Skeletal System PDF

The Skeletal System Classification of bones 1. Long - humerus, radius, ulna, metacarpals, phalanges, femur, tibia, fibula, metatarsals 2. Short - tarsals/carpals 3. Flat or membranous - ilium, sternum, scapula, flat bones of skull, ribs 4. Sesamoid - form w/in tendons - patella, als...

The Skeletal System Classification of bones 1. Long - humerus, radius, ulna, metacarpals, phalanges, femur, tibia, fibula, metatarsals 2. Short - tarsals/carpals 3. Flat or membranous - ilium, sternum, scapula, flat bones of skull, ribs 4. Sesamoid - form w/in tendons - patella, also often found at the base of 1st metacarpal and 1st metatarsal bones - Copyright © 2002 Michael H. Mitchell – All Rights Reserved Figure 6.6 Classifications of Bones Bones are classified according to their shape. From Openstax free textbook, Human Anatomy and Physiology. Figure 6.7 Anatomy of a Long Bone A typical long bone shows the gross anatomical characteristics of bone. From Openstax free textbook, Human Anatomy and Physiology.  Diploe Figure 6.9 Anatomy of a Flat Bone This cross-section of a flat bone shows the spongy bone (diploe) lined on either side by a layer of compact bone. From Openstax free textbook, Human Anatomy and Physiology.  General Structures - Diaphysis - shaft of a long bone - walls are compact bone - Medullary Cavity - "bone marrow" cavity - Red Marrow - Hemopoietic which means it produces blood cells - Yellow Marrow - fat - most of the medullary cavities of adults are filled w/ fat - Epiphysis - ends of the long Copyright © 2002 Michael H. Mitchell – All Rights Reserved  - Articular cartilage - smooth, slick Hyaline cartilage that coats the surfaces –where two bones Aticulate (meet) (the articular surfaces) - Periosteum - OUTER Dense Irregular C.T. covering of bone - within the periosteum, next to the bone are found osteoblasts and osteoclasts - Endosteum - INNER Dense Irregular C.T. that lines the Medullary Cavity, etc. © 2002 Michael H. Mitchell – All Rights Reserved Copyright Figure 6.8 Periosteum and Endosteum The periosteum forms the outer surface of bone, and the endosteum lines the medullary cavity. From Openstax free textbook, Human Anatomy and Physiology.  Microscopic Details of Compact Bone (seen in Histology portion of lab) - Histologies - Human Compact Bone – Ground - in lab Haversian System/Osteon = Structural unit of compact bone - Haversian canal - run through the center of the osteons and contain nerves, arteries, and veins - which supply the bone - 2002 Copyright © Volkmann's/Perforating Michael H. Mitchell – All Rights Reserved Canal - Figure 6.12 Diagram of Compact Bone (a) This cross-sectional view of compact bone shows the basic structural unit, the osteon. (b) In this micrograph of the osteon, you can clearly see the concentric lamellae and central canals. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School c 2012) From Openstax free textbook, Human Anatomy and Physiology.  Central Canal Osteon or Haversion System  Canaliculi – tiny little Lamellae (the 2. Interstitial Lamellae – tubes connecting layers) remnants of old osteon lacunae 1. Concentric between the new osteons 2. Interstitial 1. Concentric Lamellae – they make concentric circles – like a target Osteon or Haversion System Central Canal Lacunae – the small dark ovals – these contain osteocytes  1. Concentric Canaliculi – tiny little Lamellae – they make tubes connecting concentric circles – Central Canal lacunae like a target Lamellae (the layers) 1. Concentric 2. Interstitial Lacunae – the small dark ovals – these contain osteocytes Osteon or Haversion System 2. Interstitial Lamellae – remnants of old osteon between the new osteons Figure 6.12 Diagram of Compact Bone (a) This cross-sectional view of compact bone shows the basic structural unit, the osteon. (b) In this micrograph of the osteon, you can clearly see the concentric lamellae and central canals. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School c 2012). From Openstax free textbook, Human Anatomy and Physiology. Figure 6.13 Diagram of Spongy Bone Spongy bone is composed of trabeculae that contain the osteocytes. Red marrow fills the spaces in some bones. From Openstax free textbook, Human Anatomy and Physiology.  - Matrix - Extracellular component 1. Osteoid = organic component = 1/3 of matrix a. Ground Substance = proteoglycans (proteins + polysaccharides) & glycoproteins (proteins + sugars) b. Collagen Fibers Copyright © 2002 Michael H. Mitchell – All Rights Reserved  Development - Ossification or Osteogenesis - development of bone 1. Intramembranous Ossification - flat bones of skull and clavicle - Mesenchyme - embryonic connective tissue derived from mesoderm - develops directly into bone © 2002 Michael H. Mitchell – All Rights Reserved Copyright Figure 6.16 Intramembranous Ossification Intramembranous ossification follows four steps. (a) Mesenchymal cells group into clusters, and ossification centers form. (b) Secreted osteoid traps osteoblasts, which then become osteocytes. (c) Trabecular matrix and periosteum form. (d) Compact bone develops superficial to the trabecular bone, and crowded blood vessels condense into red marrow. From Openstax free textbook, Human Anatomy and Physiology. Figure 6.17 Endochondral Ossification Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes. (b) The cartilage model of the future bony skeleton and the perichondrium form. (c) Capillaries penetrate cartilage. Perichondrium transforms into periosteum. Periosteal collar develops. Primary ossification center develops. (d) Cartilage and chondrocytes continue to grow at ends of the bone. (e) Secondary ossification centers develop. (f) Cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage. From Openstax free textbook, Human Anatomy and Physiology. Figure 6.17 Endochondral Ossification Endochondral ossification follows five steps. (a) Mesenchymal cells differentiate into chondrocytes. (b) The cartilage model of the future bony skeleton and the perichondrium form. (c) Capillaries penetrate cartilage. Perichondrium transforms into periosteum. Periosteal collar develops. Primary ossification center develops. (d) Cartilage and chondrocytes continue to grow at ends of the bone. (e) Secondary ossification centers develop. (f) Cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage. From Openstax free textbook, Human Anatomy and Physiology.  Example of Endochondral Ossification in fetal mouse – Research project – Dr. M. H. Mitchell – Birth defects – LIF  Example of Endochondral Ossification in fetal mouse – Research project – Dr. M. H. Mitchell – Birth defects – LIF  Example of Endochondral Ossification in fetal mouse – Research project – Dr. M. H. Mitchell – Birth defects – LIF  - Hemopoiesis or Hematopoiesis = blood formation within Red Bone Marrow - Erythrocytes last for 120 days (You make 8 - 16 million per second) 1. Yolk Sac in Embryo - begins making blood cells around 3-7 weeks of gestation - from here, blood migrates to colonize in the embryo 2. Liver, Spleen, Lymphatic Tissues - begin making blood cells at end of 2nd trimester or beginning of 3rd - spleen & lymphoid tissues continue to make lymphocytes (a type of leukocyte - liver stops making blood by birth - Extramedullary Hemopoiesis i.e. OUTSIDE of medullary cavity - in an adult this may indicate loss of bone marrow function - due to cancer, toxins, radiation, etc. 3. Red Bone Marrow - Medullary Cavity - see your lab notes - this is medullary hemopoiesis because it occurs in the bone marrow cavity (medullary cavity) a. in all bones from late fetal life until about 5 years old b. By the age of 20, only occurs in Membranous bones (sternum, ilium, vertebrae, ribs) - Erythropoietin - Hormone from kidneys and liver that stimulates Erythropoiesis - erythropoietin may be used in illegal "blood doping" by athletes.....Why would Copyright © 2002use they Michael it? H. Mitchell – All Rights Reserved ID age: 28 days – 5 mm long (1/5 of an inch) The Amnion is not visible here, but it surrounds the embryo as a thin-walled sac. Just visible are the limb buds ID Somites – segmented structures of