Integumentary System Flashcards
What is the integumentary system?
Skin (integument) and its accessory
structures
What is dermatology?
Study of the skin
What are the functions of skin?
- Protection
- Body temperature regulation
- Excretion and absorption
- Cutaneous sensation
- Vitamin-D synthesis
- Blood reservoir
How does skin protect us?
• Acts as a physical, chemical, and biological barrier Protects against: • Mechanical damage • Chemical damage • Bacterial damage • Desiccation – keeps water in
Nervous system responds to
high body temperature by?
• Activating sweat glands
• Relaxing blood vessels and increasing blood flow into
capillary beds
Low body temperature is
corrected by?
• Constricting blood vessels
• Reducing blood flow into
capillary beds
What is sweat made up of?
• Mostly water • Some salts (electrolytes) • Vitamin C • Metabolic wastes (Urea, uric acid, ammonia, and lactic acid)
What does the low PH of sweat inhibit?
Bacterial growth
What are some good things that the skin absorbs?
Vitamins A,D,E and K
What are some bad things the skin can absorb?
Lead, mercury, poison ivy/oak
What is vitamin-D synthesis?
Modified cholesterol molecules
in the skin are converted into
vitamin D by sunlight.
What is vitamin-D necessary for?
Calcium absorption and play vital role in immune system.
What do free nerve endings detect in the integumentary system?
Pain and temperature
What do meissner’s corpuscles detect in the integumentary system?
Light touch
What do Pacinian corpuscles detect in the integumentary system?
Deep pressure
8-10% of total blood flow comes from where?
The Dermis
Along with sweating what other skin
response assists with thermoregulation?
a. Blood vessels near the skin can dilate, increasing blood flow and
heat loss
b. Additional secretion of sebum coats the skin and protects it against
the sun
c. Apocrine sweat glands add their sweat to eccrine glands to increase
evaporative cooling
d. As a response to cold, blood vessels dilate to bring more warmth to
the skin’s surface
a. Blood vessels near the skin can dilate, increasing blood flow and
heat loss
Which feature(s) of the skin
protect(s) us against microbes such
as bacteria?
a. The many layers of keratinized cells form a barrier against microbes
b. Sebum contains compounds which kill bacteria
c. Sweat has an acidic pH which suppresses microbial growth
d. Intraepidermal macrophages can alert the immune system should
microbes invade
e. All of these are correct
e. All of these are correct
What is the superficial epithelial layer of the integumentary system?
Epidermis
What is the deep connective tissue layer of the integumentary system?
Dermis
What is the subcutaneous tissue; connective tissue, mostly fat of the integumentary system?
Hypodermis
What are the four cell types of the epidermis?
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells (discs)
• Most abundant cell type (90%)
• Produce Keratin: fibrous protein that helps
give the epidermis it’s protective properties
• Protects against heat, microbes and
chemicals
• Produce lamellar granules: make skin
“water-proof”
• Undergo continuous mitosis - as they divide they are pushed up towards the surface of the skin
Keratinocytes
• Produce melanin: dark pigment • Found in stratum basale • Have long arm-like processes that project into neighboring keratinocytes • Produce melanin and send it to keratinocytes
Melanocytes
What does melanin do?
Melanin is used to protect the cell’s DNA from UV light and gives skin color.
- Macrophages
- Produced in red bone marrow
- Have long arm like processes
- Roam around epidermis looking for and phagocytizing foreign substances
Langerhans Cells
• Least numerous of the epidermal cells • Present at the epidermal/dermal junction • Associated with a disc-like sensory nerve ending – merkel disc • Functions as a sensory receptor for light touch
Merkel Cells
What is the outermost epidermal layer derived from?
Ectoderm
What are the 5 layers of the epidermis from superficial to deep?
- Stratus corneum
- Stratus lucidum
- Stratus granulosum
- Stratus spinosum
- Stratus basale
• Deepest layer • Cuboidal keratinocytes – mitotically active • Contain tonofilaments – form keratin • Melanocytes • Some merkel cells
Stratum basale
- Prickly layer
- 8-10- layers of keratinocytes
- Melanin granules
- Langerhan’s and some merkel cells
Stratum spinosum
• 3-5 layers of flattened dying keratinocytes • Cell death and keratinization begin • Tonofiliments become converted to keratin - keratohyalin • Lamellated granules accumulate
Stratum granulosum
• clear layer
• 2-3 rows of clear flattened
dead keratinocytes
• Only present in thick skin
Stratum Lucidum
• 20-30 cell layers of dead cells • Keratinocytes = corneocytes • Cells slough • Keratin is protective – protects against abrasion and penetration and waterproofs the skin • Average person sheds 40lbs of skin “flakes” in a lifetime
Stratum corneum
• Connective tissue layer deep to epidermis • Derived from mesoderm • Rich nerve and blood supply • Contains hair follicles, sweat glands, sebaceous glands, sensory receptors
The Dermis
• Thin, superficial layer • Areolar connective tissue - Loose tissue so macrophages roam • Dermal Papillae • Contains capillaries, free nerve endings, and meissner's corpuscles
Papillary Layer
What are the two layers of the dermis?
- Papillary layer
2. Reticular layer
• Thick, deeper layer • Dense irregular connective tissue • Contains cutaneous plexus, sweat and sebaceous glands hair follicles, pacinian corpuscles, arrector pili muscles
Reticular layer
The dermis is derived from what germ layer? a. Ectoderm b. Endoderm c. Mesoderm
c. Mesoderm