Integumentary System - Hair Development - Revision history

Z8600021 at 07:31, 1 September 2020

2020-09-01T07:31:01Z

← Older revision		Revision as of 18:31, 1 September 2020
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	===Embryonic===		===Embryonic===
	[[Hair_follicle_development_02.jpg\|thumb\|Hair follicle stem cells]]		[[File:Hair_follicle_development_02.jpg\|thumb\|Hair follicle stem cells]]
	* follicle forms in stratum germinativum of epidermis		* follicle forms in stratum germinativum of epidermis
	* hair bud -> hair bulb		* hair bud -> hair bulb

Z8600021 at 07:22, 1 September 2020

2020-09-01T07:22:48Z

← Older revision		Revision as of 18:22, 1 September 2020
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	{{#pmid:30144361}}		{{#pmid:30144361}}

			{{#pmid:29797270}}

	{{#pmid:29176608}}		{{#pmid:29176608}}

Z8600021 at 01:44, 16 Ocak 2020

2020-01-16T01:44:15Z

← Older revision		Revision as of 12:44, 16 Ocak 2020
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	==Sebaceous Gland==		==Sebaceous Gland==
	{\|		{\|
	\| Sebaceous Glands are associated with the adult hair follicle and during development secrete vernix. These glands produce "sebum", that consists of a mixture of lipids, and secret this by a "holocrine" mechanism.		\| Sebaceous Glands are associated with the adult hair follicle and during development secrete {{vernix caseosa}}. These glands produce "sebum", that consists of a mixture of lipids, and secret this by a "holocrine" mechanism.

	"Holocrine" secretion is where the entire cell is ruptured/lost to release the secreted components.		"Holocrine" secretion is where the entire cell is ruptured/lost to release the secreted components.

Z8600021 at 01:43, 16 Ocak 2020

2020-01-16T01:43:22Z

← Older revision		Revision as of 12:43, 16 Ocak 2020
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	"Holocrine" secretion is where the entire cell is ruptured/lost to release the secreted components.		"Holocrine" secretion is where the entire cell is ruptured/lost to release the secreted components.

			Postnatally these glands are associated with {{puberty}} acne, though there are also other abnormalities of these glands.{{#pmid:31056753\|PMID31056753}}

	\| width=200px\|Holocrine secretion		\| width=200px\|Holocrine secretion

	[[File:Holocrine secretion animation.gif\|150px]]		[[File:Holocrine secretion animation.gif\|150px]]

	\|}		\|}

	{\|		{\|
	!		!
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	\| [[File:Integumentary- sebaceous gland histology 02.jpg\|300px\|Adult skin sebaceous gland histology]]		\| [[File:Integumentary- sebaceous gland histology 02.jpg\|300px\|Adult skin sebaceous gland histology]]
	\|}		\|}



	:'''Links:''' {{Gland}}		:'''Links:''' {{Gland}}

Z8600021 at 01:40, 16 Ocak 2020

2020-01-16T01:40:29Z

← Older revision		Revision as of 12:40, 16 Ocak 2020
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	==Sebaceous Gland==		==Sebaceous Gland==
	{\|		{\|
	\| Sebaceous Glands are associated with the adult hair follicle and during development secrete vernix.		\| Sebaceous Glands are associated with the adult hair follicle and during development secrete vernix. These glands produce "sebum", that consists of a mixture of lipids, and secret this by a "holocrine" mechanism.

	~~The cell mechanism of~~ secretion is ~~called "holocrine"~~ where the entire cell is ruptured to release the ~~secretion~~		"Holocrine" secretion is where the entire cell is ruptured/lost to release the secreted components.
	\| width=200px\|Holocrine secretion		\| width=200px\|Holocrine secretion

Z8600021 at 01:35, 16 Ocak 2020

2020-01-16T01:35:29Z

← Older revision		Revision as of 12:35, 16 Ocak 2020
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	* long hairs that grow on the head and in many people on the body, arms and legs		* long hairs that grow on the head and in many people on the body, arms and legs
	* produced by follicles with sebaceous ~~glands~~		* produced by follicles with {{sebaceous gland}}s
	* the hairs in these follicles gradually become thinner and shorter until they look like vellus hairs		* the hairs in these follicles gradually become thinner and shorter until they look like vellus hairs

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	==Sebaceous Gland==		==Sebaceous Gland==
	{\|		{\|
	\| Sebaceous Glands are associated with the adult hair follicle and during development secrete vernix. The cell mechanism of secretion is called "holocrine" where the entire cell is ruptured to release the secretion		\| Sebaceous Glands are associated with the adult hair follicle and during development secrete vernix.

			The cell mechanism of secretion is called "holocrine" where the entire cell is ruptured to release the secretion
	\| width=200px\|Holocrine secretion		\| width=200px\|Holocrine secretion

Z8600021 at 01:34, 16 Ocak 2020

2020-01-16T01:34:21Z

← Older revision		Revision as of 12:34, 16 Ocak 2020
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	===Vellus Hairs===		===Vellus Hairs===
	* short hairs, only a centimetre or two long, and contain little or no pigment		* short hairs, only a centimetre or two long, and contain little or no pigment
	* follicles that produce them do not have sebaceous ~~glands~~ and never produce any other kind of hairs		* follicles that produce them do not have {{sebaceous gland}}s and never produce any other kind of hairs

	===Terminal Hairs===		===Terminal Hairs===
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	==Sebaceous Gland==		==Sebaceous Gland==
	~~[[File:Integumentary- sebaceous gland histology 01~~.~~jpg~~\|~~300px~~\|~~Adult skin sebaceous gland histology]]~~ [[File:~~Integumentary- sebaceous gland histology 02~~.~~jpg~~\|~~300px\|Adult skin sebaceous gland histology~~]]		{\|
			\| Sebaceous Glands are associated with the adult hair follicle and during development secrete vernix. The cell mechanism of secretion is called "holocrine" where the entire cell is ruptured to release the secretion
			\| width=200px\|Holocrine secretion

