anatomy ch 6

Bone Osseous Tissue forming whole bone, vessels, and nerves Cartilage embryonic forerunner of most bones and covering of many joint surfaces Ligaments Hold bone to bone at the joint How do you differentiate between ligaments and tendons? Ligaments = bone to bone at the joint Tendons = attach muscle to bone Functions of the Skeleton - Support - Movement - Protection of delicate organs - Blood formation in red bone marrow What has a hard matrix? Bone is a connective tissue with a hard matrix Mineralization process of hardening of the bone Another name for mineralization is? Calcification Two types of bone are? Compact and Spongy Tissues present in the bone are? Bone Cartilage Ligaments Blood Bone marrow Cartilage Adipose tissue Nervous tissue Fibrous CT Compact Bone Consists of osteons, perforating canals, circumferential lamellae, lacunae, and canaliculi Osteon Contains concentric lamellae (round circles like a dart bullseye board) with the central (Haversian) canal in center What is the basic unit for compact bone? Osteon The central canal contains? Central canal contains vessels, nerves, lymphatics for compact bone Perforating canals consists of: Consists of vessels, nerves, lymphatics shared with other osteons What are Circumferential lamellae? Circles/fills-in around the most superficial part of compact bone Lacunae Small open space where osteocytes reside Canaliculi Small canals for sharing of nutrients among osteocytes in the lacunae Describe spongy bone Has trabeculae and spicules Porous appearance Lightweight but strong Trabeculae thin plates of bones Spicules rods and spines of bone Porous appearance Imagine a sponge filled with red bone marrow; "Spaces filled with red bone marrow" Bone Marrow Soft tissue located in medullary cavities of long bones and the spaces within spongy bone What are the two types of bone marrow? Difference? Red marrow and Yellow Marrow Reason 1: Red bone marrow contains blood stem cells that can become red blood cells, white blood cells, or platelets. Yellow bone marrow is made mostly of fat and contains stem cells that can become cartilage, fat, or bone cells. Reason 2: Red bone marrow is located in flat bones or at the end of long bones (epiphysis). Yellow bone marrow is located in the marrow cavity. Red marrow Known as myeloid tissue; Contains hematopoietic tissue Hematopoietic tissue Blood-forming tissue; Both red and white blood cells are made here Yellow marrow Mainly fat Location of red marrow Skull, vertebrae, sternum, ribs, parts of pelvic girdle, and proximal heads of humerus and femur Location of yellow marrow Shaft of long bones, such as humerus, radius, ulna, femur, tibia, fibula only What are the Bone Cells? Osteogenic, osteoblasts osteocytes, osteoclasts Osteogenic cells Also called osteoprogenitor; Stem cells for Osteoblast/osteocyte Memory Trigger: I started liking K-pop through new GENES (jeans) Osteoblasts Bone-forming cells that become osteocytes; heal bones too Memory Trigger: B for build = having a blast healing bone!! Osteocytes Mature bone cells that sit in lacunae Memory Trigger: I deCYTED (decided) to mature when I got to highschool. Osteoclasts - Derived from the fusion of multiple stem cells - Bone-dissolving macrophages (phagocytic cells) Memory Trigger: My CLASsmates kept degrading me. Ossification Also called osteogenesis; bone formation Mesenchyme Ossification begins with mesenchyme; an embryonic connective tissue What are the two methods of ossification? Intramembranous and Endochondral Intramembranous Produces flat bones of the skull and most of the clavicle; Bone develops in a fibrous sheet resembling the dermis in the fetus Endochondral Most bones develop this way; Bone develops from the hyaline cartilage model in the fetus Bone Elongation Bones grow longer at epiphysial plates What are epiphysial plates? Plates made of hyaline cartilage (AKA metaphysis); remnant of the growth plate Appositional growth growth in diameter and thickness Describe the intramembranous ossification at surface when bones widen or thicken - Osteoblasts in periosteum deposit matrix - Once matrix hardens, cells become osteocytes - Circumferential lamellae are formed What do osteoclasts do to the medullary cavity? Osteoclasts widen medullary cavity Flat thin, often curved (for example, ribs) List some flat bones Skull: occipital, parietal, frontal, nasal, lacrimal, and vomer Thoracic cage: sternum and ribs Pelvis: ilium, ischium, and pubis Irregular complex shape (for example, vertebrae) List some irregular bones vertebrae, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible, palatine, inferior nasal concha, and hyoid Long rigid levers for movement (for example, femur) List some long bones the tibia, fibula, femur, metatarsals, hand phalanges, the humerus, radius, ulna, metacarpals, and feet phalanges Short bones that glide within joints (for example, carpals of wrist) List some short bones Wrist Carpals: scaphoid, lunate, triquetral, hamate, pisiform, capitate, trapezoid, and trapezium Ankle Tarsals: calcaneus, talus, navicular, cuboid, lateral cuneiform, intermediate cuneiform, and medial cuneiform Features of Long Bones - Compact and spongy bone tissues - Two epiphyses (heads) at the ends of the diaphysis (shaft) - Marrow (medullary) cavity - Epiphysial line (remnant of the growth plate) - Periosteum covering - Nutrient foramina - Endosteum lining - Articular cartilage (lines joints to make smooth joints) Osteopenia - loss of bone (severe when it develops into osteoporosis) - Fractures are more common, and when occur, heal slowly - when resorption (breakdown) is faster than deposition (creation) of bone Which is worse osteopenia or osteoporosis? Osteoporosis What happens to the skeletal system after age 35? Osteoblasts less active than osteoclasts What happens to the skeletal system after age 40? - Females lose 8% of bone mass per decade - Males lose 3% of bone mass per decade Who loses more bone mass after age 40? Men or women Women Osteoporosis - Bones lose mass and become subject to pathological fractures - Hip, wrist, vertebrae are especially vulnerable Kyphosis "dowager's hump" exaggerated thoracic curvature Who is at risk for osteoporosis? Postmenopausal, Caucasian, light-build women are at greatest risk - Because of the decline of estrogen results in less inhibition of osteoclasts True or false. By age 70, have typically lost 30-50% of bone mass True True or false. Men are not risk for osteoporosis, only women. False Prevention for osteoporosis weight-bearing exercise, adequate calcium and protein Stress fracture Caused by abnormal trauma Pathological fracture Occurs in bone weakened by a disease such as osteoporosis Classifications for Fractures Breaking of skin (Open/closed/simple/compound) Direction of fracture Separation of bone pieces (Displaced/Comminuted) Treatment for Fractures - Closed reduction: nonsurgical manipulation of fragments - Open reduction: surgical setting involving plates, screws, or pins - Cast (fiberglass) What is the difference between close and open reduction? Open reduction is surgical and uses equipment to put bones back together. Closed reduction manipulates the bones from outside the skin; the bone is not exposed. How long do fractures take to heal? Healing in 8-12 weeks (This includes the healing itself and the rehabilitation for the muscles and ligaments)