Integumentary system

Question 1

stratum corneum

Answer 1

• 25-30 dead layers of variable thickness
• filled with keratin
• surrounded by lipids
• contains lamellar granules: make water repellant

Question 2

stratum lucidum

Answer 2

• only in the palms of the hands, fingertips and soles of the feet
• 3-5 layers
• appears clear/dead

Question 3

stratum granulosum

Answer 3

• 3-5 layers of dying cells
• lamellar bodies release hydrophobic lipids

Question 4

stratum spinous

Answer 4

• contribute to length and flexibility
• 8-10 layers
• held together by desmosomes: keratin adhesion proteins

Question 5

stratum basale

Answer 5

• also called stratum germinativum
• deepest layer
• contains Merkel cells, melanocytes and stem cells that divide to produce keratinocytes
• attached by the basement membrane

Question 6

keratinocytes

Answer 6

• produce keratin: waterproofs the skin
• as they are pushed up, they accumulate keratin and die, losing their organelles along the way
• keratin is the most abundant protein in the epidermis

Question 7

melanocytes

Answer 7

• found in the stratum basale
• transfer skin pigment melanin to keratinocytes

Question 8

langerhans cells

Answer 8

• found within the stratum spinosum
• interact with helper T cells of the immune system

Question 9

Merkel cells

Answer 9

• found within the stratum basale
• attach to sensory neurons and function in touch sensation

Question 10

sebaceous glands

Answer 10

• oil glands
• glands connected to hair follicles
• absent in palms and soles
• secrete sebum (oil)
• keep skin acidic to discourage microbial growth
• acne is caused by the clogging of these glands

Question 11

sudoriferous glands

Answer 11

• sweat glands
• 2 types: eccrine and apocrine

Question 12

eccrine glands

Answer 12

• type of sudoriferous sweat gland
• most of the body
• regulate temperature through perspiration
• eliminate urea
• open directly to skin

watery sweat

Question 13

apocrine glands

Answer 13

• type of sudoriferous sweat gland
• found in arm pits, pubic region, and nipples
• secretions are more viscous
• open to hair follicles

stinky sweat

Question 14

ceruminous glands

Answer 14

• wax glands
• found in the ear canal
• produce wax-like material that act as a barrier to entrance

Question 15

mammary glands

Answer 15

• milk glands
• secrete milk for breastfeeding