ID: Paryngeal Arches – give rise to mesoderm – will become vertebrae, auditory veicles, parts of mandible, muscles, dermis, cartilage, etc. nerves, hyoid bone, thymus and other ID Chorion/Placenta neck structures ID Notice thinning of chorion on this side ID Space - Chorionic Cavity Yolk Sac 1. Primordial Germ Cells (not layers) originate here then move to the embryo proper to form the gonads (ovaries/testes) 2. Hemopoietic Stem Cells – also start here and have to migrate to the embryo proper ID: Connecting Stalk/Umbilical Cord – now contains the umbilical vessels Lab Model – Chesapeake campus – photo provided by Dr. M. H. Mitchell  - Polycythemia - "poly" or many - "cyt" cells - "hemia" of blood - abnormal elevation of erythrocytes (RBC's) - what do these cells do? - you need more RBC's for any disease that interferes w/ oxygen transport i.e. Copyright © 2002 pulmonary, Michael acute anemias H. Mitchell – All Rights Reserved  Calcitriol = Vitamin D3 - made from cholesterol - Production 1. UV light hits cholesterol in skin to begin its synthesis 2. then it goes to the liver for more reactions 3. The final active product is made in the kidneys - increases intestinal absorption of calcium Copyright &Mitchell © 2002 Michael H. phosphate, – All Rights Reserved making these  Calcitonin (aka Thyrocalcitonin or TCT) - made by Parafollicular (C) cells of the THYROID gland - REDUCES PLASMA Ca++ levels (especially in children) BY: - uses that Ca++ to build bone 1. Stimulating osteoblasts to deposit (build) bone with the calcium 2. Inhibit osteoclasts from resorbing (digesting) bone Copyright © 2002 Michael H. Mitchell – All Rights Reserved  Thyroid Gland :Thyroid Hormones Parafolliculr Cells Parathyroid Gland :Calcitonin PTH  Parathyroid Hormone (PTH) - made by ParaTHYROID glands (you have 4 of these just behind the thyroid gland) - INCREASES PLASMA Ca++ levels by: 1. cause osteoBLASTs to release OsteoCLAST Stimulating Factor (Interleukin 1) which causes the osteoCLASTs to digest bone, releasing the Ca++ into the plasma Copyright © 2002 Michael H. Mitchell – All Rights Reserved  Arthrology - Ch 8 - Arthrology - study of joint anatomy, function, dysfunction, and treatment - Kinesiology - study of musculoskeletal movement - includes neuro, arthrology, mechanics, etc. FUNCTIONAL Classification of Joints - based on amount of movement 1. © Synarthrosis Copyright =Reserved 2002 Michael H. Mitchell – All Rights name based on  STRUCTURAL Classification of Joints 1. Fibrous Joints = name based on structure - no joint cavity - connected by collagenous fibers a. Sutures (a type of Synarthrosis) - interlocking joints of skull - in young before they fuse to become synostoses in the elderly b. Syndesmoses (a type of Amphiarthrosis) - connect by connective tissue: interosseous membrane/ligament (radioulnar & tibiofibular) c. Gomphoses (a type of Synarthrosis) - periodontal ligament anchoring teeth Copyright © 2002 Michael H. Mitchell – All Rights Reserved Fetal skull Sagittal Anterior Suture fontanelle Coronal Suture Frontal Suture – usually completely fused by 3-9 months of age – a type of fibrous joint – Synarthrosis Posterior in young – becomes Synostoses once fused fontanelle Figure 9.5 Fibrous Joints Fibrous joints form strong connections between bones. (a) Sutures join most bones of the skull. (b) An interosseous membrane forms a syndesmosis between the radius and ulna bones of the forearm. (c) A gomphosis is a specialized fibrous joint that anchors a tooth to its socket in the jaw. From Openstax free textbook, Human Anatomy and Physiology. Figure 8.6 Ulna and Radius The ulna is located on the medial side of the forearm, and the radius is on the lateral side. These bones are attached to each other by an interosseous membrane. From Openstax free textbook, Human Anatomy and Physiology.  Interosseous Membrane – between tibia and fibula- increased strength and stability while allowing for flexibility. Figure 8.18 Tibia and Fibula The tibia is the larger, weight-bearing bone located on the medial side of the leg. The fibula is the slender bone of the lateral side of the leg and does not bear weight. From Openstax free textbook, Human Anatomy and Physiology.  