A&P Chapter 6

Which type of cartilage covers and protects the ends of bones at freely moveable joints?

A. elastic cartilage
B. fibrocartilage
C. hyaline cartilage
D. both hyaline and elastic cartilage

Hyaline cartilage covers the ends of long bones as articular cartilage, providing springy pads that absorb compression at joints.

Hyaline cartilage ________.

A. is the rarest of the skeletal cartilages
B. forms "shock-absorbing" pads between the vertebrae
C. gives shape to the external ear
D. is found on the ends of bones that form movable joints

Hyaline cartilage is found on the ends of bones that form movable joints, where it is referred to as articular cartilage.

When chondrocytes in lacunae divide and form new matrix, it leads to an expansion of the cartilage tissue from within. This process is called ________.

A. interstitial growth
B.hematopoiesis
C.appositional growth
D.calcification

Interstitial growth occurs when chondrocytes divide and form new matrix, thereby expanding the cartilage tissue from within. (Note: the word inter means between, and stitial means space; these are common roots for anatomical terms.)

Choose the FALSE statement.
A.The sternum is an example of a flat bone.
B. Irregular bones include the vertebrae and hip bones.
C.Long bones include all limb bones except the patella.
D.Sesamoid bones form within certain tendons.

This is false; long bones include all limb bones except the patella, tarsals and carpals.

The main role of the appendicular skeleton is to protect and support vital organs
A. True
B.False

The main role of the appendicular skeleton involves locomotion; it also allows us to manipulate our environment. The axial skeleton is mostly involved in supporting other body parts and protecting vital organs.

Hematopoiesis is a term for which of the following physiological processes?
A.blood cell formation
B.bone formation during growth
C.release of minerals into the blood
D.energy storage in fat tissue

Red bone marrow found within certain regions of spongy bone is the site of blood cell formation from the differentiation of hematopoietic stem cells.

Bones do NOT have a role in ________.
A. blood cell formation
B.support
C. movement
D. glycogen production
E. fat storage

Glycogen production (glycogenesis) is not a role of bone; it takes place primarily in muscle and liver cells.

Which of the following is stored in bones?
A.iodine
B. vitamin C
C. glycogen
D.phosphate
E.calcitonin

Bone is a reservoir for calcium and phosphate.

Dense connective tissue forms part of which labeled part of the adult long bone in the figure?
A.
B.
C.
D.

The external membrane of bone, the perisosteum, includes a fibrous outer layer composed of dense irregular connective tissue.

Which of the labeled parts of the bone is composed primarily of hyaline cartilage?
A.
B.
C.
D.

The articular cartilage at the ends of long bones is formed from hyaline cartilage.

Which of the labeled parts of the bone is composed primarily of compact bone?
A.
B.
C.
D.

The shaft of an adult long bone is composed of compact bone.

Which of the following is the major component of the part of the bone labeled E?
A.
B.
C.
D.

Yellow bone marrow within the medullary cavity is composed primarily of adipose tissue (fat).

In which of the labeled parts of the adult long bone would hematopoietic tissue be located?
A.
B.
C.
D.

Hematopoietic tissue is found in the spaces within the red bone marrow found within certain body locations consisting of spongy bone. Examples include the diploe of flat bones and the proximal epiphyses of the femur and humerus (pictured).

The indicated osteocyte is located within layers of bony matrix termed ______.
A. canaliculi
B.lacuna
C.lamellae
D.periosteum

Lamellae are layers of bony matrix synthesized by osteoblasts during bone growth and maintenance.

The indicated blood vessels and nerve are found within a ______.
A. Perforating (Volkmann’s) canal
B. Central (Haversian) canal
C. marrow cavity
D.caniculus

A Haversian (or central) canal runs lengthwise at the center of each osteon.

Osteocytes are connected to each other through which structure?
A. Haversian canal
B. Volksmann’s canal
C. lacuna
D.canaliculi

Cytoplasmic extensions of osteocytes form contacts within hairlike canals, termed canaliculi, within the lamellae. Сanaliculi allow for communication and exchange of materials between osteocytes.

