histology

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Human Anatomy & Physiology, Sixth EditionElaine N. Marieb

PowerPoint® Lecture Slides prepared by Vince Austin, University of Kentucky

5The Integumentary System

Dr. Jason SchwartzDr. Jason Schwartz

Anatomy & Physiology I Lab Anatomy & Physiology I Lab

IRCCIRCC

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Skin (Integument)

Figure 5.1

Skin Model

Eccrine

Apocrine Sweat Gland

Epidermal Layers and Keratinization

Epidermis MnemonicLayers from top down or the most superficial to deeper layers: Can Lucy Get Some Bagels

Fig. 6.2a

Epidermis Mnemonic

• Layers from top down or the most superficial to deeper layers:

• Can Lucy Get Some Bagels

EpidermisEpidermis

• Type of Epithelium?

• _vascular

• Different layers (=strata)– 4 layers in thin skin– 5 layers in thick skin

Stratum germinativum

= stratumbasale

Innermost, single layer

Stratum BasalCell types:• Stem cells (basal cells)• Melanocytes• Merkel cells (touch receptors in hairless skin only)

Stratum spinosumSeveral cells

thick

Stratum Spinosum• Stem cell daughter cells (some can still divide)• Melanocytes & Langerhans cells• Establishment of Desmosomes

Stratum granulosum

Stratum Granulosum• Cells displaced from stratum spinosum Keratinocytes• Production of keratohyalin and keratin fibers• Cells start to die. Dehydration leaves interlocked layers of

keratin & keratohyalin

Stratum lucidum

Stratum Lucidum• In palms of hands and soles of feet • Cells do not stain well clear (lucid) looking

• Many layers of flattened, dead cells, filled with keratin• Continually shed in sheaths• Water-resistant but not water proof

Stratum corneum15-30 layers

(much thicker in thick skin)

Stratum Corneum

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Sweat Glands or Sudoriferous Glands

Different types prevent overheating of the body; secrete cerumen and milk

Eccrine sweat glands – located all over the surface of the body

Apocrine sweat glands – found in axillary, anogenital area, areolae area of a woman’s breasts and a man’s bearded face area

Mammary glands – specialized apocrine sweat glands that secrete milk

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Sweat Glands Eccrine Sweat Glands [7] Simple, coiled tubular glands are much more common than

Apocrine. Regulate body temperature through evaporation of perspiration Also plays a role in elimination – perspiration is diluted urine.

Drug detection as easy as taking a swipe of someone's sweat could someday be in the hands of law enforcement, thanks to research conducted at the Arkansas Biosciences Institute at Arkansas State University. 

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Sweat Glands Apocrine Sweat Glands [15]

Found in skin of axilla, groin, anal regions, areolae areas of the breasts, and bearded areas of the face in men.

Men’s beards grow faster when they live with women.

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Sebaceous Glands [13] Simple alveolar glands found all over the body

except the palms of the hand and soles of the feet Soften skin when stimulated by hormones Secrete an oily secretion called sebum which is a

mixture of fats, cholesterol, proteins, inorganic salts and pheromones

Skin Color depends on 3 pigmentsHemoglobin (dermal blood supply)

– Reddish tones– Pale, due to?– Bluish (=?), due to?

Melanin – Produced by melanocytes of stratum basale

Carotene Obtained from plant foods

Number of melanocytes same in all people, production levels differ !

Melanocytes

Function ?

Appendages of the SkinAppendages of the Skin

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Hair Produced by

hair bulb Consists of hard

keratinized epithelial cells

Melanocytes provide pigment for hair color Figure 4.7c

Hair AnatomyHair Anatomy

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Central medulla Cortex surrounds

medulla Cuticle on outside of

cortex Most heavily

keratinizedFigure 4.7b

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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

Hair Structure

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Hair Follicle

Figure 5.6c

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Hair Follicle

Figure 5.6a

Skin and Aging Process