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The enamel covering of our teeth also withstands extreme acid-base fluctuations, some of which come from various populations of bacteria that grow in our mouths. Overall, enamel is by far the toughest material in our bodies, and scientists have been examining its structure and composition for decades.

Tooth enamel is clear and only covers and protects the crown (or top part) of teeth. Your dentin makes up the bulk of teeth and is responsible for their color. The roots of teeth are protected by something called cementum. This connective tissue is similar to bone, but not nearly as dense as tooth enamel. If your tooth enamel is weakened because of over-exposure to plaque and acid, supplemental minerals such as calcium and phosphate can strengthen your teeth. Neutralization of acids can help protect your enamel from damage. If your mouth is dry, you may have an issue producing ample saliva, which raises the mouth’s pH and assists in neutralizing acid. Seek the help of your Pella, IA family dentist if upping your hydration with water doesn’t seem to help this issue.

 

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Unlike your heart or brain, your teeth weren't ready to work from the day you were born. Although babies have the beginnings of their first teeth even before they are born, teeth don't become visible until babies are about 6 to 12 months old.

After that first tooth breaks through, more and more teeth begin to appear. Most kids have their first set of teeth by the time they are 3 years old. These are called the primary teeth, baby teeth, or milk teeth and there are 20 in all. When a child gets to age 5 or 6, these teeth start falling out, one by one.

A primary tooth falls out because it is being pushed out of the way by the permanent tooth that is behind it. Slowly, the permanent teeth grow in and take the place of the primary teeth. By about age 12 or 13, most kids have lost all of their baby teeth and have a full set of permanent teeth.

There are 32 permanent teeth in all — 12 more than the original set of baby teeth. Most people have four teeth (called wisdom teeth) grow in at the back of the mouth when they're between 17 and 25 years old. These complete the adult set of 32 teeth.

 

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Potassium plays a role in every heartbeat. A hundred thousand times a day, it helps trigger your heart to squeeze blood through your body.

It also helps your muscles to move, your nerves to work, and your kidneys to filter blood

The U.S. Department of Agriculture recommends 4,700 milligrams per day for healthy people. The easiest way to get this amount is by adding high-potassium fruits and vegetables to your diet.

It's possible to get too much of a good thing, though. Ask your doctor before starting a potassium supplement.

If you have kidney failure or other kidney problems, talk with your doctor about how much potassium you should get.

 

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Mineralized tissues, such as bone, teeth, antler and horn, are important elemental storage sites in animals. These tissues contain necessary elements, both major, such as calcium (Ca), phosphorus (P), magnesium (Mg) and sulphur (S), and trace elements, such as iron (Fe), zinc (Zn), manganese (Mn) and cadmium (Cd).

Bones are living tissue. They’re made up of the protein collagen and the mineral calcium phosphate. This enables bones to be strong but flexible.

Collagen is like scaffolding that provides the bone’s framework. The calcium fills in the rest. The inside of the bone has a honeycomb-like structure. It’s called trabecular bone. Trabecular bone is covered by cortical bone.

Teeth are not living tissue. They’re comprised of four different types of tissue: dentin, enamel, cementum, pulp

While teeth and bones might appear to be the same material at first glance, they’re actually quite different. Bones can repair and heal themselves, while teeth cannot. Teeth are more fragile in that respect, which is why it’s so important to practice good dental hygiene and see a dentist regularly.

 

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The human body is made up of four fundamental elements: carbon, hydrogen, oxygen and nitrogen (also called the CHON or HONC elements). So are rocks, plants, animals, water and air. Do you know where these elements came from? The STARS. Yes, even the calcium in your bone and iron in your blood came from the distant stars. In fact, every atom in your body was forged in the centre of stars years ago. Read on to know how...

When the universe began 13 or 14 billion years ago, with the Big Bang, the only elements that existed were hydrogen, helium and a small amount of lithium. Over time, gravity increasingly pulled gas molecules towards each other and eventually gave birth to the first generation of stars. These stars were much greater than our Sun in size and temperature. The nuclear fusion within those stars then produced heavier elements, including carbon, oxygen, and nitrogen. When the stars exploded in supernova at the end of their life-cycle, the elements were shot into the far-flung reaches of the universe. Those stellar explosions continued, making new stars and planets. As more, massive stars exploded heavier elements continued to be created. Stars and elements are still being born this way, even as you read this.

As far as our galaxy, Milky Way, is concerned, stars had generated most elements now present on Earth about 5 billion years ago. Within the next billion years, the first signs of life on Earth appeared. No one is exactly sure how life formed on the planet. But one thing is clear like Carl Sagan said. "The cosmos is also within us, we're made of star stuff.

 

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The tear glands (lacrimal glands), located above each eyeball, continuously supply tear fluid that's wiped across the surface of your eye each time you blink your eyes. Excess fluid drains through the tear ducts into the nose.

