The constructions and functiThe constructions and functions of skinons of skin

皮肤结构和功能Prof. Danqi Deng (Prof. Danqi Deng ( 邓丹琪教授、博导）邓丹琪教授、博导）

Dept. of Dermatology, the Second Affiliated Hospital ofDept. of Dermatology, the Second Affiliated Hospital ofKunming Medical UniversityKunming Medical Universityhttp ： //sy.ynderma.com.cn

Healthy body depend on health skin.

The skin is a aesthetic（审美） organ.

The skin is a vital organ like heart is.

OutlineOutline

• Epidermis 表皮• Dermis 真皮• Subcutaneous tissue 皮下组织• Cutaneous appendage 皮肤附属器• The functions of skin 皮肤的功能

The skin anatomyThe skin anatomy(( 皮肤的解剖皮肤的解剖 ))

• The skin is the integument( 外皮） of body.• It is the largest organ of the body ,making up 16%o

f body weight, with a surface of 1.5 m2

• The depth of skin is 0.5 ～ 4mm. • The epidermis( 表皮） is 0.04-1.6mm ， the average

depth of epidermis is 0.1mm.• The dermis （真皮） is 1-3mm.• In China , the average depth of man is 1.15mm, suc

h as the back of trunk is 2.23mm ， the eyelid is 0.5mm.

The skin anatomyThe skin anatomy

• It’s continuous with the digestive system (lips). 腔口部位形成皮肤黏膜的移行区

• The skin grooves( 皮沟 ) and skin ridges ( 皮嵴 )

• There are three structural layers to the skin: the epidermis （表皮） ,the dermis （真皮） and subcutis（皮下组织）

• The dermis contains nerve endings, sweat glands （汗腺） and oil glands, hair follicles （毛囊） , and blood vessels （血管） .

• The color of skin

The epidermis The epidermis (( 表皮表皮 ))

• The epidermis is an epithelium （上皮） comprised of keratinocytes （角质形成细胞） and dendritic cells(langerhans cells 朗格汉斯细胞 ,merkel cells 麦克尔细胞 ,melanocytes 黑素细胞 ).

• The main cells of the epidermis are the keratinocytes ( 角质形成细胞 80%),which synthesise the protein keratin( 角蛋白 ).

stratum basale, 基底层

stratum corneum 角质层

stratum spinosum 棘层

stratum granulosum 颗粒层

stratum lucidum stratum lucidum 透明层透明层

The epidermis The epidermis (( 表皮表皮 ))Stratum basaleStratum basale(( 基底层 ) ：： is a majis a major region of mitoticor region of mitotic(( 分裂分裂 ))activity. The activity. The basal layer is composed of columnarbasal layer is composed of columnar（柱状）（柱状） cells which are anchored to a cells which are anchored to a basement membranebasement membrane （基地膜）Epidermal transit timeEpidermal transit time(( 表皮通过时间或更表皮通过时间或更替时间替时间 ):):

New keratinocytes slowly migrate up tNew keratinocytes slowly migrate up toward the surface of the epidermis. Thoward the surface of the epidermis. The process needs e process needs 28 days.28 days.From stratum basale to From stratum basale to stratum granulosum is 14 days, then to stratum corneum and gradually shed is 14 days. gradually shed is 14 days. TotTotal is 28 days.al is 28 days.

• Stratum spinosum ( 棘细胞层 )

• is composed of 4 to 8 layers of prickle ( 多角形的） keratikeratinocytes.nocytes.

• KeratinocytesKeratinocytes are attached to each other by intercellular bridge （细胞间桥） , which are desmosomes （桥粒）

• Stratum granulosum ( 颗粒层 )

• Located the upper of stratum spinosum.

• Stratum granulosum is composed of 1 to 3 layers of rather flattened ( 扁平 ) cells .

• There are some large and basophil （嗜碱性） granule, called keratohyline granules( 透明角质颗粒） in cytoplasm( 细胞浆） . rather flattened cells containing numerous darkly-staining particles known as keratohyaline granules.

• Stratum lucidum （透明层 )

• locate the below of stratum corneum （角质层）， which is composed of 2 to 3 layers of much flat cells.

• There are seen in the palms of the hands ( 手掌 ) and soles of the feet ( 跖）

• Stratum corneum ( 角质层 ) is composed of layers of 5 to 20 dead cells. Adjacent cells overlap at their margins （边缘） and this locking together of cells, together with intercellular lipid( 脂质） , forms a very effective barrier （屏障） .

