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Anatomy & Physiology 34A Lecture
Chapter 6 - Bone & Skeletal Tissues
I.
Overview
A. Organization of the Skeletal System
B. Tissues & Organs of the Skeletal System
C. Functions of Bones
D. Bone Structure
E. Bone Tissue
F. Bone Surface Markings
G. Bone Development
H. Bone Disorders
II. Organization of the Skeletal System
A. The adult skeleton consists of about ____ bones
B. The skeleton may be divided into axial and appendicular portions
1. The _______ skeleton consists of 80 bones that form the body’s axis and support and
protect the organs of the head, neck, and trunk. These bones include the:
2.
a.
b.
_________ - composed of cranial & facial bones
c.
_______________ - 12 pr. ribs, sternum, & costal cartilages
_____________ column (backbone) - of 26 vertebrae, most separated by
intervertebral discs
The _________________ skeleton is composed of the bones of the upper & lower
extremities, and the bony girdles that anchor the appendages to the axial skeleton.
Components include:
a.
______________ girdle - paired scapulae (shoulder blades) and clavicles (collar
bones) and the sternum (axial)
b.
Upper extremities - each of the two contains a ____________, an ulna, and radius,
the carpals, metacarpals, and phalanges.
c.
______ girdle - two ossa coxae (hipbones) are the appendicular parts of this girdle,
the sacrum is the axial component
d.
Lower extremities - each contains a __________ (thigh bone), a patella (knee cap),
tibia (shin bone) and fibula, tarsals, metatarsals, and phalanges
III. Skeletal tissues
A. ____________ tissue includes both compact and spongy bone
B. __________ – composed of a matrix of mostly hyaluronic acid and collagen fibers (some
elastic fibers), and chondrocytes. 3 types:
1.
2.
3.
_________ C. - nose, articular, costal, larynx, trachea, bronchi
_____________ C. - outer ear, epiglottis, eustacian tubes
________cartilage - intervertebral discs, pubic symphysis, knee menisci
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C. _________ CT – surrounds bones and cartilage, and connect bone to bone (ligaments) and
muscle to bone (tendons)
D. Reticular tissue & ________ stem cells in red bone marrow
E. _____________ tissue stored in yellow bone marrow
E. __________ tissue permeates bone
IV. Functions of Bones
A. __________ – bones hold up the body, support muscles and nearby organs.
B. ______________ – bones surround and protect the brain, spinal cord, heart, lungs, pelvic
viscera, and bone marrow.
C. _____________ – bones form a system of levers that allows movement with skeletal
muscles
D. _____________ of lipids and minerals, esp. Ca2+ and phosphorous. Ca2+ is needed for
1. Blood _______ formation
2. ________ impulse conduction
3. ___________ contraction
A. E. Acid-base balance – bones ________ the blood against excess pH changes by
absorbing or releasing alkaline salts (e.g. CaPO4, CaCO3)
F. Blood formation (_______________) - red bone marrow produces blood cells. During
embryonic and fetal development, blood cells are first formed by a yolk sac, then by the
liver and spleen.
V. Bone Structure
A. Classification (________) of bones include:
1.
______ bones are longer than wide and function as levers
a.
b.
2.
Most bones of the upper & lower extremities are this type (e.g.: _______, tibia,
fibula, ___________, radius, ulna, metacarpals, metatarsals, phalanges)
________ bones are somewhat cube-shaped; contain mostly spongy bone; Examples
are:
a.
b.
3.
Consist of a shaft with heads at either end and are mostly _____________ bone
_________ (8 wrist bones) & __________ (7 ankle bones)
_____________ bones - develop within some tendons as a response to stress
(e.g.: patella in the quadriceps tendon)
_______ bones are thin with spongy bone between layers of compact bone (e.g.:
cranial bones, ribs, scapula, sternum, os coxae).
4.
_____________ bones have varied shapes and surface features for muscle
attachment or articulation (e.g.: vertebrae, most skull facial bones, ear ossicles,
hyoid, sacrum, coccyx).
5.
_______________ (sutural) – tiny bone clusters between joints (sutures) of some
cranial bones
B. Structure of a Typical __________ Bone
1. Two major types of osseous tissue in long bones are:
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2.
a.
___________ (cancellous) bone - very porous internal bone tissue found in the
bone ends (epiphyses), that contains ____ bone marrow, where hematopoiesis
takes place.
b.
___________ bone - dense external bone tissue; surrounds the medullary cavity,
long tube in the bone center that contains bone ___________ marrow (adipose)
Long bone structures include:
a.
________ -bone shaft composed of compact bone; surrounds the medullary
__________ containing yellow bone marrow
b.
____________ – tough membrane covering the bone surface, continuous with
tendons & ligaments; consists of:
1) Outer dense _________ fibrous CT membrane; secured to bone by Sharpey’s
fibers
2) Inner ________________ layer with bone cells
c.
d.
e.
_____________ (proximal & distal) - ends of bone composed of spongy bone
f.
_____________ - lines the medullary cavity & other internal bone surfaces;
composed of reticular CT and bone cells.
