bone repair stage 4
Bone remodelling:
compact bone replaces woven bone, and part of the internal callus is removed, restoring the medullary cavity.
Effects of aging on bone matrix-skeletal system?
Bone matrix decreases. More brittle due to lack
of collagen.
Effects of aging on bone mass-skeletal system?
. Bone mass decreases . Highest around 30 . Men denser due to testosterone and greater weight . Rate of bone loss increases 10 fold after menopause. . spongy bone lost first, then compact
Effects of aging on bone-skeletal system?
. Increased bone fractures
. Bone loss causes deformity, loss of height, pain,
stiffness