透明层透明层

角质层角质层

The epidermis The epidermis (( 表皮表皮 ))

• Dendritic cells ( 树枝状细胞 )

• Melanocyte （黑素细胞 )

• Langerhans cell （朗格汉斯细胞）

• Merkel cell （梅克尔细胞）

The epidermis The epidermis (( 表皮表皮 ))

– Melanocyte （黑素细胞） is in the basal layer of the epidermis with no desmosomes （桥粒） or tonofilaments(

张力丝） . There are 10% Melanocyte in the basal layer. Melanocyte produce melanin ( 黑色素） .

– In H E-stained, it has a small dark nucleus and a clear cytoplasm （细胞质） , also called clear cells( 透明细胞 ) . Silver stain and DOPA stain are positive.

Epidermal melanin units ( 表皮黑素单元 )

The melanin pigmentary （色素） system is composed of functional units. Each unit consists of a melanocyte that supplies melanin pigment to a group of keratinocytes (about 36).

– The differences in racial （种族） pigmentation （色

素） are not due to differences in the number of melanocytes, but rather to differences in melanocyte activity( 活性） .

Melanocyte H.E stain H.E stain DOPA stain

黑素细胞黑素细胞

Langerhans cellLangerhans cell ：：

– Langerhans cells are antigen-presenting cells （ APC 抗原呈递细胞） , mediating T-cell immunity, and play a role in allergic contact dermatitis （变应性接触性皮炎） .

– ATP stain is positive ,DOPA stain is negative（阴性） .

– CD6 and S100 stain are positive. – There are 3 ％～ 8 ％ Langerhans cells in epide

rmis– You can find Birbeck granules （颗粒） under el

ectron microscope （电子显微镜）

Langerhans cellLangerhans cell

Birbeck granules S100 +

Merkel cell （梅克尔细胞）（梅克尔细胞）

• In 1875, Merkel found the cells in the junction epidermis and dermis ， called Merkel cells.

• It is embedded （嵌入） in the basal layer of epidermal cells, with which it has desmosomal connections

• Merkel cells were tactile corpuscle ( 触觉小体） .

Merkel cell分离人表皮基底层间的 Merkel cell

Ultrastructure of the Dermo-Epidermal JunctUltrastructure of the Dermo-Epidermal Junctionion

细胞间及表真皮间的连接细胞间及表真皮间的连接

Desmosome( 桥粒 ): KeratinocytesKeratinocytes are attached to each other by desmosomes.

由相邻细胞的细胞膜发生卵圆形致密增厚而形成。

Hemidesmosome （半桥粒 ) superficially resemble focal thickening of the basal plasma membrane of keratinocytes.

表真皮间主要连接结构

Basement membrane zone （基底膜带， BMZ )

Desmosome Desmosome （桥粒（桥粒 ))

IVIV胶原胶原免疫免疫组化组化基底基底膜膜

BMZ ：：基底细胞与真皮交界面呈波浪状，用基底细胞与真皮交界面呈波浪状，用 PASPAS 染色在表皮与染色在表皮与真皮交界处有一层真皮交界处有一层 0.5~1um0.5~1um 厚的红染带称为表皮下基底膜带厚的红染带称为表皮下基底膜带 (S(Subepithetial basement membrane zone)ubepithetial basement membrane zone)

Basement memebrane zoneBasement memebrane zone （（基底膜带基底膜带 ))

• Which consists of three layers: • the lamina lucida ( 透明层 )

• the lamina densa ( 致密层 )

• the lamina fibroreticularis (sub-lamina densa, 致密下层 )

anchoring filaments anchoring filaments

Dermis Dermis 真皮真皮

• The dermis contains two layers, the papillary layer ( 乳头层） and the reticular layer （网状层） .

• It is a dense irregular, mesodermally （中胚叶） derived （来源） , connective tissue, mainly composed of fibrous and elastic （弹力） tissue (made mostly of collagen, elastin （弹性蛋白） , and fibrillin 原纤维蛋白 )

• The founctions

不

Epidermis表皮

Dermis 真 皮

Subcutaneous Subcutaneous tissuetissue皮下组织

Subcutaneous tissue Subcutaneous tissue 皮下组织皮下组织

• Subcutaneous tissue is composed of loose connective tissue （结缔组织） with large numbers of adipose( 脂肪 ,fat )cells.

• The founctions

Cutaneous appendage Cutaneous appendage (( 皮肤附属器皮肤附属器 ))

Cutaneous appendage Cutaneous appendage (( 皮肤附属器皮肤附属器 ))

• Hair （毛发 ) ： Hair can be found in varying densities of growth over the entire surface of the body, exceptions being on the palms （手掌） , soles （跖） and glans （龟头） penis （阴茎） .

