DO BIRDS HAVE VOCAL CORDS???

Although parrots have been known to talk or mimic human speech, it is true that they do not have larynx with vocal chords.  Instead, these birds have syrinx (a distended portion of the trachea) Due to the way these creatures are equipped, sound is then accomplished by expelling air across the mouth of the bifurcated trachea.  Different sounds are then produced by changing the depth and shape of the trachea.  While many parrots have been known for mimicking human speech, the African Grey Parrots of all subspecies are known for their superiority in imitating sounds and human speech and have shown that some are even able to associate words with their meanings and form simple sentences.

                          source-www.animalquestions.org

Why Are Flamingos Pink?

 

 

 

Have you ever wondered why flamingos are pink or orange? You've probably heard it has something to do with what flamingos eat, but do you know what exactly it is that produces the color?

Answer: Flamingos are pink or orange or white depending on what they eat. Flamingos eat algae and crustaceans that contain pigments called carotenoids. For the most part, these pigments are found in the brine shrimp and blue-green algae that the birds eat. Enzymes in the liver break down the carotenoids into the pink and orange pigment molecules deposited in the feathers, bill, and legs of the flamingos. Flamingos that eat mostly algae are more deeply colored than birds that eat the small animals that feed off of algae. Captive flamingos are feed a special diet that includes prawns (a pigmented crustacean) or additives such as beta-carotene or canthaxanthin, otherwise they would be white or pale pink. Young flamingos have gray plumage that changes color according to their diet.People eat foods containing carotenoids, too. Examples include beta-carotene in carrots and lycopene in watermelon, but most people do not eat enough of these compounds to affect their skin color.

WHY DO WE SNEEZE?

AHHH . . . CHOO!

If you just sneezed, something was probably irritating or tickling the inside of your nose. Sneezing, also called sternutation, is your body's way of removing an irritation from your nose.

When the inside of your nose gets a tickle, a message is sent to a special part of your brain called the sneeze center. The sneeze center then sends a message to all the muscles that have to work together to create the amazingly complicated process that we call the sneeze.

Some of the muscles involved are the abdominal (belly) muscles, the chest muscles, the diaphragm (the large muscle beneath your lungs that makes you breathe), the muscles that control your vocal cords, and muscles in the back of your throat.

Don't forget the eyelid muscles! Did you know that you always close your eyes when you sneeze?

It is the job of the sneeze center to make all these muscles work together, in just the right order, to send that irritation flying out of your nose. And fly it does — sneezing can send tiny particles speeding out of your nose at up to 100 miles per hour.

Why do we open our mouth to YAWN...

A yawn is a reflex of simultaneous inhalation of air and stretching of the eardrums, followed by exhalation of breath. Yawning is commonly associated with tiredness, stress, overwork, lack of stimulation and boredom, though recent studies show it may be linked to the cooling of the brain. In humans, yawning is often triggered by others yawning (e.g., seeing a person yawning, talking to someone on the phone who is yawning) and is a typical example of positive feedback This "infectious" yawning has also been observed in chimpanzees and dogs.
         The involuntary act of yawning usually includes opening the mouth very wide while slowly taking in a deep breath. This contortion of the mouth puts pressure on the salivary glands causing the eyes to sometimes tear-up, causes the throat to better open, and tightens the muscles around the mouth making sure the yawn is better accomplished.

Human body

why tears comes out while peeling off the onion???

As onions are sliced or eaten, cells are broken, allowing enzymes called alliinases to break down amino acid sulphoxides and generate sulphenic acids. A specific sulfenic acid, 1-propenesulfenic acid, formed when onions are cut, is rapidly rearranged by a second enzyme, called the lachrymatory factor synthase or LFS, giving syn-propanethial-S-oxide, a volatile gas known as the onion lachrymatory factor or LF.

The LF gas diffuses through the air and eventually reaches the eye, where it activates sensory neurons, creating a stinging sensation. Tear glands produce tears to dilute and flush out the irritant.Chemicals that exhibit such an effect on the eyes are known as lachrymatory agents.The amount of sulfenic acids and LF released and the irritation effect differs among Allium species.

http://in.answers.yahoo.com/question/index;_ylt=Ao9P18G.2ErQIu5LmwnurxO5HQx.;_ylv=3?qid=20120204194157AAMYrtW
Image source : http://www.google.co.in/imgres?imgurl=http://reviews.in.88db.com/images/stories/onion.jpg&imgrefurl=http://Oz4D4BA&ved=0CDEQ9QEwAg&dur=1263

why do people twich in their sleep ?

A hypnic jerk, or hypnagogic massive jerk, usually occurs just as we are falling asleep. People often describe it as a falling sensation or an electric shock, and it is a completely normal experience. It most commonly occurs when sleeping uncomfortably or over-tired.
When we drift of into sleep, the body undergoes changes in temperature, breathing and muscle relaxation. The hypnic jerk may be a result of the muscles relaxing. The brain misinterprets this as a sign of falling and signals our limbs to wake up; hence the jerking legs or arms.

