Bone tissue/other info Flashcards
What tissue
Compact bone
What structure
Osteon (Haversian system)
What structure
Central (Haversian) canal
What cell type
Osteocyte (in lacuna)
What structure
(containing cytoplasmic extensions of osteocytes) Canaliculi
What structure
(containing blood vessels and nerves)
Perforating (Volkmann’s) canal
What structure
(Containing blood vessels and nerves)
Central (Haversian) canal
What tissue
Spongy (cancellous) bone
Concentric rings of calcified material
Lamellae
What structure
Diaphysis
What structure
Epiphysis
Know both pictures
What Cavity
Medullary cavity
(filled with yellow bone marrow)
What tissue
Articular cartilage (composed of hyaline cartilage)
What tissue
Compact bone
What tissue
Spongy (cancellous) bone
(filled with red bone marrow)
What membrane lining bone surface
Periosteum
Know both pictures
Membrane lining cavity
Endosteum
Hematopoiesis
Red and white blood cell production
Produced in red bone marrow (found in spongy bone)
Calcium level
9 - 11 mg/100ml
Ca(ll) 911
Hypocalcemia
Low blood calcium levels
Hypercalcemia
High blood calcium levels
Organic components
(about 35%)
Extracellular protein fibers (mainly collagen)
Glycosaminoglycans (GAGs) and proteoglycans (protein core with GAGs attached)
Without organic components bone will shatter
Inorganic components
(about 65%)
Hydroxyapatite – crystalline pattern formed by calcium and phosphate salts (obtained from diet)
Without inorganic components bone could not hold our weight
Osteogenics
Stem cells found in periosteum and Endosteum
Able to change into osteoblasts
Osteocytes
Mature bone cells
- Secrete chemicals that maintain the bone extracellular matrix
- Most abundant cells in the bone
- Spider-shaped
- Reside in lacunae
Osteoblasts
Bone cells that produce new bone through ossification (osteogenesis)
Become osteocytes when surrounded/trapped by bone matrix
Osteoclasts
Large cells on internal and external bone surface
Secretes acid and enzymes to break down and dissolve the bone matrix
- Found in shallow depressions on bones
Primary bone
AKA woven bone
Forms first in the womb and during repair after fractures
Composed of irregularly arranged collagen fibers, maybe osteocytes, not much inorganic matrix making the bones less rigid
Primary bone gets broken down by osteoclasts over time and replaced by secondary bone
Secondary bone
AKA Lamellar bone
This is your permanent bone
Contains Lamellae and regularly arranged parallel collagen fibers, making this bone much stronger than primary bone
2 types of secondary bone:
- Compact
- Spongy
What bone category
Long bone - bone is longer than it is wide
(Humerus)
What bone category
Short bone - bone is about as long as it is wide
(Trapezium / carpal bone)
What bone category
Irregular bone - bone’s shape does not fit into other classes
What bone category
Flat bone – bone is broad, flat, and thin
What bone category
Sesamoid bone – round, flat bone found within tendons
Periosteum
Found on the outside of bones
- Protects the bone
- Blood vessels and nerves found in it before going into the bone
- Provides attachment sites for tendons and ligaments
Homogenous
Of the same or a similar kind or nature
“Compact bone appears homogenous”
Diaphysis
The central shaft (region) of long bones
- Surrounds the medullary (marrow) cavity
- Medularry cavity normally filled with yellow bone marrow
Epiphyses
The expanded portions at end of long bones
- Articulate (to make a connection) with a bone at a joint
- articular cartilage on the outside of the ends of the bone
Articular cartilage
Hyaline cartilage that helps reduce friction at joints
Endosteum
Membrane that lines the inner surface of the bone and the outer portion of the medullary cavity
- bone cells help maintain proper bone structure in growth and remodeling
Intramembranous ossification
The cranium and clavicles form this way
“Membrane bones” - having developed in a fibrous membrane made up of mesenchyme
Intramembranous ossification
Step 1
Connective tissue stem cells group together at the primary ossification center and change into osteogenic cells which start to form osteoblasts
Intramembranous ossification
Step 2
Osteoblasts make the bone matrix and become osteocytes once trapped
Intramembranous ossification
Step 3
Primary spongy bone forms
Periosteum forms
Intramembranous ossification
Step 4
Eary compact bone forms
Endochondral ossification
Hyaline cartilage if replaced by bone offering in primary ossification centers
These are cartilage bones which is how most bones are formed
Endochondral ossification step 1
Blood vessels grow and surround the hyaline cartilage
Chondroblasts from the Perichondrium starts to change and form osteogenic cells which then creates the bone matrix
Perichondrium turns to the periosteum
Endochondral ossification step 2
Osteoblasts begin to make bone matrix and surround the cartilage bone forming a ring
Chondrocytes start to calcify as more bone matrix forms due blood supply being cut off
Endochondral ossification step 3
Osteoclasts dig holes so that blood vessels can get through the bone collar
The blood brings nutrients and osteoblasts so that more bone can form inside the collar
Medullary cavity starts to form
Endochondral ossification step 4
Osteoclasts break down most of the newly formed spongy bone to enlarge the medullary cavity
Most of the ossification is complete besides growth plates (epiphyseal plate)
Epiphyseal plate
Hyaline cartilage between the epiphyses and diaphysis allows for growth long ways by chondrocytes dividing
diploe
Inner layer of spongy bone in flat bones
Resting zone
Aka Reserve cartilage
Part of the growth plate
Chondrocytes not diviting
Proliferation zone
Chondrocytes dividing and new cells pushed towards diaphysis
Due to resistance of the solid diaphysis the epiphysis is pushed in the other direction
Hypertrophic zone
The older chondrocytes enlarge
Calcification zone
The chondrocytes die which causes them to calcify
Blood vessels invade the cavities
Ossification zone
The calcified cartilage is replaced by bone tissue
Appositional growth
Growth in diameter of bones
Occurs as bones grow in length
Vitamin A
Stimulates osteoclast activity
Vitamin C
Is needed in order to make collagen
Vitamin D
Assists with increasing absorption of calcium in digestive tract to raise the calcium levels in the body
Vitamin K
Increases bone desposition by stimulating activity of osteoblasts
Human growth hormone
AKA - HGH
Produced by pituitary gland; increases general tissue growth which bone is very sensitive to
Thyroid hormone
AKA - Thyroxine
Determines metabolic rate (of all reactions in the body)
Sex hormones
AKA - Estrogen, Testosterone
Increases longitudinal growth and plate closure
Testosterone increases appositional growth
