Introduction Microvilli and cilia play a major role in many important biological processes in mammalian cells. They are very small, intricate structures found lining the cells in the body and can only be viewed under a microscope. Microvilli has been derived from the Greek word mikros, meaning “small” and the Latin word villus, meaning “hair”. Cilia means “eyelashes” in Latin(1). They are both types of projections in the plasma membrane, however, only cilia can move(2). Structure of Microvilli and Cilia Both microvilli and cilia are formed by cytoskeletal elements, which provide a stable and dynamic structure(2). Microvilli contain microfilaments called actin filaments which are positioned side by side and are kept in position by the cross-linking …show more content…
Both actin filaments and microtubules are made from subunits that are globular. The subunits are asymmetrical and polar structures as they have a minus end and a plus end which helps to orientate the actin filaments and microtubules to point in one …show more content…
They are found in large numbers which increases the surface area for absorption(3)(4). Microvilli can also be found on the surface of egg cells and white blood cells. A specialised type of microvilli called stereocilia is found in the nose and ears. The stereocilia in the ear are responsible for hearing by detecting sound vibrations(3)(4). Cilia can be both motile and non-motile. In the respiratory system, cilia are responsible for moving/beating the mucus, which contains trapped microorganisms and dust, away from the trachea and up the respiratory tract towards the mouth(2)(3)(7). Non-motile cilia also known as primary cilia can be found on the surface of all cells. Primary cilia have a 9+0 microtubules arrangement and have various functions in mammalian cells, they are most importantly found in the sensory organs where they can sense and respond to chemical stimuli from the external
Treponema pallidum 2 Introduction Treponema pallidum is a Gram-negative bacterium that has a spiral shape (1). They are about 6 to 20um in length and 18-20um in diameter (1). Treponema pallidum can only survive within a host which makes them obligate internal parasites, meaning that outside a host this organism will die due to the absence of nutrients, exposure to oxygen and heat. Also, since this organism can’t be grown on a culture medium, animal models are used to study T. pallidum (1). Treponema pallidum bacteria consist of an inner and outer membrane with a thin peptidoglycan cell wall lacking liposaccharides (1).
Unlike microtubules, actin filaments are globular chains made of a single monomer, which is called globular actin (G-Actin). Actins is somehow similar to tubulin in which actin subunits have binding site for a nucleotide, but it is mainly Adenosine Triphosphate (ATP), not GTP as in tubulins. Polymerization of actin filaments is also similar to microtubules polymerization in which assembly of subunit in head-to-tail orientation to create polarity. Actin filaments consist of two parallel helical protofilaments, or F-actin. In contrast with microtubules, actin filaments are the thinnest among cytoskeletal filaments, with a diameter of 5-9 nm, that’s why they are also known as ‘microfilaments’. Localization of actin filaments
Gardiner, L. (2004). Organelles of Eukaryotic Cells. In Windows to The Universe. Retrieved December 8, 2013, from http://www.windows2universe.org/earth/Life/cell_organelles.html.
Cilia are the microscopic hairs that line the respiratory tract and prevent any bacteria from getting inside the lungs. Nasal concha or turbinate refers to any spongy bones of the nasal passage, composed mostly of mucosal tissue responsible for filtration, humidification and heating of air. “The mucous membrane helps allow for easier transport of microorganisms out of the respiratory system, protecting the body by creating a barrier” (Biology Institute, 2010). It can also act as a lubricant, and facilitates gas exchange and absorption. Under these conditions, the nose can work normally.
One can almost feel the searing penetration of Lewis Thomas’ analytical eye as it descends the narrow barrel of the microscope and explodes onto a scene of vigorous, animated, interactive little cells—cells inescapably engrossed in relaying messages to one another with every bump and bounce; with every brush of the elbow, lick of the stamp, and click of the mouse…
Using a fluoresced antibody, the scientists observed the clustering of beta 1 integrins that occurred at the same time as actin polymerization at the ripples of the cell membrane.
to construct and or maintain the cell membrane. In a microscopic view of the cell membrane we can
The cytoskeleton is a highly dynamic intracellular platform constituted by a three-dimensional network of proteins responsible for key cellular roles as structure and shape, cell growth and development, and offering to the cell with "motility" that being the ability of the entire cell to move and for material to be moved within the cell in a regulated fashion (vesicle trafficking)’, (intechopen 2017). The cytoskeleton is made of microtubules, filaments, and fibres - they give the cytoplasm physical support. Michael Kent, (2000) describes the cytoskeleton as the ‘internal framework’, this is because it shapes the cell and provides support to cellular extensions – such as microvilli. In some cells it is used in intracellular transport. Since the shape of the cell is constantly changing, the microtubules will also change, they will readjust and reassemble to fit the needs of the cell.
Simple cuboidal epithelia can be from many glands but since the tissue in the slide is ciliated it is likely to be a gland or organ that would absorb molecules such as kidney tubules, lining of ducts in the liver. (Mitchell, B.S. & Peel, S 2009) (Urry, L.A. et al.,
1.d. The Nuclear Pore, Ribosomes and the Golgi body work together to make proteins. It all starts at the DNA, this is found inside the nucleus which holds all the important
Cnidocytes, or cnidae, are cellular organelles that are enclosed by the membrane of the ectoderm. They consist of a capsule with a eversible tubule inside.They come in many forms, but the main three types nematocyst, spirocyst, and ptychocysts. Nematocysts are the most common cnidae, and are characterized by their ability to peirce other tissue. They do this with a combination of a stylus and a tubule, which then will inject some sort of venom. All nematocysts are described by their structure and function, instead of phylogeneti...
So how big are cells? Most human cells are about ten microns in diameter. This is about o...
Mitochondria are small granular or filamentous bodies which are called the power house of the cell. They are associated with cellular respiration and are the sources of energy. In 1850, the German biologist Rudolph Kolliker first observed mitochondria as granular structures in striated muscle [Powar, C.B. 2010; Albert et al. 2010]. In 1898, the scientist Benda developed the crystal violet staining technique and called the structures mitochondria. The average length of the mitochondrion is 3-4 microns and the average diameter 0.5 to 1.0 micron. In muscles, most of the mitochondria are 2-3 microns long. Mitochondria have different shapes. The number of mitochondria is different in different types of cells of different organs. They are distributed evenly in the cytoplasm. In sperms they are present in tail, in muscles they lie between the myofibrils. Mitochondria may move freely in some cells. Where ever ATP required. Movement is less in animals than plants. In plants they change their shape and volume [Powar, C.B. 2010; Albert et al. 2010].
Microbes are microscopic life forms, usually too small to be seen by the naked eye. Although many microbes are single-celled, there are also numerous multi-cellular organisms. The human body has 10-100 trillion microbes living on it, making it one giant super-organism. Since the first link between microbes and diseases was made, people have been advised to wash their hands. Scientists, however, have recently started to investigate more closely how the microbes that call the human body home affect our health. While some microbes cause disease, others are more beneficial, working with our bodies in many subtle ways.
Dynamic equilibrium functions in the three semicircular ducts, the saccule and the utricle. The two ventical ducts are the anterior and posterior semicircular ducts. The lateral semicircular duct is horizontal. In the dilated portion of each duct, the ampulla, is a small elevation called the crista. This contains hair cells and supporting cells which are also covered by a mass of gelatinous material which is called cupula. When the head moves the attached semicircular ducts and hair cells move with it.