INTEGUMENTARY SYSTEMExercise # 8

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Competency 3: The Integumentary System

• Upon successful completion of this laboratory, the students should be able to recognize the various skin components of the integumentary system by:

– Recognizing, from prepared slides, selected skin tissues and structures.

– Explaining the structures and functions of epidermal and dermal layers of skin.

– Identifying the major parts of the hair.

INTEGUMENTARY SYSTEM(Martini, chapter 5)

• LAYERS OF THE SKIN• FROM EXTERNAL TO INTERNAL:

• 1- EPIDERMIS• 2- DERMIS• 3- HYPODERMIS

ALFONSO A. PINO MD.

EPIDERMIS• Function- protection from chemical, physical & biological agents

• 5 stratum (from external to internal)• Stratum corneum• Stratum lucidum• Stratum granulosum• Stratum spinosum• Stratum germinativum (basale)

• Stratum corneum- 15-30 layers of keratinized cells. Water • resistant F- allows insensible perspiration More or less 500 ml of water every day• Stratum lucidum- clear layer only in thick skin (palms & soles). F-contains flattered & packed cells filled with the protein

keratin• Stratum granulosum- grainy layer F- to produce protein keratin & keratohyalin basic structural component of hair & nails

• Stratum spinosum (8 to 10 layers) F- it contains Langerhands cells for Immune response against microorganisms & Cancer cells • Stratum germinativum or basale (The innermost) F- cells divide to replace superficial cells

it contains Melanocytes –to produce melanin For protection against uv radiation

ALFONSO A. PINO MD.

Epidermis (5 stratums)

DERMIS

• Function- thermoregulation & protection 2 mayor components- papillary & reticular layers

• Papillary - contains capillary & lymphatic vessels & sensory neurons function- support & nourishment of the overlaying epidermis

• Reticular - deep to papillary layer function- to resist tension in the skin

HYPODERMIS

• FUNCTION- ENERGY STORE CUSHIONING INSULATION

ACCESSORY STRUCTURES• Meissner’s corpuscles (white in models) F- light touch & tactile receptors• Pacinian corpuscles (olive in models) F- deep pressure & vibration receptors• Sebaceous glands- discharges waxy

sebum into the hair •

follicle F- lubrication• Hair: for protection, insulation, and tactile

reception. It is divided into: Shaft: exposed hair and first part under skin Root- surrounded by hair follicle. Contains

hair papilla- at the base Hair bulb- surrounds the papilla• Arrector pili- smooth muscle that erects the

hair• Sweat glands- Apocrine Merocrine

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Sebaceous Glands and Sweat Glands• Exocrine Glands in Skin

– Sebaceous glands (oil glands)

• Holocrine glands

• Secrete sebum

– Sweat glands

• Two types: apocrine glands and merocrine (eccrine) glands• Merocrine – products are secreted by exocytosis (e.g., pancreas, sweat, and salivary glands)• Apocrine-- producing a fluid secretion by pinching off one end of the secretory cell while leaving the rest intact.• Holocrine – products are secreted by the rupture of gland cells (e.g., sebaceous glands)• Watery secretions

ALFONSO A. PINO MD.

Hair follicle

ALFONSO A. PINO MD.

Hair follicle

Nails

• Nails

• protect fingers and toes

– Made of dead cells packed

with keratin

– Metabolic disorders can

change nail structure

• Nail production

– Occurs in a deep epidermal

fold near the bone called

the nail root

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Nails• Structure of a Nail

– Nail body• The visible portion of the nail• Covers the nail bed

– Lunula• The pale crescent at the base of the nail

– Sides of nails• Lie in lateral nail grooves • Surrounded by lateral nail folds

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Nails• Structure of a Nail

– Skin beneath the distal free edge of the nail

• Is the hyponychium (onyx = nail)

– Visible nail emerges

• From the eponychium (cuticle)

• At the tip of the proximal nail fold

REMEMBER, GO TO THE TUTORING ROOM AND PRACTICE WITH MODELS!

ROOM 3326