Skeletal System - Part 1 PDF

Skeletal System- Part 1 Nermin Eissa, Ph.D. College of Health Sciences Abu Dhabi University Fall-2023  Learning Outcomes: State the functions of the skeletal system. Describe the structure of a long bone. Types of cartilage found in the bo...

Skeletal System- Part 1 Nermin Eissa, Ph.D. College of Health Sciences Abu Dhabi University Fall-2023  Learning Outcomes: State the functions of the skeletal system. Describe the structure of a long bone. Types of cartilage found in the body and the function for each. Identify and explain about the bones of the skull, vertebral column, and rib cage. 2 ©2020 McGraw-Hill Education  Skeletal System 2 The skeletal system consists of two types of connective tissue: bone and cartilage. Ligaments, formed of fibrous connective tissue, join the bones. Functions of the skeleton: Supports the body. Working with the muscular system, moves the body Protection. Skull protects the brain, rib cage protects the heart and lungs, the vertebrae protect the spinal cord. Produces blood cells. Stores minerals (calcium and phosphate) and fat. 3 ©2020 McGraw-Hill Education  Anatomy of a Long Bone 1 Diaphysis—shaft of the bone. Medullary cavity—inside the diaphysis; its walls are made of compact bone. The medullary cavity is lined with the endosteum and is filled with yellow bone marrow, which stores fat. Epiphysis —expanded end of a long bone. Composed of spongy bone that contains red bone marrow, where blood cells are made. 4  Anatomy of a Long Bone 2 The epiphyses are coated with a thin layer of hyaline cartilage, which is also called articular cartilage, because it occurs at a joint. Metaphysis—between the epiphysis and diaphysis. Contains the epiphyseal plate, a region of cartilage that allows for bone growth. Periosteum—connective tissue covering all bones; continuous with ligaments and tendons. 5 ©2020 McGraw-Hill Education  Bone 1 There are two types of bone tissue: compact and spongy. Compact bone is highly organized and composed of tubular units called osteons. Osteocytes are bone cells; they lie in lacunae (singular, lacuna), tiny chambers arranged in concentric circles around a central canal. Matrix fills the space between the rows of lacunae. 6 ©2020 McGraw-Hill Education  The Anatomy of a Long Bone Access the text alternative for these images 9 ©2020 McGraw-Hill Education (photos) (compact bone): ©Ed Reschke; (osteocyte): ©Biophoto Associates/Science Source  Bone 2 Tiny canals called canaliculi (singular, canaliculus) connect the lacunae with one another and with the central canal. Osteocytes stay in contact with each other in the canaliculi. They exchange nutrients and wastes through gap junctions that connect adjacent osteocytes. 8 ©2020 McGraw-Hill Education  Bone 3 Spongy bone contains numerous thin plates called trabeculae. Although lighter than compact bone, spongy bone is still designed for strength. Red bone marrow—in the spaces of spongy bone. Produces all types of blood cells. Osteocytes of spongy bone are irregularly placed within the trabeculae. 9 ©2020 McGraw-Hill Education  Cartilage 1 Cartilage—not as strong as bone but is more flexible. Matrix contains collagen and elastic fibers. Chondrocytes—cartilage cells; lie within lacunae. Has no nerves or blood vessels; relies on neighboring tissues for nutrient and waste exchange. This makes it slow to heal. There are three types of cartilage: hyaline, fibrocartilage, and elastic cartilage. 10 ©2020 McGraw-Hill Education  Cartilage 2 Locations of cartilage. Hyaline cartilage: ends of long bones, nose, ends of ribs, larynx, and trachea. Fibrocartilage: disks between vertebrae and in the knee. Elastic cartilage: ear flaps 11 ©2020 McGraw-Hill Education  Fibrous Connective Tissue Fibrous connective tissue. Made of rows of fibroblasts separated by bundles of collagenous fibers. Makes up ligaments and tendons. Ligaments connect bone to bone. Tendons connect muscle to bone at a joint (also called an articulation). 12 ©2020 McGraw-Hill Education  Check Your Progress List the functions of the skeletal system. Summarize the structure of a long bone by describing the differences in structure. Describe the three types of cartilage and list where they are found in the body. 13 ©2020 McGraw-Hill Education  Bones of the Axial Skeleton 2 The 206 bones of the skeleton are classified as the axial or appendicular skeleton. Axial skeleton—midline of the body. Mainly consists of the skull, vertebral column, and the rib cage. 1. The skull. Formed by the cranium and the facial bones. Cranium. Contains and protects the brain. In adults, made of eight bones. In newborns, cranial bones are joined by membranous fontanels. Usually close by the age of 16 months. 14 ©2020 McGraw-Hill Education  The Axial and Appendicular Skeletons 15 ©2020 McGraw-Hill Education  The Skull 2 Bones: frontal, parietal, occipital, temporal, sphenoid, ethmoid. Foramen magnum—a hole in the occipital bone through which the spinal cord passes. External auditory canal—in each temporal bone; leads to the middle ear. The sphenoid completes the sides of the skull and contributes to forming the orbits (eye sockets). The ethmoid bone also helps form the nasal septum. 16 ©2020 McGraw-Hill Education  The Vertebral Column 1 2. Vertebral column—consists of 33 vertebrae. There are four curvatures that provide more strength for an upright posture than a straight column. Scoliosis—abnormal sideways curvature of the spine. Kyphosis—abnormal posterior curvature; “hunchback.” Lordosis—abnormal anterior curvature; “swayback.” 17 ©2020 McGraw-Hill Education  The Vertebral Column 2 Vertebral canal—in the center of the column; the spinal cord passes through. Intervertebral foramina (singular, foramen, “a hole”) on each side of the column; spinal nerves travel through. Spinal nerves control skeletal muscle contraction, among other things. If the spinal cord and/or spinal nerves are injured, there can be paralysis or even death. 18 ©2020 McGraw-Hill Education  Types of Vertebrae Types of vertebrae. Cervical vertebrae—in the neck. Atlas—first cervical vertebra; holds up the head. Movement permits the “yes” motion of the head. Axis—second cervical vertebra. Named because it rotates around the long axis of the body when we shake the head “no.” 19 ©2020 McGraw-Hill Education  The Vertebral Column Access the text alternative for these images 20 ©2020 McGraw-Hill Education  Intervertebral Disks 1 Composed of fibrocartilage. Prevent the vertebrae from grinding. Absorb shock caused by movements such as running, jumping, and even walking. Allows the vertebrae to move as we bend forward, backward, and from side to side. Become weakened with age and can rupture. Pain results if a disk presses against the spinal cord and/or spinal nerves. 21 ©2020 McGraw-Hill Education  The Rib Cage 3. Rib cage (thoracic cage)— composed of the thoracic vertebrae, the ribs and their associated cartilages, and the sternum. Part of the axial skeleton. Protects the heart and lungs. Swings outward and upward upon inspiration and then downward and inward upon expiration. 22 ©2020 McGraw-Hill Education  The Ribs 1 There are 12 pairs; all connect directly to the thoracic vertebrae in the back. Curve outward and then forward and downward. True ribs—ribs 1 to 7; connect directly to the sternum by means of a long strip of hyaline cartilage called costal cartilage. False ribs—ribs 8 to 12; their costal cartilage does not connect directly to the sternum. Floating ribs—ribs 11 and 12; they have no connection with the sternum. Sternum (breastbone) Along with the ribs, it helps protect the heart and lungs. 23 ©2020 McGraw-Hill Education  Check Your Progress List the bones of the axial skeleton. Describe the various types of vertebrae. 24 ©2020 McGraw-Hill Education