Fur and Hair

There is no difference between fur and hair; it is all just hair. Most refer to animal hair as fur, while referring to our own hair as just hair.  However, hair and fur are chemically indistinguishable, both made up of keratin.

Human hair does not grow forever nor does animal hair/fur, although the length of the growing cycle can be longer or shorter for both. Various mammals have different growth cycles for their hair than humans do. Cat hair seems to stop growing at a relatively short length, similar to the growth rate and length of the hair on a human’s arms and legs.

The maximum length of hair on various parts of a body is entirely determined by genetics and varies widely from person to person and animal to animal.

A cat’s whiskers are just hair, though these hairs are attached to special nervous system connections allowing them to work as sensory receptors.

A Porcupine's quills are extremely enlarged hairs.

Incidentally, shaving does not make your hair grow back thicker, stronger, or faster. It has been proven by numerous studies that shaving has absolutely no effect on hair growth rate or shape

Eight Eyebrow Facts

Eyebrows are tufts of hair that follow the shape of the ridge of the brow in mammals. They are very small and personal, but (mostly women) annually spend billions to pluck, tweeze, paint, scarify, shape, tattoo, pierce, puff, and generally do many unnatural things to this unique part of the human body. They are profoundly expressive of mood.

• The function of our brows is to keep moisture out of our eyes when it is raining or when we sweat. That arched shape helps divert liquid to the side of our faces.
• According to the Bosley hair transplant company, the average person has about 250 hairs per eyebrow.
• The average lifespan of an eyebrow is four months.
• A study done by MIT found that people had more trouble correctly identifying the faces of people they knew when they were presented with images of them missing their eyebrows and concluded that brows may be more important for facial recognition than eyes.
• Brows help us signal emotions, as the pitch of your voice rises, so do your eyebrows and vice versa.
• When you make an expression without thinking, eyebrows move in a way that is symmetrical to each other. Conversely, when you make what’s called an ‘intended’ expression, like suspicion and curiosity, your brows will furrow asymmetrically.
• Man is the only species that has eyebrows against bare skin.
• Every culture and time period has had a different way of shaping their brows: In Florence during the Renaissance, people shaved their eyebrows off completely, while the colonial elite in 18th-century America preferred to beef their brows up using grey mouse skin. 

Chemotherapy and Hair Loss

Chemotherapy, sometimes referred to as chemo is the use of medicines or drugs to treat cancer. There are more than 100 chemo drugs. Chemo may be used to: Keep the cancer from spreading, slow the cancer’s growth, kill cancer cells that may have spread to other parts of the body, relieve symptoms such as pain or blockages caused by cancer and, in some cases, cure cancer. Different types of chemotherapy work in different ways and have different side effects. It can be administered as a pill, liquid, shot, IV, or rubbed on the skin.

Most cells in the human body divide using a process called mitosis. When a cell reaches the end of its lifespan, it gets destroyed in a pre-programmed process called apoptosis.

There are over 200 many types of cancer. All types are a result of unregulated cell growth. Cells that divide more rapidly than apoptosis can regulate is simply too much mitosis. The result is excessive tissue, known as tumors. Tumors can be localized or spread through the lymphatic system or blood stream.

Many chemotherapy drugs are administered in combinations and work by interrupting mitosis and most cannot differentiate between abnormal cancer cells and normal healthy cells. Because of this, any cells that multiply rapidly can also be affected by chemotherapy.

Fast growing cells are found in hair follicles, lining of the mouth, stomach, and bone marrow. Since these fast growing sites are also affected by chemo, the result can be hair loss, decrease in production of white blood cells, and inflammation of the digestive tract, etc. Luckily, healthy cells, like hair follicles and the others usually repair themselves, so hair loss temporary. Radiation can cause some of the same symptoms, but that story is for another day.

Ten Facts about the Human Body

Blood vessels in a human body can be as long as 60,000 miles.
Humans are born with over 300 bones, but this number reduces to 206 in adults because some naturally fuse together as we grow.
Of the 206 bones, 106 are located in the hands and feet.
The liver is the largest solid organ and it contains 10% of the blood in a human body.
The stirrup bone in the middle ear is the smallest bone in the human body and is about .11 inches long.
The average person has 100,000 hairs on his or her head. Hair grows about five inches per year.
The strongest muscle in the human body is the tongue in proportion to its size. The hardest bone is the jawbone.
The tooth is the only part of the human body that can not repair itself.
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
We use 200 muscles to take one step and we average 10,000 steps a day.

Medical Myth

Contrary to the myth, fingernails and hair do not continue to grow after death. What does happen is that the cuticles and skin shrink after death, making it appear as if the nails and hair were lengthening.

Hair Color Facts

Hair color helps determine how dense the hair on your head is, and natural blondes, top the list. The average human head has 100,000 hair follicles, each of which is capable of producing 20 individual hairs during a person's lifetime. Blondes average 146,000 follicles. People with black hair tend to have about 110,000 follicles, while those with brown hair are right on target with 100,000 follicles. Redheads have the least dense hair, averaging about 86,000 follicles.

Shave and a Haircut, Two Bits

Shaving does not cause hair to grow back thicker, or coarser, or darker. This belief is due to the fact that hair that has never been cut has a tapered end, whereas, after cutting, there is no taper. Thus, it appears thicker, and feels coarser due to the sharper, unworn edges.

Hair can also appear darker after it grows back because hair that has never been cut is often lighter due to sun exposure. I have noticed the hair on my head has begun to grow in, because it sure isn't growing out like it used to.

PS - Two bits is an old expression in the US for 25 cents. It dates from colonial days, when a common unit of currency was the Spanish dollar. As a way of making change, these dollars were often cut into eight pie-slice shaped pieces, called bits. Hence, two bits being a quarter dollar.