Wednesday, May 1, 2024

Hair Structure, Growth & Function

hair diagram

You will find the imbricate scales in the cuticle of the horse hair without protrusion from the hair shaft. There are fine pigment granules distributed evenly in the medulla of the horse hair. But, you will not find any oval structure in the medulla of the horsehair. The root of the hair follicle is elongated in cattle, and the medullary structure is continuous into the root area. Again, you will find some follicular tissue in the root of the cattle’s hair. Again, the cuticle scales are imbricated and with no protrusion from the hair shaft.

Hair Follicles

It is made of a protein called keratin, compacted and fused together. It has three distinct layers, and is made up of amino acids (proteins) held together by chemical bonds. Hair shaft pigmentation ensures multiple benefits including UV protection, thermoregulation and sexual perceptions.

2. Structure of the hair

The base of the hair keratinizes into a hard club and the hair, now known as a club hair, loses its anchorage. Club hairs are easily pulled out by brushing the hair, and the hard club can be felt at the hair’s end. When the papilla reaches the bulge, the hair goes into a resting period called the telogen stage.

Fig. 2: Right side showed no signs of hair loss - ResearchGate

Fig. 2: Right side showed no signs of hair loss.

Posted: Thu, 08 Feb 2018 22:42:08 GMT [source]

Microscope features of hair

The alveolus of a sebaceous gland is pear-shaped and consists of a solid mass of polyhedral cells. You will find the small cells in the sebaceous alveoli at its outermost part. Again, the inner cells of the sebaceous alveolus are larger, rounded, and filled up with lipid. This cortical fusi, pigment granules, and large oval-shaped structures are called ovoid bodies. The cortical fusi is the irregular-shaped air space of varying shape and size. Under a light microscope, a medulla of an animal’s hair appears as a black or opaque structure.

hair diagram

Your hair shaft consists of three layers

Whether your hair is black or brown depends on the density of melanin in your cortex. Dark hair has more of the brownish-black eumelanin, while blonde hair and red hair have more of the reddish-yellow pheomelanin. The white hair of a person with the inherited condition albinism lacks melanin altogether. As pigment production decreases with age, hair color lightens toward gray. White hair results from the combination of a lack of pigment and the presence of air bubbles within the medulla of the hair shaft. Because the hair itself is dead and inert, changes in coloration are gradual; your hair can’t “turn white overnight,” as some horror stories suggest.

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You will find numerous pigment granules and oval structures in the hair of a rabbit. I tried to show you all the important features from the shaft and the follicles in the dog hair labeled diagram. The diagram of horses’ hair shows different important features from the shaft and follicle. You will find a great variation in the length and color of most of the hair specimens in different domestic animals. The diameter of the cattle hair is more coarse than those of human hair.

A healthy adult may lose about 70 to 100 hairs on their head per day. But because new hairs are always growing and replacing them, this natural hair loss isn't noticeable. Whether it is straight or curly will depend on the cross-sectional shape of hair. The more oval-shaped the cross-section is, the curlier the hair will be. At the base of the hair, the hair root widens to a round hair bulb.

Inner root layer of a hair follicle

hair diagram

Each of the cells possesses a free edge that overlaps with the next cells. The outer covering of the pencil is similar to the cuticle of the hair shaft. Again, the wood of the pencil is analogous to the hair shaft’s cortex. In addition, the pencil’s graphite shows a similar structure to the medulla of the hair shaft.

Breast shapes: What to know - Medical News Today

Breast shapes: What to know.

Posted: Thu, 27 Feb 2020 08:00:00 GMT [source]

The rest of the hair is anchored in the follicle and it lies below the surface of the skin. The hair root is enveloped by the hair follicle which is a skin appendage that lies deep in the dermis of the skin. The cortex forms the main bulk and pigment (colour) of your hair.

The color, size, and distribution of the pigment granules may vary within a single hair and among the different species of animals. Again, the oval structures are the solid bodies that are spherical to the oval. The medulla of a human hair may be continuous, fragmented, or absent. They possess a very regular and well-developed medulla in their hair.

The typical mammalian hair consists of the shaft, protruding above the skin, and the root, which is sunk in a pit (follicle) beneath the skin surface. Except for a few growing cells at the base of the root, the hair is dead tissue, composed of keratin and related proteins. The hair follicle is a tubelike pocket of the epidermis that encloses a small section of the dermis at its base.

The production also decreases in men, but not as much as in women. Shea butter serves as a natural replacement for decreasing sebum. The, natural conditioner, sebum inters the hair shaft at the point where the internal sheath of the shaft enters the sebaceous gland. The dermal papilla is the most important structure in a hair follicle which is responsible for hair-growth. It is the dermal papilla, the cell of which divides and differentiates to give rise to a new hair follicle. People with hair loss tend to have higher levels of 5-alpha reductase and androgen receptor sites in the hair follicles within the hair lossregion of the scalp (1).

The hair papilla, which supplies the hair root with blood, is found inside the bottom of the hair bulb. New hair cells are constantly being made in the hair bulb, close to the papilla. Each hair follicle is attached to a tiny muscle (arrector pili) that can make the hair stand up.

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