Chapter 7 - Skeletal Tissue Flashcards
Long slender bones; bones of arms, legs, fingers & toes , palms & soles
Long bones
Thin, flat bones that typically protect organs underneath; skull , sternum, ribs, scapula
Flat bones
Tiny bones found between flat bones of the skull; formed during growth & development as sutures form between the skull bones
Sutural bones or Wormian bones
small cube-shaped bones found in wrists (carpals) & ankles (tarsals)
Short bones
Small, flat, and shaped something like a sesame seed; found inside tendons ; patella
sesamoid bones
bones that have complex shapes and dont fit the other categories ; skull bones around the face, pelvis, vertebrae
Irregular bones
network of collagen fibers with the calcium phosphate salt, hydroxyapatite, crystallized in bone
Bone
a crystallized calcium phosphate salt found in bone
Hyroxyapatite
organic extracellular matrix of bone; consists of collagen fibers proteoglycans (organic)
Osteoid
Lay down new bone on surface at periosteum or endosteum
Osteoblast
The process that involves osteoblasts
Osteogenesis
Osteoblasts make bone by secreting what ?
- Collagen
- Calcium
-Phosphate
Alkaline Phosphatase
Osteoblasts trapped in the bone become ??
Osteocytes
They maintain & monitor matrix from within lucunae
Osteocytes
They connect to each other via gap junctions through cytoplasmic extensions
Osteocytes
Break down bone on surface at periosteum or endosteum
Osteoclasts
The process that involves osteoclasts
Resorption or esteolysis
they are derived from cells that also give rise to monocytes and when activated they precursor cells fuse to form large, multinucleated cells
osteoclast
Has a ruffled border and releases H+ (acid) and hydrolytic enzymes to de-mineralize and break down the collagen matrix
Osteoclast
Activate & regulate osteoclasts
Osteoblast
mesenchymal cells that divide to and form osteoblasts ; found in periosteum
Stem cells or Osteoprogenitor cells
Mature bone with organized lamellae oriented parallel and perpendicular to compression
Lamellar bone
Immatire or repairing bone with disorganized lamellae lamellae (all of orientaion)
Woven bone
Main blood vessels entering and leaving the bone
Nutrient artery & vein
Supply blood to the inner surface of each growth plate
Metaphyseal vessels
Supply blood to the periosteum & superficial osteons
Periosteal Vessels
Where the hyline version of the model is formed, ossified by the deposition of calcum phosphate salt onto the collagen fibers of the cartilage
Endochondral ossification
Osteoblasts and osteoclasts remodel the ossified cartilage into true bone at primary and secondary ossification centers
Endochondral ossification
The original woven bone is gradually remolded into lamellar bone
Enchochonral ossification
A membrane model of the bone forms in the correct place
Intramembranous ossification
Mesenchymal cells cluster in the center of the membrane and form a primary ossification center that secretes bone , blood vessels grow
Intramembranous ossification
In infants, cartilage between the skull
Frontanels
rapid growth of baby’s skull during the first __ months of life
12-18
Layer of hyaline cartilage between the diaphysis and epiphyses at the ends of long bones
Growth plate or epiphyseal plate
grows in the middle , refers to growth at the growth plates for long bones. New cartilage is produced at this time and is pushed in the direction of the bone shaft
Interstitial growth
Growth at the edges . occurs at the periosteum to add thickness to the bone all along its length. Occurs through addition of cartilage at the epiphyses during puberty
Appositional growth
the visible lines in the bones that indicate where growth plates existed
Epiphyseal lines
Estrogen
Girls
Testosterone
Boys
active form of calcitrol , also known as cholecalciferol
Vitamin D
Necessary for absorption of calcium from intestines
Insufficient ___ causes rickets and osteomalacia
Vitamin D
Necessary for collagen synthesis by osteoblasts
Deficiency results in scurvy
Vitamin C
Requirements for Normal bone growth
Calcium, phosphate, protein, Vitamin D, A, C, K & B12
stimulates osteoblast activity particularly in children
Vitamin A
Required for normal protein syntheses
Vitamin K & B12
Hormones needed for regulation of blood calcium levels
PTH, Calcitriol, & Calcitonin
- From parathyroid gland
- causes blood calcium to rise
- Releases calcium from bone through increased osteoclast activity
Parathyroid hormone
- Causes kidney to retain calcium in blood from urine
- Causes formation of calcitrol by kidney
- Secreted when blood calcium levels drop
Parathyroid hormone
- Also known as active vitamin D
- Causes blood calcium to rise
- Required for intestinal absorption of calcium
Calcitriol
- inhibits parathyroid hormone secretion
- secreted when PTH reaches kidney
Calcitriol
essential for absorption of calcium from the intestines
Calcitriol
- Causes blood calcium levels to lower
- causes increased calcium deposition in bone through increased osteoblast activity
- Important in pregnancy
Calcitonin
usually only secreted after eating a meal with very high calcium content normally
High blood calcium causes this to be secreted
Calcitonin
regulates calcium levels and bone remodeling activity
Parathyroid hormone and calcitriol
- produced by pituitary gland
- stimulate production of somatomedins
- Works with somatomedins tostimulate growth of cartilage
growth hormone
- Produced by liver & bone
- stimulates growth of cartilage, particularly at growth plates of long bones
Somatomedins
- produced by the thyroid gland
- Required for normal growth hormone secretion
- Increases metabolic activity
Thyroid hormone
- Produced by the pancreas
- Required for normal muscle growth & maintenance; stress of muscles on bones is required to stimulate growth
Insulin
Also causes blood glucose to move into tissues providing energy for growth processes
Insulin
Produced by the gonads ( overies or testes)
Sex steroids
- Stimulates spurts of growth in long bones
- Stimulates the fusion of the epiphyseal growth plates which will stop the increase in height at the end of puberty
Sex steriods
No break in the skin
Closed or simple
Open or compound
Broken bone sticks through skin
Fracture does not go completely through bone
Incomplete
Fracture goes all the way through bone
Complete
bone is not aligned properly
displaced
bone is fractured but still in alignment
Nondisplaced
Breaks a long bone across (perpendicular) to the long axis of the shaft
Transverse
Shatters the bone into many fragments
Comminuted
a spiral break in the bone caused by a twisting motion
spiral
