Bone tissue connect hw & slides
what is the percentage of ca stored in the skeleton
99%
homeostatic calcium imbalance. Which would not be life threatening?
A deficit of appositional bone growth (extra layers)
Which hormone inhibits osteoclasts and stimulates osteoblasts to lower blood calcium levels?
Calcitonin
What is the calcium-phosphate salt deposited within bone called?
Hydroxyapatite
Parathyroid hormone
Released by Parathyroid; opposite of Calcitonin. INCREASES blood calcium levels by breaking down bones.
Calcitonin:
Released by the Thyroid. It TONES down the blood calcium level
bone lacuna a small cavity within the bone matrix, containing an osteocyte
a cavity or depression, in bone
Calcitriol
a form of Vitamin D. produced by the sequential action of the skin, liver, and kidneys. most active form of Vitamin D, acts as a hormone.
bone is
a polymer= composite, ceramic= hydroxyapatite
Vitamin D (Calcitriol)
a steroid hormone, important role in regulating body levels of calcium and phosphorus, and in mineralization of bone. RAISES ca in blood.
what would directly affect osseous tissue?
a vitamin C deficiency
The skeletal system helps maintain acid-base balance by
absorbing or releasing alkaline phosphate and carbonate salts
the PTH stimulate these three responses :
bone (osteoclasts release stored calcium ions from bone), intestinal response ( rate of intestinal absorption increase, calcium is absorbed), Kidney (kidneys retain calcium ions, ca conserved, decreased ca loss in urine)
intramembrous ossification
bone development of flat bones of the skull and clavicle. such bones develop within fibrous sheet = dermal bones
osteoclast
bone dissolving cells ( found on the surface)
osteoblast
bone forming cell, *only way new ones can be formed is by mitosis and differentiation of osteogenic cells. (non mitotic, line up in a single layer on the bone surface under the endosteum and periosteum)
endochondrial ossification
bone is preceded by a hyaline cartilage, becomes replaced by osseous tissue. most bones of body develop this way.
calcitonin causes:
bone response (osteoclasts inhibited while osteoblasts continue to lock ca ions in bone matrix, ca is stored), intestinal response (rate of absorption decreases, ca is absorbed slowly), Kidney (allow ca loss, ca is excreted, increased ca loss in urine)
osteogenesis imperfecta
brittle bone disease, end result is osteoporosis with increased susceptibility to fractures.
Which mineral is most important throughout life to assist in maintaining strong bones?
calcium
Osseous tissue matrix is composed of
calcium phosphate
Mineralization is a process that extracts __________ and __________ from the blood plasma and deposits it into bone.
calcium; phosphate
To help regulate body calcium levels, bone has two reserves. The disadvantage of the stable reserve is that it __________.
cannot easily be exchanged or released into the tissue fluid
dense white osseous tissue
compact bone (cortical bone)
Haversion system aka osteon aka haversion canal
contains blood vessels and nerves
medullary canal
contains bone marrow in center of long bones
Compact bone
dense
epiphysis
expanded head at each end of bone, enlarged to provide surface area for tendons/ligaments
endosteum
fibrous membrane forming the inner bone surface
protein gives the bone what?
flexibility, without it would be brittle
osteogenesis/ossification
formation of bone
osteocyte
former osteoblasts that have become trapped in the matrix they deposited ( reside in the lacunae)
red bone marrow
found in spongey bone and is the site of red blood cell production
site of endosteum
inner most tissue layer of shaft
marrow cavity
interior portion of the bone shaft
Each osteon consists of concentric layers, called...... that surround the haversian canal
lamellae
circumferential lamellae
layers of con lamellae wrapped around the long bone; binds osteons together
articular cartilage
lining of ends of long bones, where bone meets another bone.
osteoporosis
most common bone disease, severe loss of bone density, affects especially spongey bone. bones become brittle.
stem cell
n unspecialized cell that gives rise to differentiated cells
if a bone is heavily used ______ will deposit new osseous tissue to thicken the bone
osteoblasts
Same linage
osteoblasts, osteocytes, osteogenic cells
independent origin
osteoclasts
Which bone cell is multinucleated?
osteoclasts, * each contribute to one stem cell
The __________ contains hydrogen pumps that lead to the formation of hydrochloric acid, which is used to dissolve bone minerals in a process called __________.
osteoclasts; mineral resorption
rickets
osteomalacia in on growing bone results from vitamin D deficiency. -curvature of bones . *when bones are deficient in calcium salts they become soft and easily bended
haversian system
osteon
basic structural unit of compact bone
osteons (haversian system)
periosteum
outer lining of bone tissue, outer membrane lining. external sheath (has 2 layers)
Thyroid gland response
parafollicular cells (C cells) in the thyroid gland secrete calcitonin
hormone released when ca ion levels in plasma are low AND the gland which secretes that hormone
parathyroid hormone (PTH), and parathyroid glad (back of thyroid)
hypocalciemia
parathyroid; is an electrolyte imbalance and is indicated by a low level of calcium in the blood
lysosomes in osteoclasts
perform autophagy (degration system)
medullary cavity
shell enclosed space aka marrow cavity, contains bone marrow
1/4 spongey, 3/4 compact and receives 1/2 liter of blood per min
skeleton
spongey bone
small bony plates filled with marrow
osteogenic cell
stem cells that develop from embryonic mesenchymal (found in endosteum, the inner layer of periosteum and in central canals)
yellow bone marrow
storage area for lipids in the bone
Wolffs law (wksht)
tension and compression cycles create a small electrical potential that stimulates bone deposition and increased density at points of stress
Diaphysis
the shaft, used for leverage
hypercalcemia
thyroid gland; will secrete calcitonin and bring down ca
trusses and arches, which help form an internal scaffolding network, are found in
trabecular bone
perforating volkmann cells
transfer or diagonal passages, they join with central canals
secretory vesicles
transport large particles out of cell
T? F? .. vitamin d is sufficient for absorption of calcium
true
central canal
vascular and nerve encircling cavity at the center of the osteon (only in compact bone)
nutrient foramen
vessels that supply to and drain blood from the bone enter and exit here
the matrix
1/3 organic matter; synthesized by osteoblasts includes collagen and protein. 2/3 inorganic matter; 85% hydroxyapatite= crystalized calcium phosphate salt.
bone remodeling replaces about how much the skeletal tissue per year?
10 %
collagen
an insoluble fibrous protein of vertebrates that is the chief constituent of the fibrils of connective tissue
Wolffs law of bone
architecture of a bone is determined by the mechanical stresses placed upon it and the bone thereby adapts to withstand those stresses
epiphyseal line
area in the epiphysis, used for growth (line in the epiphysis)
bones in the legs arms spine and pelvis grow
at different rates
Osteogenesis imperfecta is due to the deficiency of __________ in the matrix, which makes the bones extremely brittle.
collagen