INTEGUMENTARY SYSTEM

SKINColoring Book Assignment

SKIN: The Organ

Thin, but Tough…….Thinnest portion is over the EYES

1/50 inch thickThickest portion is on the BACK and SHOULDERS

1/5 inch thick

FUNCTIONS

• Barrier to Infection• Touch Sensation• Body Temperature• Excretion• Vitamin D

BASIC STRUCTURES

• Skin and Appendages– Glands, nails and hair

2 LAYERS• EPIDERMIS: dense

outer portion, stratified squamous epith.

• DERMIS: dense irregular connective, the deep layer

BLISTERS

• A separation between the dermis and epidermis.

HYPODERMIS

• Loose Connective Tissue • Below the Dermis• Connects the dermis to muscle or

bone. (So its not considered part of the skin.)

Layers of the Dermis

PAPILLARYleatherdermal papillae (bumps)increase the amt of

blood vessels exposure to the epidermis.

RETICULAR reti=net

Epidermal Ridges

Formed from ridges on the epidermisForm fingerprints

Increase friction between the skin and the things we touch.

Epidermal Ridges are just lines of Dermal papillae.

Reticular Layer

• Network of fibers • The collagen fibers run in all

directions providing strength in all directions• However, they tend to lie in one

direction more than another……• Lines of Cleavage or Lines of Tension

NERVES

• Send signals to and receive signals from the brain and spinal cord

• Numerous in the skin.• Hair follicle receptors– Nerves wrapped around hair in the dermis

Hair Follicle

• Made of epithelial tissue… same as the epidermis.• BURNS–1st

–2nd

–3rd

Arrector Pili

• Muscle cells associated with the hair• When the arrector pili contracts the hairs

stand on end.• goose bumps

HYPODERMIS

• Subcutaneous tissue• Loose connective tissue and adipose tissue• Loose ct connects the skin to muscle or bone• Adipose provides cushion and insulation• Lots of blood vessels

Blood Vessel Loops

• Found in the dermal papillae• Increase surface area for nutrients uptake

GLANDS

• Sweat: Sweat ducts and sweat pores– Secretion= sweat– Ducts lead to surface of skin– Cools the skin

• Sebaceous: produce oils to soften skin and protect from bacteria.

• A master criminal finds a doctor who has developed a procedure to remove the dermal papillae in a person’s hands. Why would a criminal be so interested in this procedure?

• The criminal from the previous question undergoes the unscrupulous doctor’s procedure and finds that he has constant skin problems in his hands. Why?

• In a fencing accident, a man receives two similarly sized deep cuts on the skin in the region of his abdomen. The first is horizontal along the skin, while the other is vertical. Which cut, most likely will leave the most noticeable scar?

• See Figure 3-2 page 63

The Layers of the Epidermis

Stratum corneum

Stratum LucidumStratum Granulosum

Stratum Spinosum

Stratum BasaleMelanocyte

Dead keratinocytes

Living keratinocytes

Merkel Cell

Nerve Receptor

Cancer results from the uncontrolled mitosis of a group of

cells. In what layers of the epidermis is it possible to get

cancer? Why is it impossible to get cancer in the other layers of the

epidermis?

Jaundice

Cyanosis

Hair

Hair BulbHair Root

Dermal Papillae

Hair Shaft

Sweat Gland

Hair Receptor Nerves

Hair Follicle

Sebaceous Gland

Arrector Pili Muscle

Blood Vessels

melanocytes

Dermal root sheath

Stratum basal

Hair Growth

• One-half inch a month.• Growth Stages: hair follicles have times which

the cells of the matrix reproduce a lot.• Rest Stages: times when the cells of the

matrix do not reproduce much• Hair Follicles have different growth and rest

stages. (amount of time in each stage)

Free edge

Lunule

Nail Body Root

Fold

MATRIX

http://www.mhhe.com/biosci/ap/saladin2e/student_index.mhtml

http://highered.mcgraw-hill.com/sites/0072351187/student_view0/