Which of the following substances is NOT a component of the osteoid material secreted by the cells indicated by the arrow in panel A? https://session.masteringaandp.com/problemAsset/1426334/2/MariebHAP9_ch06-03_artquest.jpg
A.calcium
B.proteoglycan
C.collagen
D. glycoprotein

Calcium is an inorganic component of the bone matrix and is deposited from the interstitial fluids. The organic osteoid secreted by bone-forming cells is composed of proteoglycans, glycoproteins, and collagen.

What bone-associated structure in panel C is indicated by the arrow? https://session.masteringaandp.com/problemAsset/1426335/3/MariebHAP9_ch06-03_artquest.jpg
A.osteon
B.epiphyseal plate
C.periosteum
D.trabeculae

The honeycomb-like network of spongy bone is constructed of bony plates called trebeculae.

Which bone cells form bone?
A.osteoclasts
B.osteoblasts
C.chondroblasts
D.osteocytes

Osteoblasts are the bone-forming cells that produce the organic bone matrix, the osteoid. Mature bone is produced once the inorganic matrix forms around the cells and collagen fibers of the organic matrix.

What is the structural unit of compact bone?
A.osteon
B.canaliculus
C. haversian canal
D.osteoid

The structural unit of compact bone is the osteon, an elongated cylinder oriented parallel to the long axis of the bone.

Which of the following is a bone projection?
A.foramen
B.groove
C.trochanter
D.sinus
E.fossa

A trochanter is a bone projection. All of the other choices listed are categorized as depressions or openings.

In adults, yellow marrow is located ________.
A. in the central canals of osteons
B. primarily in flat bones
C. in the medullary cavity of long bones
D. in the epiphyseal plates of long bones

In adults, much of the yellow marrow is located in the medullary cavity of the long bones.

Which description of bone cells is INCORRECT?
A. Osteoclasts secrete digestive enzymes and hydrogen ions.
B. Osteogenic cells can differentiate into osteoclasts.
C. Bone lining cells on the internal surfaces of bone are also called endosteal cells.
D. Osteoblasts secrete collagen and calcium-binding proteins.

Osteoclasts are derived from the same hematopoietic stem cells that differentiate into macrophages; they are not derived from osteogenic cells.

In adults, hematopoietic tissue is NOT found in ________.
A. the flat bones of the skull and sternum
B. the medullary cavity of long bones
C. the hip bones and vertebrae
D. the heads of the femur and humerus

In infants, but not adults, red marrow (hematopoietic tissue) is found in the medullary cavity of long bones.

The osteon is ________.
A. a fibrous membrane that covers and protects bone
B. the structural unit of spongy bone
C. the structural unit of compact bone
D. a network of red marrow

The osteon, also called the Haversian system, is the structural unit of compact bone.

The notable hardness of bone is attributed to ________.
A. the presence of proteoglycans
B. the presence of glycoproteins
C. the presence of cartilage
D. the presence of inorganic hydroxyapatites
E. the presence of collagen fibers

The exceptional hardness of bone, which allows it to resist compression, is attributed to the presence of mineral salts called hydroxyapatites. The hydroxyapatites, mainly calcium phosphates, form the inorganic matrix of bone.

The epiphyseal plate is ________.
A. the long axis of a bone
B. where long bone lengthening occurs
C. where yellow bone marrow is produced
D. the site of red bone marrow production

Long bones elongate from growth at the epiphyseal plate, a layer of hyaline cartilage between the epiphyses and diaphysis of long bones.

Flat bones consist of compact bone sandwiched between spongy bone.
A. True
B.False
C.
D.

Flat bones consist of two thin plates of compact bone enclosing a diploë (spongy bone layer).

The above figure depicts which of the following bone-forming processes? https://session.masteringaandp.com/problemAsset/1426331/2/MariebHAP9_ch06-03_artquest.jpg
A. bone remodeling in response to changes in mechanical stress
B. bone repair at a site of fracture
C. intramembranous ossification during embryonic development
D. endochondral ossification during bone formation and growth

The figure illustrates the formation of new bones within a fibrous membrane ("intramembranous") during embryonic development.

