Chapter 5 Flashcards
Integumentary System
The Epidermis is made up of what?
Keratinized stratified squamous epithelium
The role of epidermis cell: Keratinocytes
produce the water-insoluble protein keratin which hardens
structures
- Approx. 90% of Epidermal cells
The role of epidermis cell: Melanocytes
- produce melanin, a brown/black pigment which absorbs UV
light and is the primary skin pigment - Approx. 8% of Epidermal cells
The role of epidermis cell: Langerhans
Langerhans cells
- produced in the bone marrow
- help provide immunity to the epidermis
The role of epidermis cell: Merkel Cell (disk)
The nerve ending for touch
Describe the deepest layer of the epidermis
- Stratum Basale
- a single layer of cuboidal-shaped cells
- mitotically active
- (5/5)
Describe the epidermis layer: Stratum Spinosum
Stratum Spinosum
- 8 to 10 cell layers thick
- cells start to flatten as they reach the upper part of this
layer
- (4/5)
Describe the second layer of the skin
Dermis
- mostly connective tissue containing collagen & elastin fibers, few cells
- Two layers
Describe the epidermis layer: Stratum Granulsum
- 3 to 5 cell layers thick
- cells continue to flatten out
- cells begin to die forming a water-resistant barrier, i.e.
keratinization - (3/5)
Describe the epidermis layer: Stratum Lucidum
- only present on the fingertips, palms, and soles of the
feet - 3 to 5 layers of cells
- (2/5)
Describe the epidermis surface
Stratum Corneum
- 20 to 30 cell layers in thickness
- flattened dead keratinocytes, no nuclei
- outer layers are continually shed needing to be replaced
- Approx. 3/4 of the epidermal thickness
Describe the layer of the dermis: Papillary region
- Dermal Papillae: tiny projections into the epidermis which increase the surface area of the Stratum Basale
- Meissner corpuscles: (corpuscles of touch) = tactile receptors
located at the apex of Dermal Papillae - Epidermal Ridges: Dermatoglyphics = Finger prints assoc. with the underlying papillae
Describe the layer of the dermis: Reticular region
- the deepest and largest portion
- contains irregular C.T
Describe the last layer of the skin
Hypodermis:
- composed of Adipose and Areolar C.T.
- stores fat
- contains vessels and nerves that supply the skin
Melanin pigmentation is….
The brown pigment produced by melanocytes, made from amino acid tyrosine
Carotene is…
the yellow-orange pigment produced by vitamin A
Hemoglobin
pink/red pigment
- the oxygen carrying molecule in RBCs
- assoc. with translucent skin (i.e. skin lacking melanin)
Hair = Pili/Pilus
- covers most skin surfaces
- columns of dead keratinized cells that are bonded together
- protects the body from heat loss and UV light
Nails
plates of tightly packed, keratinized epidermal cells
Sebaceous Glands
- secrete sebum, an oily substance that softens and lubricates the
skin, water proofing, maintains hair follicles, contains
antibacterial substances - associated with hair follicles, lips, pubic region
- not found on palms and soles
Sudoriferous (Sweat) Glands
- release secretions onto the surface of the skin
Eccrine gland
- most common
- produces watery sweat that contains ions and small organic
molecules - help regulate body temperature
- eliminate wastes
Apocrine gland
- common to axilla and groin
- watery secretion, more viscous than normal sweat, contains
proteins and lipids - secondary sexual function
Superficial
- when only the Epidermis is damaged
- the cells surrounding the wound enlarge and migrate to fill the
gap created by the injury - Contact Inhibition = migration ceases when the cells on both
sides of the wound come into contact - mitosis in the Stratum Basale is stimulated, more cells are
reproduced to make up for dead cell
Deep Wound Healing
- damage effects the Dermis
- phases:
Inflammatory Phase
- clot forms over wound
- local vasodilation, leukocytes (infection) and fibroblasts
(rebuild tissue) move into the damaged area
Migratory Phase
- scab forms
- epithelial tissue migrates beneath the scab to bridge the wound
- granulation (scar) tissue begins to be laid down beneath the scab
- vessels begin to regrow_
Proliferative Phase
- epithelial tissue begins to mature
- collagen fibers continue to be laid down randomly
Maturation Phase
- scab falls off after the epidermis is repaired
- circulation is restored
- fibroblasts decrease in number
Fibrosis
scar tissue formation. (Scar tissue is not as healthy as the
original tissue
Thermoregulation:
- Average temperature is 98.6 F (37 C)
1. Temperature change is detected by nerve endings in the skin (i.e.
Thermoceptors)
2. This information is sent to the Hypothalamus
3. Nerve signals are then sent back to the sweat glands, and the
smooth muscle in the vessels of the Integumentary System.
Ambient temperature is elevated (“This one’s too hot”).
) Perspiration increases, heat is lost by evaporation.
2) Smooth muscle in the dermal vessels relax causing there diameter
to increase. More blood can now enter these vessels. Heat
is lost to the environment by radiation.
Ambient temperature decreases (“This one is too cold”).
1) Sweat gland activity decreases. Body conserves heat.
2) Smooth muscle in dermal vessels constricts, conserving heat
