7Bone Markings: Depressions and Openings MeatusCanal-like passagewaySinusCavity within a boneFossaShallow, basinlike depressionGrooveFurrowFissureNarrow, slitlike openingForamenRound or oval opening through a bone
9Cartilage – Three types Hyaline – Most abundantArticular cartilages – cover the ends of bones at moveable jointsCostal cartilages – connect the ribs and sternumLaryngeal cartilages – for the skeleton of the larynx (voice box)Tracheal and bronchial cartilages – reinforce the respiratory passagesNasal cartilages – support the external nose.
10Cartilage Elastic – Contains more stretchy elastic fibers. Found in the external ear and form the epiglottis, the flap that closes on the larynx when you swallow.Fibrocartilage – Rows of chondrocytes and thick collagen fibersVery high tensile strength and compressible. Found between the vertebral disks, the pad-like cartilages of the knee, and the pubic symphysis.
11Cartilage Cartilage grows in two ways: Appositional growth – growth from the outside.Interstitial growth – growth from within.
12Functions of BonesSupport – Bones give shape and support to the entire body and provide places for organs to attach. Allows standing, etc.Protection – Cranial bones protect the brain, vertebrae protect the spinal cord, rib cage protects the thoracic organs.Movement – Skeletal muscles, which are attached to bone by tendons, use bones to move the body and its parts.
13Functions continuedMineral storage - Calcium and phosphorus are stored in bones and are constantly being deposited and withdrawn.Blood cell formation – AKA hematopoiesis occurs in the marrow of certain bones.
14Four Classes of Bone (bases on shape) Long Bones – Longer than they are wide. Consist of a shaft and 2 ends. All bones of the limbs are long bones except the carpals, tarsals, and patella.Short Bones – Roughly cube-like. Tarsals and carpals.Flat Bones – Thin, flat, and usually somewhat curved. Sternum, ribs, scapula, and cranial bones.
15Four Classes of BoneIrregular Bones – Bones that don’t fit any of the previous shapes. Vertebrae and pelvic bones.
16Structure of BonesTwo layers. The external layer that appears smooth and solid is compact bone. Internal to this is the spongy bone.Spongy bone is comprised of small, needle-like pieces called trabeculae that form a honeycomb. The spaces between trabeculae are filled with red or yellow bone marrow.Long bones are primarily compact bone, but may have a fair amount of spongy bone.Flat bones have two parallel layers of compact bone with a layer of spongy bone between.
17General Structure of Long Bones Diaphysis – The shaft or long axis of the bone. It has a thick collar of compact bone that surrounds the central medullary cavity that contains fat (yellow bone marrow).Epiphysis – The ends of the bone consisting of the distal epiphysis and proximal epiphysis. The exterior is compact bone while the interior is spongy bone. The joint surfaces of each are covered with a thin layer of articluar (hyaline) cartilage which absorbs stress and cushions during movement.
22Location of Red Bone Marrow Red marrow is known as hematopoietic tissue because it gives rise to blood cells.Typically found within the cavities of spongy bone.In adults, the medullary cavity extends into the epiphyses, and a little red marrow is found in most long bones. Blood cell production is limited to the head of the femur and humorous.
23Location of Red Bone Marrow More important are the flat bones (sternum) and irregular bones (pelvic bones).Yellow marrow can be converted to red marrow if a person becomes anemic and needs enhanced Red Blood Cell production.
27Pages 3&4 of notes will be on a WS Bone TissuePages 3&4 of notes will be on a WS
28Composition of bone tissue Bone tissue is composed of 2 types of tissuesOrganicInorganic
29Organic portion: 35% of mass The organic portion consists of the bone cells and the organic matrixThe Bone cells are the:OsteocytesOsteoblastsOsteoclastsFYI: There are also osteoprogenitor cells that are the precursers to blasts & cytes. They are derived from mesenchyme & found on all bone surfaces.
31Organic portion The Organic Matrix aka. Osteoid is produced by the osteoblastsAnalogy: The organic matrix is the portion that is deposited first as the “grillwork” or framework of the bone during the process of OSTEOGENESISIt consists of ground substance and collagen fibers produced by CT cellsIts function is to provide the bone with tensile strength and resilience – in other words, to make the bone a little flexibleReview: ground substance, collagen fibers & EC matrix functions!!
