the skeletal system is made of?
A. skeletal bones B. cartilage
C. Ligaments D. Connective Tissue
Functions of the skeletal system
1. Support 2. Storage of mineral 3. Blood cell production 4. leverage 5. protection
Periosteum
A. is B. function (4)
A.outer bone lining
B. i. isolates and protects the bone from surrounding tissue
ii. provides a route and a place for attachment for circulatory and nervous supply
iii. actively participates in bone growth and repair
iv. attaches bone to CT network of the deep fascia
Endosteum
A. is? B. lines...
C. consists of D. actively involved in
A. inner bone lining
B. medullary cavity
C. osteoprogenitor cells
D. repair and growth
Matrix of Bone
calcium phosphate
hydroxyapatite crystals
calcuium phosphates turn into this to resist compression
Histological organization of mature bone
1. Collagen Fibers
2. Bone Cells (ONLY 2% OF BONE MASS)
The Histological organization of Mature Bone:
1. Collagen fibers
A. make up
B. contribute to
C. ___ and ___ make bone tissue extremely strong
A. 2/3 of bone matrix
B. the tensile strength of bone
c. Collagen; hydroxyapatite
Structure of bone
1. osteocytes
A. are?
B. maintain
A. mature bone cells
B. the protein and mineral content of the matrix
Structure of bone
2. Osteoblasts
A. are? B. found on? C. Produce?
D. ___ are involved in making new bone. this process is called___?
E. ___ can convert to ____.
A. immature bone cells
B. the inne rand outer surfaces of bones
C. osteiod, which is involved in making the matrix
D. osteoblasts; osteogenesis
E. osteoblasts; osteocytes
structure of bone
3. osteoprogenitor cells
A. found on? B. Differentiate to?
C. heavily involved in?
A. the inner and outer surfaces of bones
B. form new osteoblasts
C. the repair of bones after a break
structure of bone
4. osteoclasts
A. secerte?
B. process called?
A. acids, which dissolve bone causing a release of stored calcium and phosphate ions into the blood.
B. osteolysis
What are the two types of osseus tissue?
1. Compact Bone
2. Spongy Bone
types of bone tissue
1. compact bone
A. are? B. forms? C. consists of?
D. medullary cavity consists of?
A. dense and solid
B. the walls of bone outlining the medullary cavity
C. osteons
D. bone marrow
types of bone tissue
2. spongy bone
A. is?
B. trabeculae: are arranged in? C. form?
D. creates the?
A. an open network of plates
B. in parallel struts.
C. branching plates and an open network
D. lightweight nature of bones
functional differences
1. Compact Bone
A. conducts stress...
B. Generates...
C. weak strength when...
A. from one area of body to another area
B. tremendous strength from end to end
C. when stress is applied to the side
functional differences
2. Spongy Bone
A. trabeculae create...
A. strength to deal with stress from the side.

A. epiphysis B. metaphysis C. diaphysis D. metaphysis E. epiphysis F. Spongy bone
G. compact bone H. medulary cavity
I. articular surface of head of femur
Periosteum and Tendons
Tendons are cemented into the lamellae by osteoblasts, making the part of bone.
Ossification
when cartilage cells will be replaced by bone cells
Osteogenisis
Bone Formation
Calcification
the deposition of calcium ions into the bone tissue
two types of ossification
1. Intramembranous ossification
involved in the development of clavicle, mandible, skull, and face
two types of ossification
2. Endochondral ossification
involved in the development of limbs, vertebrae, and hips
two types of ossification
1. intramembranous ossification
2. endochondral ossification
Intramembranous ossification
steps (6)
1. mesenchymal cells differentiate to form osteoblasts
2. osteoblasts begin secreting a matrix
3. osteoblasts become trapped in thhe matrix
4. osteoblasts differentiate and form osteocytes
5. more osteoblasts are produced, thus move outward
6. eventually compact bone is formed
endochondral ossification
steps (1-4)
1. the developing bone begins as cartilage cells
2. cartilage matrix grows inward (interstitial growth)
3. cartilage matrix grows outward (appositional growth)
4. blood vessels grow around the cartilage
endochondral ossification
steps (5-9)
5. Perichondrial cells convert to osteoblasts
6. osteoblasts develop a superficial layer of bone around the cartilage
7. blood vessels penetrate the cartilage
8. osteoblasts begin to develop spongy bone in the diaphysis
9. this becomes the primary center of ossification
endochondral ossification
steps (10-13)
10. the cartilage near the epiphysis converts to bone
11. blood vessels penetrate the epiphysis
12. osteoblasts begin to develop spongy bone in the epiphysis
13. epiphysis becomes the secondary center of ossification
epiphysial plate
2. AKA?
3. cartilage near the diaphysis is
4. the width of this zone...
1. area of in the metaphysis
2. Epiphyseal cartilage
3. converted to bone
4. gets narrower as we age

1. As the cartilage enlarges,chondrocytes near thecenter of the shaftincrease greatly in size.The matrix is reduced to aseries of small struts thatsoon begin to calcify. Theenlarged chondrocytesthen die and disintegrate,leaving cavities within thecartilage.
2. Blood vessels growaround the edges of thecartilage, and the cells ofthe perichondrium convert to osteoblasts. The shaft of the cartilage then becomes ensheathed in a superficial layer of bone.

