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Again, the hair shaft shows three important features – cuticle, cortex, and medulla- that I have already described with the labeled diagrams. The microscopic features of the connective tissue layer of the hair follicle are similar to the normal connective tissue. This connective tissue of the hair follicle is made up of tissue continuous with the dermis of the skin. The outer cell layers also give rise to the inner root layer cells.
How to visualize the scales and medulla of hair?
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).
Outer root layer of a hair follicle
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.
Bold Hold Collection
Again, the hair follicle is the epidermis structure that develops as down growth of the epidermis into the dermis and possesses different parts. Hair serves a variety of functions, including protection, sensory input, thermoregulation, and communication. The hair in the nose and ears, and around the eyes (eyelashes) defends the body by trapping and excluding dust particles that may contain allergens and microbes. Hair of the eyebrows prevents sweat and other particles from dripping into and bothering the eyes. Hair also has a sensory function due to sensory innervation by a hair root plexus surrounding the base of each hair follicle.
Features of other hairs of animal body
In contrast to EDA and EDAR, members of the bone morphogenic protein (BMP) family of secreted signaling molecules seem to be inhibitors of placode formation. The antagonist named Noggin neutralizes BMP activity via regulation of lymphoid enhancer factor 1 (LEF1) expression [4]. Thereafter, the epithelial placode expands and generates the primary hair germ (stage 2). The second signal arises from epithelial placode and constitutes a cluster of adjacent mesenchymal cells which later develops the dermal papilla (DP). The ultimate signal from this primitive dermal papilla to the epithelial placode cells indicates a rapid proliferation and differentiation. This consecutive signaling process finally leads to the production of the mature follicle.
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.
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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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.
Anatomy, Hair
You will find numerous ovoid structures with pigment granules in the hair shaft of cattle. These are the long with medium-shaped diameter hair in animals. But, the diameter of this head hair may vary in different animal species. The medulla of the head hair may be absent or continuous and relatively narrow.
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.
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.
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.
After producing the new cells, they pass superficially and undergo keratinization. At the lower end of the hair root, these rounded nucleated cells become continuous with the hair bulb. The cells found in the hair bulb also continue with the stratum spinosum of the skin.
The germinatinglayer of the epidermisstarts growing down into the dermis, and forms the outside of each hairfollicle. Biotin (B7) is a water-soluble form of vitamin B that supports hair growth and defends hair from environmental damage. Biotin metabolizes amino acids from foods which helps keratin form in hair and is one of the most popular purported vitamins for hair according to the National Institutes of Health. In fact, as we get older, the number of hair follicles per square inch decreases as our bodies stretch and grow. Because hairs continue to enter the resting phase and then fall out, we are constantly losing hair.
The first sign of catagen is the termination of melanogenesis in the hair bulb. Follicular epithelium, mesenchyme, neuroectodermal cell populations and also perifollicular vascular and neural systems demonstrates cyclic changes in differentiation and apoptosis. However, any apoptosis is occurred in dermal papilla due to the expression of suppressor bcl-2 [11]. The duration of the phases changes based on the location of the hair and also personal nutritional and hormonal status and age [15, 33].
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