Histology

Histology (from the Greek ιστός: histos "tissue" and "-λογία"-logy, treaty, study, science) is the science of everything related to organic tissues: its microscopic structure, development and functions. The histology is sometimes identified with what has been called microscopic anatomy, as their study does not stop in the tissues, but goes further, noting also inside cells and other particles, interacting with the biochemistry and cytology.

The first histological investigations were possible from 1600, when he joined the microscopic anatomical studies. Marcello Malpighi is the founder of histology and his name is still linked to various histological structures. In 1665 discovered the existence of small units within tissues and cells receiving the designation. In 1830, accompanying the improvements introduced in optical microscopy, it is possible to distinguish the cell nucleus. In 1838 we introduce the concept of cell theory.

The technological development of modern research tools allow a breakthrough in understanding histology. Among them are the electron microscopy, immunohistochemistry, in situ hybridization technique. Recent techniques coupled with new research gave way to the emergence of cell biology.

classification

From the standpoint of general biology of organisms, the existence of tissues (such as level of biological organization) only recognized without discussion into two groups of organisms, namely, vascular plants (part of the kingdom Plantae) and metazoans (part of the animal kingdom). This is the reason why we can say that there are two separate disciplines, which is called histology histology animal and plant, each with different content and techniques.

Currently animal tissues (including of course humans) are divided into 4 main groups namely:

epithelial tissue

Connective tissue (which includes several tissue types, such as bone)

muscle tissue

nervous tissue

cellular tissue

cellular tissue

is the systematic and orderly grouping of cells that work for the same purpose and function.

a set of tissue may be an organ and a set of organs is called the organ system (digestive, urinary, nervous system, etc.).

The skin surrounds and protects the other tissues and organs, while containing the sensory receptors that provide information related to the environment, so that the body adapts to it, is the ultimate organ of touch.

Consists of two layers:

a) the surface epithelium or epidermis, with attachments that come from it, sweat and sebaceous glands, hair and nails

b) the connective tissue or dermis, below follows that contains, besides epidermal attachments, of which separates the basement membrane, blood vessels and nerves. Below these layers lies the subcutaneous adipose tissue, which from the functional point of view is a dependency of the skin

The epidermis, the most superficial composed of two layers: the Malpighian body is the innermost cell proliferation and causes the other outermost layer called the cornea, keratinous cells that die and slough off the skin. The inside of the skin is the dermis, constituted by the fibroelastic tissue that supports and nourishes the epidermis and its annexes. In the dermis there are vessels and nerves, and in some places, smooth muscle. It contains many sensory nerve endings, formed by the end of long dendrites of neurons in the spinal ganglia of the spinal nerves. Enclosed in envelopes, are tactile corpuscles, the most important are those of Pacini, Meissner's and Krause, more numerous in the palms and soles, and a lesser number on the back. The Krause are the recipients of thermal excitations, being cold about 300000 points, irregularly distributed in our body, and heat, about 35000. The most sensitive to variations in temperature are the nose, cheeks, back

of the hand and chest. The pain points are very numerous, about 4 million, and very dense: about 200 per square centimeter of skin.

 The subcutaneous tissue is loose connective tissue structure that allows the sliding skin over underlying tissues. Contains many fat cells, so that in places where it reaches a great development is called tissue or subcutaneous adipose tissue. The subcutaneous tissue lacking in some areas like the lips and eyelids. 

Hypoxia

In Medicine, hypoxia is a state in which the whole body (generalized hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply.

The symptoms of hypoxia general depend on the severity and the speed of attack. These include headaches, fatigue, nausea, shakiness, and sometimes even seizures and coma. Severe hypoxia induces a blue discoloration of the skin or cyanosis (deoxygenated blood cells lose their red color and become blue).

Hypoxia can be caused by several factors: low concentration of oxygen in the atmosphere, the gas is present it competes with oxygen, lung injury, among others.

Hypoxia is also being used on a scheduled basis, with good results in the medium to long term, for athletes looking for increased sports performance due to the overall improvement of oxygen transport system. The most used method is called intermittent hypoxia, which, in cycles and for short periods of time, the individual breathes in oxygen-poor recoveries in each cycle interspersed with ambient air. For this process use sophisticated and expensive equipments, by special filters, generate air with low oxygen concentrations, simulating become stays of up to 7500 meters.