Articular (__________) cartilage cushions ends of bone
Epiphyseal _______ - line of hyaline cartilage between epiphysis and diaphysis
that provides longitudinal growth of bone during youth, then ossifies into an
epiphyseal _______ at about age 18-21.
V. Bone Tissue
A. Composed of assorted bone cells and a _________ of both organic and inorganic
materials:
1. Inorganic – 2/3 of bone, includes _________________, mostly of calcium phosphate
(CaPO4) and calcium carbonate (CaCO3), which provide bone rigidity
2. Organic – 1/3 of bone ____________, GAGs, proteoglycans, glycoproteins, which
provide bone flexibility
B. Types of bone ______ include:
1.
______________ cells in contact with the endosteum, give rise to osteoblasts (via
osteogenesis)
2.
Osteo_______ - bone forming cells that synthesize and secrete the matrix; these give
rise to osteocytes
3.
4.
Osteo______ - mature bone cells found in lacunae spaces
Osteo______ - bone dissolving cells that break down the matrix; found in the
medullary cavity, under the endosteum
C. Spongy & Compact Bone Tissues
a. __________ bone - very porous bone tissue that consists of lamellae arranged in
an irregular lattice of thin bone plates called ___________; osteocytes get
nutrients from capillaries
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b.
___________ bone - dense bone tissue that contains osteons (Haversian systems)
consisting of:
1) Concentric ______________ rings
2) Osteocytes interspersed in ___________ spaces around a central Haversian
canal, which contains blood vessels, nerves, and lymphatic vessels
3) _______________ channels radiate out from the canal & lacunae to allow
nutrients from blood to nourish osteocytes
4) Perforating (__________) canals penetrate compact bone horizontally,
connecting osteons with blood vessels & nerves
VI. Surface Bone _____________
A. ____________ (projections) to which muscles and tendons attach.
1. ______________ - Very large bump
2. ___________ - large roughened bump that a muscle attaches to
3. _____________ - small rounded bump
4. _____________ - bump on the surface of a condyle
5. _________ - narrow ridge
6. _________ - narrow ridge of bone, less prominent than a crest
7. _________ - a sharp, slender raised area
B. ________________ that help form joints
1. _________ - end of bone supported by a constricted neck
2. _________ - smooth, nearly flat articular surface
3. ____________ - rounded, knucklelike bump that articulates with another bone
4. __________ - armlike bar of bone
C. Depressions & Openings for blood vessels and nerves
1. _________ - canal or long tube-like passageway
2. _________ – cavity within the bone
3. _________ - shallow depression or socket
4. _________ – shallow depression
5. __________ - groove or furrow
6. __________ - narrow, slit-like opening
7. __________ - round or oval opening through the bone
VII. Bone Development
A. Osteogenesis and ______________ are two names for bone tissue formation, which
proceeds rapidly from embryo though adolescence, then more slowly in the adult. Two
types are intramembranous and endochondral ossification:
1.
________________ ossification - membrane bones (e.g., in the skull & clavicle)
develop from embryonic mesenchyme tissue
a. _________________ condenses around blood vessels
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b. Some mesenchyme cells ______________ into osteoblasts
c. Osteo______ secrete osteoid matrix around themselves and become osteo______
d. Osteoid matrix wraps around blood vessels, forming interwoven _______________
bone plates
e. Vascular tissue in spaces between trabeculae becomes ____ bone marrow
f. Mesenchyme on the bone surface becomes the ___________
g. Trabeculae just under the periosteum solidifies into ________ bone
2.
_____________ ossification -most bones form by replacing the ________ cartilage
skeleton of the embryo. Bones lengthen by:
a.
b.
_________ ossification center forms in the cartilage “bone” center.
c.
Cartilage ____________ in the center of the diaphysis, chondrocytes die &
cartilage deterioriates, transforming the primary ossification center into the
primary _____________.
d.
_____________ (artery, vein, bone marrow cells, osteoblasts, & osteoclasts)
invade the diaphysis & form bone trabeculae
e.
Perichondrium around diaphysis becomes periosteum and its osteoblasts form a
bone _____________.
Heads of bones are still _______ at this point of development
3. ___________ – transitional zone between the cartilagenous head and shaft of
developing long bone. Has 5 zones of __________ from cartilage to bone:
a. Zone of ____________________ – farthest from the marrow space, resting
cartilage cells have not been transformed to bone
b. Zone of _____________ – closer to marrow space, where chondrocytes multiply
and form longitudinal columns of lacunae
c. Zone of ________________ – between proliferation and calcification zones;
chondrocytes grow larger here
d. Zone of ____________ – minerals are deposited between the chondrocyte lacunae
columns and calcify for temporary support
e. Zone of _______________ – chondrocytes die, lacunae break down, resulting
channels are invaded by marrow, blood vessels, and bone cells.
1) Osteo_________ dissolve calcified cartilage
2) Osteo________ line up along channels and deposit concentric layers of bone
matrix, stopping at the Haversian canal, and becoming osteo_______ within
their lacunae.
