Skeletal System Review PDF

Skeletal System Review: The Bone Tissue What type of tissue is bone? What are osteoblasts? What are osteocytes? What is the name of the compound that forms the bone matrix? What is an osteon? How is it structured? What are osteoclasts? Review: The Bone Tissue Bone is mineralized connective tissue an...

Skeletal System Review: The Bone Tissue What type of tissue is bone? What are osteoblasts? What are osteocytes? What is the name of the compound that forms the bone matrix? What is an osteon? How is it structured? What are osteoclasts? Review: The Bone Tissue Bone is mineralized connective tissue and forms the skeleton ü Osteoblasts are immature bone cells that deposit a matrix of collagen (as new bone is formed, a few of the active osteoblasts will mature into osteocytes) ü Then, calcium and phosphate ions combine with collagen and harden within the matrix into the mineral hydroxyapatite [Ca5(PO4)3(OH)] ü The combination of hard mineral and flexible collagen makes bone harder than cartilage without being brittle ü The microscopic structure of hard mammalian bones consists of repeating units called osteons or Haversian system (each osteon has concentric layers of mineralized matrix deposited around a central canal containing blood vessels and nerves that service the bone) ü Osteoclasts release an acid to dissolve collagen and mineral coating (in order to raise calcium levels in blood if they are too low) By Onkar Bains, with modifications by Vinicius Cavicchioli Azevedo The Two Basic Type of Bone Tissue Spongy bone Compact bone Also known as cortical bone. Makes up dense, solid portion of bone. Consists of osteons. By Onkar Bains, with modifications by Vinicius Cavicchioli Azevedo Also known as trabecular bone Creates lightweight nature of bones Small needle-like pieces of bone Many open spaces The Two Basic Type of Bone Tissue Human Skeletal System Human skeleton is the internal framework of body o Makes up ~20% of adult body weight o It is composed of bones, cartilage, ligaments, tendons and other tissues. o Newborn human skeleton has 305 bones, some of which fuse together as body develops o By the time humans reach adulthood, they have 206 bones By Onkar Bains, with modifications by Vinicius Cavicchioli Azevedo Human Skeletal System: Functions Human Skeletal System: Functions Supports the body o Just as the steel beams of a building provide scaffold to support its weight, the bones and cartilages of the human skeleton compose the scaffold that supports rest of the body o Provides framework to support body’s fat, muscle, and skin § For example, the backbone is main support center for upper body (it holds head up and protects spinal cord) § Without skeleton, you would be a limp mass of organs, muscle and skin By Onkar Bains Human Skeletal System: Functions Protection of body’s vital organs o Bones of vertebral column (spine) protect spinal cord o Rib cage, sternum and spine protect lungs, heart and major blood vessels o Skull (cranium) protects brain The cranium completely surrounds and protects the brain from nontraumatic injury By Onkar Bains Human Skeletal System: Functions Movement o Joints between bones allow movement, some allowing wider range of movement than others. o Movement is powered by skeletal muscles, which are attached to skeleton at various sites on bones. By Onkar Bains Human Skeletal System: Functions Storage of minerals ü Bone stores ~99% of body’s calcium and ~85% of body’s phosphorus Storage and release of fat ü Fat is storage in the yellow bone marrow. ü Storage of energy. Human Skeletal System: Functions Blood cell formation ü Skeleton is site of hematopoiesis ü Hematopoiesis happens in the red bone marrow Two Types of Bone Marrow Marrow is loose connective tissue that fills cavities of bone o Yellow bone marrow contains adipose tissue (triglycerides stored in this tissue can be released to serve as a source of energy for other tissues of the body) o Red bone marrow is where the production of red blood cells, white blood cells and platelets occurs Bones are classified by their shape Flat Thin, flattened, and usually a bit curved Irregular Complicated shape that does not fit any of the classes Long Considerably longer than they are wide (cylindrical in shape) A long bone has a shaft plus two ends which are often expanded Sesamoid Small, round shaped Short Roughly cube shaped Bones of the Human Skeleton Rib cage (thoracic cage) (in wrist) (in palm) (in fingers) (in toes) (in ankles) (in foot) Bones of the Human Skeleton Rib cage (thoracic cage) (in wrist) (in palm) (in fingers) (in toes) (in ankles) (in foot) Bones of the Human Skeleton Rib cage (thoracic cage) Vertebrae (in wrist) (in palm) (in fingers) Mandible, coccyx and pelvis are also irregular bones (in toes) (in ankles) (in foot) Bones of the Human Skeleton Rib cage (thoracic cage) (in wrist) (in palm) (in fingers) (in toes) (in ankles) (in foot) Bones of the Human Skeleton Rib cage (thoracic cage) (in wrist) (in palm) (in fingers) (in toes) (in ankles) (in foot) Bones of the Human Skeleton Rib cage (thoracic cage) Phalanges (in blue) (in wrist) (in palm) (in fingers) (in toes) (in ankles) (in foot) Close up of metacarpals Smallest bones of human body are found in the inner ear: the malleus, incus, and stapes Largest bone of human body is the femur Human Skeleton has TWO Divisions Axial skeleton Cranium (skull), mandible, vertebral column, sternum and rib cage Consists of 80 bones Appendicular skeleton Includes bones of pelvic (hip) girdle, pectoral (shoulder) girdle, upper extremities and lower extremities Pectoral girdle = scapula and clavicle Pelvic girdle = hip bones (ilium, ischium, pubis) Consists of 126 bones