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The cell and tissues
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Before considering the basic structure of the cell, it is important to consider its physiological environment. All human cells contain an aqueous fluid (intracellular fluid), known as cytosol. Apart from the organelles, this fluid contains substances such as proteins, other nutrient molecules, metabolic products and also a range of chemicals known as electrolytes. Outside the cells, there is the extracellular fluid, which is composed of the interstitial fluid and the circulating fluid; the latter consists of blood in the vascular system and the lymph in the lymphatic vessels. The extracellular fluid has a similar composition to the intracellular fluid. However, there are important differences in the composition of these fluids, particularly in the type and quantity of electrolytes and in the distribution of protein molecules, as well as the dissolved gases. The intracellular and extracellular environments are separated by the cell membrane, which is selectively permeable; it is able to control the movement of electrolytes and other molecules across it. This characteristic will be discussed later in the chapter. The correct balance and movement of these chemicals between the intracellular and extracellular environments is vital to the maintenance of normal function and therefore health (Marieb and Hoehn 2019). A disruption of this balance is one of the factors that can cause homoeostatic imbalance and potentially lead to a medical emergency (Kumar and Clarke 2017).
Concept of Nutrition
Published in Anil Gupta, Biochemical Parameters and the Nutritional Status of Children, 2020
Water is the inorganic molecule that represents an essential nutrient that is vital for normal maintenance of health and indispensable for the survival of organisms (Jéquier and Constant 2010). Water serves as a universal solvent and an aqueous medium essential for biochemical reactions and metabolic reactions (Iowa State University 2019). It is functionally dynamic for the integrity of plasma membrane and cell structure. Water is indispensable for sustaining the homeostasis of the body and necessary for thermoregulation (Ramsay 1998; Vokes 1987). Water helps in transporting nutrients to body tissues and removing waste materials from body tissues (Panel on Dietary Reference 2005). Water maintains the integrity of extracellular and intracellular fluid compartments. Water serves as a medium in which gas as oxygen is dissolved and transported from the pulmonary alveoli to body tissues while the carbon dioxide is transported from body tissues to the pulmonary alveoli in the dissolved form in water (Royal Society of Chemistry 2019).
Measurement of Transmembrane Potential in the Study Of Systemic Disease*
Published in Richard C. Niemtzow, Transmembrane Potentials and Characteristics of Immune and Tumor Cell, 2020
J. Hamilton Licht, Hardin Jones
There are three problems in determining intracellular electrolyte concentrations in skeletal muscle. First, accurate measurement of intracellular electrolyte concentrations requires an accurate estimate of the ratio of extracellular to intracellular fluid in the tissue sample. Total tissue water is determined gravimetrically. The extracellular space can be estimated using such markers as 60Co-EDTA, 51chromium, Na235SO4 and 14C-inulin. However, these markers are not entirely excluded from the intracellular space in normal tissue and their entry may be exaggerated in diseases that increase the permeability of the cell membrane.
Urine sodium excretion is related to extracellular water volume but not to blood pressure in 510 normotensive and never-treated hypertensive subjects
Published in Blood Pressure, 2023
Jyrki Taurio, Jenni Koskela, Marjatta Sinisalo, Antti Tikkakoski, Onni Niemelä, Mari Hämäläinen, Eeva Moilanen, Manoj Kumar Choudhary, Jukka Mustonen, Pasi Nevalainen, Ilkka Pörsti
As the major extracellular cation, Na+ is rapidly distributed throughout the body. Infusion of hypertonic 7.5% NaCl solution causes extracellular fluid expansion, followed by gradual translocation of fluid also to the intracellular space [50]. Previously, extracellular-to-intracellular fluid ratio was higher during high vs. low Na+ intake in 20 hypertensive patients with chronic kidney disease [43], while Na+ excess in tissues during high Na+ intake has been found to reflect the extracellular accumulation of water and Na+ [15]. In elderly men, Na+ intake directly correlated with leg oedema and differences in leg extracellular fluid contents between daytime and night-time [51]. Our present results suggest a direct independent relation between 24-h Na+ excretion and ECW volume in the absence of an association with the level of BP. In the regression analysis, BSA and ECW volume were the only independent factors related with urinary 24-h Na+-excretion. The observed independent association between urine Na+ excretion and ECW was not driven by age, as no association was observed between age and 24-h Na+ excretion in the regression analyses.
Efficient simulations of stretch growth axon based on improved HH model
Published in Neurological Research, 2023
Xiao Li, Xianxin Dong, Xikai Tu, Hailong Huang
The distribution of ions inside and outside the membrane in the resting state is depicted in Figure 1. Considering that the cell membrane works as an insulator, the extracellular fluid near the cell membrane is positively charged, while the intracellular fluid near the cell membrane is negatively charged, due to the exudation of a small quantity of potassium ions from the cell membrane. The combination of the positively charged external fluid, the insulating cell membrane, and the negatively charged internal fluid forms a capacitor capable of storing electrical charge, referred to as
Comparative studies on the potential use of 177Lu-based radiopharmaceuticals for the palliative therapy of bone metastases
Published in International Journal of Radiation Biology, 2020
Hesham M. H. Zakaly, Mostafa Y. A. Mostafa, Darya Deryabina, Michael Zhukovsky
In Figure 5, the models for 153Sm-EDTMP and 177Lu-EDTMP are visualized using the data provided in Table 2. However, the values of the excretion coefficients for mice were experimentally obtained for 177Lu-EDTMP (Chakraborty, Das, Sarma, et al. 2008). These data can be used as a first approximation for humans. This technique is quite common when evaluating the effectiveness of drugs before conducting preclinical studies (Chakraborty, Das, Sarma, et al. 2008). Figure 6 shows the biokinetic model of the 177Lu-EDTMP preparation, based on transformed data for the human body. All the liquid in the human body can be divided into intracellular and extracellular types. Extracellular fluid is approximately 33% of total body fluid. Intracellular fluid is the fluid circulating between cells and plasma in the bloodstream (Insel and Turner 2007).