Body fluids and electrolytes
Ian Peate, Helen Dutton in Acute Nursing Care, 2014
The extracellular fluid (ECF) consists of fluid outside the cells, decreases with advancing age and is more readily lost from the body than intracellular fluid. This fluid is commonly subdivided into smaller compartments; the intravascular and the interstitial compartments or spaces. The intravascular compartment consists of fluid within the blood vessels (i.e. the plasma volume). The average adult blood volume is approximately 5 – 6 litres, of which about 3 litres is plasma (Edwards 2001, Marieb and Hoehn 2010). The interstitial fluid is water in the ‘gaps’ between the cells and outside the blood vessels and also includes lymph fluid (sometimes called the ‘third space’). Transcellular fluid is contained within specialised cavities of the body, e.g. pleural, synovial, pericardial fluids and digestive secretions which are separated from the interstitial compartment by a layer of epithelium. This fluid is similar to interstitial fluid and is often considered as part of interstitial volume (Edwards 2001). At any given time transcellular fluid is approximately 1 litre (Heitz and Horne 2004). Figure 4.1 shows how the fluids are dis tributed in the body.
Fungi and Water
Chuong Pham-Huy, Bruno Pham Huy in Food and Lifestyle in Health and Disease, 2022
Every cell in the body contains fluid. When cells lose their fluid, they quickly shrink and die. On the other hand, when cells take in too much fluid, they swell and burst apart (170). About two-thirds of the body’s fluid is held within the walls of cells and is therefore called intracellular fluid. The remaining third of the body’s fluid is referred to as extracellular fluid because it flows outside of the cells (170). There are two types of extracellular fluid: interstitial fluid and intravascular fluid. Interstitial fluid flows between the cells that make up a particular tissue or organ, such as muscle fibers or the liver (170). Intravascular fluid is the water in the bloodstream and lymph. Plasma is specifically the extracellular fluid portion of blood that transports blood cells within the body’s arteries, veins, and capillaries (170).
A Review of Classic Physiological Systems
Len Wisneski in The Scientific Basis of Integrative Health, 2017
The lymphatic system, which includes the spleen, thymus, tonsils, and various lymph nodes, supports the immune system (see Figure 1.11). The lymphatic system filters and removes foreign particles. Lymph nodes store B and T lymphocytes for activation when an antigen is present. Lymph nodes are distributed throughout the body and filter the lymph before it is sent out into the blood circulation again. They can remove bacteria, viruses, and cancerous cells. There are other cells called macrophages that are also present in lymph nodes and contribute significantly to the immune response. Lymph is blood plasma that has filtered through capillary walls. It is called interstitial fluid until it enters the lymph capillaries, and then it is called lymph. There is a whole lymph flow system that is still somewhat enigmatic. For example, it has been believed that the brain was devoid of lymphatic vessels until the recent discovery of meningeal lymphatic vessels (Aspelund et al., 2015; Louveau et al., 2015). This discovery shattered the long-held belief that the CNS was restricted to communication with the systemic lymphatic system. This may have major implications regarding our understanding of immune-based CNS diseases such as multiple sclerosis and several others.
Antibiotic exposure at the site of infection: principles and assessment of tissue penetration
Published in Expert Review of Clinical Pharmacology, 2019
Nynke G. L. Jager, Reinier M. van Hest, Jeffrey Lipman, Jason A. Roberts, Menino O. Cotta
Interstitial fluid surrounds the tissue cells and is the main component of extracellular fluid in the human body [7]. Antibiotic concentrations within the interstitial fluid of a tissue can be measured using microdialysis. This technique consists of the insertion of a microdialysis probe into the tissue or organ of interest. The probe is continuously flushed with a tissue-compatible perfusion fluid and has a semipermeable membrane that allows substance uptake by passive diffusion. Since only low-molecular-weight substances are diffusible through the membrane, this technique only allows the sampling of unbound concentrations of small molecules present in the interstitial fluid [33]. The major advantages of microdialysis over tissue biopsies are (i) its capacity for continuous sampling within a time period, such as an antibiotic dosing interval, in the same individual and the same area with minimal tissue perturbation, allowing it to be potentially utilized in almost every human tissue and (ii) in the case of extracellular infections, which account for the majority of bacterial infections, the measurement of antibiotic concentrations at the site of interest.
Multi-scale numerical simulation on mechano-transduction of osteocytes in different gravity fields
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Chaohui Zhao, Haiying Liu, Congbiao Tian, Chunqiu Zhang, Wei Wang
The model was divided into solid and liquid domains, and the solid structure was simulated by linear elastic isotropic materials. The elastic moduli of ECM and lacunar wall were 16 GPa and 43 kPa, respectively, and Poisson’s ratios were 0.38 and 0.4, respectively (Burger and Klein-Nulend 1998). The elastic modulus of the osteocyte body and process was 4.47 kPa, Poisson’s ratio was 0.3, the density was 800 kg·m−3 and the bulk viscosity was 0.001 Pa·s. The elastic modulus of primary cilium was 178 kPa and Poisson’s ratio was 0.4 (Schwartz et al. 1997; Wang et al. 2015). The bending stiffness (EI) of the TES was 700 pN·nm2(Han et al. 2004). The fluid properties of the interstitial fluid were supposed to be similar to that of salt water, that is, an incompressible Newtonian fluid with a dynamic viscosity of 0.0008394 Pa·s and a density of 997 kg·m−3 (Rydholm et al. 2010).
Drug delivery to the intestinal lymph by oral formulations
Published in Pharmaceutical Development and Technology, 2022
Takayuki Yoshida, Hiroyuki Kojima, Kazuhiro Sako, Hiromu Kondo
Lymphatic capillaries are small thin-walled vessels with loosely overlapping walls (Thomas and Schudel 2015). Interstitial fluid enters the lymphatic capillaries and is transported into collecting vessels, filtered through lymph nodes, transported to the lymphatic trunks and then to the lymphatic ducts, and finally enters the subclavian veins (Wang and Oliver 2010; Bora et al. 2017; Bernier-Latmani and Petrova 2017). This process maintains tissue fluid homeostasis. Cellular debris, pathogens, viruses, and bacteria are taken up by lymphatic capillaries from the interstitial space and then delivered to lymph nodes (Thomas and Schudel 2015). The migration of dendritic cells and memory T cells via lymphatic vessels to lymph nodes is an important feature of the immune response (Wang and Oliver 2010; Bora et al. 2017; Bernier-Latmani and Petrova 2017).
Related Knowledge Centers
- Body Fluid
- Body Water
- Cell Biology
- Lymph
- Multicellular Organism
- Circulatory System
- Blood
- Blood Plasma
- Cell
- Fluid Compartments