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67 Cards in this Set
- Front
- Back
How many named bones are there?
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206
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How many bones are you born with?
What happends to them? |
Actually born with approximately 300 bones, but a number of these fuse during growth and development
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What is the longest bone in the body?
Shortest bone in the body? |
Longest= Femur (also strongest)
Shortest= Stapes(in the ear) |
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BONE
Characteristics of? |
Is a type of tissue
Variety of shapes, sizes, functions Made up of a variety of cell types |
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BONES: Classification of: By Group
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2 Main Groups
Axial (Skull, Ribs, Vertebrae) Appendicular (Extremeties & Pelvis) |
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OSTEOLOGY
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The study of the formation of bone
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BONE: Classification: By Shape
Name them all |
Long Bones
Short Bones Flat Bones Irregular bones |
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LONG BONES
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Longer than they are wide
Ex. humerus, femur, phalanges, radius, ulna, etc. |
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SHORT BONES
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cube shaped bones of the wrist &
ankle bones that form within tendons (ex. patella) |
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FLAT BONES
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thin, flattened, & a bit curved
(sternum, skull bones) |
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IRREGULAR BONES
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bones with complicated shapes
(ex. vertebrae, hip bones) |
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FUNCTION OF BONES
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Support (bones are primary support
involved in sitting, standing, etc) Protection (ex. skull, thorax, vertebrae Movement (ex. levers, joints) Mineral Storage (resevoir for Ca, P) Hematopoiesis ( formation of BC) |
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BONE STRUCTURE
Compact Bone |
The external layer
Visible part of bone |
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What is the structural unit of compact bone?
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Osteon
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BONE STRUCTURE
OSTEON description function |
Elongated cylinder oriented parallel
to long axis of the bone Grouping of bony tubes (called lamellae) Serves as weight bearing pillars |
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BONE STRUCTURE
How are collagen fibers arranged in the lamellae? What is the purpose of this? |
Collagen fibers in alternating lamellae run in alternating directions
This allows for great resistance to torsional stress |
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BONE STRUCTURE
Haversian canal what is it? location |
A canal filled with a blood vessel & a
nerve Located in the osteon |
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BONE STRUCTURE
Volkmans Canal what is it location which way does it run? |
Canal that connects the blood supply
of the osteon to the fibrous covering of bone called the periosteum. Osteon Runs left & right. perpendicular |
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BONE STRUCTURE
Osteocytes what are they where are they found |
Mature bone cells
Lie on the edge of the lamellae (in the osteon) |
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BONE STRUCTURE
CANALICULI |
tiny canals through which Cell to cell connections occur
Allows for cel to cell communication & transport of nutrients & waste |
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SPONGY BONE
What does it contain? Where does it accumulate? What is its function? |
Contains bony struts called
traneculae (only few cells thick) Occur in areas of stress points Built to provide structural stability (similar to the idea of an arch) |
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CHEMICAL COMPOSITION OF BONE
Is bone made of organic or inorganic constituents? |
Contains both organic & inorganic
constituents |
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ORGANIC CONSTITUENTS OF BONE
What is it comprised of? What does osteoid do? What does collagen do? |
Comprised of osteoid (glycoproteins,
proteoglycans & collagen fibers-main component) & several types of bone cells Osteoid contributes to flexibility & strength of bone Collagen forms sacrificial bonds that help to dissipate energy |
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INORGANIC CONSTITUENTS OF BONE
describe it what is it comprised of what may it also contain? |
Tightly packed crystals of mineral salts called hydroxyapatite
Comprised mostly of calcium phos phate May also contain Mg, Na, K, Carbona te, & heavy metals |
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INORGANIC CONSTITUENTS OF BONE
Mechanism of deposition? Function? |
Polymerization (can connect with
each other to form long chains) of collagen Allows for calcium salt precipitation, & formation of HAP crystals |
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SKELETAL TISSUE CELLS: OSTEOBLASTS
Where is it derived from? Function? What does it contain? Where is it located |
Derived from the mesenchyme
Function: secretes components of osteoid, contains important matrix proteins, mineralizes osteoid. Contains proteins: osteocalcin, osteopontin (binds calcium, promotes mineralization) Organic portion of bone |
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SKELETAL TISSUE CELLS: OSTEOCLASTS
what are they? what are they similar to? function? what does it contain? |
Multinucleate cells, derived from
bone marrow. Similar to macrophages F: bone resorption (combine to bone using integrins to hold on to bone) Contains intracytoplasmic acidifying vesicles that demineralize bone |
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What happends to the bone when there is too much resorption?
