Chapter 6 Flashcards
What are the primary functions of the integumentary system?
Protection, thermoregulation, sensation, vitamin D synthesis, excretion & absorption.
What percentage of body weight does the skin make up?
About 7-8% of total body weight.
What are the three layers of the skin?
Epidermis, dermis, subcutaneous layer (hypodermis).
Which layer of skin is NOT part of the integumentary system?
The subcutaneous layer (hypodermis).
What type of tissue makes up the epidermis?
Keratinized stratified squamous epithelium.
What are the five layers of the epidermis (deep to superficial)?
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum (only in thick skin)
Stratum corneum
What is the main function of the stratum basale?
Contains stem cells that regenerate new skin cells.
What is the function of the stratum spinosum?
Provides strength and flexibility to the skin.
What happens in the stratum granulosum?
Keratinization begins – cells fill with keratin and die.
Where is the stratum lucidum found?
Only in thick skin (palms, soles of feet).
What is the function of the stratum corneum?
Protects against abrasion and water loss; made of dead keratinized cells.
What are the three main cell types in the epidermis?
Keratinocytes, melanocytes, tactile (Merkel) cells.
What is the function of keratinocytes?
Produce keratin, making the skin waterproof and strong
What do melanocytes do?
Produce melanin, protecting skin from UV damage.
What are tactile (Merkel) cells responsible for?
Detect touch and pressure.
What three factors determine skin color?
Melanin, hemoglobin, carotene.
What pigment is responsible for skin darkening and UV protection?
Melanin.
What is hemoglobin’s effect on skin color?
Gives a reddish tint due to oxygen in blood.
What is carotene, and where does it come from?
A yellow-orange pigment from foods like carrots and sweet potatoes.
What condition results from a lack of melanin?
Albinism – a genetic condition where melanocytes don’t produce melanin.
What are the two layers of the dermis?
Papillary layer and reticular layer.
What tissue type makes up the papillary layer?
Areolar connective tissue.
What structures are found in the papillary layer?
Dermal papillae, capillaries, tactile receptors.
What is the function of dermal papillae?
Increase surface area for nutrient exchange, form fingerprints.
What tissue type makes up the reticular layer?
Dense irregular connective tissue.
What structures are found in the reticular layer?
Blood vessels, sweat glands, sebaceous glands, hair follicles, sensory receptors.
What is the main function of the subcutaneous layer?
Insulation, cushioning, energy storage.
What type of tissue is found in the hypodermis?
Areolar and adipose connective tissue.
Why is the hypodermis a common site for injections?
Highly vascularized, allowing rapid drug absorption.
What are the three types of hair?
Lanugo (fetal), vellus (fine body hair), terminal (coarse, long hair).
What are the three parts of a hair?
Bulb, root, shaft.
What causes goosebumps?
Contraction of the arrector pili muscle.
What determines hair color?
Melanin production in the hair matrix.
Why does hair turn gray with age?
Decrease in melanin production.
What are nails made of?
Keratin.
What are the three parts of the nail plate?
Nail root, nail body, free edge.
What is the function of the cuticle (eponychium)?
Protects the nail root from infection.
What are the two types of sweat glands?
Merocrine (eccrine) and apocrine.
What is the function of merocrine sweat glands?
Thermoregulation – cools body by sweat evaporation.
Where are apocrine sweat glands found?
Axillary, groin, nipple, and anal regions.
What causes body odor?
Bacteria breaking down apocrine sweat.
What do sebaceous glands secrete?
Sebum (oily substance).
What is the function of sebaceous glands?
Lubricates skin and hair, prevents bacterial growth.
What is the function of ceruminous glands?
Produce earwax (cerumen).
What is the function of mammary glands?
Produce milk.
What is psoriasis?
An autoimmune disease causing overproduction of skin cells.
How does Botox reduce wrinkles?
Blocks nerve signals to facial muscles.
