The Integumentary System

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The Integumentary System Skin!

• Steve Bradley
• Machin L. Norris
• Poudre High School
• Anatomy and Physiology

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INTEGUMENTARY SYSTEM

• Structure - Epidermal layer, Dermal layer,
  Subcutaneous layer
• Functions
• A. Regulation of body temperature sweat,
  vessels dilate for heat loss/heat retention
  through vessel constriction
• B. Protection keeps water and other molecules
  in, keeps water and undesirable substances out
• C. Sensation detect pain, pressure,
  temperature, touch
• D. Excretion elimination of some nitrogenous
  waste, excess salt, water (sweat/perspiration
• E. Immunity - macrophages
• F. Synthesis of Vitamin D sunlight hits skin
  cells, cholesterol is converted to precursor
  molecule that aids in absorption of Ca and P

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EPIDERMIS Stratified squamous epithelium, first
layer of skin

• Cell Types
• KERATINOCYTES in all five layers, more on the
  outside, make keratin, sealing cells
• MELANOCYTES Produce melanin
• LANGERHANS CELLS macrophages
• MERKEL CELLS sensory cells

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First Layer of the Integumentary System

• Epidermis
• Five layers of Strata from deepest to most
  superficial
• a. Stratum Basale
• (Germinativum) deepest, single layer of cells,
• only layer to undergo mitosis (millions of new
  cells daily) receives adequate nourishment,
• contains few keratinocytes, melanocytes, Merkel
  cells,
• as are pushed out become more keratinized,
• new turnover every 35-45 days

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• b. Stratum Spinosum -
• contains keratinocytes, Langerhans cells
• arise in the bone marrow and migrate
• receives nourishment
• several layers thick
• does not divide
• c. Stratum Granulosum
• 3-5 layers of flattened keratinocytes water
  repellent
• last living layer, receives nourishment
• everything beyond this layer is dead

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d. Stratum Lucidum Few layers of dead
keratinocytes Found only in thick-
skinned areas (pads of feet, palms of hands,
calluses no hair e. Stratum Corneum
20-30 layers thick of dead keratin-filled
cells, protects against abrasion and
penetration, water proof
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Second Layer of the Integumentary System

• Dermis
• 1. Cells of dermis fibroblasts, macrophages,
  adipocytes.
• 2. Thick palms, soles/Thin scrotum, eyelids
• 3. Dermal Papillae produce fingerprints,
  contain tactile receptors called Meissners
  Corpusles. These are nerve endings sensitive to
  touch.

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4. Lower Region of the Dermis
Dermis cont.

• a. Consists of dense, irregular connective tissue
  containing collagen and elastic fibers, adipose
  tissue, hair follicles, nerves, oil glands, and
  the ducts of sweat glands.
• b. These fibers give skin its strength!
• Extensibility ability to stretch (ex.
  Neck, Elbow chickenskin!)
• Elasticity the ability to return to its
  original shape after extension or contraction
  (ex. Pregnancy, Tissue swelling)
• c. Lamellated Corpuscles a subcutaneous layer
  that is sensitive to pressure

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Skin Color and Pigmentation
A. Pigments

• 1. Melanin pigment in the epidermis
• 2. Carotene pigment in the dermis
• 3. Hemoglobin pigment in the RBCs ( passes
  thru capillaries in the dermis)

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Albinisim the inability to produce melanocytes

• 1. Inherited through parents via an altered copy
  of genes that does not allow the body to make the
  usual amount of a pigment called melanin.
• 2. Melanin is a dark compound that is called a
  photoprotective pigment.
• 3. Major role of melanin is to absorb the UV
  light that comes from the sun so that the skin is
  not damaged.
• (see diagram 6 and 7 for inheritance)

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Albinism (cont.)

• 4. Common eye problems resulting from albinism
• a. Nystagmus an involuntary movement of the
  eyes back and forth (stand up and spin, then
  watch eyes. diagram 1)
• b. Photophobia - sensitivity to light but, it
  does not limit albinos from going out into the
  sunlight!
• c. Strabismus the eyes do not fixate and
  track together, but they do have some depth
  perception
• d. Iris color usually blue/gray or light
  brown. The reddish reflection comes from the
  retinaon the inside of the eye. (diagram 1).
• e. Unusual patterns of sending nerve signals
  from the eye to the brain (diagram 3)

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Malignant Melanoma

• 1. Melano dark colored oma tumor
• 2. Cancer of the Melanocytes
• 3. Due to the repeated exposure of ultraviolet
  radiation amount of darkness of melanin
  increases. Tanning Beds () Stupid Idea!!!