The main function of the lacrimal gland is the production of lacrimal fluid, which is involved in the maintenance of a healthy ocular surface. Lacrimal fluid contains proteins, antimicrobial agents, water and electrolytes that ensure adequate lubrication, protection and nutrition of the ocular surface. 

Lacrimal fluid contains a significant amount of water that keeps the surface of the eye moist as well as dissolved elements that are necessary for normal cellular functioning. The fluid also contains antimicrobial agents including phospholipase, lysozyme, peroxidase, lactoferrin and immunoglobulins that provide defence against invading pathogens. In addition, the lacrimal gland produces numerous other substances and proteins including retinol (derived from Vitamin A) and growth factors such as epidermal, fibroblast and keratinocyte growth factors. These are involved in corneal regeneration and maintenance of corneal avascularity and transparency.

 

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The pupil is the opening in the center of the iris (the structure that gives our eyes their color). The function of the pupil is to allow light to enter the eye so it can be focused on the retina to begin the process of sight.

Together, the iris and pupil control how much light enters the eye. Using the analogy of a camera, the pupil is the aperture of the eye and the iris is the diaphragm that controls the size of the aperture.

The size of the pupil is controlled by muscles within the iris — one muscle constricts the pupil opening (makes it smaller), and another iris muscle dilates the pupil (makes it larger). This dynamic process of muscle action within the iris controls how much light enters the eye through the pupil.

In low-light conditions, the pupil dilates so more light can reach the retina to improve night vision. In bright conditions, the pupil constricts to limit how much light enters the eye (too much light can cause glare and discomfort, and it may even damage the lens and retina).

 

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Myopia, otherwise known as short-sightedness, is a common eye condition that causes objects in the distance to appear blurred while close objects are often seen clearly.

Myopia occurs when the eye has too much focusing power, either due to the eye being too long or the cornea being more curved than usual making the eye too strong. As a result, when someone with short-sightedness tries to look at distant objects, the rays of light are focused in front of the retina, rather than directly onto it, causing the appearance of those objects to become blurred.

Nearsightedness is the most common vision problem. Currently, about 1.5 billion people worldwide (nearly a quarter of the global population) are nearsighted. Myopia is especially prevalent in East Asia, where 70 to 80 percent of the residents of some countries are affected.

And the rate of myopia worldwide is increasing rapidly. It's estimated that by the year 2050, roughly half of the world population will be nearsighted.

Researchers aren't sure why myopia is becoming so common, but many eye doctors attribute it to eye fatigue from close-up work including reading, studying, using computers and portable electronic devices (including tablets and smartphones) and reduced time spent outdoors.

 

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The retina is the back part of the eye that contains the cells that respond to light. These specialized cells are called photoreceptors. There are 2 types of photoreceptors in the retina: rods and cones.

The rods are most sensitive to light and dark changes, shape and movement and contain only one type of light-sensitive pigment. Rods are not good for color vision. In a dim room, however, we use mainly our rods, but we are "color blind." Rods are more numerous than cones in the periphery of the retina. Next time you want to see a dim star at night, try to look at it with your peripheral vision and use your ROD VISION to see the dim star. There are about 120 million rods in the human retina.

The cones are not as sensitive to light as the rods. However, cones are most sensitive to one of three different colors (green, red or blue). Signals from the cones are sent to the brain which then translates these messages into the perception of color. Cones, however, work only in bright light. That's why you cannot see color very well in dark places. So, the cones are used for color vision and are better suited for detecting fine details. There are about 6 million cones in the human retina. Some people cannot tell some colors from others - these people are "color blind." Someone who is color blind does not have a particular type of cone in the retina or one type of cone may be weak. In the general population, about 8% of all males are color blind and about 0.5% of all females are color blind.

 

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A cataract is a cloudy area in the lens of your eye. Cataracts are very common as you get older. In fact, more than half of all Americans age 80 or older either have cataracts or have had surgery to get rid of cataracts. 

Most cataracts are age-related — they happen because of normal changes in your eyes as you get older. But you can get cataracts for other reasons — for example, after an eye injury or after surgery for another eye problem (like glaucoma).

No matter what type of cataract you have, the treatment is always surgery.

Most cataracts are caused by normal changes in your eyes as you get older.

When you’re young, the lens in your eye is clear. Around age 40, the proteins in the lens of your eye start to break down and clump together. This clump makes a cloudy area on your lens — or a cataract. Over time, the cataract gets more severe and clouds more of the lens.

 

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Similar to ischemic brain strokes, silent strokes occur when a portion of your brain suddenly stops receiving blood. It stops oxygen supply to the brain, causing considerable damage to the brain cells. However, a silent stroke is hard to understand because it breaks the blood supply to that part of your brain that has nothing to do with any of your visible functions, such as with ambulation, seeing, or speaking. Therefore, it goes unnoticed.