Hypoxia increases production of erythropoietin that increases the production of red blood cells (eritrocitos0) until hypoxia disappears.

free radicals

is a chemical species (organic or inorganic), is generally extremely unstable and therefore very reactive power by having an unpaired electron. Not to be confused with a substituent group such as an alkyl group, which are parts of a molecule, not isolated existence.

Independent existence have half-lives even though they have very short, so may be synthesized in the laboratory, can be formed in the atmosphere by radiation and also formed in living organisms (including the human body) by contact with oxygen and act by disrupting cell membranes and attacking the genetic material of cells, such as DNA.

The radicals have electronic configuration of open layers so you have at least one unpaired electron which is very likely to create a bond with another atom or atoms in a molecule. Play an important role in the combustion, in the polymerization, at atmospheric chemistry, within cells and in other chemical processes.

The chemical reactions of free radicals are constantly in the cells of our body and are necessary for health. But the process must be controlled with adequate antioxidant protection. An antioxidant is a substance capable of neutralizing the oxidizing action of free radicals in our blood, releasing electrons that are captured by free radical molecules become unstable.

Our body is fighting free radicals any time of day. The problem for our health is when our body has to bear an excess of free radio for years, caused largely by external contaminants that enter our body products from air pollution, cigarette smoke contains polynuclear aromatic hydrocarbons and aldehydes producing different types of free radicals in our body. The consumption of hydrogenated vegetable oils such as margarine and trans fatty acid intake of fats such as meat and milk also contribute to increased free radicals.

The protection that we have to avoid the increase of free radicals in our bodies that accelerate the speed of aging and degeneration of the cells of our body is the consumption of natural antioxidants such as beta carotene (pro-vitamin A) present in the carrot, mango, tomatoes, melons, peaches, spinach.

Vitamin E (tocopherol) is an antioxidant that maintains the integrity of the cell membrane protects the destruction of vitamin A, prevents and dissolves blood clots and slows cellular aging. It is found in many fruits and vegetables such as: avocado, potato, asparagus , spinach, tomatoes, broccoli, blackberry  and carrots

Vitamin C (ascorbic acid) is another natural antioxidants that destroy excess free radicals. Needed to produce collagen in the growth and repair of tissue cells, gums, blood, bones and teeth, and for fat metabolism, so that is credited with the power to reduce cholesterol. Research has shown that a diet rich in vitamin C provides added protection against all types of cancers. Besides the common cold prevention and strengthening the body's defenses. Food sources of vitamin C are: currants, green peppers, kiwi, lemon (everyone before they have a higher content of lemon Vitamin C it and those who are following low), strawberries and cauliflower, Brussels sprouts, oranges, tomatoes, turnips and watermelon.

Chemical

A chemical element is a type of material, composed of atoms of the same class. In its simplest form has a certain number of protons in its nucleus, making it belong to a single category classified with the atomic number, even when he can deploy different atomic masses. Is an atom with unique physical characteristics, a substance that can not be decomposed by a chemical reaction into simpler. No two atoms of an element with different characteristics, in the event that these possess different mass, but belong to the same element in what is known as one of its isotopes.

Ozone (O3) and oxygen (O2) are two simple substances, each with different properties. And the chemical that forms these two simple substances is oxygen (O). Another example is a chemical element with carbon, which occurs in nature as graphite or diamond (allotropic states).

Metals, nonmetals and metalloids

The first classification of known elements was proposed by Antoine Lavoisier, who proposed that the elements are classified into metals, nonmetals and metalloids or transition metals. Although still very practical and functional in the modern periodic table, was rejected because there were many differences in physical and chemical properties.

 Metals

Most of the exhibits metallic elements that we associate with brilliant luster of metals. Metals conduct heat and electricity, are malleable (can be hit into thin sheets) and ductile (can be stretched to form wires). All are solid at room temperature with the exception of mercury (melting point = -39 ° C), which is a liquid. Two metals are melted slightly above room temperature: the cesium to 28.4 ° C and 29.8 ° C. gallium At the other end, many metals are melted at high temperatures. For example, chromium melts at 1900 °C.

Metals tend to have low ionization energies and therefore are oxidized (lose electrons) when subjected to chemical reactions. Metals have a relative ease of oxidation. Many metals are oxidized with various common substances, including acids and O2.

