catagen

• n.

• 休止期、退行期

WordNet

1. cease an action temporarily; "We pause for station identification"; "lets break for lunch" (同)intermit, break
2. a time interval during which there is a temporary cessation of something (同)intermission, break, interruption, suspension
3. temporary inactivity

PrepTutorEJDIC

1. 『小休止』,中断,休息;(会話,読み書きの間に入れる)一息,一区切り / (音楽の)延音記号,フェルマータ / (一時的に)『ちょっと休止する』,立ち止まる;(…するのを)ちょっとやめる / (…の所で)停滞する,ちゅうちょする《+『of』(『upon』)+『名』》

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/10/27 19:18:27」(JST)

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Human hair
List of hairstyles List of facial hairstyles
By type
Lanugo Androgenic Terminal Vellus
Facial hair
Beard Chin curtain Chinstrap Goatee Moustache (handlebar toothbrush) Neckbeard Shenandoah Sideburns Soul patch Stubble Van Dyke
Other areas
Head Nose Ear Eyebrow Eyelash Underarm Chest Abdominal Pubic Leg
Hair loss
Baldness Glabrousness Hair removal (waxing threading plucking chemical electric laser IPL) Shaving head leg Razor
Conditions
Alopecia Hypertrichosis Trichophilia Trichotillomania Pogonophobia
Related topics
Hair color Hair coloring Hair length Hairstyle Hairdresser Barber Hair fetishism (pubic)

Human hair grows everywhere on the body except for the soles of the feet and the palms of the hands, the lips, and the eyelids, apart from eyelashes. Like skin, hair is a stratified squamous, keratinized epithelium made of multi-layered, flat cells with overlying keratin (a protein), whose rope-like filaments provide structure and strength to the hair shaft.

Hair follows a specific growth cycle with three distinct and concurrent phases: anagen, catagen, and telogen phases. Each phase has specific characteristics that determine the length of the hair. All three phases occur simultaneously; one strand of hair may be in the anagen phase, while another is in the telogen phase.

The body has different types of hair, including vellus hair and androgenic hair, each with its own type of cellular construction. The different construction gives the hair unique characteristics, serving specific purposes, mainly warmth and protection.

Growth cycle

The three stages of hair growth are the anagen, catagen, and telogen phases. Each strand of hair on the human body is at its own stage of development. Once the cycle is complete, it restarts and a new strand of hair begins to form. The rate or speed of hair growth is about 1.25 centimetres or 0.5 inches per month, or about 15 centimetres or 6 inches per year.

Anagen phase

The anagen phase is known as the growth phase. It begins in the papilla and can last from two to six years. The span at which the hair remains in this stage of growth is determined by genetics. The longer the hair stays in the anagen phase, the faster and longer it will grow. During this phase, the cells in the papilla divide to produce new hair fibers, and the follicle buries itself into the dermal layer of the skin to nourish the strand. About 85% of the hairs on one's head are in the anagen phase at any given time.

Catagen phase

Signals sent out by the body determine when the anagen phase ends and the catagen phase begins. The catagen phase, also known as the transitional phase, allows the follicle to, in a sense, renew itself. During this time, which lasts about two weeks, the hair follicle shrinks due to disintegration and the papilla detaches and "rests," cutting the hair strand off from its nourishing blood supply. Ultimately, the follicle is 1/6 its original length, causing the hair shaft to be pushed upward. While hair is not growing during this phase, the length of the terminal fibers increase when the follicle pushes them upward.

Telogen phase

During the telogen, or resting, phase the hair and follicle remain dormant anywhere from 1–4 months. Ten to fifteen percent of the hairs on one's head are in this phase of growth at any given time. The anagen phase begins again once the telogen phase is complete. The preceding hair strand is pushed up and out by the new, growing strand. The process causes the normal hair loss known as shedding.

Growth inhibitors and disorders

Chemotherapy

Most chemotherapy drugs work by attacking fast-replicating cells. Rapid cell replication is one of the hallmarks of cancer; however, hair follicle cells also grow and divide quickly. Consequently, the chemotherapy drugs usually inhibit hair growth. The dose and type of medicine determine the severity of hair loss, but once the chemotherapy has ended, new hair growth may begin after three to 10 months.

Alopecia-related syndromes

Main article: Baldness

Alopecia is a hair loss disease that can occur in anyone at any stage of life. Specifically Alopecia areata is an autoimmune disease that causes hair to spontaneously fall out. It is mainly characterized by bald patches on the scalp or other parts of the body, and can ultimately cause baldness across the entire body. This disease interferes with the hair growth cycle by causing a follicle to prematurely leave the anagen, or active growth, phase and enter the resting, or telogen phase. The hair growth in the affected follicles is lessened or stopped completely.