2. Cartilagenous = name based on structure i.e. connected by cartilage a. Synchondroses (a type of Amphiarthrosis) - 2 bones joined by hyaline cartilage ("condr" refers to cartilage) - Epiphyseal Plate in children - before it ossifies to become a synostoses known as the Epiphyseal Line in adults - 1st costosternal joint - Copyright © 2002 Michael H. Mitchell – All Rights Reserved Figure 9.7 Cartiliginous Joints At cartilaginous joints, bones are united by hyaline cartilage to form a synchondrosis or by fibrocartilage to form a symphysis. (a) The hyaline cartilage of the epiphyseal plate (growth plate) forms a synchondrosis that unites the shaft (diaphysis) and end (epiphysis) of a long bone and allows the bone to grow in length. (b) The pubic portions of the right and left hip bones of the pelvis are joined together by fibrocartilage, forming the pubic symphysis. From Openstax free textbook, Human Anatomy and Physiology.  3. Synostoses - bony joints = name based on structure i.e. these start off as one type of joint then ossify (turn to bone) – type of synarthroses - as when certain fibrous or cartilagenous joints ossify with age a. frontal bone is two bones joined by frontyal symphysis in fetus but ossified in adult b. mandible is two bones split by Copyright © 2002 Michael H. Mitchell – All Rights Reserved  4. Synovial = name based on structure – type of diarthroses) - they have articular cartilage, synovial capsule/cavity/fluid - Synovial Capsule is the joint capsule containing the Synovial fluid which fills the synovial cavity (dense irregular CT) - Hyaluronic Acid - lubricates joints - Chondroitin Sulfate - component of cartilage Copyright making © 2002 Michael H. Mitchell – All Rightsit firm Reserved  Classification according to FUNCTION 1. Synarthrosis = name based on function - immovable joints 2. Amphiarthrosis = name based on function i.e. slightly movable 3. Diarthrosis = name based on function i.e. freely movable - elbow, shoulder, etc Classification according to STRUCTURE - be able to identify by functional name and or structural name as per below 1. Fibrous Joints = name based on structure - no joint cavity - connected by collagenous fibers a. Sutures (a type of Synarthrosis) will become synostoses in the elderly b. Syndesmoses (a type of Amphiarthrosis) - interosseous membrane/ligament (radioulnar & tibiofibular) c. Gomphoses (a type of Synarthrosis) - periodontal ligament anchoring teeth 2. Cartilagenous a. Synchondroses (a type of Amphiarthrosis) - Epiphyseal Plate /Epiphyseal Line in adults - 1st costosternal joint - especially in young before it becomes a synostoses in the elderly b. Symphyses (a type of Amphiarthrosis) - pubic symphysis (& mental symphysis in very young) - Intervertebral Discs - Anulus Fibrosus & Nucleus Pulposus 3. Synostoses a. frontal bone is two bones in fetus but ossified in adult b. mandible is two bones split by the mental symphysis in fetus but ossified in adult c. epiphyseal plate is ossified to become the epiphyseal line in the adult d. sutures in elderly e. 1st costosternal joint in elderly 4. Synovial– type of diarthroses) - they have articular cartilage, synovial capsule/cavity/fluid - elbow, knee, jaw, hip, shoulder  Classification according to FUNCTION 1. Synarthrosis 2. Amphiarthrosis 3. Diarthrosis Classification according to STRUCTURE 1. Fibrous Joints a. Sutures b. Syndesmoses c. Gomphoses 2. Cartilagenous a. Synchondroses b. Symphyses (a type of Amphiarthrosis) 3. Synostoses 4. Synovial– type of diarthroses)  Figure 9.8 Synovial Joints Synovial joints allow for smooth movements between the adjacent bones. The joint is surrounded by an articular capsule that defines a joint cavity filled with synovial fluid. The articulating surfaces of the bones are covered by a thin layer of articular cartilage. Ligaments support the joint by holding the bones together and resisting excess or abnormal joint motions. From Openstax free textbook, Human Anatomy and Physiology.  