They are used for structural purposes, manufacture of containers, heat conduction and electricity. Many metal ions important biological functions, iron, calcium, magnesium, sodium, potassium, copper, manganese, zinc, cobalt, molybdenum, chromium, tin,

vanadium, nickel,

Nonmetals

Nonmetals vary greatly in appearance, not glossy and usually are poor conductors of heat and electricity. Their melting points are lower than those of metals (although the diamond form of carbon, melts at 700 ° C at normal pressure and temperature). Several metals are not under ordinary conditions as diatomic molecules. This list includes five gases (H2, N2, O2, F2, Cl2), a liquid (Br2) and volatile solid . The rest of the nonmetals are solids that can be hard as diamond and soft as sulfur. Unlike metals, are very fragile and can not be drawn into wires or sheets. They are found in the three states of matter at room temperature: are gases (like oxygen), liquids (bromine) and solids (such as carbon). They have metallic shine and reflect light. Many non-metals are found in all living things: carbon, hydrogen, oxygen, nitrogen, phosphorus

Comparison of metals and nonmetals

Metals

They have a brilliant luster, various colors, but most are silver.

Solids are malleable and ductile

Good conductors of heat and electricity

Almost all metal oxides are basic ionic solids.

Tend to form cations in aqueous solution.

The outer layers contain few electrons usually three or less.

It should be noted that these characters are very general though some exceptions as for example, manganese metal which form acids being

No Metals

They have no luster, various colors.

The solids tend to be brittle, hard and some other soft.

Poor conductors of heat and electricity

Most non-metallic oxides are molecular substances that form acidic solutions

Tend to form anions in aqueous solution or oxyanions.

The outer layers contain four or more electrons *. Except hydrogen and helium

Location in the periodic table

nutritional imbalance

The nutrition transition (TN) is defined as the change in dietary patterns and nutrient intake when a population adopts modern lifestyles in the social and economic development, urbanization and adoption of different cultural characteristics. Is associated with the documented increase of noncommunicable diseases (NCDs). The effect of NT in the profiles of disease is exacerbated by the sedentary lifestyle and stress, increased consumption of alcohol and cigarettes in urban populations.

Have been confirmed many adverse changes in dietary patterns when compared diets nutrition transition. These include reduction in consumption of starchy staple foods and dietary fiber, increased consumption of animal products rich in total fat and saturated fatty acids, decreased plant protein sources such as legumes, increased energy snacks-dense, sweetened carbonated beverages, commercial availability of alcohol and the addition of sugar, fats and oils in food.

The change in dietary patterns towards foods with intense flavor snacks, fast food and convenience, but also with more meat, translated into a pattern where the pattern of intake of macronutrients (energy, fat, total carbohydrates, fiber dietary animal protein) may be associated with an increased risk of overweight, obesity and other NCDs.

tumor in the breast

Is a swelling, lump or mass in the breast.

Breast lumps in men and women raise concern about breast cancer, although most of them are not cancer.

Both men and women of all ages have normal breast tissue. This tissue responds to hormonal changes and because of this, the bumps may come and go.

The lumps in the breast may occur at any age:

Infants of both sexes may have breast lumps following the estrogen from the mother at birth. The lump usually disappears on its own as the estrogen disappears from the baby's body.

Young girls often develop "breast buds" that appear just before the onset of puberty. These bumps may be tender and are common around age 9, but may occur up to 6 years old.

Teenage boys may develop lumps or enlarged breasts due to hormonal changes that occur in mid-puberty. While this may be distressing for children, these lumps and bumps usually disappear on their own after a few months.

causes

Lumps in a woman are often caused by fibrocystic changes, fibroadenomas, and cysts.

Fibrocystic changes correspond to bumps and sore breasts. Fibrocystic breast changes do not increase the risk of breast cancer. Symptoms are usually worse just before the menstrual period and then get better after it starts.

Fibroadenomas are noncancerous lumps that feel like rubber and move easily within the breast tissue and, like fibrocystic changes, occur more frequently during the childbearing years. Usually, they are not sensitive. Except in rare cases, do not become cancerous later. A doctor may feel during an examination if a lump is a fibroadenoma, but the only way to be sure is to remove or biopsy it.

Cysts are fluid-filled sacs that often feel like soft grapes can sometimes be tender, especially just before your menstrual period.

Other causes of the masses or tumors in the breast are:

Breast cancer.

Injury: sometimes if your breast is badly bruised, there will be a collection of blood that feels like a lump. These masses tend to improve spontaneously within days or weeks. If you do not improve, the doctor may need to drain the blood.

Lipoma: a collection of fatty tissue.

Milk cysts (sacs filled with milk) and infections (mastitis), which can become an abscess. These two situations typically occur if you are breastfeeding or have recently given birth.