Chapter 7 Bone tissue
What are the 2 types of bone marrow?
red bone marrow (myeloid tissue) yellow bone marrow
Name the 2 types of marrow.
red marrow and yellow marrow found in adults
Bone growth on width (Appositional Growth).
view slides 7-21 thru 7-23
Lacunae
Contain osteocytes. Small spaces between lamellae.
Nutrient Foreman
An opening in the shaft of the bone allowing an artery to pass into the one
#2 osteoblasts
(bone forming cells) - single layer of cells under endosteum and periosteum, are nonmitotic synthesize soft matrix which hardens by mineral deposition stress and fractures stimulate osteogenic cells to make osteoblasts
#3 osteocytes
(former osteoblasts that have become trapped in the matrix) lacunae - tiny cavities where osteocytes reside canaliculi - little channels that connect lacunae cytoplasmic processes reach into canaliculi
Where is red marrow found?
(myeloid tissue) in nearly every bone in a child hemopoietic tissue - produces blood cells and is composed of multiple tissues, in adults, found in skull, vertebrae, ribs, sternum, part of pelvic girdle, and proximal heads of humerus and femur
PHYSIOLOGY OF OSSEOUS TISSUE
--a mature bone remains a metabolically active organ involved in its own maintenance of growth and remodeling exerts a profound influence over the rest of the body by exchanging minerals with tissue fluid --Disturbance of calcium homeostasis in skeleton disrupts function of other organ systems
bone remodeling (Wolff's law of bone)
--dead portions of the original fragments of broken bone are gradually resorbed by osteoclasts -- osteoblast --bone remodeling occurs throughout life - 10% per year
Describe Spongy Bone.
-sponge-like appearance -spongy bone consists of: thin plates of bone called trabeculae and spaces filled with red bone marrow -few osteons and no central canals -provides strength with minimal weight, trabeculae develop along bone's lines of stress
Calcitriol Synthesis and Action (Vit. D)
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Control of calcium
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Correction for Hypercalcemia
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Correction for Hypocalcemia
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Healing of Fractures
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How do fetal / infant bones develop?
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Nutrient Foramen
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Phosphate Homeostasis
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central canal vertical canal
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compact spongy bone
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irregular bones sesamoid bone
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marrow cavity
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osteocytes
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What are the 5 zones interstitial growth? (Zone of metaphysis)
...slide 7-20 add the rest in Zone of reserve cartilage--Typical histology of resting hyaline cartilage
The 4 steps of intramembranous ossification. (see pic in the book.)
1) Condensation of mesenchyme cells permeated with blood capillaries - turn Into osteoblast cells. 2) Deposition of matrix by osteoblasts on mesenchymal surface; entrapment of first osteocytes; formation of periosteum occurs (mesencyme to osteoblast cells on surface of trabeculae). 3) bony trabeculae formed by continued mineral deposition; creation of spongy bone. 4) Surface bone filled in by bone deposition, converting spongy bone to compact bone. Persistence of spongy bone in the middle layer.
endochondral ossification. (see pic in book)
1) Early cartilage model 2) Periochonrium turns to periosteum (osteoblasts), bony collar, Hypertrophy of chondrocytes (POC) 3) Vascular invasion, formation of primary marrow cavity, death of chondrocyetes, Osteoclastys, appearance of SOC 4) Bone at birth, with enlarged primary marrow cavity and appearance of secondary marrow cavity in one epiphysis 5) Bone of child, with epiphyseal plate at distal end 6) Adult bone with a single marrow cavity and closed epiphyseal plate
1) support 2) protection 3) assistance in movement 4) electrolyte balance 5) acid base balance 6) blood cell production
1) Skeletal Structural Framework: supports soft tissues, provide attachment points for the tendons of most skeletal muscles 2) Skeletal function that protects most important internal organs from injury 3) Skeletal muscles attach to bones; upon muscle contraction they pull on bones to produce movement 4) 5) 6) Red bone marrow consist of developing blood cells, adipocytes, fibroblasts, and macrophages within a network of reticular fibers.
What are the 2 methods that the the human fetus/infant develop bone?
1. intramembranous ossification (produces flat bones of skull and clavicle) 2. endochondral ossification
What is the matrix made of?
1/3 organic and 2/3 inorganic matter
Other Factors Affecting Bone
20 or more hormones, vitamins, and growth factors affect osseous tissue bone growth especially rapid in puberty & adolescence surges of growth hormone, estrogen, and testosterone occur and promote ossification girls grow faster than boys males grow for a longer time and taller
What is inorganic matter made of?
85% hydroapatite (crystallized phosphate salt) 10% calcium carbonate other minerals (fluoride, sodium, potassium, magnesium)
What is the inorganic matter of the matrix made of?
85% hydroxyapatite (crystallized calcium phosphate salt) 10% calcium carbonate other minerals (fluoride, sodium, potassium, magnesium)
Medullary Cavity /Marrow Cavity ...right place
A hollow, cylindrical space within the diaphysis that contains fatty yellow bone marrow in adults
Epiphyseal Growth Plate
A layer of hyaline cartilage that allows the diaphysis of the bone to grow in length.