3. Blood vessels penetrate thecartilage and invade the centralregion. Fibroblasts migratingwith the blood vesselsdifferentiate into osteoblastsand begin producing spongybone at a primary center ofossification. Bone formationthen spreads along the shafttoward both ends.
4.Remodeling occurs as growthcontinues, creating a medullarycavity. The bone of the shaftbecomes thicker, and the cartilagenear each epiphysis is replaced byshafts of bone. Further growthinvolves increases in length (Steps 5and 6) and diameter (see Figure 5.9).

5. Capillaries and osteoblastsmigrate into the epiphyses,creating secondaryossification centers.
6. Soon the epiphyses are filled withspongy bone. An articular cartilageremains exposed to the joint cavity;over time it will be reduced to a thinsuperficial layer. At each metaphysis, an epiphyseal cartilage separates the epiphysis from the diaphysis.
Enlarging the diameter of bone
1. called
2. blood vessels that run parallel to the bone becomes...
3.____ begin to form
4. each____ has
1. appositional growth
2. surrounded by bone cells
3. "tunnels"
4. "tunnel", a blood vessel in it

1. Bone formation at the surfaceof the bone produces ridgesthat parallel a blood vessel.
2. The ridges enlarge and createa deep pocket.
3. The ridges meet and fuse, trappingthe vessel inside the bone.

4. Bone deposition proceeds inward towardthe vessel, beginning the creation of atypical osteon.
5. Additional circumferential lamellae aredeposited and the bone continues toincrease in diameter.
6. Osteon is complete with new centralcanal around blood vessel. Second bloodvessel becomes enclosed.
Four major sets of blood vessels associated with the long bones
1. nutrient vessels
2. metaphyseal vessels
3. Epiphyseal vessels
4. periosteal vessels
four major blood vessels: long bones
1. Nutrient Vessels
A. enters...
B. Re-enters...
A. the diaphysis and branch toward the epiphysis
B. the compact bone leading to the central canals of the osteons.
Four major blood vessels: long bones
2. Metaphyseal Vessels
3. Epiphyseal Vessels
4. Periosteal Vessels
2. Supply nutrients to the diaphyseal edge of the epiphysis
3. supply nutrients to the medullary cavities of the epiphysis
4. supply nutrients to the superficial osteons
factors regulating bone growth
(9)
1. nutrition 2. calcium ions 3. phosphate ions
4. citrate 5. carbonate ions 6. magnesium ions
7. sodium ions 8. vitamins A,C,D 9. hormones
factors regulating bone growth
9. Hormones: parathyroid gland
Release_A___ -> stimulates__B__
-> stimulates__C__ -> Increases_D___
A. parathyroid hormone
B. osteoclasts
C. osteoblasts
D. calcium ion absorption from the small intestine to the blood.
factors regulating growth
9. hormones: Thyroid gland 1
Release__A__ -> Inhibit__B__ -> Removes __C__
A. Calcitonin
B. osteoclasts
C. calcium ions from blood and adds in to bone
factors regulating growth
9. Hormones: thyroid gland 2
releases__A__ -> Maintains __B__
A. thyroxine (T4)
B. normal activity of the epiphyseal cartilage
factors regulating bone growth
9. Hormones: pituitary gland
Releases__A__ -> Maintains__B__
A. growth hormone (somatotropin)
B. normal activity of the epiphyseal cartilage
Aging and the skeletal System
1. When we’re young, osteoblast activity balances with osteoclast activity
2. When we get older, osteoblast activity slows faster than osteoclast activity
3. When osteoclast activity is faster than osteoblast activity, bones become porous
4. Estrogen keeps osteoclast activity under control
Aging and the skeletal system: Women
1. As women age,
2. osteoclast control is
A. osteoclast are
3. bone becomes
A. this is
1. estrogen levels drop
2. lost
A. overactive
3. porous
A. osteoporosis
Bone maintenance, remodeling, and repair
When a bone is broken...(4)
1. bleeding occurs
2. A network of spongy bone forms
3. Osteoblasts are overly activated, thus resulting in enlarged callused area
4. This area is now stronger and thicker than normal bone

1. Immediately after the fracture,extensive bleeding occurs.Over a period of severalhours, a large blood clot, orfracture hematoma, develops.
2.An internal callus forms asa network of spongy boneunits the inner edges, andan external callus ofcartilage and bonestabilizes the outer edges.

3. The cartilage of the externalcallus has been replaced by bone,and struts of spongy bone nowunite the broken ends. Fragmentsof dead bone and the areas ofbone closest to the break havebeen removed and replaced.
4. A swelling initially marksthe location of the fracture.Over time, this region willbe remodeled, and little evidence of the fracturewill remain.
Seven broad categories of bones according to their shape
1. sutural bones 2. irregular bones
3. short bones 4. pneumatized bones
5. flat bones 6. long bones
7. sesamoid bones

1. sutural bones 2. irregular bones
3. short bones 4. pneumatized bones
5. flat bones 6. long bones
7. sesamoid bones
Bone markings include: (5)
1. projections 2. depressions
3. fissures 4. foramina
5. canals (meatuses)

1. trochanter 2. head 3. Neck
4. facet 5. tubercle 6. condyle

1. fissure 2. ramus
3. process 4. foramen

1. canal 2. sinuses 3. meatus

1. tubercle 2. head 3. sulcus
4. neck 5. tuberosity 6. fossa
7. trochlea 8. condyle

1. spine 2. line 3. foramen
4. crest 5. fossa 6. ramus