Category Human Body

What is an ulcer?

Ulcers are sores that are slow to heal or keep returning. They can take many forms and can appear both on the inside and the outside of your body.

They can be found on places of your body you can see, such as a leg ulcer found on the skin, or in places you can’t see, such as a peptic ulcer in the lining of your stomach or upper intestine. From your eye to your foot, you can get them just about anywhere on your body.

Injuries, diseases, and infections can cause them. What they look like depends on where you have them and how you got them. While some go away on their own, others cause serious problems if you don’t treat them.

 

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Which is the smallest and lightest bone in the human body?

The stapes is the smallest and lightest bone in the human body at 3mm x 2.5 mm in size. The shape of a stirrup, it is one of three tiny bones in the middle ear, collectively known as the ossicles, that convey sound waves from the outer ear to the inner ear. The other two are the malleus (hammer) and the incus (anvil).

The stapes develops from the second pharyngeal arch during the sixth to eighth week of embryological life. The central cavity of the stapes, the obturator foramen, is due to the presence embryologically of the stapedial artery, which usually regresses in humans during normal development.

The stapes is one of three ossicles in mammals. In non-mammalian four-legged animals, the bone homologous to the stapes is usually called the columella; however, in reptiles, either term may be used. In fish, the homologous bone is called the hyomandibular, and is part of the gill arch supporting either the spiracle or the jaw, depending on the species. The equivalent term in amphibians is the pars media plectra.

The stapes appears to be relatively constant in size in different ethnic groups. In 0.01–0.02% of people, the stapedial artery does not regress, and persists in the central foramen. In this case, a pulsatile sound may be heard in the affected ear, or there may be no symptoms at all. Rarely, the stapes may be completely absent.

 

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How many sweat glands are there in the human body?

Humans have 2,000,000 to 5,000,000 eccrine sweat glands, with an average distribution of 150 to 340 per square centimetre. They are most numerous on the palms and soles and then, in decreasing order, on the head, trunk, and extremities. Some individuals have more glands than others, but there is no difference in number between men and women.

The specific function of sweat glands is to secrete water upon the surface so that it can cool the skin when it evaporates. The purpose of the glands on the palms and soles, however, is to keep these surfaces damp, to prevent flaking or hardening of the horny layer, and thus to maintain tactile sensibility. A dry hand does not grip well and is minimally sensitive.

The glands on the palms and soles develop at about 3 1/2 months of gestation, whereas those in the hairy skin are the last skin organs to take shape, appearing at five to 5 1/2 months, when all the other structures are already formed. This separation of events over time may represent a fundamental difference in the evolutionary history of the two types of glands. Those on palms and soles, which appear first and are present in all but the hooved mammals, may be more ancient; those in the hairy skin, which respond to thermal stimuli, may be more recent organs.

 

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What is gustatory sweating?

Gustatory sweating is sweating that occurs on the forehead, scalp, neck, and upper lip while eating, talking, or thinking about food.

Gustatory sweating can occur for no apparent reason or as a result of an underlying condition, such as diabetes or Parkinson’s disease. These diseases can also cause damage to the nerves in the mouth. When the nerves become injured, they can become confused and cause sweating.

Gustatory sweating may cause some people distress, as thinking about food can trigger the reactions of sweating. Since there is often an underlying cause, a person should talk to their doctor to find out what may be causing the sweating.

People do not necessarily need to see a doctor after sweating from eating food. Those who only sweat while eating either very hot or spicy foods have no reason to be concerned.

Some people who experience Frey’s syndrome may consider it to be a nuisance but do not consider it significant enough to seek help.

 

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Sweat is made of 99% water. What is the remaining 1%?

A body has between two and four million sweat glands lying deep in the skin. They are connected to the surface by coiled tubes called ducts. You perspire constantly, even without exercise. Sweat is a liquid made from 99% water and 1% salt and fat. Up to a quart of sweat evaporates each day.

When your body becomes overheated, you sweat more. The evaporation of sweat from your skin cools your body down.

When you’re frightened or nervous (imagine being pinned under heavy weights) you also sweat more. Your palms and forehead begin to sweat. So do the soles of your feet and your armpits. These are sites where sweat glands are most abundant.

So why do you smell when you sweat? You may notice the smell mostly comes from our pits (hence why we put deodorant there). This is because the apocrine glands produce the bacteria that break down our sweat into “scented” fatty acids.

“Apocrine sweat by itself does not have an odor, but when the bacteria that lives on our skin mixes with apocrine secretions, it can produce a foul-smelling odor,” Haimovic says.

 

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What is perspiration?

Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals.

Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distributed over much of the body and are responsible for secreting the watery, brackish sweat most often triggered by excessive body temperature. The apocrine sweat glands are restricted to the armpits and a few other areas of the body and produce an odorless, oily, opaque secretion which then gains its characteristic odor from bacterial decomposition.

Sweat contributes to body odor when it is metabolized by bacteria on the skin. Medications that are used for other treatments and diet also affect odor. Some medical conditions, such as kidney failure and diabetic ketoacidosis, can also affect sweat odor. Areas that produce excessive sweat usually appear pink or white, but, in severe cases, may appear cracked, scaly, and soft.

 

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