The cells indicated by the arrow at the center of panel A arise from the differentiation of whttps://session.masteringaandp.com/problemAsset/1426333/2/MariebHAP9_ch06-03_artquest.jpghich precursor stem cell?
A. mesenchymal cells
B. adipose cells
C. osteocytes
D. chondroblasts

Mesenchymal cells are stem cells that differentiate into the matrix-forming cells of the various connective tissues, including the osteoblasts that form bone.

A step in which bone-forming process is shown in the figure? https://session.masteringaandp.com/problemAsset/1426337/2/MariebHAP9_ch06-04A_artquest.jpg
A. endochondral ossification
B. intramembrounous ossification
C. bone remodeling
D. bone fracture repair

The figure illustrates a step in the embryonic formation of a bone from a cartilage model.

A step in what bone forming process is shown in the figure?
A. intramembranous ossification
B. bone remodeling
C. bone fracture repair
D. endochondral ossification

The figure illustrates a step in the embryonic formation of a bone from a cartilage model.

The structure indicated by the arrow is composed primarily of what material? https://session.masteringaandp.com/problemAsset/1426342/2/MariebHAP9_ch06-04B_artquest.jpg
A. dense connective tissue
B. hyaline cartilage
C. fibrocartilage
D. compact bone

The cartilage models used to form bones are composed of hyaline cartilage. This tissue persists within the epiphyseal plate at the boundary between primary and secondary ossification centers.

During bone growth, which event is most significant at the surface indicated by the letter A? https://session.masteringaandp.com/problemAsset/1426343/2/MariebHAP9_ch06-05_artquest.jpg
A. expansion of the cartilage matrix
B.conversion
of bone into cartilage
C. expansion of articular cartilage
D. conversion of cartilage into bone

The expansion of the matrix results in the pushing of the epiphysis away from the diaphysis. This leads to the lengthening of the bone by interstitial growth.

During bone growth, which event is most significant at the surface indicated by the letter B?
A. formation of compact bone.
B. cell division of chondrocytes
C. conversion of bone into cartilage
D. calcification of the cartilage matrix

Calcification of the cartilage matrix leads to its deterioration and replacement by bone.

During bone growth, which significant event occurs at the surface indicated by the letter C? https://session.masteringaandp.com/problemAsset/1426345/2/MariebHAP9_ch06-05_artquest.jpg
A. bone resorption
B. conversion of spongy bone to compact bone
C. expansion of the articular cartilage
D. appositional growth

Growth in width involves the adding of layers of lamellar (compact) bone along the bone’s outer surface. This process of growth by "layering" is termed appositional growth and is distinct from growth by expansion of the interior matrix (interstitial growth).

During bone growth, which significant event occurs at the surface indicated by the letter D?
A. production of hyaline cartilage
B. bone resorption
C. interstitial growth
D. production of compact bone

As the bone widens, the matrix at the endosteal surface is resorbed to maintain the proper thickness of the walls surrounding the medullary cavity.

What is endochondral ossification?
A. the formation of bone from pre-existing elastic cartilage models
B. the formation of bone from fibrous membranes
C. the formation of bone from pre-existing hyaline cartilage models
D. the formation of bone from pre-existing fibrocartilage models

Endochondral ossification is the formation of bone from hyaline cartilage models. The hyaline cartilage must be broken down and replaced with the bone tissue.

During infancy and childhood, the most important stimulus of epiphyseal plate activity is ________.
A. testosterone
B. growth hormone
C. estrogen
D. the thyroid hormones

During infancy and childhood the single most important stimulus for bone growth is growth hormone. It directly stimulates growth of the hyaline cartilage that forms the epiphyseal plates in long bones, causing the bones to lengthen.

Hypercalcemia can be caused by_________.
A. insufficient vitamin D levels in the body
B. hypersecretion of parathyroid hormone
C. reduced parafollicular cell activity
D. All of the listed responses are correct.