Types of Synovial Joints - shapes, axis etc a. Plane Joint – nonaxial gliding joints: intercarpal, intertarsal joints, vertebrocostal joints b. Hinge - elbow, knee, interphalangeal - uniaxial c. Pivot - atlantoaxial (dens w/ atlas) and proximal radioulnar joint (at annular ligament) Copyright © 2002 Michael H. Mitchell – All Rights Reserved Figure 9.10 Types of Synovial Joints The six types of synovial joints allow the body to move in a variety of ways. (a) Pivot joints allow for rotation around an axis, such as between the first and second cervical vertebrae, which allows for side-to-side rotation of the head. (b) The hinge joint of the elbow works like a door hinge. (c) The articulation between the trapezium carpal bone and the first metacarpal bone at the base of the thumb is a saddle joint. (d) Plane joints, such as those between the tarsal bones of the foot, allow for limited gliding movements between bones. (e) The radiocarpal joint of the wrist is a condyloid joint. (f) The hip and shoulder joints are the only ball-and- socket joints of the body. From Openstax free textbook, Human Anatomy and Physiology.  - Tendon – attach muscle to bone - Aponeurosis – broad sheet-like tendon – galea aponeurotica & abdominal aponeurosis - Ligament – attach bone to bone - Tendon sheath - fluid filled membrane surrounding tendons - Bursa - connect to synovial cavity, filled with synovial fluid, these cushion between bone and soft tissue (muscle, ligament, tendon) Copyright © 2002 Michael H. Mitchell – All Rights Reserved  Figure 9.9 Bursae Bursae are fluid-filled sacs that serve to prevent friction between skin, muscle, or tendon and an underlying bone. Three major bursae and a fat pad are part of the complex joint that unites the femur and tibia of the leg. From Openstax free textbook, Human Anatomy and Physiology.  Movement of Synovial Joints Define, identify from a picture from the OpenStax text, and be able to apply terms to movement: Flexion - limbs – decreasing the angle between bones (bending of the elbow or knee) - moving straight arm forward and up - digits – making a fist - thumb – cross thumb over palm - head – bending head anteriorly looking down w/ chin against the chest - thigh – moving leg up and forward or bowing at the waist = flexion of hip - Lateral flexion – bending head towards shoulder Extension - limbs – increasing the angle between bones (straightening the limb - thigh – up from flexion or any posterior movement - bending vertebral column backwards Hyperextension – abnormal or excessive extension of a joint beyond normal range of motion Movement of Synovial Joints Abduction – moves part away from midline (takes it away) - moving arms out laterally - spreading fingers apart (or toes) - thumb – move thumb anteriorly to 90o perpendicular - foot – point toes away from midline w/ feet level (on the ground) Adduction – moves part towards the midline - bringing arms from lateral position back to side of body - bringing fingers back together - returning thumb from abducted position back to anatomical position along side the - index finger - foot – point feet towards each other w/ feet level (on the ground) Rotation – - twisting vertebral column - turning head left/right as indicating “no” - atlantoaxial joint – neck pivots around the dens - head of the radius rotates within the annular ligament - rotating humerus or femur around their long axis Circumduction – proximal end of limb relatively stationary, distal end describes a circle Movement of Synovial Joints Pronation – from anatomical position, face palms backwards - with arms extended in front of you, palms down - radius rotates in annular ligament and distal radius crosses over distal ulna - Pronation of the foot is a complex movement including abduction, eversion and dorsi flextion - it is considered a tri-planar motion of the sub talar joint (calcaneotalar joint) - ankle forms Calcanial Valgus – cancaneous angles outward so ankle appears to bend inwards - arch drops - foot towards