PT4002 - Case Study (Healing & Repair) PDF

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This is my submission for Formative - Component 3 PT4002 with my own personal answers. These are only to be used as reference. ...

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PT4002 Applied Healthcare Science Component 3: Case studies A Case Study on Bone Tissue Structure and Repair Mrs. Usba Malik is a 45-year-old female who works as an architect. While she was on a site visit today she tripped on an unsecured cable and fell awkwardly down a small slope, colliding with a wheelbarrow at the bottom. The ambulance personnel reported that she had lost a substantial amount of blood at the accident scene and was “unconscious” when they arrived. To minimize further hemorrhage, the paramedics applied a pressure bandage to her leg. You are observing in A&E when Mrs. Malik arrives, she is awake and alert, but complaining of severe left arm and back pain, plus she has a “killer headache.” To examine her injuries the staff remove four blood-soaked bandages from her arm. You notice a large open wound on her leg with what appears to be bone tissue sticking out of the skin. She also has bruises covering her left hip, left shoulder and lower back. To determine the extent of her injuries Mrs. Malik undergoes several x-rays, which reveal the following: 1) fracture of the left tibia at the proximal diaphysis. 2) fracture of the 3rd lumbar vertebral body.

Short Answer Questions 1. Define the following terms, used in the case and also in associated questions: a. Hemorrhage - loss of blood from the vessels by flow through ruptured walls b. Fracture - a break in bone c. Proximal - towards the attached end of a limb or the origin of a structure d. Diaphysis - elongated shaft of a long bone Definitions taken from Marieb (2015) 2. One way bones are classified is by their shape. How would you classify the bones fractured by Mrs. Malik? Mrs. Malik has fractured her tibia and 3rd lumbar vertebral body. The tibia is a long bone as it is longer than it is wide. Whilst the vertebral body is an irregular bone as it does not have a distinctively characterized shape. 3. The body of Mrs. Malik’s vertebra is fractured. What type of bone tissue makes up the majority of the vertebral body? Describe the structure and function of this type of bone.

The vertebral body consists mostly of spongy bone (trabecular bone). Microscopically, it can be seen to have a honeycomb structure made up of small needle-like pieces called trabeculae. The trabeculae align precisely along stress lines and help the bone resist stress. 4. The diaphysis of Mrs. Malik’s tibia is fractured. What type of bone makes up the majority of the diaphysis of long bones like the tibia? Describe the layers of bone tissue found here. The diaphysis of long bones mainly consists of compact bone with structural units called osteons or Haversian systems. An osteon is a group of hollow tubes of bone matrix (lamella), with one placed outside the next. There are three types of lamellae.  Interstitial: lies in between osteons  Circumferential: surrounds the shaft of compact bone  Concentric: forms around each osteon 5. Most connective tissue, including bone, is highly vascular. Which anatomical structures in Mrs. Malik’s compact bone house blood vessels? What sign or symptom in Mrs. Malik’s case is directly related to disruption of these structures by her bone fractures? How is the sign or symptom related to these anatomical structures? Central and perforating canals, hold small blood vessels and nerve fibers within compact bone. Mrs. Malik hemorrhaged when her bones fractured and pierced her skin, nicking surrounding blood vessels and causing her to bleed out. Similarly, the blood vessels within the bone might have ruptured as the bone broke. She was also covered in bruises, indicating that she hemorrhaged internally. 6. Within days after a fracture, a “soft callus” of fibrocartilage forms. What fibers are found in this type of cartilage? Identify the cells required for fibrocartilaginous callus formation and list their functions. Collagen fibres are found in fibrocartilage. The cells required for callus formation include fibroblasts, chondroblasts and osteogenic cells. Fibroblasts produce collagen fibres to fuse the bone together, while the chondroblasts secrete cartilage matrix and osteoblasts begin to form spongy bone. 7. As a fracture is repaired, new bone is added to the injury site. What term is used to describe the addition of new bone tissue? Identify which bone cell is responsible for this process and explain how it occurs. Ossification/bone deposition. Osteoblasts help lay down new bone tissue through the secretion of unmineralized bone matrix including collagen, bone proteins and calciumbinding proteins via exocytosis. This new matrix will harden (ossify) later on with the addition of calcium and phosphorus. 8. In the final stage of bone repair, some of the osseous tissue must be broken down and removed. What term is used to define the breaking down of osseous tissue? Which bone cell would be best suited for this task?

The breaking down of osseous tissue is known is as bone resorption. The bone cells involved are osteoclasts. 9. The extracellular matrix (ECM) of bone is considered to be a composite material made up of organic and inorganic matter. What makes up the organic and inorganic portions of the matrix? Describe the cellular mechanism involved in breaking down this matrix; include the bone cell required for the process. The osteogenic cells, osteocytes, osteoblasts and osteoclasts are considered the organic portions. While calcium, phosphorus and other minerals salts make up the inorganic portions. Osteoclasts are responsible for breaking down the matrix. When actively resorbing bone, the osteoclasts will stay in a shallow indentation and produce ruffled edges that come directly into contact with the bone. The deep plasma membrane infoldings of the ruffled edges help increase the surface area to enzymatically degrading the bones and seal off that area from the surrounding matrix. Reference List 1. Marieb, E.N., Hoehn, K.N. (2015) Human Anatomy & Physiology, Global Edition. Harlow, U.K.: Pearson Education Limited 2. BC Open Textbooks (2018) Bone Structure. Available at: https://opentextbc.ca/anatomyandphysiology (Accessed: 10th February 2019)...