2 General Info…….. Skin has 2 layers Epidermis - outer layer Dermis – inner layerSweat glands excrete sweat through pores.Sweat is made up of urea, salts, and water.Body’s first line of defense!Largest organ of the body.
3 The “Birthday Suit” Combination of 4 main tissues: Epithelial – outer layerConnective – underlies dermisSmooth Muscle – goose bumpsNervous – sensory receptors
4 Functions of the Skin Protection Temperature regulation Sensations Storage of chemical compoundsExcretion of wastesSynthesis of compoundsDetermines characteristics
5 The Skin FG04_02.JPG Title: Components of the Integumentary System Notes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails
6 Epidermis Outer layer of dead skin cells called cuticle . Layer you see everyday.“Ashiness” is caused by this layer of dead skin cells being very rough and raggedy.DUST you see around is made up of dead skin cells!Under the cuticle is another layer of living epithelial cells that make up the rest of the epidermis.
7 Epidermis and Dermis Epidermis is avascular (no blood vessels) Dermis is highly vascular (has blood vessels)Epidermis receives nourishment from dermisCells far away from nourishment die
8 Epidermis FG04_03.JPG Title: The Structure of the Epidermis Notes: A light micrograph through a portion of the epidermis, shows the major stratified layers of epidermal cells.Keywords: epidermis, structure, layers, stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum germinativum, dermis
9 Dermis Thick layer under the epidermis Contains blood vessels Oil glandsSweat glandsHair folliclesFat tissueNervesConnective tissue
10 Deeper Layer of the Dermis Dense connective tissueContainsBlood vesselsGlandsDeep pressure receptorsAttached to underlying organs by the subcutaneous layerLoose connective tissuePacked with adipose cellsStabilizes position of skin
12 What Else Comes from the Epidermis? HairGlandsNails
13 Functions of HairProtectionThermoregulationSensoryMinor role in humans
14 Hair Structure Shaft Superficial portion Root Below the surface CuticleOutermost layer of hairHair develops in folliclesDownward continuation of epidermis
15 Hair Structure FG04_10A.JPG Title: Hair Follicles Notes: Hairs originate in complex organs termed follicles. (a) A longitudinal section and a cross section through a hair follicle. (b) and (c) A section along the longitudinal axis of a hair follicle.Keywords: hair follicle, longitudinal section, cross section, sebaceous gland, arrectory pili muscle, cortex, cuticle, internal root sheath, connective tissue layer, glassy membrane, external root shaft
16 Growth of Hair At the base of the follicle, hair papilla Bulb Contains blood vessels and nervesNourishes hairBulbContains matrix – epithelial cells responsible for growthContains melanocytes
17 Smooth muscle attaches to follicle Raises hairs Arrector PiliSmooth muscle attaches to follicleRaises hairsResponse to fright or coldFunction?
18 GlandsSebaceous glandsConnected to hair folliclesSecrete a waxy, oily substance (sebum)BlackheadsSecretion increases at puberty
19 Sebaceous Glands FG04_13A.JPG Title: Sebaceous Glands and Follicles Notes: The structure of sebaceous glands and sebaceous follicles in the skin.Keywords: sebaceous glands, sebaceous follicles, structure, sebum, germinative cells
20 Glands Sweat glands Found just about everywhere Produce “perspiration” Water, salt, met. WastesFunction – cooling of the bodyScent GlandsSpecific type of sweat glandFound near hair folliclesAxillary & genital regionsDevelop at puberty
21 The Skin with Sweat Glands FG04_02.JPGTitle: Components of the Integumentary SystemNotes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails
22 Nail StructureNail bodyFree edgeNail rootMatrixLunula (moon)
23 Nail Structure FG04_15.JPG Title: Structure of a Nail Notes: These drawings illustrate the prominent features of a typical fingernail as view from the surface and in section.Keywords: fingernail, hyponychium, nail bed, lateral nail groove, lunula, eponychium, phalanx, dermis, epidermis
24 The skin also helps control body temperature- Homeostasis! When you sweat, heat leaves the body through your pores.When the sweat hits the outer surface of the skin, it is cooled by the air.This lowers your body temperature.