Growth and Repair of the Skeletal System
Growth and Repair of the Skeletal System
Learning Objective Covered
LO 02.01 – Describe the process for growth and repair of the skeletal system
Career Relevancy
As a Medical Assistant, you ‘ll be a key player in assessing and educating patients. Every interaction with a patient is an opportunity to educate them on health issues and risk factors associated with musculoskeletal disorders, which can involve muscles, tendons, joints, vertebral discs, bursa, and nerves. These disorders can happen as a result of injury, poor posture habits, or repeated forceful movements over time. Understanding the risk factors of musculoskeletal disorders is important to help treat and prevent injuries.
Background
Your skeletal system is truly a work of heart. With 206 bones, 900 ligaments, 3 types of cartilages, and other vital tissues, it’s not difficult to understand the importance your skeletal system has in your overall health. In this discussion, we will focus primarily on the skeletal system and how it grows and heals when injured.
Review How to Grow a Bone (4:36 min) for a step-by-step process of how your bones developed.
Growth of the Skeletal System
Growth of the skeletal system, known as osteogenesis or ossification, begins 6-7 weeks into embryonic life. The way bones develop is that they serve as replacement tissue. In other words, minerals form over and around pre-existing tissue, hardening into bone. By the time of birth, bones have replaced most of the cartilage that served as a template of sorts. As the child grows, bones will continue to develop around some additional cartilage, while some cartilage will remain once the skeleton is fully grown.
There are two ways that bones form—intramembranous ossification and endochondral ossification. No matter which pathway is used, bone is the same regardless.
Intramembranous Ossification. This is the process that forms the flat bones in the face, most of the bones in the cranium, and the collarbones or clavicles. Beginning during the fetus’s developmental period in the womb, intramembranous ossification will continue after birth into adolescence because the skull and clavicles are not fully ossified at the time of birth. Furthermore, the sutures in the skull are not completely closed, which makes it possible for the skull and shoulders to deform during birth. In intramembranous ossification, the last bones to ossify, or to transform into bones, are the flat bones of the face, which will fully develop by the end of adolescence.
In the process of intramembranous ossification, mesenchymal stem cells—cells that can transform into many types of other cells, including osteoblasts, which are the cells that release the formula for bone formation—join together and then separate into specialized cells, some of which will become osteogenic cells (Links to an external site.) and then osteoblasts, which will eventually become bone.
Endochondral Ossification. This is the process that forms the bones at the base of the skull and long bones in the face. During endochondral ossification, cartilage is replaced by bone, rather than cartilage transforming into bone. The cartilage is merely a template for new bone growth to replace. Since the bones are replacing the cartilage completely—rather than the bones being transformed from the cartilage—the process for endochondral ossification is much longer than the process for intramembranous ossification.
About 6-8 weeks into fetal development, some of the mesenchymal stem cells transform into chondrocytes or cartilage cells. These cartilage cells make up the cartilaginous skeletal, which is a precursor of bone development. Then, the perichondrium, a membrane that covers the cartilage, forms.
Next, as the chondrocytes grow and calcify, nutrients no longer can reach them; so, they die and begin to disintegrate, which causes blood vessels to fill the now-empty spaces, enlarging the spaces and bringing in soon-to-be osteoblasts. The enlarged spaces will eventually combine to become the cavity that stores red and/or yellow bone marrow—otherwise known as the medullary cavity.
Capillaries penetrate the cartilage as it continues to grow, while the membrane covering the cartilage begins to transform into the periosteum, or connective tissue that produces bones. Around 2-3 months into fetal life, ossification intensifies through the creation of the primary ossification center, the region that is responsible for the majority of the ossification process.
Cartilage continues to expand on both ends of the bone, increasing the bone’s length. The joint’s surface is the only place cartilage remains once the fetus’s skeleton is fully developed. After birth, the sequence of events—the mineralization of the bone matrix, the death of chondrocytes, the invasion of blood vessels, and the arrival of soon-to-be osteoblasts—continues in the end parts of long bones, which is referred to as a secondary ossification center and aids in further bone development.