anterior leg, toes outward away from midline and plantar flexion - tarsal bones move apart and more mobile – shock absorption Supination – anatomical position w/ palms facing forward - with arms extended in front of you, palms up (sup is up) - radius and ulna are parallel, not crossed - Supination of the foot is a complex movement including adduction, inversion, and plantar flexion - it is considered a tri-planar motion of the sub talar joint (calcaneotalar joint) - ankle forms Calcanial Varus – cancaneous angles inward so ankle appears to bend outwards - arch raises - foot away from anterior leg, toes inward towards midline and dorsiflextion - tarsal bones move together – stronger push off Inversion – turn foot to angle bottom towards midline as when “twisting” your ankle Eversion – turn bottom of foot away from midline – very limited from anatomical position Dorsiflexion – lifting front of foot up towards anterior leg Plantar flexion – pointing front of foot downwards (standing on tip toes with elevated heal) Movement of Synovial Joints Protraction - of scapula when shoulders move forward like when you push against something or throwing a ball - pushing mandible forward Retraction - pulling scapula posteriorly and medially towards the vertebral column - pulling mandible backward Depression – downward movement of scapula or mandible Elevation - upward movement of scapula or mandible - shrugging shoulders Excursion – Lateral and Medial – moving mandible side ways Opposition – touching finger tip with thumb Figure 9.12 Movements of the Body, Part 1 From Openstax free textbook, Human Anatomy and Physiology. Figure 9.12 Movements of the Body, Part 1 From Openstax free textbook, Human Anatomy and Physiology. igure 9.13 Movements of the Body, Part 2 igure 9.13 Movements of the Body, Part 2  PATHOLOGIES Hyperparathyroidism - too much PTH (Parathyroid Hormone) so increase in bone - digestion/resorption 1. bones thin and become brittle 2. plasma Ca++ levels rise 3. premature closure of epiphyseal plate - too much Ca++ in blood causing  - Rickets - lack of Vit D3 in children - bones rubbery and bend due to deminerilization (loss of Ca++) - Osteomalacia = rickets in adults - via poor diets, sun exposure, multiple pregnancies Copyright © 2002 Michael H. Mitchell – All Rights Reserved  - Giantism - too much Growth Hormone (GH) from Anterior Pituitary Gland - from birth prior to ossification of epiphyseal plates - Acromegaly - too much GH in adults - hypertrophy of bones: face, hands, and feet - often due to Pituitary Adenoma - thickening bones (face, hands, feet - protruding mandible & forehead, hands) Copyright © 2002 Michael H. Mitchell – All Rights Reserved  - Neoplasms = Cancers - Osteoma - benign - especially found in facial/skull - sinuses - in response to infection, trauma - Osteogenic Sarcoma = Osteosarcoma - malignant - most osteosarcomas are pediatric cases - very virulent "moth-eaten" pattern Copyright ofH. Mitchell © 2002 Michael bone – All Rights Reserved  Pathologies of Joints - Strain - excessive stretch of ligament or tendon - Sprain - tearing of portions of ligaments or tendons - Subluxation - partial dislocation - Luxation - dislocation - bones forced out of alignment - Anterior or posterior open hip dislocations - Double Jointed - joint ligaments are loose allowing greater than normal Copyright © 2002 Michael H. Mitchell – All Rights Reserved  Osteophytes – horizontal bony secretions along edge of vertebral bodies Syndesmophytes – vertical bony secretions along edge of vertebral bodies https://www.mdpi.com/2077-0383 /11/7/2009 Spondylosis Copyright © 2002 Michael H. Mitchell – – type All Rights of Reserved  - Arthritis - inflammation of joints - The most widespread crippling disease in the U.S. - destroys articular cart. & bone - causes the production of Osteophytes or bone spurs - Osteoarthritis - most common type of arthritis - caused by age and inflammation - normal wear and tear (over 16 million cases, 85% of all Americans will Copyright © 2002 Michael H. Mitchell – All Rights Reserved