Parathyroid hormone functions to stimulate the activity of osteoclasts in bone tissue.

What is the final stage in the healing of a bone fracture?
A. formation of a fibrocartilaginous callus
B. bone remodeling
C. formation of a bony callus
D. formation of a hematoma

In order, here are the stages of bone fracture healing: (1) formation of a hematoma, (2) formation of a fibrocartilaginous callus, (3) formation of a bony callus, and (4) bone remodeling.

Which of the following is UNLIKELY to affect bone remodeling?
A. low blood Ca2+ concentration
B. glucagon
C. mechanical stress
D. parathyroid hormone

Glucagon’s main action is to increase blood glucose levels by triggering the breakdown of glycogen in the liver; it does not affect bone remodeling.

Which of the following is CORRECTLY matched?
A. linear fracture: the break is perpendicular to the bone’s long axis
B. nondisplaced fracture: the fractured bone ends are misaligned
C. compound fracture: the fractured bone ends penetrate the skin
D. incomplete fracture: the bone is broken through

In a compound (open) fracture the fractured bone ends penetrate the skin. Such open injuries carry a higher risk of infection.

The correct order (from start to finish) of fracture repair is ________.
A. bony callus formation, hematoma formation, fibrocartilaginous callus formation, and bone remodeling
B. hematoma formation, bony callus formation, bone remodeling, and fibrocartilaginous callus formation
C. bone remodeling, hematoma formation, fibrocartilaginous callus formation, and bony callus formation
D. hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling

From start to finish, a fracture is repaired by: (1) formation of a hematoma, (2) formation of a fibrocartilaginous callus, (3) formation of a bony callus, and (4) bone remodeling. Use the pneumonic HFBR (His Femur Better Repair!) to help you remember the order. H = hematoma, F = fibrocartilaginous callus, B = bony callus, R = remodeling.

Which of the following refers to a bone disorder found most often in the aged and resulting in the bones becoming porous and light?
A. osteomalacia
B. osteoporosis
C.rickets
D. Paget’s disease

Osteoporosis refers to groups of diseases in which bone resorption outpaces bone deposit. The bones become fragile and easily fractured. The composition of the matrix remains normal, but bone mass declines, and the bones become porous and light.

Choose the CORRECT pairing.

A. rickets: deficiency of vitamin
B. osteomalacia: excessive mineralization of the bone
C. paget’s disease: excessive and haphazard bone deposition and resorption
D. osteoporosis: increased bone density

Correct, Paget’s disease is associated with excessive and haphazard bone deposition and resorption.

What are skeletal cartilages that help form the skeleton?

-Hyaline cartilage -elastic cartilage -fibrocartilage

Skeletal cartilage is primarily _____________.
This allows it to ___________________________.

Skeletal cartilage is primarily WATER. (matrix of cartilage has lots of water) -This allows it to RESIST COMPRESSION.

Hyaline cartilage is found in ____________.

End of long bones

Elastic cartilage is found in _____________.

Ear and epiglottis

Fibrocartilage is found in ____________.

Intervertebral discs, pubic symphysis, meniscus

Which skeletal cartilage:
-Provides support, flexibility, and resilience
-only contains collagen fibers
-include articular, costal, respiratory, and nasal cartilages

Hyaline Cartilage

Which skeletal cartilage:
-contains elastic fibers
-maintains shape
-allows great flexibility
-is in external ear and epiglottis

Elastic Cartilage

Which skeletal cartilage:
-thick collagen fibers (great tensile strength)
-menisci of knee
-vertebral discs
-pubic symphysis

Fibrocartilage

Skeletal cartilage have no __________, no ____________ ______________
-surrounded by ___________________ (membrane)
-Layer of ‘_____________ _______________’ connective tissue surrounding cartilage
-Source of ‘____________ ____________ ___________________ ________________’ by diffusion to cartilage cells’ (nutrients are diffused from here)

FUNCTIONS: ____________ & _____________, ________________ ____________ _______________ _____________, & _______________________ _______________

