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Columnar
Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of many internal organs, the corresponding inner surfaces of body cavities, and the inner surfaces of blood vessels. Epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. These tissues also lack blood or lymph supply. The tissue is supplied by nerves. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either simple squamous, simple columnar, or simple cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tissue (biology)
In biology, tissue is an assembly of similar cells and their extracellular matrix from the same embryonic origin that together carry out a specific function. Tissues occupy a Biological organisation#Levels, biological organizational level between cell (biology), cells and a complete organ (biology), organ. Accordingly, organs are formed by the functional grouping together of multiple tissues. The English word "tissue" Morphological derivation, derives from the French word "", the past participle of the verb tisser, "to weave". The study of tissues is known as histology or, in connection with disease, as histopathology. Xavier Bichat is considered as the "Father of Histology". Plant histology is Studied Space Shuttle designs, studied in both plant anatomy and Plant physiology, physiology. The classical tools for studying tissues are the Microtome#Applications, paraffin block in which tissue is embedded and then sectioned, the staining, histological stain, and the Microscope, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through transepidermal water loss. The epidermis is composed of stratified squamous epithelium, multiple layers of flattened cells that overlie a base layer (stratum basale) composed of Epithelium#Cell types, columnar cells arranged perpendicularly. The layers of cells develop from stem cells in the basal layer. The thickness of the epidermis varies from 31.2μm for the penis to 596.6μm for the Sole (foot), sole of the foot with most being roughly 90μm. Thickness does not vary between the sexes but becomes thinner with age. The human epidermis is an example of epithelium, particularly a stratified squamous epithelium. The word epidermis is derived through Latin , itself and . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell (biology)
The cell is the basic structural and functional unit of all life, forms of life. Every cell consists of cytoplasm enclosed within a Cell membrane, membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word meaning 'small room'. Most cells are only visible under a light microscope, microscope. Cells Abiogenesis, emerged on Earth about 4 billion years ago. All cells are capable of Self-replication, replication, protein synthesis, and cell motility, motility. Cells are broadly categorized into two types: eukaryotic cells, which possess a Cell nucleus, nucleus, and prokaryotic, prokaryotic cells, which lack a nucleus but have a nucleoid region. Prokaryotes are single-celled organisms such as bacteria, whereas eukaryotes can be either single-celled, such as amoebae, or multicellular organism, multicellular, such as some algae, plants, animals, and fungi. Eukaryotic cells contain organelles including Mitochondrion, mitochondria, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcellular Transport
Transcellular transport involves the transportation of solutes by a cell ''through'' a cell. Transcellular transport can occur in three different ways active transport, passive transport, and transcytosis. Active Transport Active transport is the process of moving molecules from an area of low concentrations to an area of high concentration. There are two types of active transport, primary active transport and secondary active transport. Primary active transport uses adenosine triphosphate (ATP) to move specific molecules and solutes against its concentration gradient. Examples of molecules that follow this process are potassium K+, sodium Na+, and calcium Ca2+. A place in the human body where this occurs is in the intestines with the uptake of glucose. Secondary active transport is when one solute moves down the electrochemical gradient to produce enough energy to force the transport of another solute from low concentration to high concentration. An example of where this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesothelium
The mesothelium is a membrane composed of simple squamous epithelium, simple squamous epithelial cells of mesodermal origin, which forms the lining of several body cavities: the pleura (pleural cavity around the lungs), peritoneum (abdominopelvic cavity including the mesentery, omentum (other), omenta, falciform ligament and the perimetrium) and pericardium (around the heart). Mesothelial tissue also surrounds the male testis (as the tunica vaginalis) and occasionally the spermatic cord (in a patent processus vaginalis). Mesothelium that tunica (biology), covers the internal organs is called visceral mesothelium, while one that covers the surrounding body walls is called the :wikt:parietal, parietal mesothelium. The mesothelium that secretes serous fluid as a main function is also known as a serosa. Origin Mesothelium derives from the embryonic mesoderm cell layer, that lines the body cavity, coelom (body cavity) in the embryo. It develops into the layer of cells that c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pericardium
