Muscle cells have a specialized type of smooth endoplasmic reticulum called sarcoplasmic reticulum, which stores calcium ions. Smooth muscle tissue appears non-striated because of the less orderly arrangement of their filaments. Under light microscopy, skeletal and cardiac muscles appear striated due to the parallel arrangement of their contractile filaments into repeating units called sarcomeres. These cells contain contractile filaments ( myofibrils) called actin (thin) and myosin (thick). Based on their functional properties, these are described as either voluntary (skeletal) or involuntary (cardiac and smooth muscle). Despite their differences, they all have one thing in common specialized elongated muscle cells, called muscle fibers. It is categorised as skeletal, cardiac or smooth. Muscle tissue maintains synthesizing and contractile functions. Get an overview of the different types of epithelial tissue: Additional sub-classifications are possible, based on the cell specializations. Together this gives us the various types of epithelial tissues, such as simple squamous epithelium, stratified cuboidal epithelium, pseudostratified columnar epithelium and many more. Depending on the number of layers, epithelial tissue is classified into simple (single layered) or stratified (multi-layered). Based on morphology, epithelial cells can be either squamous (flat), cuboid (cube) or columnar (rectangular). The cells are laid down on top of dense irregular connective tissue, the basement membrane (BM).Įpithelium is classified by both it’s cellular morphology and the number of cell layers. It is composed of densely packed epithelial cells with only a little extracellular matrix (ECM). These include epithelial cells, fibroblasts, neutrophils, erythrocytes, keratinocytes, chondrocytes just to name a few.Įpithelial tissue can cover external surfaces ( skin), line the inside of hollow organs ( intestines) or form glands. Cells are categorized into various types, all of which perform different functions. Kind of like border police, it controls everything that comes in or out of the cell. All cells are enveloped by a semipermeable two-layered membrane, which serves as a dynamic medium for the cell’s interaction with the external environment. DNA is condensed and coiled up into chromosomes. It houses information about each and every structure and process of the cell and organism, in the form of DNA (deoxyribonucleic acid).
The nucleusis considered to be the brain of the cell. Thoroughly learn the parts of a cell using our diagrams and cell quizzes! Then, get ready to test your knowledge! Organelles can be membranous (mitochondria, Golgi apparatus, endoplasmic reticulum) or non-membranous (ribosomes, nucleolus, centrioles). The cytoplasm contains specialized subunits called organelles which work like ‘little organs’. All cells of the human body are eukaryotic, meaning that they are organized into two parts: nucleus and cytoplasm. Tissue preparation, tissue staining, microscopy, hybridisationĪ cellis the smallest functional unit of an organism. The study of cells and tissues, from their intracellular components to their organization into organs and organ systems.Ĭellular membrane, cytoplasm, organelles, nucleusĪ unity of cells with a similar structure that as a whole express a definite and unique function.Ī unity of tissues with a more complex set of functions, defined by the combination of structure and function of the comprising tissuesĪ group of organs united by similar functions.Ĭardiovascular, nervous, integumentary, musculoskeletal, respiratory, digestive, excretory, endocrine, lymphatic, reproductive In this article, we will introduce you to the microscopic world of histology. By examining a thin slice of bone tissue under a microscope, colorized with special staining techniques, you see that these seemingly simple bones are actually a complex microworld containing an array of structures with various different functions. It also helps us understand the relationship between structure and function. Histology is the science of the microscopic structure of cells, tissues and organs.
However, if you take a much closer look, you’ll see that the histology of bones, is a whole other story. If you were to look at some bones on a skeleton, you’d see a greyish rigid mass with some bumps and depressions.
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