Skeletal cartilage have no NERVES, no BLOOD VESSELS -surrounded by PERICHONDRIUM (membrane) -Layer of ‘DENSE IRREGULAR’ connective tissue surrounding cartilage -Source of ‘BLOOD VESSELS SUPPLYING NUTRIENTS’ by diffusion to cartilage cells’ (nutrients are diffused from here) FUNCTIONS: SUPPORT & PROTECTION, CUSHIONING SHOCK BETWEEN BONES, & CONNECTING TISSUES

GROWTH OF CARTILAGE:

-growth from the outside
-Cells secrete new matrix against external face of existing cartilage

APPOSTITIONAL GROWTH

GROWTH OF CARTILAGE:

-growth from the inside
– Chondrocytes divide and secrete new matrix ‘expanding cartilage from within’

INTERSTITIAL GROWTH

GROWTH OF CARTILAGE:

-Hardens (due to deposit of calcium salts), but ‘calcified cartilage is not bone’
-Occurs during normal bone growth (youth & old age)

CALCIFICATION OF CARTILAGE

CLASSIFICATION OF BONES:

-Long axis of body
-skull, vertebral column, rib cage

AXIAL SKELETON

CLASSIFICATION OF BONES:

-bones of upper and lower limbs
-girdles (shoulder and hip bones) attaching limbs to axial skeleton

APPENDICULAR SKELETON

CLASSIFICATION OF BONES BY SHAPE:

-Longer than they are wider
-Limb, wrist, ankle bones

LONG BONES

CLASSIFICATION OF BONES BY SHAPE:

-Complicated shapes
-Vertebrae, coxal bones

IRREGULAR BONES

CLASSIFICATION OF BONES BY SHAPE:

-Thin, flat, slightly curved
-Sternum, scapulae, ribs, most skull bones

FLAT BONES

CLASSIFICATION OF BONES BY SHAPE:

-cube shaped bones in wrist and ankle
-sesamoid bones (within tendons ex: patella)
-vary in size and number in different individuals

SHORT BONES

7 IMPORTANT FUNCTIONS OF THE BONES

-SUPPORT -PROTECTION -MINERAL AND GROWTH FACTOR STORAGE -HEMATOPOIESIS IN RED MARROW CAVITIES (BLOOD CELL FORMATION) -TRIGLYCERIDE (FAT) STORAGE IN BONE CAVITIES AS SOURCE OF ENERGY -HORMONE PRODUCTION OSTEOCALCIN, HELPS REGULATE INSULIN SECRETION, GLUCOSE LEVELS, AND METABOLISM -ANCHORAGE LEVERS FOR SKELETAL MUSCLE ACTION

BONES:
-Bones are ___________ since they contain different types of tissues

ORGANS

BONES:
-Different types of tissues in bones

-OSSEOUS TISSUE -NERVOUS -CARTILAGE FIBROUS CONNECTIVE -SMOOTH MUSCLE -EPITHELIAL CELLS IN ITS BLOOD VESSELS

GROSS STRUCTURE OF ALL BONES CONSISTS OF ________________ _______________ SANDWICHING ________________ ________________

COMPACT BONE; SPONGY BONE

BONE TEXTURES:

-dense external layer; smooth and solid

COMPACT (LAMELLAR)

BONE TEXTURES:

-Honeycomb or sponge of small needle-like or flat pieces of bone called trabeculae

SPONGY (TRABECULAR) – INTERNAL LAYER

TWO SETS OF MEMBRANES FOR SHORT, IRREGULAR, AND FLAT BONES:

___________ are covered ‘_____________ & ______________’ by two connective tissue membranes – osteogenic cells

PLATES

TWO SETS OF MEMBRANES FOR SHORT, IRREGULAR, AND FLAT BONES:

-Inner layer, contains osteogenic cells
-important for bone ‘resorption and deposition’

ENDOSTEUM

Trabeculae is a structural unit of the ______________.

Spongy Bone

Osteon is the structural unit of the ____________.