4. ________________ ossification center forms at birth
a. Cartilage of the epiphyseal _______ between the diaphysis and epiphyses
continues to grow, become calcified, and be replaced by bone trabeculae
b. About age 18-21, the epiphyseal plate ossifies into an epiphyseal _______ and
longitudinal growth ceases.
5. ___________ growth (of bone width in mature bone) continues to occur as osteoblasts
add bone to the diaphysis surface and osteoclasts remove bone from the inner
diaphysis
6. _______________ that affect bone growth
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a.
b.
Pituitary growth hormone (___)- stimulates epiphyseal plate growth
c.
Parathyroid hormone (___) – raises blood Ca2+ levels by
1) Activates osteo_______ to dissolve bone
2) Stimulates calcitriol (Vit. __) synthesis
3) Increases intestinal _____ absorption
d.
____________ (from thyroid) – reduces blood Ca2+ levels by activating
osteo_______ to deposit bone matrix
e.
Sex hormones (____________ & ____________) stimulate osteoblasts to cause a
bone growth spurt at adolescence, and later induce epiphyseal plates to close
f.
g.
h.
Vit. ___ – promotes chondroitin sulfate synthesis
_________ hormones work with GH to ensure that the skeleton retains proper
proportions during growth.
Vit. __ – promotes collagen formation, bone growth & repair
Vit. __ (calcitriol) – increases intestinal Ca2+ uptake
B. Bone _____________ occurs in the adult skeleton as bone deposit & removal occur at the
periosteal and endosteal surfaces
1.
Bone _____________ occurs as osteo______ lay down osteoid matrix and calcium
salts on bone surfaces; this solidifies around the cells and they become osteocytes.
2.
Bone _____________ occurs as osteo______ secrete HCl to dissolve calcium
phosphate, which enters the bloodstream
3.
Bones are continually remodeled for two reasons:
a.
Helps to maintain constant ____ PO43- level in body fluids; __________ hormone
stimulates osteoclasts to reabsorb bone
b.
Response to mechanical _______ - bone thickens in response to weight-bearing
exercise and gains in weight
C. Bone Fractures
1. ____________ - break across the bone is incomplete
a.
b.
c.
2.
____________ - tear in the epiphyseal plate, can stop bone growth
_______________ - bone fragments into 3 or more pieces; common in the aged
Closed (______) - bone does not break through the skin (usually a partial break)
a.
b.
c.
4.
______ - ragged break, occurs when bone is twisted; common sports fracture
_______________ - is broken into 2 or more pieces
a.
3.
____________ - bone breaks incompletely, like a green twig; common in children
______________ - bone is crushed (e.g., a vertebra) or
______________ (e.g., skull) due to extreme trauma
__________ - microscopic fracture from repeated stressful impact
Open (____________) - bone protrudes through skin (usually a complete break)
D. Bone Fracture ____________ - occurs in several stages
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1.
2.
____________ formation - blood clots form around the fracture
3.
_______ formation (4-6 weeks) – fibroblasts deposit collagen; some osteogenic cells
become chondroblasts and produce ____________ soft callus, other osteogenic cells
become osteoblasts that form a hard callus bone __________ around the damaged
area.
Formation of _____________ tissue (1-2 days) - a soft, fibrous tissue is produced as
the hematoma is invaded by blood capillaries, fibroblasts, macrophages, and
osteogenic cells.
4.
Bone ___________ (3-4 months) – osteo_____ dissolve broken bone fragments;
osteo_____ secrete matrix to reconnect broken ends with spongy bone, which is
remodeled into compact bone.
VIII. Bone Disorders
A. Osteo_________ - decrease in bone mass that occurs when bone reabsorption exceeds
bone deposition due to increased osteoclast activity
1.
2.
3.
____ of American women have this by age 80
4.
Treatments include supplemental _____________ & vit. ___, exercise, HRT,
bisphosphonate drugs, and SERMs)
Makes bones very susceptible to ___________
Factors include less estrogen & ____________ after menopause, smoking,
insufficient exercise, diabetes mellitus, carbonated beverages, and a diet poor in
calcium, vit. C, & protein
B. Osteo________ - adult bones soften & weaken when inadequately mineralized due to
poor nutrition
C. _______________ - more serious than osteomalacia in children
1. Symptoms are weak & _________ legs, deformities of the head & rib cage
2. Treatments include vit. __ & ______________ phosphate supplementation and skin
exposure to sunlight
D. Osteo__________ – inflammation of osseous tissue and bone marrow due to bacterial
infection, treated with antibiotics
E. Osteitis deformans (_______ disease) – rapid, disorderly bone remodeling, leads to weak,
deformed bones. Most common in males over 50.
B. F. Osteogenesis _____________ – hereditary disorder of collagen formation, leads to
very brittle, easily broken bones
D. Osteo________ - form of bone cancer arising from osteoblast-like cells of mesenchyme
origin
1.
2.
3.
Primarily affects __-__ yr. old males
Symptoms - ______ & swelling in affected bone
Treatment - ________ & chemotherapy; 60-70% survival rate if detected ______