In most people, a hypnic jerk usually occurs just once or twice a night. However, when a person is deprived of sleep or trying to fight sleep, it may happen more often. In extreme cases, the muscle twitches can happen every thirty seconds or more. This disorder is called periodic limb movement.

Another theory put forward to try and explain the hypnic jerk is that the body reacts to falling asleep much in the way that a body may twitch when dying. The hypnic jerk is a reflex used to keep the body functioning. The brain might register falling asleep as a situation in which the body needs to be stimulated.

source: http://au.answers.yahoo.com/question/index;_ylt=Aoi9d1Ig2NBBCSxVdtNj8BoV6Qt.;_ylv=3?qid=20070325222037AA1ijuv
          


 

DIFFERENT TYPES OF TROPISMS

A tropism is a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus. In tropisms, this response is dependent on the direction of the species. The word tropism comes from the Greek trope ("to turn" or "to change"). Tropisms are usually named for the stimulus involved and may be either positive (towards the stimulus) or negative (away from the stimulus).

Phototropism

Phototropism is the growth response of a plant in response to light direction. Different parts of a plant exhibit different reactions to light. Stems exhibit positive phototropism while most roots exhibit negative phototropism.

                                

 Geotropism is the growth response of a plant in response to gravity. Roots exhibit positive geotropism while stems and leaves exhibit negative geotropism.

                        

Thigmotropism is the growth response of a plant to physical contact (touch). Plants that cling to physical structures such as walls exhibit positive thigmotropism.

                              

Hydrotropism is the growth response of a plant to water. Roots exhibit positive hydrotropism.

                            

              Chemotropism is the growth response of a plant to a particular chemical. Roots grow toward useful minerals in the soil but away from acids.               

EXCRETRY SYSTEM IN HUMAN BEINGS

ALL ABOUT ELEMENTS.....!!

• Copper was probably the first metal mined and crafted by man. It was discovered in the Middle east.
• Phosphorus was the first element to be discovered chemically and it was prepared from urine.
• Pottasium (discovered by H. Davy) was discovered by using electrolysis on potash.
• Calcium was discovered by electrolysis on quick lime and sodium by the electrolysis on sodium hydroxide
• Caesium was discovered by its blue emission lines in a sample of mineral water.

source : https://en.wikipedia.org/wiki/Discoveries_of_the_chemical_elements

RIGHT HAND THUMB RULE

Right Hand Rule for Magnetic Field Due 
to a Straight Wire
• To find the direction of the magnetic field use the 
right hand rule.
• Point thumb in direction of current
• The fingers will curl in the direction of the 
magnetic field 

human nervous system

SOME INTERESTING FACTS ABOUT NERVOUS SYSTEM

• When we accidentally touch a hot object, the nerves that are connected to our skin transmit the message of pain to the brain. In response, the brain directs the muscles of the affected area to pull away from the source of pain. The whole process is executed in fractions of a second -- lot lesser than the time you will take to read these two lines. There are several such facts about the human nervous system; a few of these are listed below.

1.  There are billions of nerve cells in the human body; whether their number is actually more than the number of stars in the Milky Way galaxy is debatable, but their number is definitely more than the number of people on Earth.
2.  The human brain alone consists of about 100 billion neurons on an average. If all these neurons were to be lined up, it would form a 600-mile long line.
3.  While most of the sources maintain that the average number of neurons in the human brain is 100 billion, a 2009 study by neuroscientist, Herculano - Houzel revealed that the same is actually 86 billion.
4.  The human spinal cord, with an average length of 19 inches, consists of around 13,500,000 neurons. All the messages relayed between the brain and other parts of the body go via the spinal cord.
5.  The diameter of these neurons ranges between 4 to 100 microns. Though they are the largest cells in the human body, they do not undergo the process of mitosis like the other cells.
6.  The nervous system is able to transmit impulses at the speed of 100 meters per second. In fact, the speed of message transmission to the brain can be as high as 180 miles per hour.

SOURCE: http://www.buzzle.com/articles/interesting-facts-about-nervous-system.html

 

Introduction to magnetic effects of the electric current

Why does a compass needle get deflected?

Compass needle get deflected when brought near magnet due to the force of the magnet.
The lines along which the iron fillings align themselves represent magnetic lines of force.

Magnetic field is a quantity that has both magnitude and direction. The direction of the magnetic field is taken to be the direction in which a north pole of the compass needle moves inside it.





The field lines emerge from the north pole and merge at the south pole out side magnet
.Inside the magnet, the direction of field lines is from its south pole to its north pole. Thus the magnetic field lines are closed curves. This is why no two field-lines are found to cross each other.