Compact bone

VERY IMPORTANT FOR BONE GROWTH AND REPAIR:

__________________ is bone resorption (breaking down of bone)

OSTEOGENIC

TWO SETS OF MEMBRANES FOR SHORT, IRREGULAR, AND FLAT BONES:

-Double-membrane outer layer
-Contains an inner osteogenic and an outer fibrous layer
-osteogenic layer is important for ‘growth and repair’

PERIOSTEUM

VERY IMPORTANT FOR BONE GROWTH AND REPAIR:

__________________ is making the bone again

DEPOSITION

STRUCTURE OF FLAT BONE:

_________________ is the spongy bone for flat bones (NO MARROW CAVITIES)

DIPLOË

STRUCTURE OF A LONG BONE (HUMERUS OF ARM):

__________________ _____________________ contains the articular cartilage (contains hyaline cartilage), spongy bone, epiphyseal line.

__________________ (shaft) contains the periosteum (outer 2x layered membrane. Nerves and blood vessels; provides anchoring points for tendons and ligaments), Compact bone, Medullary cavity (lined by endosteum)

_______________ _________________ is the bottom portion of the bone.

-Proximal epiphysis -Diaphysis (shaft) -Distal epiphysis

HEMATOPOIETIC TISSUE IN BONE:

RED MARROW
-found within ____________________ _________________ of _______________ _____________ of long bones and _____________ (flat bones) ex: sternum; called _________ ______________ _______________

-found within TRABECULAR CAVITIES of SPONGY BONE of long bones and DIPLOE (flat bones) ex: sternum; called RED MARROW CAVITIES

formation of red blood cells

Hematopoietic

HEMATOPOIETIC TISSUE IN BONE:

-‘________’ long bones have ‘__________ red marrow’
*Only found in ________ of __________ & _____________
-Red marrow in diploe & some irregular bones is the ________ __________

-‘ADULTS’ long bones have ‘LITTLE red marrow’ Only found in HEADS of FEMUR & HUMERUS -Red marrow in diploe & some irregular bones is the MOST ACTIVE

HEMATOPOIETIC TISSUE IN BONE:

-__________ _____________ can convert to ‘_____________ _______________’ if red blood cells are needed (ex: anemia)

YELLOW MARROW can convert to ‘RED MARROW’ if red blood cells are needed (ex: anemia)

FIVE CELLS OF OSSEOUS TISSUE:

-Stem cell
-Mitotically active
-can convert to other types of cells
-reside in endosteum & periosteum

Osteogenic cell

FIVE CELLS OF OSSEOUS TISSUE:

-Matrix-synthesizing (produces matrix) cell responsible for cell growth
-bone forming cell
-mitotic, secrete un-mineralized bone matrix that includes collagen (90% of bone protein) & Ca-binding proteins that make up initial un-mineralized bone (osteoid)

Osteoblast

FIVE CELLS OF OSSEOUS TISSUE:

-mature bone cell that monitors and maintains the mineralized bone matrix
-osteoblast that got trapped
-are osteoblasts that have ;become trapped’
-reside in lacunae and connected to each other via ‘canaliculi’ (transports nutrients via canals)
-signal osteoblasts and osteoclasts about mechanical stresses

Osteocyte

FIVE CELLS OF OSSEOUS TISSUE:

-giant bone-resorbing cell (bone destroying cell for calcium)
-multinucleated, reside in resorption bays, ruffled border increases surface area for enzymatically degrading bone (release digestive enzymes)

Osteoclast

MATRIX OF OSSEOUS TISSUE:

-cells
-osteoid (unmineralized bone matrix)
-Ground substance (glycoproteins and proteoglycans) and collagen fibers

ORGANIC MATTER

MATRIX OF OSSEOUS TISSUE:

-85% hydroxyapatites (mineral salts) (largely crystallized Ca2+ phosphate salts)
-10% calcium carbonate
-other minerals

INORGANIC MATTER

MATRIX OF OSSEOUS TISSUE:

-dry weight is _/_ organic, _/_ inorganic matter
-combination provides for ‘_____________ & _______________’
-minerals resist compression; collagen resists tension(stretching)