Traction alopecia is caused by adding too much strain on the hair on one's head. Tight ponytails and other styles that require added tension to the hair are often what cause this disease. It can also occur on the face in areas where the hair is often styled. Plucking or waxing one's eyebrows frequently, for example, can yield suppressed hair growth in the area.

On the scalp, the hair is usually known to be lost around the hair line, leaving the densest amount of hair at the crown. Small vellus hair will often replace the hair that is lost. In most people, scalp hair growth will halt due to follicle devitalization after reaching a length of generally two or three feet. Exceptions to this rule can be observed in individuals with hair development abnormalities, which may cause an unusual length of hair growth.

Hair-growth stimulants

• Minoxidil
• Finasteride

See also

• Evolution of hair

References

UpToDate Contents

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• 1. 男性における男性型脱毛症：病因、臨床的特徴、および診断 androgenetic alopecia in men pathogenesis clinical features and diagnosis
• 2. 無駄毛の除毛 removal of unwanted hair
• 3. 化学療法による脱毛 chemotherapy induced alopecia
• 4. 男性型多毛症の病因と原因 pathogenesis and causes of hirsutism
• 5. 脱毛の評価および診断 evaluation and diagnosis of hair loss

English Journal

• Immunolocalization of Wnt5a during the hair cycle and its role in hair shaft growth in mice.

• Xing Y, Xu W, Yang K, Lian X, Yang T.SourceDepartment of Cell Biology, Third Military Medical University, Chongqing, People's Republic of China.
• Acta histochemica.Acta Histochem.2011 Oct;113(6):608-12. Epub 2010 Jul 24.
• Previous studies have shown that the Wnt signaling pathway plays an important role in the growth and development of hair follicles. It has been generally accepted that Wnt5a, a non-canonical Wnt gene, inhibits the Wnt/β-catenin signaling pathway. Several reports have addressed its mRNA expression i
• PMID 20656336

• The canine hair cycle - a guide for the assessment of morphological and immunohistochemical criteria.

• Muntener T, Doherr MG, Guscetti F, Suter MM, Welle MM.SourceInstitute of Animal Pathology, Vetsuisse Faculty, University of Bern, Langgassstrasse 122, CH-3012 Bern, Switzerland.
• Veterinary dermatology.Vet Dermatol.2011 Oct;22(5):383-95. doi: 10.1111/j.1365-3164.2011.00963.x. Epub 2011 Mar 14.
• The hair follicle has a lifelong capacity to cycle through recurrent phases of controlled growth (anagen), regression (catagen) and quiescence (telogen), each associated with specific morphological changes. A comprehensive classification scheme is available for mice to distinguish the cycle stages a
• PMID 21401741

Japanese Journal

• Spatial and temporal control of laminin-511 and -332 expressions during catagen

• TATEISHI Chiharu,TSURUTA Daisuke,SUGAWARA Koji,YOSHIZATO Katsutoshi,IMANISHI Hisayoshi,NISHIDA Kazuyo,ISHII Masamitsu,KOBAYASHI Hiromi
• Journal of dermatological science 58(1), 55-63, 2010-04-01
• NAID 10027400392

• Cutaneous consequences of inhibiting EGF receptor signaling in vivo : Normal hair follicle development, but retarded hair cycle induction and inhibition of adipocyte growth in Egfr^<Wa5> mice

• SUGAWARA Koji,SCHNEIDER Marlon R.,DAHLHOFF Maik,KLOEPPER Jennifer E.,PAUS Ralf
• Journal of dermatological science 57(3), 155-161, 2010-03-01
• NAID 10027399831

Related Links

• Hair follicle - Wikipedia, the free encyclopedia

The catagen phase is a short transition stage that occurs at the end of the anagen phase. It signals the end of the active growth of a hair. This phase lasts for about 2?3 weeks while the hair converts to a club hair. ...

Related Pictures

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★リンクテーブル★

リンク元	「pause」「involutional」「resting stage」「silent period」

「pause」

　　[★]

• n.

• 休止、中止、休止期、ポーズ

関

abort、catagen、cessation、diapause、discontinuance、discontinuation、discontinue、dwelling、resting stage、silent period、stop、suspend、telogen、withdraw、withdrawal

　 　 　 　

「involutional」

　　[★]

• adj.

• 退行性の、退行の、退行期の

関

catagen、degenerative、involute、involution、regress、regression、regressive、retrogression、retrogressive

「resting stage」

　　[★]

• 休止期

関

catagen、pause、silent period、telogen

「silent period」

　　[★]

• 休止期

関

catagen、pause、resting stage、telogen