Chapter 6 Lecture Slides PDF

Chapter 6 Lecture Slides Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Content: Components of the Skeletal System Classification of Bones Compact Bone Spongy Bone Bone Formation Intramembranous Endochondral Bone Growth...

Chapter 6 Lecture Slides Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Content: Components of the Skeletal System Classification of Bones Compact Bone Spongy Bone Bone Formation Intramembranous Endochondral Bone Growth Bone Remodelling Bone Repair Calcium Homeostasis Hematopoietic tissue Bone Anatomy 2  Chapter 6-Skeletal System Functions 1. Support 2. Protect 3. Movement 4. Storage 5. Blood cell production 3  Components of Skeletal System Bone Cartilage: reduce friction and model for bone formation Tendons: attach bone to muscle Ligaments: attach bone to bone 4  Background Information Bones, cartilage, tendons, and ligaments are connective tissues. Proteoglycans: - large polysaccharides attached to proteins - part of ground substance - store water 5  Bone’s extracellular matrix is collagen and minerals (flexible and able to bear weight) Cartilage’s extracellular matrix is collagen and proteoglycans (good shock absorber) Tendons and ligaments’ extracellular matrix is collagen (very tough) 6  Classification of Bones Based on shape: long, short, flat, irregular Type of bone tissue: compact and spongy (cancellous) 7  Bone Shapes Long: - Ex. Femur, tibia, fibula Short: – Ex. Carpals, tarsals, phlanges Flat: – Ex. Ribs, sternum, skull Irregular: – Ex. Vertebrae and facial 8  Long Bone Structures Diaphysis: – shaft – compact bone tissue (on outside) Epiphysis: – ends – spongy bone tissue Articular cartilage: - covers epiphyses - reduces friction 9  Epiphyseal plate: – site of growth – between diaphysis and epiphysis Medullary cavity: – center of diaphysis – red or yellow marrow  Periosteum: membrane around bone’s outer surface Endosteum: membrane that lines medullary cavity 11  Compact Bone Tissue Location: outer part of diaphysis (long bones) and thinner surfaces of other bones Osteon: - structural unit of compact bone - includes lamella, lacunae, canaliculus, central canal, osteocytes Lamella: rings of bone matrix 12  Lacunae: spaces between lamella Canaliculus: - tiny canals - transport nutrients and remove waste Central canal: - center of osteon - contains blood vessels 13 Figure 6.3b  Spongy Bone Tissue Cancellous bone Location: epiphyses of long bones and center of other bones Trabeculae: interconnecting rods, spaces contain marrow No osteons 15  Bone Cells Osteocytes: maintain bone matrix Osteoblasts: build bone Osteoclasts: carve bone 16  Bone Formation Ossification: process of bone formation (occurs in utero) Osteoblast’s role: - build bone - after an osteoblast becomes surrounded by bone matrix it becomes an osteocyte 17 18  Ossification center: where bone formation begins Primary ossification center: - where bone 1st begins to appear - forms diaphyses Secondary ossification center: forms epiphyses 19 Intramembranous Ossification Bone formation within connective tissue membranes Osteoblasts build bone Ex. Skull bones 20  Endochondral Ossification Bone formation inside cartilage Cartilage models are replaced by bone Ex. All bones (except skull) 22 Steps in Endochondral Ossification 1. Chondroblasts build a cartilage model, the chrondroblasts become chondrocytes. 2. Cartilage model calcifies (hardens). 3. Osteoblasts invade calcified cartilage and a primary ossification center forms diaphysis. 4. Secondary ossification centers form epiphysis. 5. Original cartilage model is almost completely ossified and remaining cartilage is articular cartilage. 23 25  Bone Growth Infancy and youth: - long bones lengthen at epiphyseal plate - long bones widen by adding more lamella End of bone growth (in length): epiphyseal plate is replaced by an epiphyseal line 26 Figure 6.2b 28  Bone Remodeling What is it? - removal of existing bone by osteoclasts and deposition of new bone by osteoblasts - occurs in all bones - responsible for changes in bone shape, bone repair, adjustment of bone to stress, and calcium ion regulation 29  Bone Repair 1. Broken bone causes bleeding and a blood clot forms. 2. Callus forms which is a fibrous network between 2 fragments. 3. Cartilage model forms first then, osteoblasts enter the callus and form cancellous bone this continues for 4-6 weeks after injury. 4. Cancellous bone is slowly remodeled to form compact and cancellous bone. 30  Bone and Calcium Homeostasis Bone is a major storage site for calcium Movement of calcium in and out of bone helps determine blood levels of calcium Calcium moves into bone as osteoblasts build new bone Calcium move out of bone as osteoclasts break down bone Calcium homeostasis is maintained by parathyroid hormone (PTH) and calcitonin 32  Hematopoietic Tissue What is it? tissue that makes blood cells Red marrow: location of blood forming cells Yellow marrow: mostly fat 34  Location of hematopoietic tissue in newborns: most bones (red marrow) Location of hematopoietic tissue in adults: - red is replaced with yellow marrow - red marrow is mainly in epiphyses of femur and humerus 35 36  Bone Anatomy Foramen: - hole - Ex. Foramen magnum Fossa: - depression - Ex. Glenoid fossa Process: - projection - Ex. Mastoid process 37  Condyle: - smooth, rounded end - Ex. Occipital condyle Meatus: - canal-like passageway - Ex. External auditory meatus Tubercle: - lump of bone - Ex. Greater tubercle 38  Axial Skeleton Mastoid process: attached to neck muscles External auditory meatus: ear canal Nasolacrimal canal: - canal between nasal cavity and eye - conducts tears 39  Styloid process: attachment site for tongue Mandibular fossa: depression where lower jaw and skull meet Glenoid fossa: where humerus meets scapula 40  Hard palate: roof of mouth Foramen magnum: hole where spinal cord joins brainstem 41  Zygomatic: cheek bone Mandible: lower jaw Maxilla: upper jaw 42  Vertebral Column 7 cervical vertebra 12 thoracic vertebra 5 lumbar vertebra 1 sacrum 1 coccyx Atlas: - 1st vertebra - holds head Axis: - 2nd vertebra - rotates head 46 Functions of Vertebral Column Support Protect spinal cord Movement 50  Thoracic Cage Protects vital organs 12 pair of ribs Sternum: breastbone True ribs: attach directly to sternum by cartilage False ribs: attach indirectly to sternum by cartilage Floating ribs: not attached to sternum 51 Pectoral Girdle Scapula: shoulder blade Clavicle: collar bone 53 Upper Limb Bones Humerus: upper limb Ulna: forearm Radius: forearm Carpals: wrist Metacarpals: hand 55  Pelvic Girdle Where lower limbs attach to body Pelvis: includes pelvic girdle and coccyx Ischium: inferior and posterior region Ilium: most superior region Acetabulum: hip socket (joint) 60 Lower Limb Bones Femur: thigh Patella: knee cap Tibia: large lower leg Fibula: small lower leg 64  Tarsals: ankle Metatarsals: foot Phalanges: toes and fingers 65  Articulations What are they? where 2 bones come together (joint) Synarthrosis: - nonmovable joint - Ex. skull Amphiarthrosis: - slightly movable joint - Ex. Between vertebrae Diarthrosis: - freely movable joint - Ex. knee, elbow, wrist 69  Types of Movement Flexion: bending Extension: straightening Abduction: movement away from midline Adduction: movement toward the midline Pronation: rotation of the forearm with palms down Supination: rotation of the forearm with palms up Rotation: movement of a structure about the long axis 70