Long Bone Features Diaphysis o Shaft of long bone o Composed of compact bone Epiphysis o Ends of long bone o Composed mostly of spongy bone Compact bone (also known as cortical bone) Spongy bone (also known as cancellous or trabecular bone) Medullary cavity – contains marrow Periosteum A thin layer of dense (fibrous) connective tissue around a bone (more specifically, it forms the outside covering of diaphysis) Serves as attachment for muscle Osteoblasts (bone-forming cells) are found here Periosteum covers all surfaces of the bone except for those capped with cartilage, as in the joints, and sites for attachment of ligaments and tendons Endosteum üInner lining of bones that make up medullary cavity üContains osteoclasts (bone-destroying cells) and osteoblasts Articular cartilage üCovers external surface of epiphyses üMade of hyaline cartilage üDecreases friction at joint surfaces between bones Cartilage As an infant, most of your skeleton is cartilage Over time cartilage is replaced by solid bone, usually completed by time you stop growing However, not all cartilage is replaced in adults üFor example, many joints contain cartilage, protecting ends of bones (as well as in ears and end of the nose) Three types of cartilage: üHyaline (most common type in body) üElastic üFibrocartilage Cartilage Locations: Hyaline – in nose; makes up articular cartilage of a joint; makes up costal cartilage in rib cage; cartilage found in trachea Elastic – in external ear and epiglottis Fibrocartilage – in intervertebral discs and cartilage that is found in knee joint The Vertebral Column Vertebrae (normally 33 in total) separated by intervertebral discs Each vertebrae is given a name according to its location o Cervical: first 7 neck vertebrae (C1–C7) o Thoracic: 12 mid to upper back vertebrae (T1– T12) o Lumbar: 5 lower back vertebrae (L1–L5) o Sacral: 1 large vertebra fused from five original bones o Coccyx: (tailbone)—1 vertebra fused from four original bones The Vertebral Column Vertebrae protect spinal cord The Vertebral Column Intervertebral discs separate vertebrae to absorb shock and allow flexibility. o These discs are flat, round cushioning pads o Made up of fibrocartilage The Vertebral Column The spine has a normal “S”- shaped curvature üHelps spine withstand great amounts of stress by providing a more even distribution of body weight The Rib (or Thoracic) Cage Forms thorax (chest) portion of body Consists of 12 pairs of ribs with their costal cartilages and sternum Ribs are anchored posteriorly to the 12 thoracic vertebrae (T1-T12) Main job of thoracic cage is to protect heart and lungs The Rib (or Thoracic) Cage Ribs 1 – 7 are classified as true ribs üCostal cartilage from each of these ribs attaches directly to sternum The Rib (or Thoracic) Cage Ribs 8 – 12 are false ribs o Costal cartilage from each of these ribs DO NOT attach directly to sternum o Instead, costal cartilages are attached to the cartilage of next higher rib. o For example, the cartilage of rib 10 attaches to cartilage of rib 9 while cartilage of rib 9 attaches to the cartilage of rib 8, etc. The Rib (or Thoracic) Cage Ribs 11 and 12 are also called floating ribs since these ribs do not have costal cartilage attached to them Types of Joints Hinge – A hinge joint allows extension and retraction of an appendage üAngular movement in a single plane üFound at elbows and knees Types of Joints Ball and socket – A ball and socket joint allows for radial movement in almost any direction üFound in hips and shoulders Types of Joints Gliding – In a gliding or plane joint bones slide past each other üFound at end of clavicles, as well as between carpals and tarsals Types of Joints Saddle – This type of joint occurs when touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement üFound in thumb Type of bone fractures Simple versus Comminuted: o Simple: the bone breaks in one spot o Comminuted: the bone breaks in several spots Type of bone fractures Closed versus Compound: o Closed: bone do not protrude through the skin o Compound: the bone protrudes through the skin Closed Compound Type of bone fractures Complete versus greenstick: o Complete: bone is completely fractured (fracture across the bone) o Greenstick: bone partly fractures on one side but does not break completely because the rest of the bone can bend. § More common in children whose bones are softer and more elastic. Common Bone Diseases and Disorders Osteoporosis ü Metabolic bone disorder where bone becomes porous, brittle and prone to fracture. Scoliosis ü Lateral curvature of the spine, usually in the thoracic region. Arthritis ü Joint inflammation. Practice Questions Skeletal System BIOL100 – Concepts in Human Health and Biology Columbia College Which bone in the human skeleton is CORRECTLY paired with its shape? a) b) c) d) e) Humerus – short bone Vertebrae – sesamoid bone Radius – long bone Carpals – flat bone Phalanges – short bone Answer: C Which bone in the human skeleton is CORRECTLY paired with its shape? A. B. C. D. E. Sternum – short bone Skull (cranium) – irregular bone Tibia – flat bone Scapula – flat bone Metatarsals – short bone Answer: D Which bone in the human skeleton is INCORRECTLY paired with its shape? A. B. C. D. E. Pelvis – irregular bone Mandible – flat bone Patella – sesamoid bone Tarsals – short bone Coccyx – irregular bone Answer: B (mandible is irregular bone) Which bone is NOT part of the appendicular skeleton? A. Pelvis B. Clavicle C. Scapula D. Sternum E. Femur Answer: D Name the following bones of the human skeleton Carpals Metacarpals Phalanges 2 1 Femur Pelvis 5 3 4 Fibula Patella Tibia 3 2 Clavicle Scapula 1 Humerus Radius 4 5 Ulna Sternum 1 2 3 4 Phalanges Metatarsals Tarsals