Interstitial Lamellae
Area between osteons. Fragments of older osteons that have been partially destroyed during bone rebuilding or growth
#4 osteoclasts
Arise from bone marrow stem cells and are unusually large cells
Concentric lamellae
Around the central canals are rings of calcified extracellular matrix much like the rings of a tree trunk
osteoblast
Bone cells that make the matrix
Endochrondral Ossification
Bone development first through a cartilaginous stage. Begins in a primary center in the shaft of the cartilage model with hypertrophy of chondrocytes (cartilage cells) and calcification of the cartilage matrix. The cartilage model is then vascularized, osteogenic cells form a bony collar around the mode, and osteoblasts lay down bony matrix around the calcareous spicules. The formation of most bones
Ossification
Bone formation develops by either ENDOCHRONDRAL ossification or INTRAMEMBRANOUS (dermal) ossification begins during the fourth week of prenatal development.
Osteoblasts
Bone-building cells, Synthesize and secrete collagen fibers and other organic components needed to build the extracellular matrix of bone tissue, initiates calcification, surrounds themselves within their own extracellular matrix, become osteocytes.
Osteoclasts
Bone-destroying cells that contain lysosomes and phagocytic vacuoles that demineralize bone tissue. Help regulate blood calcium level. Target cells for drug therapy to treat osteoporosis. Ruffled border.
Histology of osseous tissue
Connective tissue!!!!!!! cells, fibers and ground substance
Perforating Canal...
Canal that goes through the bone from the outside to the inside to the outside again
What are the two types of bone tissue?
Compact Bone Tissue and Spongy Bone tissue
Define Compact Bone.
Dense outer layer of Bone, found in diaphysis
Decribe spongy bone tissue.
Does not contain osteons or a central canal, Consists of lamellae trabeculae surrounding many red bone marrow-filled spaces.
Intramembranous (dermal) Ossification
Forming directly as a bone. (Facial bones, most cranial bones, and the clavicle)
Endostium
Is a thin membrane that lines the internal bone surface facing the medullary cavity. Contains a single layer of cells and a small amount of connective tissue
Yellow Bone Marrow
Is found in adults consists mainly of adipose cells, which store triglycerides.
What are the parts of the Osteon?
It consists of a central (haversian) canal, with arranged lamellae, lacunae, osteocytes, and canaliculi.
What are the 5 shapes of bone?
Long bones, short bones flat bone irregular bones and sesamoid bones
Long Bones
Longer than wider - a shaft plus ends. Ex: humerus
Osteocytes
Mature bone cells, the main cells in bone tissue and MAINTAIN its daily metabolism such as the exchange of nutrients and wastes with blood
Endochrondral Osssification
Ossification from primary centers occurs before birth; from secondary centers in the epiphyses, it occurs during the first 5 years.
Define Osteon.
Osteon is the functional unit of compact bone.
Resorption
Part of normal development, maintenance, and repair of bone
Triglyceride storage
Potential chemical energy reserve. With increasing age, much of the red bone marrow turn yellow
Circumferential Lamellae
Rings of hard calcified matrix found just beneath the periosteum and in the medullary cavity
Short Bones
Roughly cube-shaped. Ex: triquetral
Central or Haversian Canals
Run longitudinally through the bone
Where is spongy bone found?
Short, flat, and irregular bones with the interior appearance of a sponge . Also fonud in the of the epiphyses in long bones
Canaliculi
Small channels filled with extracellular fluid. Inside contains slender fingerlike processes of osteocytes. Connects lacunae with one another and with the central canals, provides routes for nutrients and oxygen to reach the osteocytes and for the removal of wastes
What is the second type of bone tissue?
Spongy bone.
Compact Bone
Strongest form of one tissue. Provide protection and support and resists the stresses produced by weight and movement. Found beneath the periosteum of all bones and make up the bulk of the diaphyses of long bones
Periosteum
Surrounds the external bone surface wherever it is not covered by articular cartilage. Protects the bone, assists in fracture repair, helps nourish bone tissue, and serves as an attachment point for ligaments and tendons
Osteons
The functional unit of compact bone. Consists of a central (haversian) canal, with arranged lamellae, lacunae, osteocytes, and canaliculi. they are aligned in the same direction along lines of stress which helps the long bone resist bending or fracture. Changes over time in response to the physical demands placed on the skeleton
Mesenchyme
The tissue from which almost all connective tissues are formed
Perforating (Sharpey's) Fibers
Thick bundles of collagen fibers that extend from the periosteum into the extracellular bone matrix. Provide attachment of the periosteum to the underlying bone.
articular cartilage
Thin layer of hyaline cartilage that covers the part of the epiphysis where the bone forms an articulation (joint) with another bone. Reduces friction and absorbs shock at freely movable joints
What are trabeculae?
Thin plates of bone that offer resistance along lines of stress, support and protect red bone marrow, and make bones lighter for easier movement.
