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Biochemistry of Exercise Training: Effects on Bone
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Panagiota Klentrou, Rozalia Kouvelioti
Oestrogen also increases the sensitivity of bone to mechanical loading during the reproductive years, i.e., before menopause, through its influence on osteoblastic cells (39). During menopause, with oestrogen deficiency occurring, women experience an increase in bone resorption; this increase in bone resorption increases bone loss compared to bone replenishment, and therefore, compromises the skeletal structure. In turn, this causes an overall reduction in bone mass and mineralization (39, 66, 115, 147). The compromise to the skeletal system in post-menopausal women causes an increased risk of low BMD and an increased fragility and fracture rate. In short, a decrease in oestrogen lessens bone formation and increases the risk of bone deterioration, which leads to osteoporosis (66, 115). This effect indicates that women have a high risk of developing osteoporosis after menopause (115).
The Hematologic System and its Disorders
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
The circulatory system is composed of the heart and vessels, which circulate blood, and the skeletal system consists of bone and its connective tissues. Yet these two are intimately related to the hematologic system, the system of the body that, largely within the bone marrow, forms the cells circulated in the blood. The hematologic system is responsible for the formation of red blood cells (RBC) that transport oxygen, white blood cells that protect the body from bacteria and other foreign invaders, and platelets involved in blood coagulation. In addition to bone marrow, the liver, spleen, and lymphatic system also produce hematologic constituents.
Animal Models of Spinal Instability and Spinal Fusion
Published in Yuehuei H. An, Richard J. Friedman, Animal Models in Orthopaedic Research, 2020
Harvinder S. Sandhu, Linda E. A. Kanim, Federico Girardi, Frank P. Cammisa, Edgar G. Dawson
The spine is one of the most frequently modeled parts of the skeletal system, in part because of its complexity, and in part because of its simplicity. The complex coupled motions of different segments of the spinal column, the assessment of spinal instability, and the effects of spinal fixation are not completely understood and continue to be rigorously investigated in a variety of selected animal models. On the other hand, because of the anatomic and kinematic consistency of selective spinal segments, interventions to the spinal column are often reliably predictable. In fact, creation of a spinal fusion is often a useful preliminary test of the biologic characteristics of an experimental implant meant for general skeletal repair.
Application of 3D printing navigation system in pediatric epiphyseal complex lesion surgery
Published in Computer Assisted Surgery, 2023
Haoqi Cai, Haiqing Cai, Zhigang Wang
The most significant difference in the skeletal system between children and adults lies in the epiphysis and physeal plate and the epiphyseal complex [1]. Epiphyseal injury is a general term involving damage to the longitudinal growth mechanism of bone, including epiphysis, epiphyseal plate, ring around the epiphyseal plate (Ranvier area), growth-related articular cartilage, and metaphyseal injury. The incidence of epiphyseal injuries in children under 16 years of age ranges from 6% to 30% [2]. Innate metabolic diseases, infections, tumors and fractures may lead to epiphyseal damage [1,3]. According to statistics, about 5 to 10% of children experience growth failure after epiphyseal injury [2]. It mainly involves two aspects: abnormalities in limb length and abnormalities in limb alignment that will seriously affect children’s joint quality and walking function and then affect life quality [4–9]. They will be secondary to abnormalities in the spine, hip joints, and other joints over time [10].
Simulation study on the effect of resistance exercise on the hydrodynamic microenvironment of osteocytes in microgravity
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Hai-Ying Liu, Chao-Hui Zhao, Hao Zhang, Wei Wang, Qing-Jian Liu
Bone is typically comprised of dense bone, cancellous bone, and tissue fluid. The osteon is the basic structural and physiological unit of dense bone, and it also has the highest bone density in the human skeletal system (Liu et al. 2020; Larcher and Scheiner 2021). The central tubular area of the osteon is called the Haversian canal, which contains arterial and venous capillaries that permit the transport of nutrients and metabolic waste needed for cell metabolism. The multi-layer circumferential lamellae around the Haversian canal consist of a complicated lacunar-canalicular system (LCS). The osteocytes are located in bone lacunae, and the adjacent osteocytes form a complex spatial mechanical signal transduction network through synaptic connections in the canaliculi. The LCS is an important channel for material exchange between osteocytes and capillaries in the Haversian canal (Kwon et al. 2010). The deformation of the bone matrix under loading can induce liquid flow in the LCS, and the mechanical signals produced by the liquid flow are perceived and responded to by osteocytes, thus regulating the activity of osteoblasts and osteoclasts to adjust bone mineral density to adapt to the current mechanical environment (Tovar et al. 2004).
Molecular Genetics of Cleidocranial Dysplasia
Published in Fetal and Pediatric Pathology, 2021
Jamshid Motaei, Arash Salmaninejad, Ebrahim Jamali, Imaneh Khorsand, Mohammad Ahmadvand, Sasan Shabani, Farshid Karimi, Mohammad Sadegh Nazari, Golsa Ketabchi, Fatemeh Naqipour
In 1997, two researchers generated a mouse model for the mutated locus of RUNX2 (Cbfa1). Mice with homozygous mutations in RUNX2 died after a birth without breathing. The examination of their skeletal system revealed a complete absence of osteogenesis. Although osteogenesis was completely blocked throughout the body, but the development of the cartilage was almost normal. Therefore, RUNX2 is essential for maturation of osteoblasts in both endochondral and intramembranous ossification. Heterozygous mice (Cbfa1+/-) showed skeletal abnormalities similar to cleidocranial dysplasia in humans. The heterozygote embryos of the mice had open fontenelles, hypoplasia of clavicles and nasal bones, and delayed ossification of nasal bones and calvarial bones. Therefore, the two researchers suggested that the RUNX2 gene plays an important role in osteogenesis and osteoblast differentiation [19,20].