Skeletal System - Bone formation, growth, healing 2 (2).pptx

The Skeletal System - II. Bone Formation, Growth, & Healing NSCI5720 Vertebrate Anatomy & Physiology Learning Objectives Be able to briefly describe bone formation and growth Be able to briefly describe bone remodellin...

The Skeletal System - II. Bone Formation, Growth, & Healing NSCI5720 Vertebrate Anatomy & Physiology Learning Objectives Be able to briefly describe bone formation and growth Be able to briefly describe bone remodelling and healing Recap from last lecture What are some functions of the skeletal system? What are the three types of bone cells? What are the two main types of bone? What are the end sections of the long bones called? What is the name of the middle section of a long bone? Bone Formation & Growth Bone ways: is formed in the body in two Endochondral (Cartilage) bone formation Intramembranous (Intraosseous) bone formation Endochondral Bone Formation Majority of bone formation Most bones start as cartilage in the fetus (like a template) Long bone formation begins in the primary growth centre in diaphysis and radiates outwards ⚬ Cartilage is removed gradually as bone is created ⚬ Additional secondary growth centres develop in the epiphysis of bone (the ends) At birth most cartilage has been replaced by bone Only growth plates/epiphyseal plates remain as cartilage ⚬ These allow long bone growth Full skeletal maturity- epiphyseal plates ossify ⚬ The age at full ossification depends on species, breed, size, desexing status etc... Repetitive exercise ⚬ Risk of damaging growth plates Endochondral Bone Formation Endochondral Bone Formation Endochondral Bone Formation Endochondral Bone Formation 3 day old pup > 26 day old pup > 62 day old pup > adult Endochondral Bone Formation 3 day old pup > 26 day old pup > 62 day old pup > adult For interest only (not examinable) Intramembranous Bone Formation Bone forms from fibrous membranes covering the brain in the developing fetus Only occurs in certain skull bones, mandible, (note: dogs and cats do not have a clavicle like humans) This creates bones of the cranium which surround the brain Why might we want these bones to ossify earlier than the rest of the skeleton? Not Examinable Bone Healing Bones are one of the best healing tissues in the body! Fractures (breaks) can occur in any bones but are most common in long bones Three factors necessary for optimal healing: ⚬ Alignment ⚬ Immobilisation ⚬ Time Bone Healing- Alignment Alignment is also known as “reduction” of a fracture (or “fx”) Fractured ends must be brought together in reasonable alignment and kept from moving apart during the healing process Interrnal and external devices (such as plates, pins and screws implanted during surgery) are used to reduce a fx ⚬ They may remain in the bone or be removed later Bone Healing- Immobilisation Also called “fixation” of a fracture Achieved through internal fixtures and external fixtures – pins, plates, screws, and splints, casts Length of time external fixators are in place depends on species, age, activity level – all affect healing time Bone Healing- Immobilisation Lack of stability has resulted in dealyed healing and a larger callus Fracture Healing Bones have a large blood supply – this results in large amount of bleeding (haemorrhage) when a fracture occurs A clot is formed – known as the fracture haematoma Osteoblasts form healing tissue known as a callus ⚬ First a fibrocartilage/soft callus followed by a bony/hard callus Callus bridges the fracture gap – the size of the callus indicates how much movement has occurred during healing Small callus = faster healing Remodeling occurs after callus has formed and fracture has stabilised Fracture Healing - Steps Clot forms (haematoma ) Osteoblasts create Haemorrhage Callus 1. Soft/fibrocartilage 2. Bony/hard Fracture Remodelling occurs occurs Fracture Healing Fracture Healing Callus Recap: Bone Formation & Growth Bone is formed in the body in what two ways? Bone Formation & Growth Bone is formed in the body in two ways: Endochondral/Cartilage bone formation Intramembranous/Intraosseous bone formation Recap: Can you briefly describe this process? Recap: Bone Healing Can you name and describe three factors necessary for optimal bone healing? Recap: Bone Healing Three factors necessary for optimal healing: ⚬ Alignment ⚬ Immobilisation ⚬ Time What are the steps in fracture healing? Steps in Fracture Healing He pātai tā tētahi? Any Questions?  Tēnā koutou Thank you Email [email protected]