-dry weight is 1/3 organic, 2/3 inorganic matter -combination provides for ‘STRENGTH & RESILIENCE’ -minerals resist compression; collagen resists tension(stretching)

COMPACT BONE (LAMELLAR):

GROUP OF CONCENTRIC RINGS

A SINGLE OSTEON

COMPACT BONE (LAMELLAR):

CONCENTRIC RINGS

LAMELLAE

COMPACT BONE (LAMELLAR):

OSTEOCYTES IN LACUNAE

CANALICULI

COMPACT BONE (LAMELLAR):

WITH HELP OF THE COLLAGEN FIBERS

WITHSTAND TORSION STRESSES (TWISTING FORCE)

COMPACT BONE (LAMELLAR):

STRUCTURES IN THE CENTRAL CANAL

ARTERIES, VEINS, NERVE FIBER

MICROSCOPIC ANATOMY OF COMPACT BONE:

CONNECTS BLOOD VESSELS AND NERVES OF MEDULLARY CAVITY TO CENTRAL CANALS

PERFORATING (VOLKSMANN’S) CANALS

MICROSCOPIC ANATOMY OF COMPACT BONE:

LINES BONY CANALS AND COVERS TRABECULAE

ENDOSTEUM

MICROSCOPIC ANATOMY OF COMPACT BONE:

CONNECTS LACUNAE WITH CENTRAL CANAL – NUTRIENTS

CANALICULI

MICROSCOPIC ANATOMY OF COMPACT BONE:

WAS REPAIRING BUT DIDN’T COMPLETE – INCOMPLETE

INTERSTITIAL LAMELLA

MICROSCOPIC ANATOMY OF SPONGY BONE:

-APPEARS ___________ _______________, ONLY A FEW CELLS THICK

-APPEARS POORLY ORGANIZED, ONLY A FEW CELLS THICK

MICROSCOPIC ANATOMY OF SPONGY BONE:

– NO _____________
-______________________ ‘ALIGN ALONG LINES OF STRESS’ TO HELP BONE ‘RESIST STRESS’

<b>CAPILLARIES IN ENDOSTEUM SUPPLY NUTRIENTS</b>

– NO OSTEONS -TRABECULAE ‘ALIGN ALONG LINES OF STRESS’ TO HELP BONE ‘RESIST STRESS’

MICROSCOPIC ANATOMY OF SPONGY BONE:

ARE IRREGULARLY ARRANGED

LAMELLAE

MICROSCOPIC ANATOMY OF SPONGY BONE:

ARE INTERCONNECTED BY CANALICULI

OSTEOCYTES

MICROSCOPIC ANATOMY OF SPONGY BONE:

A SPONGY BONE HAVE A CENTRAL CANAL.

TRUE
FALSE

FALSE

BOES DEVELOP EITHER BY INTRAMEMBRANOUS OR ENCHONDRIAL OSSIFICATION:

PROCESS OF BONE TISSUE FORMATION

<b>IN ADULTS, IT MAINLY SERVES FOR BONE REMODELING AND REPAIR (CONSTANT LIFELONG PROCESS)</b>

OSSIFICATION (OSTEOGENESIS)

BONE DEVELOPMENT: 2 TYPES OF OSSIFICATION <b>MK</b>

-BONE DEVELOPS FROM ‘FIBROUS MEMBRANE’
-FORMS FLATBONES, CLAVICLES, AND CRANIAL BONES

INTRAMEMBRANOUS OSSIFICATION

BONE DEVELOPMENT: 2 TYPES OF OSSIFICATION <b>MK</b>

-BONE FORMS BY REPLACING HYALINE CARTILAGE
-FORMS MOST OF THE SKELETON

ENDOCHONRAL OSSIFICATION

FORMATION OF THE BONY SKELETON… INTRAMEMBRANOUS OSSIFICATION

-FOUR MAJOR STEPS INVOVLED:

1. MESENCHYMAL CELLS CLUSTER AND BECOME OSTEOBLASTS, FORMING OSSIFICATION CENTERS 2. OSTEOID IS SECRETED, THEN CALCIFIED 3. OSTEOID IS LAID DOWN BETWEEN BLOOD VESSELS, RESULTING IN TRABECULAE CALLED WOVEN BONE – MESENCHYME CONDESES TO FROM PERIOSTEUM 4. LAMELLAR BONE REPLACES WOVEN BONE AND RED MARROW APPEARS (VIA ITS VASCULAR TISSUE)

ENDOCHONDRAL OSSIFICATION IN A LONG BONE (REPLACEMENT OF HYALINE CARTILAGE)

-5 STEPS INVOVLED

1 BONE COLLAR FORMS AROUND THE DIAPHYSIS OF THE HYALINE CARTILAGE MODEL 2 CARTILAGE IN THE CENTER OF THE DIAPHYSIS CALCIFIES AND THEN DEVELOPS CAVITIES 3 THE PERIOSTEAL BUD (blood vessels, nerves, red marrow, osteogenic cells, and osteoclasts) INVADES THE INTERNAL CAVITIES AND SPONGY BONE 4 THE DIAPHYSIS ELONGATES AND A MEDULLARY CAVITY FORMS. SECONDARY OSSIFICATION CENTERS APPEAR IN THE EPIPHYSES 5 THE EPIPHYSES OSSIFY. WHEN COMPLETED, HYALINE CARTILAGE REMAINS ONLY IN THE EPIPHYSEAL PLATES AND ARTICULAR CARTILAGES

which of the following bone cell types is primarily responsible for initiating ossification of bone?

A. osteoclasts
B. osteoblasts
C. osteogenic cells
D. osteocyte

Osteoblasts

Growth in length of a long bone occurs at?

Epiphyseal plate

Interstitial growth requires the presence of epiphyseal cartilage in the epiphyseal plate?

True
False

True

Growing bones ‘widen’ as they lengthen
-osteoblasts beneath periosteum secrete bone matrix on the external bone surface
-osteoclasts remove bone on endosteal surface of the diaphysis (from within)

Appositional growth

most important in stimulating epiphyseal plate activity in infancy and childhood?

A. thyroid hormone
B. growth hormone
C. appositional growth
D. interstitial growth

Growth hormone

is replaced every 3-4 years

spongy bone

New bone matrix is deposited by?

osteoblasts

what signal is involved in trigger for calcification?

Mechanical signals

Bone resorption is the function of?

Osteoclasts

Osteoclasts activation involves T cell-secreted proteins and ?

parathyroid hormone (PTH)

remodeling is regulated by which genetic factors?

negative feedback hormonal loop for Ca2+ homeostasis – controls blood Ca2+ levels Responses to mechanical stresses – including gravitational forces

BONES GROW OR REMODEL IN RESPONSE TO THE DEMANDS PLACED ON THEM

WOLFF’S LAW

-bones poorly mineralized
-calcium salts not adequate
-soft, weak bones
-pain upon bearing weight

osteomalacia (soft bones)

-bone ends are enlarged and abnormally long
-bowed legs and deformities of pelvis, skull, rib cage
cause: vitamin D deficiency or insufficient dietary Ca2+

rickets (osteomalacia or children)

-group of diseases
-bone resorption outpaces deposit(bone mass declines)
-spongy bone of spine and neck of femur most susceptible

osteoporosis

4 MAJOR STAGES IN THE HEALING OF A BONE FRACTURE

1. a hematoma forms 2. fibrocartilaginous callus forms 3. bony callus forms 4. bone remodeling occurs

RISK FACTORS FOR __________________________

-lack of exercise
-vitamin D needed
-excess alcohol/carbonated drinks
-most often aged, postmenopausal women

osteoporosis

-excessive and haphazard bone deposit and resorption
-bone made fast and poorly
-excessive deposit: very high ratio of spongy to compact bone; weak and poorly mineralized
-rarely occurs before age 40
-treatment includes calcitonin and biphosphonates

Paget’s disease