So, what about Silent Stroke Diagnosis? In most cases, people get to find out about their stroke only when they undergo a CT scan or an MRI of the brain for any other health condition. That is when a doctor can identify that a small portion(s) of your brain has sustained some amount of damage.

Also, if a person has had several episodes of silent stroke, they may notice the onset of several neurological symptoms, including difficulty concentrating and loss of memory.

As per the American Stroke Association, silent or asymptomatic stroke puts you at the risk of having symptomatic brain strokes later on in your life. Recent studies confirm that if you have had multiple episodes of silent strokes, you are at a higher risk for vascular dementia (multi-infarct dementia). The symptoms include:

? Problems with remembering things or loss of memory.

? Losing control over bladder and bowel movements.

? Difficulty in decision-making.

? Emotional outbursts like crying or laughing inappropriately.

? Not identifying previously visited places.

 

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If a Deaf person stands next to the loudest noise in the world, they would die just like any other person would. Did I say die? I meant that they would be pulverized.

The loudest sound ever produced in recorded history came about due to the Krakatoa volcanic eruption in 1883. It is estimated to have made a sound equivalent to 310 dB.

It was so loud, that it could be heard 3100 miles away, 4 hours later! That’s like hearing something that happened in California from New York.

It was directly responsible for the death of more than 36,000 people all over the world.

It created a gigantic tsunami that destroyed hundreds of boats and killed thousands of people.

It cooled the Earth and affected the weather for 5 years.

Let’s put this into perspective.

The nearest location that could record the explosion was 100 miles away, and measured the sound at 170 decibels. At that level, it sounds like a piece of dynamite exploding in your face.

At 190 dB, sound waves become shock waves. You can experience permanent hearing loss or become Deaf due to your eardrums rupturing

At 202 dB there is a chance that you can die from the shock.

235 dB is equivalent to 31,624 tons of TNT exploding in your face.

248 dB is equivalent to the sound that the atomic bombs dropped on Hiroshima and Nagasaki made.

286 dB is the equivalent of the sound Mt. Saint Helens made during its eruption in 1980.

The sound Krakatoa made was a whopping 310 dB.

 

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Sleep apnea is a potentially serious sleep disorder in which breathing repeatedly stops and starts. If you snore loudly and feel tired even after a full night's sleep, you might have sleep apnea.

The main types of sleep apnea are:

• Obstructive sleep apnea, the more common form that occurs when throat muscles relax


• Central sleep apnea, which occurs when your brain doesn't send proper signals to the muscles that control breathing


• Complex sleep apnea syndrome, also known as treatment-emergent central sleep apnea, which occurs when someone has both obstructive sleep apnea and central sleep apnea

Obstructive sleep apnea is caused by a blockage of the airway, usually when the soft tissue in the rear of the throat collapses during sleep. Central sleep apnea is usually observed in patients with central nervous system dysfunction, such as following a stroke or in patients with neuromuscular diseases like amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease). It is also common in patients with heart failure and other forms of heart, kidney or lung disease.

 

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Pneumonia is an infection in one or both lungs. Bacteria, viruses, and fungi cause it.

The infection causes inflammation in the air sacs in your lungs, which are called alveoli. The alveoli fill with fluid or pus, making it difficult to breathe.

Bacteria, viruses, or fungi can cause pneumonia.

Common causes include:

• Flu viruses


• Cold viruses


• RSV virus (the top cause of pneumonia in babies age 1 or younger)


• Bacteria called Streptococcus pneumoniae and Mycoplasma pneumoniae

Some people who are in the hospital get “ventilator-associated pneumonia” if they got the infection while using a ventilator, a machine that helps you breathe.

If you get pneumonia while you’re in a hospital and aren’t on a ventilator, that’s called “hospital-acquired” pneumonia. But most people get “community-acquired pneumonia,” which means they didn’t get it in a hospital.

 

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What we do know is that asthma is a chronic inflammatory disease of the airways. The causes can vary from person to person. Still, one thing is consistent: When airways come into contact with a trigger, they become inflamed, narrow, and fill with mucus.

Allergies with asthma is a common problem. Eighty percent of people with asthma have allergies to things in the air, like tree, grass, and weed pollens, mold, animal dander, dust mites, and cockroach droppings. In one study, children with high levels of cockroach poop in their homes were four times more likely to have childhood asthma than children with low levels. An allergy to dust mites is another common asthma trigger.

For about 80% of people with asthma, a heavy workout can cause airways to narrow. Exercise is often the main asthma trigger. If you have exercise-induced asthma, you will feel chest tightness, cough, and have trouble breathing within the first 5 to 15 minutes of an aerobic workout. For most people these symptoms go away in the next 30 to 60 minutes of exercise. But up to 50% of people with exercise-induced asthma may have another attack 6 to 10 hours later. A slow warm up may help prevent this.

 

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