Chapter 6 Flashcards
where is cartilage located?
external ear nose ends of most movable joints ribs to sternum larynx and epiglottis air tubes of the respiratory system intervertebral discs pubic symphysis articular discs
types of cartilage
hyaline, elastic, and fibrocartilage
appositional cartilage growth
chondroblasts in the perichondrium produce new cartilage by secreting matrix; cartilage grows from the outside (layers are added)
interstitial cartilage growth
chondrocytes inside the cartilage divide and secrete new matrix (growth from within)
(cartilage stops growing in the late teens when the skeleton stops growing)
bones contain several types of tissue
osseous tissue nervous tissue blood cartilage epithelia (lining blood vessels) other connective tissues
functions of bones
support movement (levers for muscle) protection mineral storage (calcium & phosphate) blood-cell formation energy storage
long bones
most bones of the limbs (humerus, femur, radius, ulna)
short bones
roughly cube shaped
mainly located in the wrists and ankles
flat bones
thin, flattened, and usually curved
includes most cranial bones, ribs, sternum, and scapula
irregular bones
various shapes that do not fit into other categories
include the vertebrae and pelvic bones
compact bone
external layer of bones
appears smooth and solid
spongy bones
a “honeycomb” of small needle-like pieces of bone called trabeculae
open spaces are filled with red or yellow
osteogenesis
process of bone-tissue formation
occurs during growth (embryo –> adult) or when bones are remodeled due to stress or injury
two types of bone growth
intramembranous ossification
endochondral ossification
intramembranous
begins with a mesenchymal membrane
forms membrane bones
results in most bones of the skull and the clavicles
endochondral ossification
development of endochondral bones from a template of hyaline cartilage
forms all of the bones from the base of the skull down (except the clavicles)
longitudinal bone growth
occurs from the time of bone development until adulthood
due to the presence of the epiphyseal growth plates
growth plates eventually become ossified and bone lengthening is complete
appositional bone growth
growth of a bone by the addition tissue to its surface
osteoblasts in the periosteum add bone tissues to the external face of the diaphysis
the bone get wider
(can occur due to stress on a bone, after it is fully grown)
bone remodeling
spongy bone is entirely replaced every 3 or 4 years, and compact bone is replaced every 10 years
includes: bone resorption and bone deposition
bone resorption
osteoclasts break down bone tissue releasing calcium and phosphate into the blood
bone deposition
osteoblasts deposit bone salts onto bone surfaces forming bone tissue on the outside of bones
osteoporosis
bone resorption outpaces bone deposition
bones become porous and light
results in increased bone fractures
osteomalacia
insufficient calcification of bones
caused by inadequate amounts of vitamin D or calcium in the diet
results in soft, weak bones
rickets
osteomalacia in children
effects are more severe because bones are still growing
Paget’s disease
characterized by excessive rates of bone resorption and deposition
Pagetic bones have an abnormally high ratio of immune woven bone to mature compact bone, and are soft and weak
bones thicken in irregular ways
osteosarcoma
a type of bone cancer
tumors develop that erode the medullary cavity internally and the compact bone externally
tumors can metastasize (usually to the lungs)