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Accessory Organs of the Skin develop from the
embryo of the developing fetus.

• Hair Protect the body
• Glands help regulate the body
• Nails protect the body

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Hair

• 1. Primary function is protection, guards the
  scalp from injury and the suns rays.
• a. Eyebrows and Eyelashes protect the eyes from
  foreign particles.
• b. Nostril hair protects against inhaling
  insects and foreign particles.

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Hair - Composition

• Hair is Keratinized cells, that consist of a
  shaft and a root.
• a. SHAFT projects above the surface of the
  skin.
• b. ROOT below the surface that penetrates into
  the dermis and into the subcutaneous layer.
• c. HAIR FOLLICLE composed of two layers of
  epidermal cells
• External and Internal root sheaths surrounded
  by a connective tissue sheath.

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Anatomy of the Hair Follicle
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More Hair Composition!!!

• d. BULB onion shaped structure, contains
  papilla of the hair, which have many blood
  vessels and provide nourishment for the hair.
• e. MATRIX included in the bulb, produces new
  hairs by cell division when older hairs are shed.

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Growth cycles of the hair.

• a. GROWTH STAGE
• Cells of matrix differentiate
  Keratinization Death
• New cells are added at base of root making the
  hair grow longer.
• b. RESTING STAGE
• Growth of the hair stops, innactive matrix and
  shortening of hair follicle.
• c. NEW GROWTH CYCLE
• New hair replaces old hair and old hair is
  pushed out of the growth cycle.

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Thought you were done..Nope!

• Melanin hair color is due to melanin (brown,
  black, blonde). FYI decreased melanin
  production and increased air in the hair shaft
  produces grey and white hairs.
• Canadian Goosebumps! due to the contraction
  of the arrector pili, under stresses of froght
  and cold which pull hairs into a verticle
  position.

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Glands

• 1. Sebaceous Oil Glands secreting portion lies
  in the dermis and open into the necks of hair
  follicles or directly onto a skin surface.
• no sebaceous glands on the palms or soles
• a. Sebum oily secretion that .
• - Keeps hair from drying out
• - Prevents excessive evaporation of water from
  skin
• - Keeps skin soft
• - Inhibits the growth of certain bacteria

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Glands Again!

• BLACKHEADS accumulated sebum and enlargement of
  sebaceous glands in face.
• PIMPLES sebum acts as a nutrient to bacteria
  thats why you get the yucky puss out of them!

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Glands almost.

• 2. Sudoriferous (Sweat) Glands Two types
• a. APOCRINE SWEAT GLANDS
• a. armpit, pubic region, and areolae of
  breasts.
• b. produce sticky viscous secretion
• b. ECCRINE SWEAT GLANDS more watery secretion
  during emotional stress or cold sweat.
• a. not found in lips, nail beds, labia minora,
  glans penis, and eardrums.
• b. Palms and soles!!

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Bad Odor (BO)

• Perspiration or Sweat (comes from the eccrine)
  functions to.
• - Help regulate body temperature
• - Elimination of wastes
• Antiperspirants v.s. Deodorants

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The Last of the Sweat Glands

• 3. Ceruminous Glands located in the outer ear
  canal.
• a. EAR WAX cerumen (cera wax)
• a combination of ceruminous secretions and
  sebaceous glands
• b. HAIRS EAR WAX provide a sticky barrier
  against foreign bodies.

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Nails

• 1. Structure - Plates of tightly packed,
  keratinized cells of the epidermis.
• a. NAIL BODY visible portion of nail (PINK
  PART)
• b. FREE EDGE part that extends past the end of
  the finger or toe.
• c. NAIL ROOT non-visible portion
• d. LUNULA thickened, whitish semilunar area
• Near the nail root and cuticle

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2. Growth of the nails

• a. Occurs by transformation of superficial cells
  of the nail matrix into nail cells.
• b. Growth slower in toenail.
• c. The longer the digit the faster the nail grows
• d. The more the had used, the faster the hand
  nail growth.
• e. Nails help us grasp and manipulate objects and
  provide a protection against damage to the
  fingertips.

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Integumentary System Over!!!!