			[[File:Holocrine secretion animation.gif\|150px]]

			\|}

	{\|		{\|
	~~\| width=200px\|[[File:Holocrine secretion animation.gif\|150px]]~~		!
			Adult skin sebaceous gland histology
	\|-		\|-
	\| ~~Holocrine secretion~~		\| [[File:Integumentary- sebaceous gland histology 01.jpg\|300px\|Adult skin sebaceous gland histology]]
			\| [[File:Integumentary- sebaceous gland histology 02.jpg\|300px\|Adult skin sebaceous gland histology]]
	\|}		\|}


	~~Adult skin sebaceous gland histology~~

	* associated with hair development
	* except plans penis and labia minora
	* these glands secrete vernix

	:Links: {{Gland}}		:'''Links:''' {{Gland}}
	==Arrector Pili Muscle==		==Arrector Pili Muscle==
	[[File:Integumentary-_hair_follicle_03.jpg\|thumb\|Arrector Pili Muscle]]		[[File:Integumentary-_hair_follicle_03.jpg\|thumb\|Arrector Pili Muscle]]

Z8600021 at 01:29, 16 Ocak 2020

2020-01-16T01:29:54Z

← Older revision		Revision as of 12:29, 16 Ocak 2020
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	==Sebaceous Gland==		==Sebaceous Gland==
	[[File:Integumentary- sebaceous gland histology 01.jpg\|300px\|Adult skin sebaceous gland histology]] [[File:Integumentary- sebaceous gland histology 02.jpg\|300px\|Adult skin sebaceous gland histology]]		[[File:Integumentary- sebaceous gland histology 01.jpg\|300px\|Adult skin sebaceous gland histology]] [[File:Integumentary- sebaceous gland histology 02.jpg\|300px\|Adult skin sebaceous gland histology]]

			{\|
			\| width=200px\|[[File:Holocrine secretion animation.gif\|150px]]
			\|-
			\| Holocrine secretion
			\|}


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	* these glands secrete vernix		* these glands secrete vernix

			:Links: {{Gland}}
	==Arrector Pili Muscle==		==Arrector Pili Muscle==
	[[File:Integumentary-_hair_follicle_03.jpg\|thumb\|Arrector Pili Muscle]]		[[File:Integumentary-_hair_follicle_03.jpg\|thumb\|Arrector Pili Muscle]]

Z8600021 at 01:28, 16 Ocak 2020

2020-01-16T01:28:24Z

@@ Line 168: / Line 168: @@
 * (primarily collagens, proteoglycans and adhesive glycoproteins) and dermal cell processes close to the epidermal basement membrane become distributed in a microheterogeneous fashion, thus providing a changing substratum for the overlying epidermis. It is assumed that the latter is able to somehow sense the texture and composition of its substratum, and by doing so to appropriately engage in the formation of glabrous, feathered or scaly skin.
 * Sengel P Int J Dev Biol 1990 Mar;34(1):33-50
 == Puberty Hair Development ==
@@ Line 225: / Line 245: @@
 Melanocytes produce melanin which influences hair colour.
 == Hair Loss ==

Z8600021 at 03:23, 27 Mayıs 2019

2019-05-27T03:23:18Z

← Older revision		Revision as of 14:23, 27 Mayıs 2019
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	Hair formation, hair follicle or pilli development, is an excellent example of two distinct developmental processes: epithelio-mesenchymal interactions and pattern formation. The differentiated hair follicle will eventually contain 20 or more different cell types. Melanocytes, which provide the hair colour, have a neural crest origin, and with ageing their numbers decline leading to whitening (grey) of the hair process.		Hair formation, hair follicle or pilli development, is an excellent example of two distinct developmental processes: epithelio-mesenchymal interactions and pattern formation. The differentiated hair follicle will eventually contain 20 or more different cell types. Melanocytes, which provide the hair colour, have a neural crest origin, and with ageing their numbers decline leading to whitening (grey) of the hair process.

	Hair follicle development in humans begins as an epithelial-mesenchymal interaction at week 9 - 12. This initial lanugo hair is replaced in the late fetal or early neonate by vellus and terminal hairs. A second round of development occurs during puberty under the influence of steroidal hormones.		Hair follicle development in humans begins as an epithelial-mesenchymal interaction at week 9 - 12. This initial {{lanugo hair}} is replaced in the late fetal or early neonate by vellus and terminal hairs. A second round of development occurs during puberty under the influence of steroidal hormones.

	The hair follicle is also a site for stem cells, allowing replacement of the follicle.		The hair follicle is also a site for stem cells, allowing replacement of the follicle.
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	== Lanugo Hair ==		== Lanugo Hair ==
	~~From about the third month lanugo hair~~ (Latin, ''lana'' = wool) ~~hiar~~ is ~~initially formed~~ and it has a role in binding vernix to skin.		Lanugo (Latin, ''lana'' = wool) hair is the first hair produced by the fetal hair follicles, appearing at about before 5 months of gestation. The hair is very fine, soft, and usually unpigmented. Normally lost (shed) before birth, though sometimes present at birth. The hair has a role in binding {{vernix caseosa}} to skin.



	Hair grows over the entire body at the same rate, so the hairs are the same length, and is shed abut 4 weeks before birth. Premature infants can still be covered with these hairs.		Hair grows over the entire body at the same rate, so the hairs are the same length, and is shed abut 4 weeks before birth. Premature infants can still be covered with these hairs.