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Introduction: Background Material
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
An important subset of living cells is excitable cells, which, when stimulated by an adequate stimulus of appropriate strength, undergo specific changes in the ionic permeabilities of their cell membranes. These permeability changes cause variations in the voltage across the cell membranes of excitable cells, which can result in a characteristic electric signal known as the action potential (AP) or nerve impulse (Chapter 3). The most important excitable animal cells are: (i) sensory cells, or receptors, which respond directly to environmental stimuli such as light, touch, taste, and smell, (ii) nerve cells, or neurons, whose primary function is the processing and transmission of information, and (iii) muscle cells, whose primary function is the development of a mechanical force of contraction. Neurons are discussed in Chapter 7, muscle cells and their receptors in Chapter 9.
Introduction to the Biological System
Published in Ashutosh Kumar Dubey, Amartya Mukhopadhyay, Bikramjit Basu, Interdisciplinary Engineering Sciences, 2020
Ashutosh Kumar Dubey, Amartya Mukhopadhyay, Bikramjit Basu
Tissue is a self-assembly of groups of cells having a similar structure and origin, which together perform a specific function. Various cell types and their functionality are summarized in Table 8.1. Based on the structure and function, tissues are classified into four major types, connective tissue, muscle tissue, nervous tissue, and epithelial tissue. Among these, the connective tissues consist of fibrous tissues embedded in ECM and provide structural framework to an organ. Connective tissue also contains spindle-shaped fibroblasts. Bone, adipose tissues, tendon, ligament, and blood are classical examples of connective tissues. As shown in Figure 8.5, the muscle tissue consists of muscle cells which have contractile nature that produce force and control the motion (movement or locomotion) in an organism. Among different types of muscle tissues, smooth muscle constitutes the inner linings of hollow organs like digestive tracts, blood vessels, etc., while the skeletal muscle are found to be attached to bone. Another type of muscle tissue is cardiac muscle, which is found only in the heart, has self-contracting nature that helps in rhythmic blood pumping throughout an organism. The neural tissue consists of neurons and neuroglia. In the central and peripheral nervous system, the nerve tissue constitutes the brain and spinal cord, and cranial nerves and spinal nerves, respectively. The epithelial tissues consist of closely packed epithelial cells, which cover the outer and inner surfaces of the organ.
Regeneration of Cardiomyocytes from Bone Marrow Stem Cells and Application to Cell Transplantation Therapy
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
It is well known that skeletal muscle cells contain stem cells, called “satellite cells”. Satellite cells can both proliferate by cell division and differentiate into skeletal muscle cells, and the differentiated skeletal muscle cells can fuse to form myotubes. By contrast, fetal cardiomyocytes can proliferate by cell division, but they undergo terminal differentiation and stop dividing after birth. A number of studies have reported that cardiomyocytes increase in size by cell hypertrophy, not by cell hyperplasia. To our knowledge there have been no reports of the presence of satellite-cell-like cardiac stem cells in the heart. Beitrani et al recently reported that human cardiomyocytes express Ki67, a marker of cell division, and the M phase of the nucleus of the cardiomyocytes was observed in the border zone area of recent myocardial infarction in autopsied hearts.13 These findings suggested that only a very few adult cardiomyocytes can divide after the terminal differentiation. Although their findings were very interesting, these cells were insufficient to improve cardiac function, since the population of these cells was very small.
A Functional BCI Model by the P2731 working group: Physiology
Published in Brain-Computer Interfaces, 2021
Ali Hossaini, Davide Valeriani, Chang S. Nam, Raffaele Ferrante, Mufti Mahmud
Action potentials are not limited to neurons. Muscle cells generate action potentials to contract, and, when multitudes act synchronously, their aggregate contraction produces bodily movement. Muscles in the face and neck are relatively powerful compared to cerebral neurons. They are often physically closer to brain sensors, and, without the insulation of the skull and the brain’s protective membranes, they easily interfere with detection of cortical potentials [182].
