Cells, Tissues and Organs
David Sturgeon in Introduction to Anatomy and Physiology for Healthcare Students, 2018
The second ‘essential’ component of a human cell is cytoplasm (essentially cell water). The liquid component of cytoplasm is known as cytosol and accounts for approximately 70% of the total volume of a typical human cell. We have already observed that the intracellular compartment contains approximately 25 litres of fluid (about 40% of our body weight) so it is no surprise that much of the cell comprises this watery substance. The cytoplasm helps maintain the structural integrity of the cell and provides a medium for transport and the many chemical reactions that take place within the cell. Cytoplasm also contains a high percentage of solutes and ions, chief amongst which, as we know, is potassium (K+). The final ‘vital’ component of a human cell (except when it’s a red blood cell) is the nucleus.
From cells to systems
Nick Draper, Helen Marshall in Exercise Physiology, 2014
The cytoplasm, meaning cell-forming matter, comprises cytosol, a cytoskeleton and organelles which carry out a wide range of functions within the cell. Cytosol or intracellular fluid is a gel-like substance, largely composed of water that contains suspended and dissolved particles such as ATP, glucose, lipids, amino acids and a variety of different ions. Many metabolic reactions take place within the cytosol including glycolysis, one of the major pathways for synthesising ATP. The cytoskeleton is literally that, a cellular ‘skeleton’ within the cytoplasm which is made out of protein (see Figure 3.2). It includes three main types of protein filament that, among other roles, maintain cell structure and hold in place many of the cell’s organelles. The microtubules are responsible for support and structure within the cell giving the cytoskeleton strength and rigidity. The intermediate filaments give the cell strength, help to maintain the structure and stabilise the position of the cells organelles, while microfilaments (which are illustrated in Figure 3.5) help to give the cell shape by anchoring the cytoskeleton to the plasma membrane. The microfilaments (which are comprised of the protein actin) are also one of the filaments responsible for muscular contraction (see Chapter 5).
Introduction: Background Material
Nassir H. Sabah in Neuromuscular Fundamentals, 2020
All living cells have a surrounding envelope referred to as the cell membrane, or plasma membrane. Animal cells are eukaryotic, that is, they have a well-developed nucleus and other membrane-bounded organelles, which are cell elements that perform some specialized functions. Figure 1.1 illustrates a typical eukaryotic cell and some of its organelles. The part of the cell that is outside the nucleus and bounded by the cell membrane is the cytoplasm. The cytosol, or intracellular fluid, is the liquid part of the cytoplasm, exclusive of organelles. It consists of a complex mixture of substances that are dissolved or suspended in water. The cell membrane is discussed in considerable detail in Sections 2.1 and 2.2. The following cell organelles are particularly relevant for our purposes.
The possible protective effect of N-acetyl-L-cysteine and folic acid in combination against aspartame-induced cerebral cortex neurotoxicity in adult male rats: a light and transmission electron microscopic study
Published in Ultrastructural Pathology, 2018
Hala F. Abd-Ellah, Nadia R. A. Abou-Zeid, Nadia M. Nasr
At the ultrastructural level, the neurons of ASP-treated rats appeared shrunken with a corrugated electron-dense nuclei and deformed cytoplasm containing dilated rough endoplasmic reticulum, and damaged mitochondria. Astrocytes appeared with shrunken hyperchromatic nuclei and vacuolated cytoplasm. The neuropil showed vacuolation and damaged nerve fibers. According to Tiso et al.42 early-phase apoptosis is characterized by invagination of the nuclear membrane. In the late phase, the chromatin becomes condensed and segregated on the inner surface of the nuclear membrane. The cytoplasm contains densely packed organelles, including mitochondria and electron-dense vesicles. The appearance of dark neurons in this work reflects a certain phase of apoptosis as they displayed markedly condensed cytoplasm and nucleoplasm.43 This was confirmed by a significant decrease in the immunoreactivity of the anti-apoptotic marker Bcl-2 observed in ASP-treated rats. These findings are in agreement with the previous study of Ratan et al.43 who mentioned that glutamate might excite the brain cells until death. The report of Majno and Joris44 highlighted that the dark staining of the degenerated neurons reflects an accumulation of denatured proteins and that this might be caused by a failure of the antioxidant system and uncompensated oxidative stress. Furthermore, dark ischemic neurons are usually due to substantial abnormalities in the capillary wall with disorders in the structural elements of the BBB.45
Development of computational model for cell dose and DNA damage quantification of multicellular system
Published in International Journal of Radiation Biology, 2019
Ruirui Liu, Tianyu Zhao, Maciej H. Swat, Francisco J. Reynoso, Kathryn A. Higley
In this work, a module, CellMaker, which is a simulation program, was developed in C++ to create a computational multicellular system. This is the first step of the multicellular simulation. It is necessary to make an accurate representation of the multicellular geometry as the cell and its relative arrangement are the basic building blocks of the realistic tissue, and include all microstructures and contents in which all the physical and biological interactions take place. In this work, we propose a 3D cellular model including two cellular compartments: the nucleus and the cytoplasm. These are the most important compartments due to their dominant volume with respect to other organelles, and where most secondary electrons that inflicted DNA damage are most likely to originate from. In addition, the nucleus contains the DNA, which plays a central role in the simulation and should be modeled explicitly in the cell model. Other cellular organelles, such as mitochondria, are embedded within the cytoplasm and are not radiologically different in terms of cross-section data and subsequent secondary electron generation. Hence, the cytoplasm was treated as representative of all other cellular organelles inside it.
A simple geometric method for 3D morphology reconstruction of a cell based on two orthogonal phase images
Published in Computer Assisted Surgery, 2019
Yawei Wang, Hao Han, Lei Wang, Jingrong Liao, Bing Xie, Ying Ji, Yuanyuan Xu
Binucleate cells are very common in human blood cells, such as binucleate eosinophils and binucleate neutrophils. Figure 1(a) is a diagram of binuclear cell captured by a conventional microscope. We establish its appropriate model, as shown Figure 1(b). It is composed of a cell membrane, cytoplasm, and two nuclei. Among which, the membrane is a sphere with the radius of 8.0 μm, one nucleus is an ellipse and its semiaxis lengths along x, y and z axes are 4.0 μm, 2.7 μm and 2.5 μm, respectively. The other nucleus is a sphere, and its radius is 2.5 μm. The central coordinates of the membrane, ellipsoidal nucleus and spherical nucleus are (0, 0, 0) μm, (−3.0, 0, 0) μm and (4.5, 1.5, 0) μm, respectively. For the quantitative phase distribution, the RI of the cytoplasm, the ellipsoidal nucleus and the spherical nucleus are set to be 1.37, 1.40 and 1.45, respectively. In addition, similar to the real phase imaging, the cell is required to be immersed in the matched environmental medium. Here, the refractive index of the environmental medium is set to be 1.33 in simulation.
Related Knowledge Centers
- Cell Biology
- Eukaryote
- Nuclear Envelope
- Nucleoplasm
- Cell Membrane
- Cell Nucleus
- Organelle
- Cell
- Cytosol
- Inclusion