Ch 6 Osseous Tissue and Bone Structure PDF

CH 6: Osseous Tissue and Bone Structure  6.1 © 2015 Pearson Education, Inc.  Module 6.1: The Skeletal System Skeletal system components Bones (~206 total) Divisions 1. Ax...

CH 6: Osseous Tissue and Bone Structure  6.1 © 2015 Pearson Education, Inc.  Module 6.1: The Skeletal System Skeletal system components Bones (~206 total) Divisions 1. Axial skeleton (80 bones) Bones of skull, thorax, and vertebral column Form longitudinal axis of body 2. Appendicular skeleton (126 bones) Bones of the limbs and girdles (pectoral and pelvic) that attach them to the axial skeleton Associated cartilages Ligaments and other connective tissues © 2015 Pearson Education, Inc. Divisions of the skeletal system Axial Skeleton (80 Bones) Appendicular Skeleton (126 Bones) Figure 6.1 1 © 2015 Pearson Education, Inc.  …and calcium homeostasis Figure 6.1 2 © 2015 Pearson Education, Inc.  6.2 © 2015 Pearson Education, Inc.  Module 6.2: Bone Classification and Surface Markings Six categories of bone based on shape 1. Flat bones 2. Sutural bones 3. Long bones 4. Irregular bones 5. Sesamoid bones 6. Short bones © 2015 Pearson Education, Inc. Classification of bones Sutural Bones Flat Bones Sutures Parietal bone Sutural bone Long Bones Irregular Bones Humerus Vertebra Sesamoid Bones Short Bones Patella Carpal bones Figure 6.2 1 © 2015 Pearson Education, Inc.  Module 6.2: Bone Classification and Surface Markings Surface markings Also known as bone features (projections, depressions, and openings related to particular functions) Related to particular functions Elevations/projections Tendon and ligament attachment At joints where adjacent bones articulate Depressions/grooves/tunnels/openings Sites for blood vessels or nerves to lie alongside or penetrate bone © 2015 Pearson Education, Inc.  Module 6.2: Bone Classification and Surface Markings Surface markings – general Head Expanded proximal end of a bone that forms part of a joint Diaphysis (shaft) Elongated body of a long bone Neck Narrow connection between the head and diaphysis of a bone © 2015 Pearson Education, Inc.  Module 6.2: Bone Classification and Surface Markings Surface markings – elevations or projections Process – any projection or bump Tubercle – small, rounded projection Tuberosity – small, rough projection that takes up a broad area Trochlea – smooth, grooved articular process shaped like a pulley Condyle – smooth, rounded articular process © 2015 Pearson Education, Inc. Surface features of the skull Sinus Canal or Meatus Foramen Process Fissure Figure 6.2 2 © 2015 Pearson Education, Inc. Surface features of the humerus and femur Head Trochanter Head Tubercle Sulcus Neck Tuberosity Diaphysis (shaft) Diaphysis Trochlea Facet Condyle Condyle Figure 6.2 2 © 2015 Pearson Education, Inc.  Module 6.2: Bone Classification and Surface Markings Surface markings – elevations or projections (continued) Trochanter – large, rough projection Facet – small, flat articular surface Crest – prominent ridge Line – low ridge, more delicate than a crest Spine – pointed or narrow process Ramus – extension of a bone that makes an angle with the rest of a structure © 2015 Pearson Education, Inc.  Module 6.2: Bone Classification and Surface Markings Surface markings – depressions, grooves, and tunnels Canal or meatus – large passageway through a bone Sinus – chamber within a bone, normally filled with air Foramen – small, rounded passageway for blood vessels or nerves to pass through bone Fissure – elongated cleft or gap Sulcus – deep, narrow groove Fossa – shallow depression or recess in bone surface © 2015 Pearson Education, Inc. Surface features of the pelvis Crest Fossa Line Spine Ramus Figure 6.2 2 © 2015 Pearson Education, Inc.  6.3 © 2015 Pearson Education, Inc.  Module 6.3: Functional Anatomy of a Long Bone Long bone features (humerus is an example) Epiphysis (expanded area at each end of the bone) Consists largely of spongy bone Network of struts and plates Resists forces from various directions and directs body weight to diaphysis and joints Outer covering of compact bone (cortical bone) Strong, organized bone Articular cartilage Covers portions of epiphysis that form articulations Avascular, so relies on diffusion from synovial fluid for nutrient delivery and waste elimination © 2015 Pearson Education, Inc. Functional anatomy of a long bone Body weight (applied force) Spongy bone Epiphysis Metaphysis Compact bone Tension Medullary cavity on lateral side of Diaphysis Compression shaft on medial side of shaft Metaphysis Epiphysis Figure 6.3 1 – 2 © 2015 Pearson Education, Inc.  