Modelling and simulation of sprinters’ health promotion strategy based on sports biomechanics
Published in Connection Science, 2021
Wang Huifeng, Achyut Shankar, G.N. Vivekananda
As the knee flexes deeper, the natural knee femoral posterior roll increases, accompanied by the internal rotation of the tibia. The knee joint is forced or twisted by the flexion position, and the tension of the iliac crest is increased, and the tibial articular surface is displaced, twisted, impacted and rubbed. If the long-term load of these forces exceeds the physiological limit of cartilage and hinders the normal metabolism, it will lead to changes in articular cartilage, which will lead to a series of pathological changes such as fibrosis, calcification and chondrocyte swelling. If the action is wrong, contrary to the human anatomy and the dynamic biomechanical law, it will cause anti-joint activity, the muscle is in a “passively insufficient” state, and the ligament is excessively pulled, resulting in a sprain or strain. All kinds of human movements are accomplished by the contraction of muscle cells. From the molecular level, the contraction of various muscles is related to the contraction ability of contractile proteins in muscle cells, that is, the interaction ability between myosin and myofibrin. Muscle contraction results from a communication between the myosin and actin filaments that generates movement relative to one another. On the molecular basis, interaction is the binding of myosin to actin filaments and it allows myosin to function as a motor that drives the filament sliding. Myofibril is a functional unit of skeletal muscle and it composed of syncytia of multinucleated cells that differ considerably in their physiological and biochemical properties. Therefore, in the support stage, in order to reduce the loss of the horizontal speed of the body's centre of gravity and bring greater acceleration effect to the centre of gravity, we emphasise that fast leg swing and hip extension are very meaningful, they are effective means to improve the speed of running. When the knee joint is moving at different positions and speeds, the activity of each muscle has important guiding significance for the evaluation of muscle strength test results and the formulation of specific strength training plans.
A review on the recent progress, opportunities, and challenges of 4D printing and bioprinting in regenerative medicine
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Parvin Pourmasoumi, Armaghan Moghaddam, Saba Nemati Mahand, Fatemeh Heidari, Zahra Salehi Moghaddam, Mohammad Arjmand, Ines Kühnert, Benjamin Kruppke, Hans-Peter Wiesmann, Hossein Ali Khonakdar
Tracy et al. [62] suggested a new method for reprogramming human adipogenic mesenchymal stem cells to form Purkinje cells to bioprint Purkinje networks. Purkinje networks had the capability of physiologic stimulus responding such as concentration or electrical alteration. Bioink was a mixture of type I collagen and Purkinje cells. A negative mold was designed by computer-aided design (CAD) with pluronic acid, eliminated after bioprinting. The response to the electrochemical stimulation analyzed the printed structures. It was found that the programmed Purkinje cells were successfully bioprinted in a type I collagen matrix with approximately 300000 cells per 200 μL. The printed network was capable of expressing Cx40 protein and responding successfully to electric stimulation and acetylcholine changes. One of the major parameters in muscle tissue engineering is topological cues; therefore, Yang et al. [146] suggested a new electrical response method to overcome this challenge. Gelatin methacryloyl (GelMA) mixed with C2C12 cells created an electrical response microfibrous. The contraction mechanism starts with the stimulation of the skeletal muscle cells using voltage-gated calcium channel activation of cell membranes. The electrical response capability of smart material changes geometry over time and mimics the complex structure of muscle structure, so, electrical response material was studied. For this purpose, 2-hydroxy-4′-(2- hydroxyethoxy)-2-methylpropiophenone was utilized as photo-initiator and GelMA was dissolved in phosphate buffer solution (PBS), and cells were added to the bioink. Curing was performed by 365 nm wavelength UV for 60 s. An electrical field with the intensity of 0.8 kV cm−1 was applied for 12 s to cells, and higher myotube formation was observed compared to non-conductive samples. In addition, the myotube formed was more regular and mature. On the other hand, the swelling response of gelatin led to bundle formation by GelMA microfibers. A 4-month in-vivo study by Cui et al. [147] demonstrated the successful application of mechanical and humidity responsible cardiac patches. GelMA and polyethylene glycol diacrylate (PEGDA) were used with myocardial fiber orientation. The patch was constructed using the beam scanning stereolithography method, and the fabricated structure showed improved biomechanical properties and integration with the beating heart. Under mechanical and humidity stimulation, it revealed enhanced vascularization, cardiomyocyte maturation, cell engraftment, and vascular supply.