Ch 6 Bones And Skeletal Tissue Flashcards
Water tends resilience
No blood vessels or nerves
Surrounded by perichondrium
3 types: hyaline, elastic, fibrocartilage
Skeletal cartilage
What are the types of skeletal cartilage
Hyaline, fibrocartilage, elastic
Acts like a girdle to resist outward expansion when the cartilage is compressed
Contains blood vessels from which nutrients diffuse through matrix
Perichondrium
Most abundant skeletal cartilage
Chindrocytes are spherical
Only fiver is fine collagen fibers
Provide support with flexibility and resilience
Includes: articulate, costal, respiratory, nasal
Hyaline cartilage
Resembles hyaline
More stretchy fibers and are better able to stand up to repeated bending
Found in external ear and epiglottis
Elastic cartilage
Most compressible cartilage
Resistant to stretch and pressure
Forms vertebral discs and knee joint cartilages
Roughly parallel rows of chondrocytes with thick collagen fibers
Fibrocartilage
Growth accomplished by the addition of new layers onto those previously formed
Growth from outside ring
Apposition also growth
Two ways that cartilage grows
Appositional and interstitial
Growth from inside
Chondrocytes divide and secrete new matrix which expands cartilage from within
Interstitial growth
Seven functions of bone?
Support, protection, anchorage, mineral and growth factor storage, blood cell formation, fat storage, hormone production
What is bone
Organ
Includes the bones of skull, vertebral column, and rib cage
Protect, support, or carry other body parts
Axial skeleton
Upper and lower limbs and shoulder bones and hip bones
Locomotion and manipulation
Appendicular skeleton
These bones are longer than they are wide
Shaft plus two ends which are often expanded
Long bones
Roughly cube shaped bones
Examples are wrist and ankle
Special type of this is sesamoid
Short bone
Special type of short bone that form in a tendon
Example patella
Sesamoid bone
Thin, flattened and usually abbot curves bones
Example sternum and scapulae and skull bones
Flat bones
Complicated shapes that fit no other bone classes
Example vertebrae and hip bones
Irregular bones
Dense outer layer of every bone
Looks smooth and solid to the naked eye
Compact bone
Internal to compact bone
Also called cancellous bone
Made up of trabecula
Spongy bone
Fibrous bands extending from the capsule into the interior organ
Strut of thin plate of bone in spongy bone
Honeycomb of needle/flat pieces
Trabecula
What is the structure of short, irregular, and flat bones
Thin plates of spongy bone covered by compact bone
Plates between periosteum and endosteum
No shaft or epiphyses
Bone marrow throughout, NO MARROW CAVITY
hyaline cartilage covers articulate surfaces
What is the structure of long bone
Diaphysis: tubular shaft: compact bone, medullary cavity, yellow marrow cavity
Epiphyses: end of bone: external is compact, internal is spongy, epiphyseal line or plate
Glistening, white double layered membrane
Covers external surface of entire bone except the joint surfaces
Outer fibrous layer
Inner osteogenic cells
Many nerve fibers and blood fibers through the nutrient foramen
Periosteum membrane
Delicate connective tissue membrane
Covers trabeculae spongy bone and canals that pass through compact bone
Membrane endosteum
Red marrow
Hematopoietic tissue
Typically found within the trabecular cavities of spongy bone of long bone and in flat bone
Red marrow
Trabecular cavities of spongy bone and dipole of flat bone
Red marrow cavities
What are the cells of bone tissue
Osteogenic cells, osteoblasts, osteocytes, osteoclasts
Mitotically active stem cells in periosteum and endosteum
Become osteoblasts or bone lining cells
In growing bones they are flattened or squamous cells
Osteogenic cells(osteoprigenitor)
Bone forming cells
Secrete unmineralized bone matrix(osteoid)
Actively mitotic
Osteoblasts
Shaped like a spider
Mature in lacunae
Monitor and maintain bone matrix
When they die the surrounding matrix is re absorbed
Osteocytes
Come from hematopoietic stem cells
Resorption bay
Bone breakers in matrix
Osteoclasts
Flat cells found on bone surfaces where bone remodeling is not going on
Bone lining cells
Structural unit is osteon or Haversian system
Canals are canaliculi
Lacunae-have osteocytes
Lamellar
Compact bone
AKA lamellar bone
Structural unit of compact bone
Osteon or haversian system
