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.

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.

HYPOXIA

Hypoxia is a state of oxygen deficiency in the blood, cells and tissues, with engagement of the function thereof. This oxygen deficiency may be due to many causes, but the most frequent, especially in the aviation environment is the reduction of oxygen partial pressure as a consequence of reduced atmospheric pressure with altitude. This usually occurs by Exposure to high, failure or misuse of oxygen equipment of aircraf

 

TYPES OF HYPOXIA

A. Hypoxic hypoxia

This type of hypoxia is due to impaired alveolar ventilation phases and / or diffusion of the alveolar

respiration, which produces a deficient supply of atmospheric oxygen to the blood capillaries

lung.

 

The causes of hypoxic hypoxia are:

•Exposure to altitude.

•Loss of cabin pressurization.

•Malfunction of oxygen equipment.

•Diseases of the lung (pneumonia, emphysema, etc..).

 

B. Hypoxia Hipémica

Hipémica hypoxia due to an alteration of the transport phase of respiration. Is essentially in a reduced ability to transport oxygen from the blood. Certain drugs or chemicals such as nitrite and carbon monoxide, can alter the characteristics of the hemoglobin contained in red blood cells or, directly combined with it, reducing its Oxygen-carrying capacity. Carbon monoxide is of importance for the pilot because it is present in combustion gases produced by both conventional aircraft in aircraft reaction, and cigarette smoke. Hemoglobin has an affinity for carbon monoxide 250 times greater than for oxygen, so it is not easy to remove this element from the bloodstream.

 

The most common causes of hypoxia hipémica are:

•Carbon Monoxide Poisoning.

•Blood loss (hemorrhage, blood donation).

•Smoking.

 

C. Stagnation hypoxia

This type of hypoxia is also due to an alteration of the transport phase of respiration. Consists of reduction of blood flow through an area of the body or in its entirety. This condition can due to a failure of the heart pump capacity or local flow conditions (G forces).

 

The most common causes of hypoxia by estanacamiento are:

•Heart failure.

•Shock.

•Continuous positive pressure breathing.

•Extreme cold

 

D. Histotoxic hypoxia

This type of hypoxia due to an alteration in the use phase of respiration and consists of the

inability of cells to utilize oxygen properly. Occurs by the action of certain

substances on cell metabolism.

The most common causes histotoxic hypoxia are:

•Cyanate poisoning (combustion of certain plastics).

•Alcohol intoxication

 

CHARACTERISTICS OF HYPOXIA

A. Insidious onset: This is the most dangerous characteristic of hypoxia, with its great variation

Single and different tolerances showing different people, added to the fact that the presence of hypoxia does not cause significant pain or discomfort, their presence is often so impereceptible, which may progress over time until the total incapacitation of the subject. Under 10,000 feet, the decrease

Night Vision is the only sign that can indicate the presence of hypoxia, which usually occurs from 5,000 feet.

B. Symptom severity: The onset and severity of the symptoms of hypoxia varies individually and according to oxygen deficiency, including susceptibility to hypoxia is affected by factors such as altitude, number of red cells, fitness, etc..

C. Mental commitment: The commitment of intellectual functions is an early sign of the presence of hypoxia, which compromises the ability of the pilot course to realize its own incapacitation. There is commitment of thought, which slows the calculation is inaccurate, the trial poor memory uncertain and the reaction time is considerably delayed.

D. Time span of consciousness: The uptime of consciousness (TUC) is the interval between stoppingintake or exposure to an atmosphere poor in oxygen, until the moment when the pilot loses the ability

to take corrective and protective actions. The TUC is not considered until the total loss of consciousness.

In Table No. 1 shows the average times of the TUC to different heights according to publications U.S. Air Force.

 

FACTORS AFFECTING THE HYPOXIA

A. Altitude

The height directly affects the oxygen partial pressure of inspired air and reduces the partial pressure alveolar oxygen. At altitudes of 40,000 feet or more, the oxygen partial pressure is so low that the useful time of consciousness is just a few seconds.

B. Rate of climb

The reason for the rise of modern aircraft prevents adaptation to altitude. Rapid decompression, which is a very fast rise can reduce the TUC by up to 50%.

C. Exposure time

The effects of hypoxia increase
as this condition continues over time

 

 

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.

 

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.

 

 

Breast lump

A breast lump is swelling, a growth, or a lump in the breast.

Breast lumps in both men and women raise concern for breast cancer, even though most lumps are not cancer.

Considerations

Both males and females of all ages have normal breast tissue. This tissue responds to hormone changes. Because of this, lumps can come and go.

Breast lumps may appear at any age:

• Both male and female infants may have breast lumps from their mother's estrogen when they are born. The lump will usually go away on its own as the estrogen clears from the baby's body.
• Young girls often develop "breast buds" that appear just before the beginning of puberty. These bumps may be tender. They are common around age 9, but may happen as early as age 6.
• Teenage boys may develop breast enlargement and lumps because of hormone changes in mid-puberty. Although this may be upsetting to boys, the lumps or growth almost always go away on their own over a period of months.

Causes

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

Fibrocystic changes are painful, lumpy breasts. Fibrocystic breast changes do not increase your risk of breast cancer. Symptoms are usually worse right before your menstrual period, and then improve after your period starts. 

Fibroadenomas are noncancerous lumps that feel rubbery. They move easily inside the breast tissue. Like fibrocystic changes, they occur most often during the reproductive years. Usually, they are not tender. Except in rare cases, they do not become cancerous later. A doctor can feel during an exam whether a lump is a fibroadenoma. The only way to be sure, however, is to remove or biopsy the lump.

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

Other causes of breast lumps include:

• Breast cancer
• Injury -- sometimes if your breast is badly bruised, there will be a collection of blood that feels like a lump. These lumps tend to get better on their own in a few days or weeks. If they do not improve, your doctor may have to drain the blood.
• Lipoma -- a collection of fatty tissue
• Milk cysts (sacs filled with milk) and infections (mastitis), which may turn into an abscess. These typically occur if you are breastfeeding or have recently given birth.

Home Care

See your health care provider if you have any new lumps or breast changes. Ask about your risk factors for breast cancer, and screening and prevention for breast cancer.

When to Contact a Medical Professional

Call your doctor if:

• The skin on your breast appears dimpled or wrinkled (like the peel of an orange)
• You find a new breast lump during your monthly self-exam
• You have bruising on your breast, but did not experience any injury
• You have nipple discharge, especially if it is bloody or pinkish (blood-tinged)
• Your nipple is inverted (turned inward) but normally is not inverted

Also call if:

• You are a woman, age 20 or older, and want guidance on how to perform a breast self-examination
• 

  You are a woman over age 40 and have not had a mammogram in the past year