Module 6.3: Functional Anatomy of a Long Bone Long bone features (continued) Metaphysis (connects epiphysis to shaft) Diaphysis (shaft) Long, tubular portion of the bone Wall composed of thick layer of compact bone Contains medullary cavity (marrow cavity) Filled with two types of marrow Red bone marrow (involved in red blood cell production) Yellow bone marrow (adipose tissue; important as energy reserve) © 2015 Pearson Education, Inc.  Module 6.3: Functional Anatomy of a Long Bone Growth and maintenance require extensive blood supply Vascular features Nutrient artery and nutrient vein (commonly one of each per bone) Nutrient foramen (tunnel providing access to marrow cavity) Supply osteons of compact bone with blood Metaphyseal artery and metaphyseal vein Carry blood to/from metaphysis Connect to epiphyseal arteries/veins © 2015 Pearson Education, Inc. Blood supply to osseous tissue Articular cartilage Epiphyseal artery and vein Metaphysis Metaphyseal artery (red) and vein (blue) Periosteum Compact Nutrient artery (red) bone and vein (blue) Medullary cavity Nutrient foramen Metaphyseal artery and vein Metaphysis Epiphyseal line Figure 6.3 3 © 2015 Pearson Education, Inc.  6.4 © 2015 Pearson Education, Inc.  Module 6.4: Bone Tissue Four cell types 1. Osteocytes (osteo-, bone + cyte, cell) Mature bone cells that cannot divide Maintain protein and mineral content of surrounding matrix Dissolve matrix to release minerals Rebuild matrix to deposit mineral crystals Occupy lacunae (pockets) Separated by layers of matrix (lamellae) Interconnected by canaliculi © 2015 Pearson Education, Inc.  Module 6.4: Bone Tissue Four cell types (continued) 2. Osteoblasts (blast, precursor) Produce new bony matrix (process called osteogenesis or ossification) Osteoblasts makes and release proteins and other organic components to produce un-mineralized matrix (“pre-bone” organic matrix called osteoid) Osteoblasts then deposit calcium salts to convert osteoid to bone Osteoblasts become osteocytes once surrounded by bony matrix © 2015 Pearson Education, Inc.  Module 6.4: Bone Tissue Four cell types (continued) 3. Osteogenic cells (osteoprogenitor cells) Mesenchymal (stem) cells that produce cells that differentiate into osteoblasts Important in fracture repair Locations Inner lining of periosteum Lining endosteum in medullary cavity Lining passageways containing blood vessels © 2015 Pearson Education, Inc.  Module 6.4: Bone Tissue Four cell types (continued) 4. Osteoclasts (clast, to break) Remove and remodel bone matrix Giant cells with 50 or more nuclei Derived from same stem cells as macrophages Release acids and proteolytic enzymes to dissolve matrix and release stored minerals Process called osteolysis (lysis, loosening) © 2015 Pearson Education, Inc. Cell types found in bone tissue Lamellae Endosteum Osteogenic cell Lacuna Canaliculi Osteoclast Nuclei Osteoblast Osteoid Figure 6.4 1 – 4 © 2015 Pearson Education, Inc.  Module 6.4: Bone Tissue Bone matrix Collagen fibers account for ~1/3 bone weight Provide flexibility Calcium phosphate (Ca3(PO4)2) accounts for ~2/3 bone weight © 2015 Pearson Education, Inc.  6.5 © 2015 Pearson Education, Inc.  Module 6.5: Compact and Spongy Bone Structure Compact bone Functional unit is osteon Organized concentric lamellae (Greek work lamina means thin plate) around a central canal Osteocytes (in lacunae) lie between lamellae Central canal contains small blood vessels Canaliculi connect lacunae with each other and central canal Because compact bone does not contain capillaries, it receives nutrients through its canaliculi. Strong along its length © 2015 Pearson Education, Inc.  