Repair of the Skeletal System
Fracture Types. The most common type of injury to the skeletal system is a fracture, and there are several types of fractures:
Open (compound): A fracture that has at least one end of the broken bone tearing through the skin; increases the risk of infection
Closed (simple): A fracture where the skin remains undamaged
Comminuted: A fracture that has several breaks resulting in many small bone particles between two other large pieces
Impacted: A fracture that has one piece forced into another
Transverse: A fracture that occurs straight across (horizontally) the bone
Oblique: A fracture that occurs at a diagonal angle
Spiral: A fracture that results from a twisting motion
Greenstick: A fracture that is incomplete with the bone only partially separated
Fractures
Bone Repair. Bones do not necessarily need to be reset by a doctor in order to heal, but resetting them does ensure that the bone heals properly. There are two ways to set an injured bone: open reduction and closed reduction. Open reduction requires doctors to go in surgically to set the broken bone. These injuries are typically more severe and can result in serious complications. Closed reduction, on the other hand, does not require surgery for the bone to be reset. The location of the fracture is overextended and manipulated back into place. Review the video, Wrist Fracture – Open Reduction and Internal or External Fixation for examples of when open versus closed reductions are completed.
The healing process
It is not uncommon for blood vessels near the fracture to be damaged at the time of the injury. These torn blood vessels cause blood to flow from them, resulting in blood clots that form what’s called a fracture hematoma (Links to an external site.). This causes the blood flow to the bone to be hindered, which causes the bone cells near the fracture to die.
Approximately 48 hours after the bone injury, the fracture stabilizes. The way this happens is that on either end of the fractured bone, an internal callus is formed and secreted by chondrocytes (Links to an external site.). Simultaneously, an external callus, made of cartilage and bone, forms around the outside of the break.
The dead bone is gradually broken down by osteoclasts over following several weeks. Osteoblasts form, and trabecular bone replaces the cartilage in the internal and external calli through the process of endochondral ossification.
As the healing process concludes, the internal (Links to an external site.) and external calli (Links to an external site.) join together, and compact bone replaces the spongy bone outside the fracture. While some swelling is not uncommon even after the bone heals, usually there is no visible evidence of the fracture.
Resources and References
OpenStax. (2013, March 06). Bone Formation and Development. Retrieved April 23, 2019, from https://opentextbc.ca/anatomyandphysiology/chapter/6-4-bone-formation-and-development/ (Links to an external site.)
OpenStax. (2013, March 06). Fractures: Bone Repair. Retrieved April 24, 2019, from https://opentextbc.ca/anatomyandphysiology/chapter/6-5-fractures-bone-repair/ (Links to an external site.)
TedEd. (2015, June 25). How to grow a bone – Nina Tandon. Retrieved from YouTube: https://youtu.be/yJoQj5-TIvE (Links to an external site.)
Prompt
Broken bones are usually painful and limit mobility to varying degrees, which do not make them a particularly enjoyable injury. Often, due to their higher levels of activity, children are more susceptible to bone fractures than most adults. Consider how bones form and heal in adults and children. Also, consider these questions as you write your main post: Why might children be more susceptible to fracture? How might a child heal differently than adults when it comes to bone fractures? How might a broken bone in a child be treated or cared for differently than a broken bone in an adult?
For your initial post discuss the appropriateness of waiting to visit the doctor in the event of a suspected fracture. Does the appropriateness change if you are an adult or child? Explain and support your position.
For your peer replies, consider a stand opposite your peer and argue against what they have stated.
For your citation, you might use articles that discuss bone healing and development.
Your initial and reply posts should work to develop a group understanding of this topic. Challenge each other. Build on each other. Always be respectful but discuss this and figure it out together.
Reply Requirements
You must submit:
1 main post of 150+ words with 1 in-text citation and reference (follow the Institution Writing Guidelines)
2 follow-up posts (replies) of 50+ words
Responses can be addressed to both your initial thread and other threads but must be:
Your own words (no copy and paste)
Unique (no repeating something you already said)
Substantial in nature, which means there has to be some meat to the reply not something like: “Good job, Rasha, your post is excellent.” A substantial post will do one of the following:
Extend the conversation deeper,
Challenge the post being responded to, or
Take the conversation in a career-relevant tangent
Remember that part of the discussion grade is submitting on time and using proper grammar, spelling, etc. You’re training to be a professional—write like it.
Collepals.com Plagiarism Free Papers
Are you looking for custom essay writing service or even dissertation writing services? Just request for our write my paper service, and we'll match you with the best essay writer in your subject! With an exceptional team of professional academic experts in a wide range of subjects, we can guarantee you an unrivaled quality of custom-written papers.
Get ZERO PLAGIARISM, HUMAN WRITTEN ESSAYS
Why Hire Collepals.com writers to do your paper?
Quality- We are experienced and have access to ample research materials.
We write plagiarism Free Content
Confidential- We never share or sell your personal information to third parties.
Support-Chat with us today! We are always waiting to answer all your questions.
