Chapter 5_Skeletal System P1.pdf

Essentials of Human Anatomy & Physiology Thirteenth Edition Global Edition Chapter 5 The Skeletal System Lecture Presentation by...

Essentials of Human Anatomy & Physiology Thirteenth Edition Global Edition Chapter 5 The Skeletal System Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. The Skeletal System Parts of the skeletal system – Bones (skeleton) – Joints – Cartilages – Ligaments Two subdivisions of the skeleton 1. Axial skeleton 2. Appendicular skeleton Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Functions of the Bones Support the body Protection of soft organs – Skull and vertebrae protect brain and spinal cord – Rib cage protects thoracic cavity organs Allow movement via attached muscles Store minerals and fats – Calcium and phosphorus – Fat in the internal marrow cavity Blood cell formation (hematopoiesis) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Classification of Bones (1 of 6) The adult skeleton has 206 bones Two basic types of osseous (bone) tissue 1. Compact bone ▪ Dense, smooth, and homogeneous 2. Spongy bone ▪ Small needlelike pieces of bone ▪ Many open spaces Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.1 Flat Bones Consist of a Layer of Spongy Bone Sandwiched Between Two Thin Layers of Compact Bone Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Classification of Bones (2 of 6) Bones are classified on the basis of shape into four groups – Long – Flat – Short – Irregular Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.2 Classification of Bones on the Basis of Shape Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Classification of Bones (3 of 6) Long bones – Typically longer than they are wide – Shaft with enlarged ends – Contain mostly compact bone; spongy bone at ends – All of the bones of the limbs (except wrist, ankle, and kneecap bones) are long bones – Examples: ▪ Femur ▪ Humerus Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.2a Classification of Bones on the Basis of Shape Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Classification of Bones (4 of 6) Flat bones – Thin, flattened, and usually curved – Two thin layers of compact bone sandwich a layer of spongy bone between them – Examples: ▪ Most bones of the skull ▪ Ribs ▪ Sternum Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.2b Classification of Bones on the Basis of Shape Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Classification of Bones (5 of 6) Short bones – Generally cube-shaped – Contain mostly spongy bone with an outer layer of compact bone – Sesamoid bones are a type of short bone that form within tendons (patella) – Examples: ▪ Carpals (wrist bones) ▪ Tarsals (ankle bones) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.2c Classification of Bones on the Basis of Shape Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Classification of Bones (6 of 6) Irregular bones – Irregular shape – Do not fit into other bone classification categories – Examples: ▪ Vertebrae ▪ Hip bones Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.2d Classification of Bones on the Basis of Shape Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Concept Link 1 As we learn about the structure and organization of bones, remember the levels of structural organization (Figure 1.1, p. 25). Bones are organs, so they contain not only osseous tissue but also other connective tissues: fibrous tissue, cartilage, adipose tissue, and blood. Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (1 of 10) Long bone anatomy – Diaphysis (shaft) ▪ Makes up most of bone’s length ▪ Composed of compact bone – Periosteum ▪ Outside covering of the diaphysis ▪ Fibrous connective tissue membrane ▪ Perforating (Sharpey’s) fibers secure periosteum to underlying bone Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.3a The Structure of a Long Bone (Humerus of Arm) (1 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.3c The Structure of a Long Bone (Humerus of Arm) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (2 of 10) Long bone anatomy – Epiphysis (ends) ▪ Composed mostly of spongy bone enclosed by thin layer of compact bone – Articular cartilage ▪ Covers the external surface of the epiphyses ▪ Made of hyaline cartilage ▪ Decreases friction at joint surfaces Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.3b The Structure of a Long Bone (Humerus of Arm) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (3 of 10) Long bone anatomy – Epiphyseal line ▪ Remnant of the epiphyseal plate ▪ Seen in adult bones – Epiphyseal plate ▪ Flat plate of hyaline cartilage seen in young, growing bone ▪ Causes lengthwise growth of a long bone Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.3a The Structure of a Long Bone (Humerus of Arm) (2 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (4 of 10) Long bone anatomy – Endosteum ▪ Lines the inner surface of the shaft ▪ Made of connective tissue – Medullary cavity ▪ Cavity inside the shaft ▪ Contains yellow marrow (mostly fat) in adults ▪ Contains red marrow for blood cell formation until age 6 or 7 Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.3a The Structure of a Long Bone (Humerus of Arm) (3 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (5 of 10) Bone markings – Sites of attachments for muscles, tendons, and ligaments – Passages for nerves and blood vessels Categories of bone markings – Projections or processes—grow out from the bone surface ▪ All projections begin with “T” – Depressions or cavities—indentations ▪ All depressions begin with “F” (except facet) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 5.1 Bone Markings (1 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 5.1 Bone Markings (2 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 5.1 Bone Markings (3 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (6 of 10) Microscopic anatomy of spongy bone – Composed of small, needlelike pieces of bone called trabeculae and open spaces – Open spaces are filled by marrow, blood vessels, and nerves Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.4a Microscopic Structure of Bone Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (7 of 10) Microscopic anatomy of compact bone – Osteocytes ▪ Mature bone cells situated in bone matrix – Lacunae ▪ Cavities in bone matrix that house osteocytes – Lamellae ▪ Concentric circles of lacunae situated around the central (Haversian) canal Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (8 of 10) Microscopic anatomy of compact bone – Central (Haversian) canal ▪ Opening in the center of an osteon (Haversian system) ▪ Runs lengthwise through bone ▪ Carries blood vessels and nerves – Osteon (Haversian system) ▪ A unit of bone containing central canal and matrix rings ▪ Structural and functional unit of compact bone Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.4b Microscopic Structure of Bone (1 of 2) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.4c Microscopic Structure of Bone Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (9 of 10) Microscopic anatomy of compact bone – Canaliculi ▪ Tiny canals ▪ Radiate from the central canal to lacunae ▪ Form a transport system connecting all bone cells to a nutrient supply – Perforating (Volkmann’s) canal ▪ Canal perpendicular to the central canal ▪ Carries blood vessels and nerves Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.4b Microscopic Structure of Bone (2 of 2) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Structure of Bone (10 of 10) Bone is relatively lightweight and resists tension and other forces Organic parts (collagen fibers) make bone flexible and have great tensile strength (stretch without breaking) Calcium salts deposited in the bone make bone hard (resists compression) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Formation, Growth, and Remodeling (1 of 6) Bone formation and growth – Ossification is the process of bone formation – Occurs on hyaline cartilage models or fibrous membranes – Long bone growth involves two major phases Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Formation, Growth, and Remodeling (2 of 6) Two major phases of ossification in long bones 1. In an embryo, osteoblasts (bone-forming cells) cover the hyaline cartilage model with bone matrix 2. In a fetus, the enclosed cartilage is covered by bone; the cartilage is digested away, opening up a medullary cavity Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.5 Stages of Long-Bone Formation in an Embryo, Fetus, and Young Child Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Formation, Growth, and Remodeling (3 of 6) By birth, most cartilage is converted to bone except for two regions in a long bone 1. Articular cartilages 2. Epiphyseal plates New cartilage is formed continuously on external face of these two cartilages Old cartilage is broken down and replaced by bony matrix Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.6ab Growth and Remodeling of Long Bones Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.6cd Growth and Remodeling of Long Bones Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Formation, Growth, and Remodeling (4 of 6) Appositional growth – Bones grow in width – Osteoblasts in the periosteum add bone matrix to the outside of the diaphysis – Osteoclasts in the endosteum remove bone from the inner surface of the diaphysis Bone growth is controlled by hormones, such as growth hormone and sex hormones Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Formation, Growth, and Remodeling (5 of 6) Bones are remodeled throughout life in response to two factors 1. Calcium ion level in the blood determines when bone matrix is to be broken down or formed 2. Pull of gravity and muscles on the skeleton determines where bone matrix is to be broken down or formed Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Formation, Growth, and Remodeling (6 of 6) Calcium ion regulation – Parathyroid hormone (PTH) ▪ Released when calcium ion levels in blood are low ▪ Activates osteoclasts (bone-destroying cells) ▪ Osteoclasts break down bone and release calcium ions into the blood – Hypercalcemia (high blood calcium levels) prompts calcium storage to bones by osteoblasts Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Fractures (1 of 3) Fracture: break in a bone Types of bone fractures – Closed (simple) fracture is a break that does not penetrate the skin – Open (compound) fracture is a broken bone that penetrates through the skin Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Fractures (2 of 3) Bone fractures are treated by reduction and immobilization – Closed reduction: bones are manually coaxed into position by physician’s hands – Open reduction: bones are secured with pins or wires during surgery Healing time is 6–8 weeks Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 5.2 Common Types of Fractures (1 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 5.2 Common Types of Fractures (2 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Table 5.2 Common Types of Fractures (3 of 3) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Bone Fractures (3 of 3) Repair of bone fractures involves four major events – Hematoma (blood-filled swelling, or bruise) is formed – Fibrocartilage callus forms ▪ Cartilage matrix, bony matrix, collagen fibers splint the broken bone – Bony callus replaces the fibrocartilage callus ▪ Osteoblasts and osteoclasts migrate in – Bone remodeling occurs in response to mechanical stresses Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.7 Stages in the Healing of a Bone Fracture Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Axial Skeleton Forms the longitudinal axis of the body Divided into three parts 1. Skull 2. Vertebral column 3. Bony thorax Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.8a The Human Skeleton (1 of 2) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.8b The Human Skeleton (1 of 2) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Skull (1 of 5) Two sets of bones form the skull 1. Cranium bones enclose the brain 2. Facial bones ▪ Hold eyes in anterior position ▪ Allow facial muscles to express feelings Bones are joined by sutures (immovable joints) Only the mandible is attached by a freely movable joint Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Skull (2 of 5) 8 cranial bones protect the brain 1 Frontal bone 2 Occipital bone 3 Ethmoid bone 4 Sphenoid bone 5,6 Parietal bones (pair) 7,8 Temporal bones (pair) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Skull (3 of 5) 14 facial bones 1, 2 Maxillae (pair) 3, 4 Palatine bones (pair) 5, 6 Lacrimal bones (pair) 7, 8 Zygomatic bones (pair) 9, 10 Nasal bones (pair) 11 Vomer bone 12, 13 Inferior nasal conchae (pair) 14 Mandible Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.9 Human Skull, Lateral View Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.10 Human Skull, Superior View (Top of Cranium Removed) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.11 Human Skull, Inferior View (Mandible Removed) Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.12 Human Skull, Anterior and Posterior Views Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Skull (4 of 5) Paranasal sinuses – Hollow portions of bones surrounding the nasal cavity – Functions of paranasal sinuses ▪ Lighten the skull ▪ Amplify sounds made as we speak Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.13a Paranasal Sinuses Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Figure 5.13b Paranasal Sinuses Copyright © 2022 Pearson Education, Ltd. All Rights Reserved. Skull (5 of 5) Hyoid bone – Closely related to mandible and temporal bones – The only bone that does not articulate with another bone – Serves as a movable base for the tongue – Aids in swallowing and speech Copyright © 2022 Pearson Education, Ltd. All Rights Reserved.