Capillary and venule (small vein) Central canal Central canal Concentric lamellae Canaliculi Osteon Endosteum Compact bone Osteocytes in lacunae Figure 6.5 1 © 2015 Pearson Education, Inc. Module 6.5: Compact and Spongy Bone Structure Long bone organization Periosteum – outermost layer Compact bone – outer bone tissue layer Circumferential lamellae (circum-, around + ferre, to bear) at outer and inner surfaces Interstitial lamellae fill spaces between osteons Osteons Contain central canals (parallel to bone surface) Central canals are connected by perforating canals (perpendicular to surface) Spongy bone – innermost layer Periosteum Circumferential lamellae Vein Artery Interstitial lamellae Central canal Perforating canal  Module 6.5: Compact and Spongy Bone Structure Spongy bone Located where bones are not heavily stressed or stress is in many directions Lamellae form struts and plates (trabeculae) creating an open network Reduces weight of skeleton Red bone marrow is found between trabeculae Trabeculae are organized along stress lines (lines of the greatest stress in the bone) © 2015 Pearson Education, Inc. Trabeculae of spongy bone Trabeculae of Canaliculi Endosteum Lamellae spongy bone opening on surface Figure 6.5 4 © 2015 Pearson Education, Inc.  6.6 © 2015 Pearson Education, Inc.  Module 6.6: Appositional Bone Growth Appositional growth in bones Increases bone diameter of existing bones (bones get wider) Does not form original bones Osteogenic cells differentiate into osteoblasts that add bone matrix under periosteum Adds successive layers of circumferential lamellae Trapped osteoblasts become osteocytes © 2015 Pearson Education, Inc. Circumferential lamellae added through appositional growth Slide 1 Additional circumferential lamellae are deposited, and the bone continues to increase in diameter. Periosteum Figure 6.6 1 © 2015 Pearson Education, Inc.  6.7 © 2015 Pearson Education, Inc.  Module 6.7: Endochondral Ossification Endochondral ossification Initial skeleton of embryo formed of hyaline cartilage Cartilage gradually replaced by bone through endochondral (endo-, inside + chondros, cartilage) ossification Uses cartilage as small model Bone grows in diameter and length Diameter growth involves appositional bone deposition © 2015 Pearson Education, Inc.  Module 6.7: Endochondral Ossification Steps in endochondral ossification 1. Cartilage model enlarges 2. Blood vessels grow around the edge of the cartilage model 3. Blood vessels penetrate cartilage and enter central region 4. Growth continues along with remodeling 5. Capillaries and osteoblasts migrate into the epiphyses, forming secondary ossification centers 6. Epiphyses fill with spongy bone 7. Bone grows in length at the epiphyseal cartilage © 2015 Pearson Education, Inc. Endochondral ossification Slide 1 Hyaline cartilage Articular cartilage Enlarging Articular chondrocytes Spongy cartilage within bone Epiphysis calcifying matrix Medullary Epiphysis Metaphysis cavity Epiphyseal Primary cartilage ossification Medullary Epiphyseal Blood cavity Periosteum Diaphysis line vessel center Compact Spongy bone bone Superficial Diaphysis bone Bone Spongy Metaphysis Medullary formation bone cavity Hyaline cartilage bone Secondary model ossification center Figure 6.7 1 – 7 © 2015 Pearson Education, Inc. Module 6.7: Endochondral Ossification Bone growth At puberty, hormones stimulate increased bone growth, and epiphyseal cartilage is replaced Osteoblasts produce bone faster than chondrocytes produce cartilage Epiphyseal cartilage narrows until it disappears Process called epiphyseal closure Leaves epiphyseal line in adults Epiphyseal line  6.8 © 2015 Pearson Education, Inc. Module 6.8: Intramembranous Ossification Some bones form without a cartilaginous model Process called intramembranous ossification Begins when mesenchymal (stem) cells / osteogenic cells within the embryonic ,or fibrous connective tissue, differentiate into osteoblasts Normally occurs in deeper layers of dermis Bones called dermal bones or membrane bones Examples of dermal bones: roofing bones of skull, lower jaw, collarbone, sesamoid bones (patella) Osteogenic = mesenchymal stem cell – interchangeable – know both terms! Module 6.8: Intramembranous Ossification Steps of intramembranous ossification 1. At an ossification center Mesenchymal / cells secrete osteoid matrix Osteoid matrix becomes mineralized 2. Bone grows out in small struts (spicules) 3. Blood vessels enter area 4. Continued deposition of bone by osteoblasts close to blood vessel 5. Remodeling around blood vessels produces osteons of compact bone Intramembranous ossification Slide 1 