The pericardium (: pericardia), also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong inelastic connective tissue (fibrous pericardium), and an inner layer made of serous membrane (serous pericardium). It encloses the pericardial cavity, which contains pericardial fluid, and defines the middle mediastinum. It separates the heart from interference of other structures, protects it against infection and blunt trauma, and lubricates the heart's movements. The English name originates from the Ancient Greek prefix ''peri-'' (περί) 'around' and the suffix ''-cardion'' (κάρδιον) 'heart'. Anatomy The pericardium is a tough fibroelastic sac which covers the heart from all sides except at the cardiac root (where the great vessels join the heart) and the bottom (where only the serous pericardium exists to cover the upper surface of the central tendon of diaphragm). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endothelium
The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. Endothelial cells in direct contact with blood are called vascular endothelial cells whereas those in direct contact with lymph are known as lymphatic endothelial cells. Vascular endothelial cells line the entire circulatory system, from the heart to the smallest capillaries. These cells have unique functions that include fluid filtration, such as in the glomerulus of the kidney, blood vessel tone, hemostasis, neutrophil recruitment, and hormone trafficking. Endothelium of the interior surfaces of the heart chambers is called endocardium. An impaired function can lead to serious health issues throughout the body. Structure The endothelium is a thin layer of single flat (squamous) cells that line the inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type 1 Pneumocyte
A pulmonary alveolus (; ), also called an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where pulmonary gas exchange takes place. Oxygen is Molecular diffusion#Biology, exchanged for carbon dioxide at the blood–air barrier between the alveolar air and the Pulmonary circulation, pulmonary capillary. Alveoli make up the functional tissue of the mammalian lungs known as the lung parenchyma, which takes up 90 percent of the total lung volume. Alveoli are first located in the respiratory bronchioles that mark the beginning of the respiratory zone. They are located sparsely in these bronchioles, line the walls of the alveolar ducts, and are more numerous in the blind-ended alveolar sacs. The Pulmonary acinus, acini are the basic units of respiration, with gas exchange taking place in all the alveoli present. The alveolar membrane is the gas exchange surface, surrounded by a network of capillary, capillaries. Oxygen is Diffusion#Dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung
The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their function in the respiratory system is to extract oxygen from the atmosphere and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their musculoskeletal systems to support and foster breathing. In early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians. In humans, the primary muscle that drives breathing is the Thoracic diaphragm, diaphragm. The lungs also provide airflow that makes Animal communication#Auditory, vocalisation including speech possible. Humans have two lungs, a ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Alveolus
A pulmonary alveolus (; ), also called an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where pulmonary gas exchange takes place. Oxygen is exchanged for carbon dioxide at the blood–air barrier between the alveolar air and the pulmonary capillary. Alveoli make up the functional tissue of the mammalian lungs known as the lung parenchyma, which takes up 90 percent of the total lung volume. Alveoli are first located in the respiratory bronchioles that mark the beginning of the respiratory zone. They are located sparsely in these bronchioles, line the walls of the alveolar ducts, and are more numerous in the blind-ended alveolar sacs. The acini are the basic units of respiration, with gas exchange taking place in all the alveoli present. The alveolar membrane is the gas exchange surface, surrounded by a network of capillaries. Oxygen is diffused across the membrane into the capillaries and carbon dioxide is released fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Skin
The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue (biology), tissue guarding Skeletal muscle, muscles, bones, ligaments and organ (anatomy), internal organs. Human skin is similar to most of the other mammals' skin, and it is very similar to pig skin. Though nearly all human skin is covered with hair follicles, it can appear Nudity#Evolution of hairlessness, hairless. There are two general types of skin: hairy and glabrous skin (hairless). The adjective List of medical roots, suffixes and prefixes#C, ''cutaneous'' literally means "of the skin" (from Latin ''cutis'', skin). Skin plays an important immunity (medical), immunity role in protecting the body against pathogens and excessive transepidermal water loss, water loss. Its other functions are Thermal insulation, insulation, thermoregulation, temperature regulation, sensation, synthesis of vitamin D, and the protection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology (from Ancient Greek μορφή (morphḗ) "form", and λόγος (lógos) "word, study, research") is the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, color, pattern, size), as well as the form and structure of internal parts like bones and organs, i.e., anatomy. This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of the overall structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Fried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
