Tag Info

Hot answers tagged

5

It would be better to say that they go into an inactive, low metabolic state. This low metabolic state is often driven by the temperature in the air itself; ectothermic butterflies require outside heat-energy to become active. Basically they use this time to digest their food and produce sperm/eggs. (reference). At night, or during inclement weather, most ...


5

Our eyelids close when we sleep probably for the obvious reason that it prevents the sclera and cornea from drying out, becoming accidentally scratched (such as blowing dust) and allowing oxygen diffusion from the inside of the eyelid (to the sclera and cornea). Fragile corneas are a requirement for our vision. Thick corneas are much less fragile but then ...


5

Sneezing does not occur during REM sleep, due to REM atonia.(1) Coughing on the other hand does occur during sleep, most commonly due to sickness. The following paper describes a study on the effect of honey for treating nocturnal coughing in children: http://www.ncbi.nlm.nih.gov/pubmed/22869830


4

The medical term is "lagophthalmos" if the person is unable to close their eyes at night. There are several factors involved, and unless it's due to physical obstruction, lid archetecture (such as short lid length (due to surgery etc)), or facial nerve (CN VII) problems, it's not well understood. I have seen numerous people with varying degrees of this ...


4

Disclaimer: Not in any way my area of expertise. Maybe someone else can expand In relation to pregnancy, there exist one australian study (Stacey et al. 2011) that reports an increased risk of still-birth for women that sleep on their back at the later stages of pregnancy. The purported mechanism is pressure from the uterus on the inferior vena cava and ...


4

The enWikipedia article summarizes the best/only real research on positions that I am aware of. I read a book in high school (that is to say it was old and I have no idea what the title was) that claimed that the semi-fetal position was the best, as it supposedly maximized protection without compromising breathing too much. I can't say I've seen anything ...


3

These symptoms have a name: Computer vision syndrome. Basically our eyes are made to look at longer distances from 1-6 meters without much accommodation. Typically computer screens are located at a much closer distance (30-50cm), which requires constant accommodation by the eye. This leads to high stress on the muscles in the eye which subsequently get ...


3

Humans have evolved for 24 hour days and our bodies would not adapt well to this short of sleep/wake cycles (whether or not they were born there, unless they have been there for many generations and have been able to evolve for the new time). Our bodies would still want to spend about the same amount of time sleeping and being awake. If we tried to adjust ...


3

Since mammals all share the same neural structures it is quite likely that most non human species dream, but as yet, the simplest animal I could find that has been scientifically demonstrated to dream is the rat, as proven by Massachusetts Institute of Technology (MIT). MIT not only established that rat were capable of dreaming about the events they had ...


3

Have you ever tried to read a complicated book after several hours of hard work that required a high concentration? Imagine that you have forced a particular area of your brain. After a hard work, the areas of the brain that we used to finish a work seem don't respond to any stimulation and make us feeling tired and as we can't understand what we are doing ...


2

The release of the hormone melatonin is responsible for the feeling of sleepiness. It is released by the pineal gland and production starts when the light fades, as it's production is inhibited by light stimulation of the retina, the onset of the production is called dim-light melatonin onset. Read more about this at this previous answer. This study on ...


2

For those who have access, here's the full text. Having read the paper, I can't give you a good answer. This study was performed in mice, not humans, and "sleep" was achieved in a few ways. Mice normally sleep most of the day, so it was easy to get mice sleeping normally. They also induced "sleep" through anesthesia (incidentally, they saw these same ...


2

Only certain drugs can cross the blood brain barrier (BBB). However, there exist techniques to deliver drugs to the brain that otherwise cannot permeate through the BBB. One such technique is called intrathecal delivery that injects drugs directly into the cerebrospinal fluid, avoiding the BBB problem and allowing the drug to reach cells, including neurons, ...


2

At least one study from University of Chicago showed that birds dream...about singing.


2

Actually, for your example it would be pretty easy to adapt. You just have a 25.5 hour day with 12.75 hours of day and 12.75 hours of night. Except you have a 4.25 hour period in the middle of the day where you stay inside and use lights (like in the evening for most people on Earth) and a 4.25 hour period at night where you make sure your eye mask is on. ...


1

Caffeine is the stimulant in tea. It has different effects on different people, but if you can sleep right after drinking it, it probably isn't strong enough to have long term 'refreshing effects', And yes, the duration of your sleep does matter. If you sleep for 12 hours, much more caffeine will filter out of your blood stream than after a 1 hour nap. ...


1

There's definitely something to the fact that eyes work better when they are closed periodically and don't work well when they are open constantly, but there is another angle to this topic. I think its worth adding that not all animals sleep with their eyes closed. This is because many animals only sleep with half of their brain at once. Ducks, some ...


1

Underneath the superficial layers of your skin there are receptors which sense pressure, temperature and pain. These receptors are part of the peripheral nervous system which senses stimuli and they take the message conveying details about the stimulus to the somatosensory cortex of the brain. Here is where the perception of pain, burning, pressure etc is ...


1

The name used frequently for this phenomenon is "Post-lunch dip". "The post-lunch dip is a real phenomenon that can occur even when the individual has had no lunch and is unaware of the time of day. This dip has its roots in human biology, and may be linked to the size of the 12-hour harmonic in the circadian system. It is certainly exacerbated by a ...


1

This is a very interesting but difficult to answer question. That is because scientists are still debating about the various stages of consciousness. As it stands, there is evidence that people can learn even though they are asleep indicating that it is likely that sensory channels are open and information is being processed even when asleep. That likely ...


1

I have to add that the authors do not show any evidence for cell shrinkage. In fact, the word shrink is not mentioned even once in the article. Therefore the BBC article is not correct. To answer your question, all we know is that there is more fluid clearance; the authors do not show the mechanisms for this.


1

The immediate thought came to my mind was relation between Melatonin and Serotonin. Because both hormones have sleep related function. I read that both are light sensitive. Melatonin is produced by pineal gland in brain whereas Serotonin is at gut and CNS. Light dependence(Wikipedia) of Melatonin is explained here where they say blue light produces more ...


1

At night several changes occur in the body due to absence of sunlight and other surrounding changes. The biological clock inside the body performs certain function in a healthy body whenever changes are sensed. There are many receptors in our body located on cell membrane. They are made up of proteins and their function is to receive information from ...


1

Adenosine causes humans to become sleepy. But how ? During day time we consume food which is broken down into glucose. This glucose is broken down by "Glycolysis" in cell's cytoplasm during which ATP is produced. This produced ATP is is then used by body as an energy supplier. ATP breaks down into ADP and then AMP with the release of energy which our body ...



Only top voted, non community-wiki answers of a minimum length are eligible