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Integument
Skin
39
Anatomy
Undergraduate 2
02/04/2013

Additional Anatomy Flashcards

 


 

Cards

Term
Skin's two regions
Definition

Epidermis - outermost superficial region (thin)

Dermis- middle region (leathery, fibrous connective tissue)

Term
hypodermis
Definition
superficial fascia (deepest region)
Term
epidermis composed of
Definition
keratinized squamous epithelium consisting of four distinct cell types & four or five layers
Term
Intermediate Filaments
Definition

tough, insoluble proteins

stable & permanent

form internal structure (keratin in epithelials)

look like ropes with tensile

diameter between MF & MT

Term
Keratinocytes
Definition
  • produce the fibrous protein keratin
Term
  • Melanocytes
Definition
  • produce the brown pigment melanin
    • Bound into granules called melanosomes
    • Transported to keratinocytes
    • Accumulate on the “sunny” side of the nucleus
    • Makes a pigment shield protecting the nucleus
Term
  • Langerhans’ cells
Definition
  • epidermal macrophages that help activate the immune system
    • “Epidermal dendritic cells” (not neurons, dumb name cause it makes you think of neurons but they are not.  They have a lot of branches.  Should have been called “Double Tree”, or, “Weeping Willow”)
    • Phagocytes, activate the immune system
    • Lots of ‘em, form a network.
Term
  • Merkel cells
Definition
  • function as touch receptors in association with sensory nerve endings
    • Cell plus nerve ending = Merkel Disc
Term
  • Keratinocytes 
Definition
  • produce the fibrous protein keratin
Term
Keratinocytes
Definition
  •  produce the fibrous protein keratin
  • Millions rub off daily – new skin every 45 days
  • House dust is mostly you floating around
Term

Stratum Basale 

Definition
  • Deepest epidermal layer firmly attached to the dermis
  • Consists of a single row of the youngest keratinocytes
  • Cells undergo rapid division, hence its alternate name, stratum germinativum
Term

Stratum Spinosum 

Definition
  • Cells contain a weblike system of intermediate filaments attached to desmosomes
  • Melanin granules and Langerhans’ cells are abundant in this layer
Term

Layers of the Epidermis: Stratum Granulosum
(Granular Layer)

Definition
  • Thin; three to five cell layers in which drastic changes in keratinocyte appearance occurs                                         
  • Keratohyaline and lamellated granules accumulate in the cells of this layer
Term

Stratum Lucidum
(Clear Layer)

Definition
  • Thin, transparent band superficial to the stratum granulosum
  • Consists of a few rows of flat, dead keratinocytes
  • Visible only in thick skin
Term

Layers of the Epidermis: Stratum Corneum
(Horny Layer)

Definition
  • Outermost layer of keratinized cells
  • Accounts for three quarters of the epidermal thickness
  • Functions include:
  • Waterproofing – glycolipids between cells
  • Protection from abrasion and penetration - keratin
  • Rendering the body relatively insensitive to biological, chemical, and physical assaults
Term

Dermis

Definition
  • Second major skin region containing strong, flexible connective tissue
  • Cell types include fibroblasts, macrophages, and occasionally mast cells and white blood cells
  • If skinned and tanned = leather
    • Composed of two layers – papillary and reticular
Term

Layers of the Dermis: Papillary Layer

Definition
  • Papillary layer
  • Areolar connective tissue with collagen and elastic fibers
  • Its superficial surface contains peglike projections called dermal papillae
  • Dermal papillae contain capillary loops, Meissner’s corpuscles, and free nerve endings
  • In fingers and feet, on top of “dermal ridges” they form epidermal ridges = fingerprints
    • Epidermal ridges on top of dermal papillae or dermal ridges in fingers and feet plus a little sweat oil = fingerprints
Term

Layers of the Dermis: Reticular Layer

Definition
  • Reticular layer
  • Accounts for approximately 80% of the thickness of the skin
  • Collagen fibers in this layer add strength and resiliency to the skin
  • Elastin fibers provide stretch-recoil properties
Term

Hypodermis

Definition
  • Subcutaneous layer deep to the skin
  • Composed of adipose and areolar connective tissue
Term

Three pigments that contribute to skin color

Definition
  • Melanin 
  • Carotene
  • Hemoglobin
Term
  • Melanin
Definition
  • yellow to reddish-brown to black pigment, responsible for dark skin colors
Term
  • Freckles and pigmented moles 
Definition
  • result from local accumulations of melanin
Term
  • Carotene 
Definition
  • yellow to orange pigment, most obvious in the palms and soles of the feet
Term
  • Hemoglobin
Definition
  • reddish pigment responsible for the pinkish hue of the skin
Term

Skin appendages

Definition
  • Sweat Glands
  • Sebaceous Glands, (Oil)
  • Hairs and hair follicles
  • Nails
Term

Sweat (sudoriferous) Glands

Definition
  • Different types 
  • 1) prevent overheating of the body 
  • 2) secrete cerumen 
  • 3) secrete milk
  • Up to 3 million glands per person
Term
  • Eccrine sweat glands
Definition
  • found mostly in palms, soles of the feet, and forehead but really are everywhere.
  • 99% water, some salts (NaCl), vit C, antibodies, and dermicidin (a microbicide) (What the heck is a microbicide?), some wastes
Term
  • Apocrine sweat glands – 
Definition

found mostly in axillary and anogenital areas and wherever there is body hair


  • Same content as eccrine + fats and proteins
  • Odorless, but smell when decomposed by bacteria
  • Empty onto hair follicles
  • Could be human equivalent of animal sexual scent glands
Term
  • Ceruminous glands
Definition
  • modified apocrine glands 
  • One place, or, rather, two places, each ear canal
  • Secrete cerumen
Term
  • Mammary glands
Definition
  •  specialized sweat glands that secrete milk
Term

Sebaceous Glands

Definition
  • Found all over the body
  • Holocrine type (cells fill up and burst)
  • Soften skin when stimulated by hormones
  • Become active at puberty
  • Secrete an oily secretion called sebum
Term

Hair

Definition
  • Cover entire body surface EXCEPT
  • Palms, soles, lips, nipples and some external genitalia
  • Not much use, now, mostly decorative
    • Dead, keratinized cells
    • Harder keratin than skin type
      • Tougher
      • Does not flake off
Term

Structure of a Nail

Definition
  • Scalelike modification of the epidermis on the distal, dorsal surface of fingers and toes
  • Corresponds to a hoof or claw
  • Useful to pick up stuff or scratch
  • Hard keratin
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