integumentary system the skin and related structures

22
Integumentary System The skin and related structures

Upload: rafe-parsons

Post on 12-Jan-2016

224 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: Integumentary System The skin and related structures

Integumentary System

The skin and related structures

Page 2: Integumentary System The skin and related structures

Functions of Your Skin

• Barrier against microorganisms• Prevents water loss• Thermoregulation - helps control body temperature (click

for link)• Cutaneous sensation (for sensing your environment)• Excretion of wastes (sweating)• Aids in vitamin D production (helps body absorb calcium

and protects against some cancers)• Stores 5% of body’s blood

Page 3: Integumentary System The skin and related structures

Layers of the skin

• Epidermis (outer most layer)

• Dermis (below epidermis)

• Hypodermis (consists of adipose tissue (fat) - separates skin from muscles (technically not part of skin))

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

See Figure 5.1 on pg 153

Page 4: Integumentary System The skin and related structures

Epidermis (see figure 5.2 on pg 154)

• Top portion of the skin

• Avascular (has no blood vessels - nutrients diffuse from the blood vessels in dermis)

• Contains four types of cells:

• Melanocytes (produce melanin (pigment) - blocks UV radiation)

• Keratinocytes (produce keratin - helps prevent water loss and acts as “tough” covering)

• Langerhans’ (dendritic) cells (part of immune system - prevents infection in the skin)

• Merkel cells (sensory receptors for touch)

Page 5: Integumentary System The skin and related structures

Epidermal layers (see figure 5.2 on pg 154)

Outer (superficial) to inner (deep)• Stratum corneum (dead cells filled with

keratin - makes resistant to penetration and abrasions)

• Stratum lucidium (only in thick skin)• Stratum granulosum• Stratum spinosum • Stratum basale (bottom layer) - new cells

arise from this layer through mitosis (cell division). Melanocytes found here

Page 6: Integumentary System The skin and related structures

Epidermal Layers

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 7: Integumentary System The skin and related structures

Dermis• Contains blood

vessels supplying cells of epidermis

• Contains nerve endings, sweat glands, hair follicles, sebaceous (oil) glands

• Composed of the proteins collagen (strength) and elastin (stretch & recoil)

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 8: Integumentary System The skin and related structures

Dermal Layers

Papillary layer - top portion- forms ridges called

dermal papillae (forms fingerprints)

- Rich in blood vesselsReticular layer- mostly collagen and

elastin fibers- Hair rooted here - Contains coiled portion of

sweat glands

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 9: Integumentary System The skin and related structures

Appendages of the skin

• Sudoriferous (sweat glands)

• Sebaceous (oil) glands

• Hair

• Nails

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 10: Integumentary System The skin and related structures

Sudoriferous Glands (main types)

Eccrine (merocrine) glands

• Most abundant type• Most numerous on

forehead, palms and soles of feet

• Empty secretion on skin surface

• Secretion is 99% water, some salts, and small amounts of urea, ammonia, lactic acid

Apocrine glandsFound in axillary (armpit) and anogenital regionEmpty secretions onto hair folliclesSecretions also have fatty acids and proteins (broken down by bacteria - causes body odor)

Page 11: Integumentary System The skin and related structures

Other Sudoriferous Glands

Ceruminous glands• Make cerumen (earwax)Mammary glands• Produce milk in females

Page 12: Integumentary System The skin and related structures

Sebaceous (oil) glands

• Attached to hair follicle: release sebum (oil) onto hair

• Found throughout skin, but most numerous on face, neck, upper chest

• Help to moisturize and waterproof hair and skin

• A pimple results when a sebaceous gland is infected

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 13: Integumentary System The skin and related structures

Hair- Shaft - part of hair

extending out of the skin- hair follicle (pinching in of

the epidermis - surrounds hair)

- Hair matrix (area of dividing new cells)

- Papilla - dermal tissue at the hair root which supplies nutrients to the matrix

- Hair follicle receptor - nerve ending surrounding base of follicle

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 14: Integumentary System The skin and related structures

Hair Growth

Growth phase:- last from weeks to years (scalp)- Gets shorter (especially for men)

after 40s*- Regulated by hormones and

nutritionRegressive phase:- follicle shrinks, matrix cells die,

hair falls out

*Hair loss occurs when growth phase becomes too short for new hair to emerge from scalp

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 15: Integumentary System The skin and related structures

Homeostatic Imbalances of the Skin

• Skin cancers (3 main types)• Burns (1st, 2nd, and 3rd)

Page 16: Integumentary System The skin and related structures

Genes that Control Cell Division

Proto-Oncogenes

• Initiate mitosis (accelerator)

Tumor suppressor

genes• Inhibit mitosis

(brake)*mutations must occur to both types of genes for cancer to develop

Page 17: Integumentary System The skin and related structures

Skin CancersBasal Cell

carcinoma• most common (30%

of fair skinned people will get it

• 99% cure rate (surgically removed)

• involves stratum basale cells

• slow to metastasize

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 18: Integumentary System The skin and related structures

Skin CancersSquamous Cell

carcinoma• common on head and

hands (but can happen on any exposed area)

• Can appear as red scaly elevated bump

• Can spread rapidly if not detected early

• arises from cells in stratum spinosum (keratinocytes)

Page 19: Integumentary System The skin and related structures

Skin CancersMelanoma

• metastasizes (spreads) quickly/ highest mortality rate

• Appears as spreading brown/black patch

• one-third of cases arise from pre-existing moles QuickTime™ and a

TIFF (Uncompressed) decompressorare needed to see this picture.

Page 20: Integumentary System The skin and related structures

Self-examination for melanoma

ABCD(E) rule• Asymmetry (sides are not

the same)• Border (has

indentations/bumpy texture)

• Color (variation in the same patch)

• Diameter (larger than a pencil eraser)

• Evolution (the patch changes)

Page 21: Integumentary System The skin and related structures

Second Degree Burns

• Epidermis and papillary layer of dermis (or deeper into dermis)

• Blistering occurs due to damaged blood vessels

• Skin heals in 3-4 weeks on average

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Page 22: Integumentary System The skin and related structures

Third Degree Burns

• Involves full thickness of skin (dermis, epidermis, hypodermis)

• Dehydration most immediate threat

• Low blood pressure due to fluid loss

• Threat of infection• Skin grafts often

necessary

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.