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Posted by bio_man   August 16, 2022   1757 views

Human smell has often been characterized as being deficient when compared to the smell abilities of some lower organisms. Summarized below are four myths about human smell that have been contradicted by research.

Myth 1: Human smell is less sensitive than that of other animals.

Research indicates that the individual smell receptor cells in humans will respond to a single odorant molecule. The difference in overall sensitivity appears to be due to the fact that some lower organisms, such as dogs, have more smell receptors.

Myth 2: Humans have a relatively poor ability to detect changes in smell intensity.

Although earlier research indicated that the difference threshold for smell was the largest of all the senses, more recent research, carefully ...

Physiology Sense of Smell Senses Perception Nose
Posted in Interesting Facts
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Posted by Biology Forums   August 8, 2022   2171 views

Do animals see the same way we do? Do some animals have better vision than humans? The senses of animals have evolved to give members of the species an optimum chance for survival. Here are a few examples:

Some animals, such as cats, have a reflective surface ( tapetum) on the back of the eye behind the sensory receptors (left image above). When light first enters the eye, some light is detected by the sensory receptors. The light not detected by the sensory receptors continues onto the reflective surface at the back of the eye. This light is then reflected outward toward the sensory receptors, providing a second opportunity for detection. This feature produces two results. First, the outward reflection results in the shining of the cat's ey ...

Eye Anatomy Comparison Animals Humans Rods Cones Cats Fish
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Posted by Biology Forums   August 6, 2022   2203 views

The fear of heights experienced by acrophobics is no small matter; tall buildings, airplane rides, bridges, even stepladders may present a paralyzing challenge. A new therapeutic approach, however, can help to lessen the anxiety experienced by acrophobics.

Ralph Lamsen, of the Kaiser Permanente Medical Group, uses virtual reality to desensitize acrophobes to their fear. The virtual world experienced through the helmet, glove, and handgrip presents a series of challenges relevant to the phobic situation. For example, clients are presented with a plank they must cross, an experience that usually produces elevated heart rate and blood pressure. Clients are encouraged to progress at a comfortable pace, staying at the edge of the plank until read ...

Phobia Technology Virtual Reality Treatment Mental Health
Posted in Research
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Posted by Biology Forums   August 5, 2022   2275 views

"I'd better check......one more time.....just let me make sure.....I'd better go back...." In isolation these comments might come from anyone wondering whether the headlights are turned off on the car. But as the mantra of people suffering from obsessive-compulsive disorder (OCD) these thoughts plague their daily lives. Whether its washing one's hands 25 times a day (above, scene taken from The Aviator (2004)) or checking to make sure the stove burner is off every hour on the hour, OCD can severely hobble one's peace of mind.

More rightly, it may be a piece of brain that produces these intrusive thoughts. UCLA's Jeffrey Schwartz and his colleagues used PET scans to study the brains of obsessive-compulsive patients. They found that the orbita ...

OCD Mental Health Compulsion Psychology
Posted in Discoveries
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Posted by bio_man   June 28, 2022   4051 views

Did you know that the Moon's rotation is locked to its orbit around Earth by a bulge of material under the Moon's surface? This material is denser than the rest of the Moon's surface material, and Earth's gravity pulls on it especially strongly. The side of the Moon containing the bulge always faces Earth. We call it the near side and we call the other side, which we never see from Earth, the far side. People often mistakenly use the term "dark side" when referring to the far side of the Moon, forgetting that the far side is fully illuminated by the Sun whenever we see a new moon from Earth.

If we were to look from high above the Earth-Moon system, we would see the Moon rotate once per month with respect to the stars. This is its sidereal ro ...

astronomy moon earth
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