Chapter 6: Bones and Skeletal Tissues Flashcards
Skeletal Cartilages
embryonic skeleton composed of membranes and cartilages (no bones), most of which will be ossified by age 25; all are avascular and surrounded by perichondrium
Perichondrium
dense irregular CT that contains blood vessels and all bones are surrounded by it
What are the types of skeletal cartilages?
hyaline, elastic, fibrocartilage
Hyaline Cartilage
most abundant type; fiber type: fine cartilage (invisible); includes articular cartilage, costal cartilages, respiratory cartilage, and nasal cartilages
Articular Cartilages
cover ends of most bones at moveable joints
Costal Cartilages
connect ribs to sternum
Respiratory Cartilages
association with respiratory tract
Nasal Cartilages
external nose
Elastic Cartilages
least amount of matrix between cells; fiber type: elastic; include external ear and epigolittis
Fibrocartilage
found where there is a lot of stress; a lot of fibers, fewer cells; include: knee meniscus, pubic symphysis, intervertebral discs
What are the two types of cartilage growth?
appositional growth and interstitial growth
Appositional Growth
widening from the outside; chondroblasts in perichondrium secrete new matrix on surface of existing cartilage
Interstitial Growth
chondrocytes within lacunae divide and secrete new matrix from within; widening from inside to outside
Cartilage Growth ends…
during adolescence; but some cartilages may calcify as we age
What are the functions of bones?
support, protection, skeletal muscle attachment sites, mineral storage (calcium and phosphate), hematopoiesis (red bone marrow), triglyceride (fat) storage (yellow bone marrow)
What are the bone classifications?
long bones, short bones, flat bones, irregular bones, sesamoid bones
Long Bones
longer than they are wide; all limb bones are long bones except patella, carpals, and tarsals
Short Bones
cube shaped/about as long as they as wide; carpals and tarsals
Sesamoid Bones
short bones embedded in a tendon; patella
Flat Bones
thin, flattened and usually curved; skull, ribs, sternum, scapulae, most cranial bones
Irregular Bones
complex shapes; vertebrae, hip bones, and most facial bones
Compact vs. Spongy Bone
compact: external layer, looks smooth and solid; Spongy: internal region, network of trabeculae
Structures of Long Bone
diaphysis, epiphysis, epiphyseal line, periosteum, endosteum, nutrient foramen
Diaphysis
shaft; encloses medullary cavity containing yellow marrow
Epiphysis
bone ends; capped with articulcar cartialge
Epiphyseal Line
epiphysis/disphysis junction
Periosteum
membrane attached to outerbone surface via perforating fibers; made of dense irregular CT; osteoblasts under
Endosteum
membrane covering inner bone surface, trabaculae, and canals of compact bone; osteoclasts under
Nutrient Foramen
hole in diaphysis thru which an artery, vein, and nerves enter
Structure of Short, Irregular, and Flat Bones
no diaphysis, epiphysis or medullary cavity; thin plates of spongy bone (diploe) covered with compact bone; have periosteum and endosteum
Red Bone Marrow vs. Yellow Bone Marrow
infants (<1 yr old): red bone marrow found in medullary cavity of disphysis and all spongy bone; Adults: red replaced by yellow marrow except in the spongy bone of skull, sternum, ribs, clavicle, scapula, hip bones, vertebrae, head of femur, and head of humerus (all of these still have red bone marrow)