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Lab _11

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									     Lab #7

Integumentary System
Overview of the Integumentary
           System
Organization of the Epidermis:




                            Figure 5–2
Layers of the epidermis are
    known as “strata”
      Layers of the Epidermis
Top: Free surface of skin
  - stratum corneum
  - stratum lucidum
  - stratum granulosum
  - stratum spinosum
  - stratum germinativum
Bottom: Basal lamina
       A note on thick vs. thin skin
• Thick skin has an
  extra layer (lucidum)
  but that is NOT the
  reason that it is thicker
  than thin skin.
• Real reason is the
  other layers are
  thicker in thick skin
  than in thin skin.
                The Dermis
• Deeper part of cutaneous layer
• Located between epidermis and
  subcutaneous layer
• Anchors epidermal accessory structures
  (hair follicles, sweat glands)
• Has 2 components:
  – outer papillary layer
  – deep reticular layer
        The Papillary Layer
• Consists of areolar tissue
• Contains smaller capillaries, lymphatic
  vessels, and sensory neurons
• Has dermal papillae projecting between
  epidermal ridges
        The Reticular Layer
• Consists of dense irregular connective
  tissue
• Contains larger blood vessels, lymph
  vessels, and nerve fibers
• Contains collagen and elastic fibers
           Integumentary
        Accessory Structures
• Hair, hair follicles, sebaceous (oil) glands,
  sweat glands, and nails:
  – are derived from embryonic epidermis
  – are located in dermis
  – project through the skin surface
          The Hair Follicle
• Is located deep in dermis
• Is made of epidermal tissue (with
  connective tissue around the outside)
• Produces nonliving hairs
• Is wrapped in a dense connective-tissue
  sheath
• Base is surrounded by sensory nerves
Hair
Structures of Hair and Follicles




                             Figure 5–9a
   Accessory Structures of Hair
• Arrector pili:
  – involuntary smooth muscle
  – causes hairs to stand up
  – produces “goose bumps”
• Sebaceous glands:
  – lubricate the hair
  – control bacteria
Inside the
Follicle




             Figure 5–9b
   Exocrine Glands in the skin
• Sebaceous glands and follicles (oil
  glands):
  – holocrine glands
  – secrete sebum
• Sweat glands:
  – merocrine glands
  – watery secretions
  Types of Sebaceous Glands
• Sebaceous glands:
  – associated with most hair follicles (on head
    and body)
• Sebaceous follicles:
  – discharge directly onto skin surface
  – found on face and trunk
  – when clogged  acne
Sebaceous glands
      Types of Sweat Glands
• Apocrine:
  – found in armpits, around nipples, and groin
• Merocrine:
  – more numerous, widely distributed on body
    surface
  – especially on palms and soles (thick skin)


 Both are actually merocrine
    “Apocrine” Sweat Glands
• Merocrine secretions, not apocrine
• Associated with hair follicles in groin,
  nipples, and axillae (armpits)
• Become active at puberty
• Produce sticky, cloudy secretions (thick
  sweat) that breaks down and causes odor
     Merocrine Sweat Glands
• Also called eccrine glands:
  – coiled, tubular glands
  – discharge directly onto skin surface
  – sensible perspiration for cooling (thin sweat)
  – water, salts, and organic compounds
  Sweat Glands of the Skin




                      Merocrine
Apocrine
                Epidermis
What to look for:
• Usually darkest between stratum
  germinativum and stratum granulosm
  (granulosm often a dark meandering line)
• Keratinized cells (s. corneum) often lift off
  the underlying layers
• S. germinativum along basal lamina, along
  with melanocytes
Dermis: Papillary vs. Reticular layer
            What to look for
• Papillary layer
  – has ridges
  – is areolar
  – Just under basal lamina
• Reticular layer
  – much thicker
  – Dense irregular CT
• Hypodermis
  – Loose CTP
More skin
       Merocrine sweat gland
• What to look for
  – Found in most skin
  – Coiled, tubular
  – Small lumens in cross
    section
  – Have duct that goes all
    the way to the
    epidermal surface and
    ends in sweat pore
  – Smaller than apocrine,
    don’t extend as deep
    into dermis
       Apocrine sweat gland
What to look for:
• Associated with
  hair follicle
• Only in nipples,
  groin, armpit
• Large lumens
• Deeper in dermis
  than merocrine
Apocrine sweat gland
Hair with
sebaceous
glands and
arrector pilli
                    Hair
What to look for:
• Follicles are rarely complete
• Can often see root, papilla at base of hair
• Arrector pilli muscle at an angle
• Associated glands (which are?)
Sebaceous
glands
         Sebaceous glands
What to look for:
• Associated with hair follicle
• Found most everywhere hair follicles are
  found in skin
• Look like cauliflower (maybe?)
Sebaceous follicle
         Sebaceous follicle
What to look for:
• Also look like cauliflower
• Found on face and trunk only
• NOT associated with hair follicle
• Have duct that opens onto skin surface
            Lab Activity #7
• Look at slides:
  – Axillary skin (armpit)
  – Pigmented and Nonpigmented thin skin slide
  – Scalp
   What will you find there?

                     Armpit    Scalp
– Hair?                    Y    Y
– Hair follicle?           Y    Y
– Sebaceous gland?         Y    Y
– Sebaceous follicle?      ?    N
– Apocrine sweat gland?    Y    N
– Merocrine sweat gland?   Y    Y
          Pigmented Thin Skin
• Find:
  – Epidermis
     • Identify layers, starting with germinativum
     • Find melanocytes
  – Dermis
     • Papilary and reticular CT layers
  – Hypodermis
               Axillary skin
• Locate:
  – an apocrine sweat gland.
  – a merocrine sweat gland
  – also look for a sebaceous follicle (not
   associated with a hair)
  Turn in one drawing page with…
• Three types of glands (one sebaceous, a
  merocrine sweat gland and an apocrine
  sweat gland)
• Epidermis (label the four layers)
• Dermis (label papillary and reticular)
• Hair follicles and shaft (label follicle,
  sebaceous gland, arrector pilli muscle if
  seen)
              Assignment
• For Next Thursday turn in:
  – Your drawing
  – Review Sheet #7 (you do not have to do the
    parts about plotting sweat glands and
    fingerprinting on page 104)

								
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