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Thermography by Specialty
Published in James Stewart Campbell, M. Nathaniel Mead, Human Medical Thermography, 2023
James Stewart Campbell, M. Nathaniel Mead
Any skeletal muscle under active contraction produces heat as a byproduct; this in turn directly warms the muscle and any surrounding tissues via heat conduction. Thus the skin over active, enervated muscles appears warmer than skin over non-metabolizing tissues. A muscle at rest or with flaccid paralysis can be expected to be cooler than active muscle. (Figure 11.7)22 A completely fibrosed muscle is cooler than active muscle because it has become a low-metabolizing tissue similar to tendons or ligaments. Increased muscle tone due to CNS disruption from brain stroke or cerebral palsy may appear paradoxically cool due to reduced blood flow to the overlying dermis (see the section on Neurology for more details). The thermal appearance of abnormal muscle contraction due to recent tendon rupture requires further study, though an acute increase in local skin temperature is expected from possible inflammation, with later decrease in local temperature due to muscle atrophy if the tendon is not repaired.23 Muscles acting across a chronically painful or “frozen” joint may also appear relatively cool due to reduced contractions caused by the pain and resultant inactivity.24
Cardiac Tumours
Published in Mary N. Sheppard, Practical Cardiovascular Pathology, 2022
Histologically, the papillary fronds consist of a central core of dense connective tissue surrounded by a layer of myxoid loose connective tissue and covered by hyperplastic endothelial cells (Fig. 7.25). The layer of loose connective tissue contains dense collagen and elastic fibres as well as occasional smooth muscle cells (Fig. 7.26). The amount of elastic is variable, but usually a fine mesh work surrounds the central collagen core. Sometimes, the entire central core may consist of elastic fibres. The central core is continuous with the underlying connective tissue of the endocardium and appears to be a direct extension of the endocardium. The hyperplastic endocardial cells covering the papillary fronds merge with the endocardium. Sometimes unusually located papillary fibroelastomas can be noted on the mural endocardium, and may lead to confusion with myxoma because of the mucopolysaccharide rich loose stroma especially on frozen sectioning when the fronds collapse together to give a solid appearance to the mass.13
Functional Anatomy
Published in James Crossley, Functional Exercise and Rehabilitation, 2021
Muscles are the largest group of tissues in the body, accounting for almost half of the body’s weight. Muscles are contractile tissue that convert energy into motion. There are three main types of muscle, skeletal muscle, known as voluntary muscle because we have conscious control over its action, cardiac muscle forming the wall of the heart, and smooth muscle that forms the walls of most vessels and organs. Both cardiac and smooth muscle are involuntary, working without conscious awareness.
Skeletal muscle plasticity and thermogenesis: Insights from sea otters
Published in Temperature, 2022
Traver Wright, Melinda Sheffield-Moore
Although the metabolic rate in resting skeletal muscle is low, it can rapidly increase to support metabolic demand. In skeletal muscle, this increased demand often powers muscle contractions for movement during physical activity, but can also increase for thermogenesis. Increased metabolic heat production can result from shivering (thermogenic muscle contractions that do not support functional movement), or nonshivering thermogenesis. Nonshivering thermogenesis has the advantage of not requiring muscle contraction to increase cellular energy expenditure. Instead, the sequestration of ions in membrane-bound intracellular chambers is made less efficient by “leaky” membranes. This leak requires additional energy expenditure to maintain trans-membrane concentration gradients, and includes proton leak across the inner mitochondrial membrane (where the proton gradient is used to generate ATP) as well as sarcolipin-mediated leak of sequestered calcium from the sarcoplasmic reticulum [4]. Through these mechanisms, skeletal muscle tissue contributes significantly to thermogenesis. Skeletal muscle metabolic capacity must be maintained at a level adequate to support not only thermogenesis, but also peak simultaneous demands for sustained physical activity and cellular maintenance. While increased demand for physical activity (e.g. endurance exercise training) is recognized as the primary work-producing stimulus to upregulate skeletal muscle aerobic capacity, the role of cold exposure is often underappreciated for its ability to stimulate an upregulation of metabolic capacity and thermogenic leak.
Dysfunction of epithelial permeability barrier induced by HMGB1 in 2.5D cultures of human epithelial cells
Published in Tissue Barriers, 2022
Takashi Kojima, Yuma Shindo, Takumi Konno, Yuki Kodera, Wataru Arai, Maki Miyakawa, Kizuku Ohwada, Hiroki Tanaka, Mitsuhiro Tsujiwaki, Yuji Sakuma, Shin Kikuchi, Tsuyoshi Ohkuni, Kenichi Takano, Atsushi Watanabe, Takayuki Kohno
The airways are broadly classified into conducting and respiratory regions. The conducting airways consist of the trachea, bronchi, and bronchioles, while respiratory regions consist of respiratory bronchioles and alveoli. The conducting airways are lined by a continuous layer of bronchiolar epithelial cells, which act as a first barrier for inhaled materials and play an important role in protection from external pathogens such as bacteria, viruses, chemical substances and allergic components.23,24 On the other hand, alveolar epithelial cells, which are vital for gas exchanges, form a barrier for an air-liquid interface.25 To maintain the air-liquid interface and control gas exchanges, alveolar epithelial cells provide a proper permeability barrier.26 The main characteristic of epithelial tissues is that epithelial cells are arranged in monolayers or stratified layers and tightly adhere to each other. This sheet-like structure provides a barrier function that separates the apical and basolateral compartments of various tissues, and maintains homeostasis.
Design of lower limb prosthetic sockets: a review
Published in Expert Review of Medical Devices, 2022
Minghui Wang, Qingjun Nong, Yunlong Liu, Hongliu Yu
Full-contact prosthetic sockets have the characteristics of a large bearing area of the stump. The stress in each area is uniform, and the pressure on the unit area of the stump is small, so the local stress is avoided, and the blood circulation of the stump is improved. However, due to the large contact area, it is easy to cause heat dissipation and skin problems. In daily use, muscle tissue generates heat due to the movement of the stump. If the heat is not released in time, the skin surface temperature will rise and sweat will be discharged. Sweat can’t evaporate freely in a large area or be cleaned up in time, which will lead to skin edema, blisters, bacterial infection, etc. However, the full contact vital interface has higher requirements for the coordination between the stump end and the inner surface of the prosthetic socket. Too tight fit is not conducive to blood circulation. Too loose fit will reduce the suspension performance and thus causing relative sliding between the stump and the prosthetic socket, resulting in the ‘piston phenmenon,’ which is very easy to cause skin problems [30].