Osteoblasts Osteoblasts are responsible for building new bone and lie at the centre of bone physiology. Their functions include the synthesis of collagen and the control of mineralisation. Osteoclasts Osteoclasts are specialised cells that resorb bone. They work by sealing off an area of bone surface then, when activated, they pump out hydrogen ions to produce a very acid environment, which dissolves the hydroxyapatite. Osteocytes Bone adapts to applied forces by growing stronger in order to withstand them; it is known that exercise can help to improve bone strength. Osteocytes are thought to be part of the cellular feed-back mechanism which directs bone to form in the places where it is most needed. They lie within mineralised bone and it is thought that they may detect mechanical deformation and mediate the response of the osteoblasts.
General Zoology Class <ul><li>By: Sharnie Faye G. Buctuan </li></ul>Skeletal System
Functions of the Skeletal System <ul><li>Support - framework that supports body and cradles its soft organs. </li></ul><ul><li>Protection - for delicate organs, heart, lungs, brain </li></ul><ul><li>Movement - bones act as levers for muscles. </li></ul><ul><li>Mineral storage - calcium & phosphate </li></ul><ul><li>Blood cell formation - hematopoiesis </li></ul>
Bone Classification (e) Sesamoid bone (patella)
Distal epiphysis Proximal epiphysis diaphysis yellow marrow Epiphyseal line periosteum compact bone spongy bone Endosteum hyaline cartilage Anatomy of a Bone Sharpey’s fibers
GENERAL DIVISIONS OF THE SKELETON Skeletal system is divided into two general divisions. Axial & appendicular skeleton.
cartilage calcified cartilage bone epiphyseal plate epiphyseal line Endochondral Ossification 2 o ossification center Fetus: 1 st 2 months Adult Childhood Just before birth
Osteoblast Osteocyte Osteoclast Eats bone Builds new bone Mature bone cell Bone cells that aid in remodeling
hematoma callus bony callus Repair of Fractures bone remodeling
VERTEBRATES VS INVERTEBRATES Scientists divided the Animal Kingdom into two main groups: vertebrates (animals with a backbone) and invertebrates (animals without a backbone)
Similarities & d ifferences between Vertebrate & Invertebrate Invertebrate Vertebrate Kingdom: Animalia Animalia Phylum: Chordata Chordata Size: Small and slow moving. Big in size. Number of species: 2 million 57,739 Examples: Insects, flatworms etc. Parrots, Humans, snakes etc About: Animals without a backbone Animals with an internal skeleton made of bone are called vertebrates. Physical Characteristics: Multicellular; no back bone; no cell walls; reproduce sexually; heterotrophic. Well-developed internal skeleton; highly developed brain; have advanced nervous system; outer covering of protective cellular skin. Species: 98% of animal species areinvertebrates. 2% of the animal species are vertebrates. Classification: 30 phyla Classified into five groups: fish, amphibians, reptiles, birds, and mammals. Subphylum: Vertebrata
Vertebrates Animals with backbones can be divided into five more groups: Mammals Birds Amphibians Fish Reptiles
Invertebrates Invertebrates don't have an internal skeleton made of bone. Many invertebrates have a fluid-filled, hydrostatic skeleton, like the jelly fish or worm. Others have a hard outer shell, like insects and crustaceans. There are many types of invertebrates. The most common invertebrates includes the following: Coelenterates Echinoderms Arthropods Worms Mollusks