Why do some people go bald?

What do Charles Darwin, Michael Jordan, and Yoda have in common. They , like many other historical and fictive individuals , are bald, in some cases by their own choice.

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For centuries, a shining dome has been a symbol of intelligence. But despite this many balding people still wish their hair would return. Scientists have long pondered, " why do some people loose their hair, and how can we bring it back?". The full headed among us have 100,000 to 150,000 hair on our scalp , and scientists have discovered two things about their dense ticket.
Firstly, the sprouting hair we see is mostly made of keratin, the protein left over by dead cells that are forced upwards as new cells grow beneath them.
Secondly, the structures that drive hair growth are called Hair Follicels, a network of complex organs that form before we are born, and grows hair in an ever lasting cycle.
This cycle has three main phases.
The first is ANANGEN, the growth phase, which upto 90%of your hair follicle are experiencing right now, causing them to push up hair at the rate of 1 centimetre per month.
Anagen can last for two to seven years, depending on your genes. After this productive period, signals within the skin instruct the follicles to enter the new phase, known as catagen, or a regressing stage. causing hair follicles to shrink to a friction of their of their origin length. Catagen lasts to over two to three weeks, and cuts blood supply to the follicle, creating a club hair, meaning it is ready to be shed. Finally hairs enter Telogen, the resting phase, which lasts for ten to twelve weeks, and effects about 5 to 15% of your scalp follicles.
During Telogen, up to 200 club hairs can be shed in a day which is quite normal. then, the growth cycle begins anew. But not all heads are hairy, and, in fact, some of them grow increasingly patchy overtime, in response to bodily changes 95% of baldness in men can be attributed to male pattern baldness. Baldness is inherited, and in people in this condition, follicles become incredibly sensitive to the effects of dihydrotestosterone, a hormonal product made from the testosterone . DHT causes shrinkage in these overly sensitive follicles, making hair shorter and wispier. But loss is not sudden. It happens gradually, along a metric known a s Norwood scale, which describes the severity of hair loss. First, hair recedes along the temples, then hair on the crown begins to thin in a circular pattern. At the highest rating on the scale, these balding areas meet and expand dramatically, eventually leaving only a ring of sparse hairs around the temples and back of the head. Genetics isn't all that drives hair loss. Long period of stress can release signals that shock follicles and force them into the resting phase prematurely. Some women experience this after child birth. Follicles might also loss the ability to go into anagen, the growth phase. People going through chemotherapy treatment temporarily experience this. But while balding may look permanent, scientific investigation has revealed the opposite. Below the skin's surface, the roots that give rise to our hair actually remain alive. Using this knowledge, scientists have developed drugs that shorten the resting phase and force follicles into anagen. Other drugs combat male pattern baldness by blocking the conversion of testosterone to DHT so that it doesn't effect those sensitive follicles. Stem cells also play a role in regulating the growth cycle, and so scientists are investigating whether they can manipulate the activity of these cells to encourage follicles to start producing hair again. And in the mean time, while scientists hone their hair-reviving method and anyone going bald, or considering baldness can remember that they are in great company.