Perforating or Volkmann's Canals
Transverse or diagonal canals that allow blood vessels, lymphatic vessels, and nerves from the periosteum to penetrate compact bones
Osteogenic Cells
Unspecialized stem cells derived from mesenchyme. Found along the inner portion of the periosteum, in the endosteum, and in the canals within the bone that contain blood vessels. The only bone cells that goes through cell division. Give rise to all bone cells
Epiphyseal Line
When the bone ceases to grow in length (ages 18-24), this is the replacement of the Epiphyseal Plate. Boney structure.
Osteoblasts
adds bone tissue to the external surface of the diaphysis
Endochondria Ossification stages
bone cells invade cartilage; center of cartilage calcifies; blood supply brings more bone cells; calification of epiphysis; after birth, bones grow using the epiphyseal plates
Define appositional growth.
bones increase in width throughout life -the deposition of new bone at the surface
Central Canal...
canal that contains blood vessels, it's in the center from top to bottom, feeding the bone
What the periosteum have int he outer portion made of?
collagen fibers
What is the organic matter made of?
collagen, carbohydrates-proteins complexes (ex. glycosaminoglycans, proteoglycans, and glyoproteins
Define skeletal system.
composed of bones, cartilages, ligaments, tendons strong flexible framework of the body cartilage - forerunner of most bones
Describe the anatomy of a flat bone.
diploe - spongy layer in the cranial flat bones absorbs shock marrow spaces lined with endosteum
Describe the anatomy of a long bone.
epiphyses and diaphysis compact and spongy bone marrow cavity articular cartilage Periosteum- (Inner: osteogenic stem cells) (Outer: collagen fibers ) Endostium Nutrient Foramen
Flat Bones
flat and thin, usually curved. Ex: sternum
Osteon... move right place
found in conpact bone
Appositional Growth
growth of a bone by adding bone tissue to its surface
The ending -clasts
in a bone cell means that the cell breaks down extracellular matrices
The ending -blasts
in the name of a bone cell or any other connective tissue cell means that the cell secretes extracellular matrix
The ending -cytes
in the name of a bone cell or any other tissue cell means that the cell maintains the tissue
periosteum
inner portion is made osteogenic stem cells outer portion is made of collagen fibers
Define interstitial growth.
interstitial growth - bones grow in length - cartilage!
What is the matrix made of?
matrix of osseous tissue (by dry weight), ~ one-third organic and ~ two-thirds inorganic matter
MINERAL DEPOSITON
mineral deposition (mineralization): calcium phosphate, and other ions are taken from the blood plasma and deposited in bone tissue osteoblasts produce collagen fibers that spiral the length of the osteon fibers become encrusted calcium and phosphate (hydroxyapatite) from blood plasma are deposited along the fibers - hardens matrix the calcium and phosphate ion concentration must reach a critical value called the solubility product for crystal formation to occur most other tissues have inhibitors IN BONE: osteoblasts neutralize these inhibitors and allow salts to precipitate in the bone matrix abnormal calcification (ectopic ossification)
List 4 parts on compact bone....
nutrient foramina - on bone surface perforating (Volkmann's) canals - transverse or diagonal canals central canals - vertical canals circumferential lamellae interstitial lamellae
What is the organic matter of the matrix made of?
organic matter - synthesized by osteoblasts collagen, carbohydrate-protein complexes (e.g., glycosaminoglycans, proteoglycans, and glycoproteins)
What are the 2 ways that bone develop?
ossification or osteogenesis - the formation of bone
Which cell makes the organic matter?
osteoblast
What are the four principal types of bone cells?
osteogenic (osteoprogenator) cells osteoblasts osteocytes osteoclasts
What the periosteum have int he inner portion made of?
osteogenic stem cells
Osteoporosis
osteoporosis - (most common bone disease) - severe loss of bone density bones loses mass and becomes brittle due to loss of organic matrix and minerals -- affects spongy bone the most since it is most metabolically active estrogen maintains density in both sexes inhibits resorption by osteoclasts
epiphysis diaphysis
proximal and distal ends of the bone shaft of the bone
zones of epiphyseal plates in a growing long bone
resting zone; growth zone; hypertrophic zone; calicification zone, ossification zone
#1 osteogenic (osteoprogenator) cells
stem cells found in endosteum, periosteum, and in central canals
Fractures and Their Repairs
stress fracture - break caused by abnormal trauma to a bone pathological fracture - break in a bone weakened by some other disease closed reduction - bone fragments are manipulated into normal positions open reduction - involves surgical exposure of the bone
What are the functions of skeletal system?
support, protection, assistance in movement, electrolyte balance, acid base balance, blood cell production,
Defineperiosteum
surrounds the external bone surface wherever it it is not covered by articular cartilage
MINERAL RESORPTION
the process of dissolving bone and releasing minerals into the blood Osteoclasts: hydrogen pumps in osteoclast membrane secretes H+ into space between osteoclast and bone surface chloride ions (Cl-) follow by electrical attraction hydrochloric acid (pH 4) dissolves bone minerals acid phosphatase enzyme digests the collagen
Define osteology.
the study of bone
Irregular Bones
various shapes, do not fit into other categories. Ex: vertebra
Where is yellow marrow found?
yellow marrow is found in adults
