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Myocyte
A muscle cell is also known as a myocyte when referring to either a cardiac muscle cell (cardiomyocyte), or a smooth muscle cell as these are both small cells. A skeletal muscle cell is long and threadlike with many nuclei and is called a muscle fiber. Muscle cells (including myocytes and muscle fibers) develop from embryonic precursor cells called myoblasts. Myoblasts fuse to form multinucleated skeletal muscle cells known as syncytia in a process known as myogenesis. Skeletal muscle cells and cardiac muscle cells both contain myofibrils and sarcomeres and form a striated muscle tissue. Cardiac muscle cells form the cardiac muscle in the walls of the heart chambers, and have a single central nucleus. Cardiac muscle cells are joined to neighboring cells by intercalated discs, and when joined in a visible unit they are described as a ''cardiac muscle fiber''. Smooth muscle cells control involuntary movements such as the peristalsis contractions in the esophagus and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Muscle Cell
Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium), with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix. Cardiac muscle contracts in a similar manner to skeletal muscle, although with some important differences. Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum. The rise in calcium causes the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myogenesis
Myogenesis is the formation of skeletal muscular tissue, particularly during embryonic development. Muscle fibers generally form through the fusion of precursor myoblasts into multinucleated fibers called ''myotubes''. In the early development of an embryo, myoblasts can either proliferate, or differentiate into a myotube. What controls this choice in vivo is generally unclear. If placed in cell culture, most myoblasts will proliferate if enough fibroblast growth factor (FGF) or another growth factor is present in the medium surrounding the cells. When the growth factor runs out, the myoblasts cease division and undergo terminal differentiation into myotubes. Myoblast differentiation proceeds in stages. The first stage, involves cell cycle exit and the commencement of expression of certain genes. The second stage of differentiation involves the alignment of the myoblasts with one another. Studies have shown that even rat and chick myoblasts can recognise and align with one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myoblasts
Myogenesis is the formation of skeletal muscular tissue, particularly during embryonic development. Muscle fibers generally form through the fusion of precursor myoblasts into multinucleated fibers called ''myotubes''. In the early development of an embryo, myoblasts can either proliferate, or differentiate into a myotube. What controls this choice in vivo is generally unclear. If placed in cell culture, most myoblasts will proliferate if enough fibroblast growth factor (FGF) or another growth factor is present in the medium surrounding the cells. When the growth factor runs out, the myoblasts cease division and undergo terminal differentiation into myotubes. Myoblast differentiation proceeds in stages. The first stage, involves cell cycle exit and the commencement of expression of certain genes. The second stage of differentiation involves the alignment of the myoblasts with one another. Studies have shown that even rat and chick myoblasts can recognise and align with on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Muscle
Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium), with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix. Cardiac muscle contracts in a similar manner to skeletal muscle, although with some important differences. Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum. The rise in calcium causes the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcomere
A sarcomere (Greek σάρξ ''sarx'' "flesh", μέρος ''meros'' "part") is the smallest functional unit of striated muscle tissue. It is the repeating unit between two Z-lines. Skeletal muscles are composed of tubular muscle cells (called muscle fibers or myofibers) which are formed during embryonic myogenesis. Muscle fibers contain numerous tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as alternating dark and light bands. Sarcomeres are composed of long, fibrous proteins as filaments that slide past each other when a muscle contracts or relaxes. The costamere is a different component that connects the sarcomere to the sarcolemma. Two of the important proteins are myosin, which forms the thick filament, and actin, which forms the thin filament. Myosin has a long, fibrous tail and a globular head, which binds to actin. The myosin head also binds to ATP, which is the source of energy for muscle movement. Myo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcoplasmic Reticulum