32Inorganic matrix: 65% of mass The inorganic matrix consists of inorganic salt compounds mainly:Calcium & phosphorus salt compoundsIts function is to give Strength to the boneAnalogy: It is formed during OSTEOGENESIS by the process of MineralizationThe inorganic matrix minerals are deposited into the organic matrix “grillwork”The enzyme alkaline phosphatase mediates this process
33Two types of bone tissue Know slides, locations, functions
34Compact bone tissue (cbt) Arranged in OSTEONS aka Haversian systemContains a series of openings that permit exchange of materials between osteocytes (& other bone cells) and the blood.Location: look at diagrams
38Cancellous (spongy) bone tissue Main structures are the trabeculae which are needlelike structures of minerals that are arranged along stress lines to provide strengthMaterials are exchanged by diffusion since there are NO canals for passageLocation: ends of long bones & middle of flat, short, and irregular bones
41Bone marrow Aka myeloid tissue Yellow bone marrow Red bone marrow Fat storageFound in medullary canal of long bonesRed bone marrowFound in spongy bone (ends of long bones, flat bones, irregular bones)Hematopoiesis (formation of all blood cells)
44Types of growthLongitudinal growth – bone growth in length at epiphyseal plates (till plates ossify)Appositional growth – bone growth in diameter (throughout life)Known as remodelingThese 2 types work together to make the bones long enough & strong enough
45Regulation of bone growth Bone is a dynamic and active tissue. They are constantly being remodeled according to the activities that we do.Main factor = Ca levels in bloodCa imp for bone strength but also for nervous & muscular system to work correctly!!!
46Regulation by hormonal feedback Purpose: to maintain optimal ionic calcium levels in bloodThis is your body’s TOP priority!!!A main factor that affects what our bone tissue does is our blood calcium levelOptimum blood Ca 2+ level = 9-11 mg/100 ml of bloodCalcium ions are VERY important for muscle & nervous function – our body cares more about this level than it does our bone strength!!
48Regulation by hormonal feedback PTH (parathyroid gland) – activated when Ca levels in blood are too low(hypocalcemia) - promotes calcium reabsorptionCalcium will go from bone to bloodCalcitonin (thyroid gland) activated when Ca levels in blood are too high(hypercalcemia) - promotes calcium depositionCalcium will go from blood to bone
49Regulation by mechanical stress Purpose: keep bones strongThis is the secondary purposeWolff’s law states that bones will grow according to the stresses placed upon themSo activities that compress bones and pull on muscles which pull on bones can make bones stronger
50How they work together to regulate PTH & calcitonin (hormones) determine WHEN the remodeling will occurPrimary purpose = Ca 2+ regulation in bloodThe Mechanical stresses determine WHERE the remodeling will occurSecondary purpose = where will the calcium ions be deposited or reabsorbed from
51Fractures & DisordersThis section of info will be part of a lab practical quiz along with the tissue slides & functions from earlier in the notes
52InstructionsConstruct a chart or other type of graphic organizer for the 9 types of fracturesYou will also need to be able to identify the X-rays or pictures of each.See Lab practical slide study on webpage for quiz review.
53Common types of fractures 1. ComminutedBone breaks into many fragmentsCommon in aged whose bones are more brittle (contain less organic matrix)
54Common types of fractures 2. CompressionBone is crushedCommon on osteoporotic bones (or bones that are porous for other reasons)
55Common types of fractures 3. DepressedBroken bone portion is pressed inwardTypical of skull fracture
56Common types of fractures 4. ImpactedBroken bone ends are forced into each otherCommonly occurs when one attempts to break a fall with outstretched armsOr when one jumps off something too high
69Osteoporosis Define: Who is affected? reabsorption outpaces deposition chemical composition remains the same BUT less total bone massSO bones become more porous & lighterWhich leads to fractures & deformities from body weightWho is affected?Mainly: Aged, post-menopausal women
70osteoporosis Contributing factors Treatments Decreased estrogen Decreased calcium & proteinVitamin D metabolic disordersHormone conditionsInsufficient exerciseImmobilityTreatmentsReplace what is missingMedication for metabolic disorders
72Osteomalacia (rickets) Define:Chemical composition is abnormal (% are not right)Increase in organic matrix – decrease in inorganic matrixIndequate mineralization so bones are too softLack of calcium depositionWho is affected?More severe effects in children since they are still growingbut primarily a nutritional disorder
73osteomalacia Contributing factors: Treatments: Vitamin D &/or calcium deficiencyPoor nutritionTreatments:SupplementationSunlight: think about why Vitamin D deficiency would lead to this disorder!
75Other disorders – add to notes Osteomyolitis: inflammation of bone and muscleGigantism: excess of growth hormone before epiphyseal plates have ossifiedAcromegaly: excess of growth hormone after epiphyseal plates have ossifiedDwarfism: deficit of growth hormone as well as other factorsAchondroplasia: most common form of dwarfism– autosomal dominant but can be from mutation
76gigantism Robert Wadlow Lots of internal health problems including joint problems
77acromegalyEpiphyseal plates are sealed so bones can only grow in diameter/thickness
78achondroplasia Disproportionate dwarfism Normal torso & head Short arms & legs
79Hypopituitary dwarfism More proportionate dwarfism