Tag: sleeping time

Aestivation is a state of prolonged sleep during summer, exhibited by certain animals in response to high temperature and arid conditions. Example - frogs and toads, bees, salamander etc.

In Unihemispheric sleep, also known as asymmetric slow-wave sleep, one half of the brain is in deep sleep, a form of non-rapid eye movement sleep and the eye corresponding to this half is closed while the other eye remains open. It keeps the organism alert for predators.

• New born baby sleeps up to 16-17 hours a day.
  
• One of the reasons behind what appears to be excessive babies' sleep is the fact that the baby is still adjusting to a new environment, and experiencing a rapid bit of growth at the same time. Proper development demands that babies sleep a lot. Growth hormones are secreted by the pituitary gland at a much faster rate while babies sleep.
  

Aestivation is the type of summer sleep, performed by cold-blooded animals. It helps in maintaining the body temperature by avoiding the excessive water loss and any internal body damaged due to high temperatures. It is performed by bees, snails, earthworms, salamanders, frogs, earthworms, crocodiles, tortoise, etc.

• Giraffes have the shortest sleep requirements of any mammal, with an average of just 30 minutes per day.
  
• They sleep in a reclined position with their long necks curled right round and their heads resting on their rears.

The iris is the coloured circular structure concentrically surrounding the center of the eye, the pupil, which appears to be black. The size of the pupil, which controls the amount of light entering the eye, is adjusted by the iris's dilator and sphincter muscles. A device known as an ophthalmoscope is used to see inside the eye. Therefore, the correct answer is option B.

Meissner corpuscles are one of the three types of cutaneous receptors which are sensitive to fine touch. Three types are cutaneous receptors are sensitive to pressure which are namely Pacinian corpuscles, Ruffini endings and Krause end bulbs. Out of these, onion-shaped Pacinian corpuscles lie deep inside the dermis. The Ruffini endings are present deeper in epidermis near the base while the Krause end bulbs are present in specialized regions only, for example, conjunctiva of eyes, mucous membrane of lips and tongue etc. Thus, the correct answer is option D.

In mammals, tactile receptors are most densely concentrated on the face, particularly around the mouth and nose, to facilitate sensory input for feeding and environmental interaction.

• Sensitivity to temperature is a skin sense that is related to the human need to maintain internal temperature balance or thermal homeostasis. 
• When the body becomes hotter than the normal temperature the sweat glands releases sweat which in turns cools the skin as it evaporates. This helps the lower internal temperature of the body
  
• Hence the organ which senses temperature is skin.
• So, the correct answer is 'Skin'.