The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the smooth endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions (Ca2+). Calcium ion levels are kept relatively constant, with the concentration of calcium ions within a cell being 10,000 times smaller than the concentration of calcium ions outside the cell. This means that small increases in calcium ions within the cell are easily detected and can bring about important cellular changes (the calcium is said to be a second messenger). Calcium is used to make calcium carbonate (found in chalk) and calcium phosphate, two compounds that the body uses to make teeth and bones. This means that too much calcium within the cells can lead to hardening (calcification) of certain intracellular structures, including the mitochondria, leading to cell death. Therefore, it is vital that calcium ion levels are controlled tightly, and can be released in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smooth Endoplasmic Reticulum
The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum (RER), and smooth endoplasmic reticulum (SER). The endoplasmic reticulum is found in most eukaryotic cells and forms an interconnected network of flattened, membrane-enclosed sacs known as cisternae (in the RER), and tubular structures in the SER. The membranes of the ER are continuous with the outer nuclear membrane. The endoplasmic reticulum is not found in red blood cells, or spermatozoa. The two types of ER share many of the same proteins and engage in certain common activities such as the synthesis of certain lipids and cholesterol. Different types of cells contain different ratios of the two types of ER depending on the activities of the cell. RER is found mainly toward the nucleus of cell and SER towards the cell membrane or plas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcoplasm
Sarcoplasm is the cytoplasm of a muscle cell. It is comparable to the cytoplasm of other cells, but it contains unusually large amounts of glycogen (a polymer of glucose), myoglobin, a red-colored protein necessary for binding oxygen molecules that diffuse into muscle fibers, and mitochondria.Roberts, Michael D.; Haun, Cody T.; Vann, Christopher G.; Osburn, Shelby C.; Young, Kaelin C. (2020). "Sarcoplasmic Hypertrophy in Skeletal Muscle: A Scientific "Unicorn" or Resistance Training Adaptation?". Frontiers in Physiology. 11. . . . . The calcium ion concentration in sarcoplasma is also a special element of the muscle fiber; it is the means by which muscle contractions take place and are regulated. The sarcoplasm plays a critical role in muscle contraction as an increase in Ca2+ concentration in the sarcoplasm begins the process of filament sliding. A decrease in Ca2+ in the sarcoplasm subsequently ceases filament sliding.Shahinpoor, Mohsen (2013). Muscular Biomimicry. Elsevier. pp. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are cytosol (a gel-like substance), the organelles (the cell's internal sub-structures), and various cytoplasmic inclusions. The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance or cytoplasmic matrix which remains after exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, the plant plastids, lipid droplets, and vacuoles. Most cellular activities take place within the cytoplasm, such as many metabolic pathways including glycolysis, and proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histology
Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures visible without a microscope. Although one may divide microscopic anatomy into ''organology'', the study of organs, ''histology'', the study of tissues, and '' cytology'', the study of cells, modern usage places all of these topics under the field of histology. In medicine, histopathology is the branch of histology that includes the microscopic identification and study of diseased tissue. In the field of paleontology, the term paleohistology refers to the histology of fossil organisms. Biological tissues Animal tissue classification There are four basic types of animal tissues: muscle tissue, nervous tissue, connective tissue, and epithelial tissue. All animal tissues are considered to be subtypes of these four principal tissue type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stomach
The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach is involved in the gastric phase of digestion, following chewing. It performs a chemical breakdown by means of enzymes and hydrochloric acid. In humans and many other animals, the stomach is located between the oesophagus and the small intestine. The stomach secretes digestive enzymes and gastric acid to aid in food digestion. The pyloric sphincter controls the passage of partially digested food ( chyme) from the stomach into the duodenum, where peristalsis takes over to move this through the rest of intestines. Structure In the human digestive system, the stomach lies between the oesophagus and the duodenum (the first part of the small intestine). It is in the left upper quadrant of the abdominal cavity. The top of the stomach lies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Esophagus
The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about long in adults, that travels behind the trachea and heart, passes through the diaphragm, and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word ''oesophagus'' is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω (phérō, “I carry”) + ἔφαγον (éphagon, “I ate”). The wall of the esophagus from the lumen outwards consists of mucosa, submucosa (connective tissue), layers of muscle fibers between layers of fibrous tissue, and an outer layer of connective tissue. The mucosa is a stratified squamous epith ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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