• Three types of hair: vellus hair( 毫毛 ),lanugo( 汗毛或毳毛） , long hair and short hair.

• Hair shaft ( 毛干 ) • Hair root （毛根）• Hair follicle （毛囊）• Hair bulb （毛球）• Hair papilla( 毛乳头）

HairHair （毛发（毛发 ))

• Three stages: • an active (anagen, 生长期 ) stage, three years.• a resting (catagen, 退化期 ) stage, three weeks.• a telogen stage,( 静止期 ) three months, where the hair st

ops growing to be finally shed.• 毛的长度（ length) 取决于生长周期，• 但毛的粗细 (thickness) 则与毛球 (hair bulb) 大小有

关。

Follicle(Follicle( 毛囊毛囊 ))

一个成熟的毛囊从解剖结构上可分为上、下两段，上段由漏斗部和峡部构成，较稳定，不参与毛囊周期；下段可分为茎部和球部，是暂时的，参与毛囊周期。

Cutaneous appendageCutaneous appendage(( 皮肤附属器皮肤附属器 ))

• Sebaceous glands ( 皮脂腺 ) ： are found on all areas of the skin with the exception of the palms( 手掌） , soles （跖） , and dorsa （背） of the feet.

• They are holocrine glands （全分泌腺 ), i.e., their secretion is formed by complete destruction( 破裂） of the cells.

• The production of sebum( 皮脂） is under hormonal （激素） control and sebaceous secretion is a continuous process. Average density is 100 ／ cm2 of body ， but is 400 ～ 900 ／ cm2 of face and chest.

• Most sebaceous glands have their ducts opening into hair follicles (pilosebaceous apparatus, 毛囊皮脂单位 ).

• Free sebaceous glands (not associated with hair follicles) open directly to the surface of the skin

• Sebaceous areas 脂溢区• 乳化脂膜：

Sweat Glands Sweat Glands 汗腺汗腺

• Eccrine glands （小汗腺 ):Humans have several million eccrine sweat glands distributed over nearly the entire body surface (except labia minora 小阴唇 and glans penis 龟头 ).

• Eccrine glands control the body temperature through evaporative ( 蒸发） heat loss.

• Apocrine glands （顶泌汗腺 ) ： in the axillae( 腋窝 )and anogenital ( 肛门及生殖器） area which are under the control of sex hormones, mainly androgens （雄激素） .

• It have a duct that opens into a hair follicle.

NailNail 甲甲

• The nail acts as a protective covering to the end of the digit and assists in take small objects.

• Fingernails （指甲） grow faster than toenails.

NailNail 甲甲

nail plate

the matrix

nail bed

nail root

nail fold

Cutaneous Sensory System皮肤感觉系统

• The skin is innervated （神经支配） with around one million afferent （传入） nerve fibers.

• The brain receives two types of sensations （感觉） : • (1) superficial （浅 )sensations, including pain, tem

perature and crude （粗糙） touch.• (2) deep sensations, including sense of position, sens

e of movement, vibration( 震动 ) sense, muscle sense and fine (精巧） touch.

Cutaneous Vascular System 血管

• It comprises two types of vessels:

• Superficial vascular plexus (丛 )

• Deep vascular plexus• Two functions: • (1) nutrition(营养 ) of the

skin tissue.• (2) regulation(调节 ) of

body temperature

Arteries(动脉 ) H.E 染色 Wergert-van Gieson染色

Veins( 静脉 ) H.E

Veins Wergert-van Gieson

Cutaneous Lymph System 淋巴管

• Lymph gland:

• Lymph duct:

• 皮肤的淋巴管网与几个主要的血管丛平行 .

Muscle 肌肉

• Smooth muscle:

• 立毛肌、阴囊肌膜、乳晕平滑肌、血管壁平滑肌等，汗腺周围肌上皮细胞。

• Muscle: Face

Functions of the Skin Functions of the Skin 皮肤的功能

(1)Serves as a barrier to physical, biological, and chemical agents and to radiation ( 屏障作用屏障作用 ))

(2) Absorption (吸收作用吸收作用 ))

(3)Serves as a sensory organ ( 感觉作用感觉作用 ))

(4)Site of excretion 分泌和排泄分泌和排泄

(5)Regulates body temperature 体温调节体温调节

(6) Metabolism 代谢作用代谢作用

(7)Plays a role in immunological surveillance 免疫功能免疫功能

Functions of the Skin Functions of the Skin 皮肤的功能

QuestionsQuestions

• What is epidermal transit time epidermal transit time (( 表皮通过时间 ) ？

• The constructions and functions of

epidermal ?epidermal ?• What is epidermal melanin units ( 表皮黑素单元 )?