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