Each matrix tube
Interstitial and circumferential
Lamella
Runs through the core of each osteon
Contains small blood vessels and nerve fibers
Central canal or haversian canal
Canals
Lie at right angles to the long axis of the bone and connect the blood to nerve supply of the medullary cavity to the central
Not surrounded by lamella
Lines with endosteum
Perforating canals or volkmans canals
Incomplete lamella that lie between intact osteons
Full gaps between forming osteons
Representing the remnants of an osteon that has been cut through by bone remodeling
Interstitial lamella
Located under periosteum
Extends around the diaphysis
Resist twisting of long bone
Circumferential lamella
Bone looks poorly organized tissue
Trabeculae (beam)align along lines of stress to help resist it
Spongy bone
Includes cells and osteoid
Sacrificial bonds-resilience of bone
Organic components
65% of bone mass
Hydroxyapatites (mineral salts)
Calcium phosphate
Hardness
Inorganic components
Process of bone formation
Ossification or osteogenesis
Bone develops by replacing hyaline cartilage
Most bones
Endochondral bone
Bone develops from a fibrous membrane
Formed by mesenchymal cells
Most formed by this are flat bones
Intramembranous ossification
First step of endochondral ossification
Bone collar forms around diaphysis of the hyaline cartilage model
Second step of endochondral ossification
Cartilage in the center of the diaphysis calcified and then develops cavities
Third step of endochondral ossification
The periosteal bud invades internal cavities and spongy bone forms
Fourth step of endochondral ossification
The diaphysis elongates and a medullary cavity forms
Fifth step of endochondral ossification
The epiphyses ossify
First step of intramembranous ossification
Ossification centers appear in the fibrous connective tissue membrane
Second step of intramembranous ossification
Ostoid is secreted within the fibrous membrane and calcifies
Third step of intramembranous ossification
Woven bone and periosteum form
Fourth step of intramembranous ossification
Lamellar bone replaces woven bone just deep to the periosteum
Red marrow appears
Increase in length of bone
Interstitial growth
Increase in bone thickness
Occurs throughout life
Appositional growth
Where does growth in length of a long bone occur
Epiphyseal plate
First zone of long bone growth
Cartilage cells undergo mitosis
Proliferation zone
Second zone of long bone growth
Older cartilage cells enlarge
Hypertrophic zone
Third zone of long bone growth
Matrix calcifies
Cartilage starts to die
Calcification zone
Fourth zone of long bone growth
New bone forms
Ossification zone
Most important hormone in stimulation throughout childhood
Growth hormone
Hormone that makes sure bones grow in proportion
Thyroid hormone
Male and female hormones
Testosterone and estrogen
Males sex hormone
Like testosterone
Androgen
Hormone secreted by parathyroid glands
It is important in bone remodeling
Parathyroid hormone
Hormone that opposes parathyroid hormone
Helps regulate the bloods calcium and phosphate levels
Calcitionin
Every week we recycle ____ of our bone mass
5-7%
Process involving bone formation and destruction in response to hormonal and mechanical factors
Bone remodeling
The two processes of bone remodeling
Bone deposit and bone resorption
Abrupt transition between the osteoid Sean and older mineralized bones
Calcification front
Unminerlaized band of gauzy looking bone
Osteoid Seam
Osteoid seam and calcification front
Bone deposit
Function of osteoclasts
Bone resorption
Irregular shape Multiple nuclei Hydrochloric acid Lesechymal enzyme Brush vs soap
Osteoclasts
Negative feedback and hormonal loop
Control of remodeling
Bones grow in response to demands placed on it
Wolfs law
How many grams of calcium in body
1200-1400 grams
Functions of calcium
Muscle contraction, blood coagulation, cell division, nerve impulse transmission
First stage in healing of bone fracture
Hematoma forms
Second stage in healing of bone fracture
Fibrocartilaginous callus form
Third stage in healing of fractured bone
Bony callus forms
Fourth stage in healing of fractures bone
Bone remodeling occurs
Disorder when bones are poorly mineralized
Osteomalacia
Analogous disease of osteomalacia in kids
Rickets
Group of diseases in which bone reapportion outpaces bone deposit
Osteoporosis