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Weakened, brittle bone
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SKELETAL TISSUE CELLS: OSTEOCYTES
Derived from? Contains? Function? What does strain do? |
Derived from "trapped" osteoblasts
(only until signaled back into osteo blasts) Contains: Sensory cells that form a network of communication with the bone F: May act as mechanosensory cells F: Conveys info relating to the microenvironment of the neighborin bone Strain may initiate signaling of osteoblasts/osteoclasts |
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BONE MARROW
How many types of bone marrow are there? What are they called? |
2 Types
Red Yellow |
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YELLOW MARROW
What is it? What is its function? |
Mostly adipose tissue
Used as an energy reserve |
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RED MARROW
Contains? |
Contains pluripotential stem cells from which all circulating blood cells are derived
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STEM CELLS
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Undifferentiated cells that can be signalled to make necessities
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STEM CELLS DIFFERENTIATION: PROERYTHROBLASTS
what are they? where do they develop? what do they develop into? how many generations? what does it regulate? |
Newly forming immature RBCs
Develop in the bone marrow into erythrocytes Several generations, each successive step gains more Hgb Regulation: erythropoietin |
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ERYTHROCYTES
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Anucleate
Short living because of no nucleus so they must constantly reproduce |
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ERYTHROPOIETIN
what is it what does it do what does it secrete? |
hormone
promotes formation of proethryroblas ts secreted by kidneys when 02 levels are low |
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MEGAKARYOCYTES
what is it? what is it regulated by? |
Huge cell type that gets fragmented
into smaller cells called platelets Regulated by thrombopoietin & interleukins |
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PLATELETS
what are they? what is a special feature of them? |
Fragments of a cell, not cells of their
own Anucleate Biochemically active |
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PHAGOCYTIC CELLS
what does it produce? What does it regulate? |
Produce a wide variety of WBCs
Regulates granulocyte Stimulating Factor (secreted by other cells) |
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WHITE BLOOD CELLS
what is their primary role? Example? |
Predominately involved in immunity
(ex. anitbodies) |
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LYMPHATIC CELLS
what are they? |
B & T Cell pathways
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B CELLS
what are they what do they do? |
Immunoglobulin secreting
Signals T cells to come & kill the antigen |
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T CELLS
what are they? where do they travel? what is so special about these cells |
Killer Cells
Travel through thymus glands They are the only cells that can recognize the difference between good cells & antigens. |
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HORMONE CONTROL
Name 3 ways hormones are controlled in bone |
Bone Growth
Bone Remodeling Calcium Homeostasis |
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BONE GROWTH
what is it stimulated by? What are the steps of bone growth? |
Stimulated by Growth Hormone (GH)
1. Secreted by Anterior Pituitary 2. GH binds to liver 3. GH secretes insulin growth factor (IGF-1) 4. IGF-1 binds to cartilage & stimul ates movement of chondroblasts from G1 to S phase. |
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CALCIUM HOMEOSTASIS
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Maintained by the parathyroid horm
one |
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PARATHYROID HORMONE
what is it secreted by? what does it increase/decrease? |
secreted by parathyroid gland
increases calcium reabsorption from bone decreases renal calcium excretion |
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PARATHYROID GLAND
where is it located? what does it contain? what does it secrete? |
Located near thyroid gland but can
be ectopic (in chest) Contains calcium receptors that signal to either make more or less calcium Secretes parathyroid hormone |
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CALCITONIN
secreted by? what does it reduce/decrease? |
Secreted by parafollicular cells of the
thyroid Reduces calcium levels in the blood decreases osteoclast activity decreases formation of new osteocl asts |
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BONE HEALTH
Name the molecules that contribute to bone health |
Vitamin A
Vitamin D Vitamin C Alkaline Phosphate |
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VITAMIN A
why is this important for bone health |
Important in the balance of mineral
deposition & resorption as well as cell growth |
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VITAMIN D
what does it do? |
Acts as a steroid in the intestine to
increase the production of a transporter protein which increases calcium absorption |
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VITAMIN C
what does it do? what is a unique characteristic about it? where is it located? |
involved in collagen synthesis
water soluble Makes up organic portion of bone |
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ALKALINE PHOSPHATE (ALP)
Secreted by? what is it? what does it do? |
Secreted by osteoblasts, kidneys, &
other organs It is an enzyme that is essential for collagen mineralization ALP splits phosphorous compounds which can combine with calcium to form Hydroxyapatite (HAP) |
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OSTEOGENESIS
what does it mean? how many types are there? what are the types? |
bone formation & growth
2 types intramembranous & endochondral |
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INTRAMEMBRANOUS
what is it? |
bone formation from fibrous tissue
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ENDOCHONDRAL
what is it? |
bone fromation from hyaline cartilage
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ENDOCHONDRAL OSSIFICATION
when does it begin? how does it know where to form bone? what does it require? |
-begins in the second month of development
-uses hyaline cartilage "bones" as models for bone construction -requires breakdown of hyaline cartilage prior to ossification |
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STAGES OF INTRAMEMBRANOUS
OSSIFICATION explain the 4 stages |
1. An ossification center appears in the fibrous connective tissue membrane
2.bone matrix is secreted w/in fibrous tissue 3.Woven bone & periosteum form 4.Bone collar of compact bone forms & red marrow appears |
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WHAT IS AN OSSIFICATION CENTER?
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place where bones form
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STAGES OF ENDOCHONDRAL OSSIFICATION
explain the 5 stages |
1. Formation of bone collar
2. Cavitation of the hyaline cartilage 3.Invasion of internal cavities by periosteal bud & spongy bone formtn 4.Formation of medullary cavity, appearance of secondary ossification centers in epiphyses 5. Ossification of epiphyses, with hyaline cartilage remaining only in the epiphyseal plates. |
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POSTNATAL BONE GROWTH
name 3 things that happen in terms of growth in the length of long bones |
Growth in length of long bones
*cartilage on side of epiphyseal plate closest to epiphysis is relatively inactive *cartilage abutting shaft of bone organizes into pattern that allows fast, efficient growth *cells of epiphyseal plate proximal to resting cartilage form 3 functionally different zones: growth, transformation, & osteogenic |
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FUNCTIONAL ZONES IN LONG BONE GROWTH
Growth Bone |
Cartilage cells undergo mitosis,
pushing epiphysis away from diaphysis |
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FUNCTIONAL ZONES IN LONG BONE GROWTH
Transformation Zone |
older cells enlarge, matrix becomes calcified, cartilage cells die, matrix begins to deteriorate
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FUNCTIONAL ZONES IN LONG BONE GROWTH
Osteogenic Zone |
new bone formation occurs
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LONG BONE GROWTH
what happends here? |
cartilage continulally grows and is replaced by bone
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REMODELING
what happends to bone here? |
bone is resorbed & added by appositional growth
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