Mesenchymal Bone Blood Spicules Osteocytes Osteoblast Fibrous Cellular Osteoid cell matrix vessel in lacunae layer periosteum periosteum Ossification Osteoblast Osteocyte Blood vessel trapped Blood vessels Blood vessel trapped center within bone matrix within bone matrix Steps of intramembranous ossification 1. Mesenchymal stem cells (osteoenic) cluster together, differentiate into osteoblasts, osteoblast make the “pre-bone” matrix (called the osteoid) – the location where this ossification is occurring is called the “ossification center” 2. Bone grows out in small struts (spicules) 3. Blood vessels enter area 4. Continued deposition of bone by osteoblasts (remember that osteocytes – mature bone cells – develop from osteoblasts) close to blood vessel 5. Remodeling around blood vessels produces osteons of compact bone Figure 6.8 1 – 5 Module 6.9: CLINICAL MODULE: Abnormalities in Bone Growth Disorders causing shortened bones Pituitary growth failure Inadequate growth hormone production Reduced epiphyseal cartilage activity; abnormally short bones Rare in United States due to treatment with synthetic growth hormone Module 6.9: CLINICAL MODULE: Abnormalities in Bone Growth Disorders causing shortened bones (continued) Achondroplasia Epiphyseal cartilage of long bones grows slowly Replaced by bone early in life Short, stocky limbs result Trunk is normal size No effects on sexual or mental development Module 6.9: CLINICAL MODULE: Abnormalities of Bone Growth Disorders causing lengthened bones Marfan’s syndrome Inherited metabolic condition Excessive cartilage formation at epiphyseal cartilages Results in very tall person with long, slender limbs Affects other connective tissues throughout the body Commonly causes cardiovascular problems Module 6.9: CLINICAL MODULE: Abnormalities of Bone Growth Disorders causing lengthened bones Gigantism Overproduction of growth hormone before puberty Can reach heights of over 2.7 m (8 ft. 11 in.) Puberty often delayed Most common cause is a pituitary tumor Treated by surgery, radiation, or medications suppressing growth hormone release Module 6.9: CLINICAL MODULE: Abnormalities of Bone Growth Other skeletal growth abnormalities Acromegaly Overproduction of growth hormone after epiphyseal plates close Bones get thicker, not longer Especially those in face, jaw, and hands Alterations in soft-tissue structure changes physical features Irreversible changes prevented with early diagnosis and treatment with pituitary surgery and/or medications that reduce growth hormone levels Module 6.9: CLINICAL MODULE: Abnormalities of Bone Growth Other skeletal growth abnormalities Fibrodysplasia ossificans progressiva (FOP) Gene mutation that causes bone deposition around skeletal muscles Bones develop in unusual places No effective treatment Life span of patients only into their 40s Module 6.9: CLINICAL MODULE: Abnormalities of Bone Growth Other skeletal growth abnormalities Congenital talipes equinovarus (clubfoot) Inherited developmental abnormality Affects 2 in 1000 births Boys roughly twice as often as girls Abnormal muscle development distorts growing bones Feet turn medially and are inverted Treated with casts or supports (fewer than half of cases require surgery)  6.10 © 2015 Pearson Education, Inc. Module 6.10: Bones as Mineral Reservoirs Bones are important mineral reservoirs Minerals Inorganic ions contributing to the osmotic balance of body fluids Vital in many physiological processes Bone composition 67 percent inorganic components 33 percent organic components (primarily collagen) Bones contain 99 percent of the body’s calcium Bone Composition Bone Contains Calcium 39% 99% of the body’s calcium Potassium 0.2% 4% of the body’s potassium Sodium 0.7% 35% of the body’s sodium Organic Magnesium 0.5% 50% of the body’s magnesium compounds Carbonate 9.8% 80% of the body’s carbonate (mostly collagen) 33% Phosphate 17% 99% of the body’s phosphate Total inorganic 67% components Module 6.10: Bones as Mineral Reservoirs The importance of calcium Most abundant mineral in body ~99 percent deposited in skeleton Variety of physiological functions (muscle contraction, blood coagulation, nerve impulse generation) Concentration variation greater than 30–35 percent affects neuron and muscle function Normal daily fluctuations are