Chapter 5 Integumentary

Question 1

Functions of the integumentary system

Answer 1

Regulate body temperature
Store blood
Protection from external environment
Detect cutaneous sensations
Excrete and absorb substances
Synthesize vitamin D

Question 2

Epidermis

Answer 2

Composed of epithelial tissue. Superficial, thinner portion of the skin. Avascular.

Question 3

Dermis

Answer 3

Deeper, thicker connective tissue portion of skin. Vascular.

Question 4

Subcutaneous tissue

Answer 4

Consists of areolar and adipose tissue. Anchors fibres from the dermis.

Question 5

Keratinocytes

Answer 5

85% of epidermal cells, which are arranged in four or five layers and produce the protein keratin. Also produce lamellar granules, which release water repellent sealant.

Question 6

Melanocytes

Answer 6

8% of epidermal cells. Produce the pigment melanin.

Question 7

Melanin

Answer 7

Yellow-red or brown-black pigment which contributes to skin colour and absorbs UV light. Melanin granules protect keratinocytes from UV.

Question 8

Dendritic cells

Answer 8

Langerhans cells. Originate in red bone marrow. 5% of epidermal cells. Participate in immune response.

Question 9

Tactile epithelial cells

Answer 9

Merkel cells. 2% of epidermal cells. Located in deepest layer of epidermis. Make contact with non encapsulated (merkel disc) corpuscle.

Question 10

4 layers of thin skin epidermis

Answer 10

Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum

Question 11

Thick skin epidermis layers

Answer 11

Stratum basale
Stratum spinosum
Stratum granulosum
Stratus lucidum
Stratus corneum

Question 12

Stratum basale

Answer 12

Deepest layer. Single row of cuboidal or columnar keratinocytes. Some cells in this layer are epidermal stem cells.

Question 13

Stratum spinosum

Answer 13

Superficial to stratum basale. Consists of numerous keratinocytes in 8-10 layers. Produces coarser bundles of keratin than basal layer.

Question 14

Stratum granulosum

Answer 14

Mid epidermis. 3-5 layers of flattened keratinocytes undergoing apoptosis. Presence of keratohyalin. Lamellar granules present. Marks transition state between metabolically active strata and dead superficial strata.

Question 15

Stratum lucidum

Answer 15

4-6 layers of flattened dead keratinocytes. Can contain large amounts of keratin and thickened plasma membranes.

Question 16

Stratum corneum

Answer 16

25-30 (sometimes 50) layers of flattened dead keratinocytes. Cells overlap one another in a layer.

Question 17

Keratinization

Answer 17

Cells being pushed from one epidermal layer to the next, accumulating more keratin.

Question 18

Papillary dermis

Answer 18

Superficial. 1/5 the thickness of dermis. Contains collagen and elastic fibres. Surface area increased by dermal papillae, which contain capillary loops, free nerves, or meissner corpuscles.

Question 19

Reticular dermis

Answer 19

Deeper part. Attached to subQ tissue. Contains collagen, fibroblasts, macrophages, some adipocytes.

Question 20

Hair

Answer 20

Composed of columns of dead, keratinized epidermal cells.

Question 21

Types of hairs

Answer 21

Lanugo: fine, downy hairs
Terminal: coarse, heavily pigmented
Vellus: peach fuzz

Question 22

Sebaceous glands

Answer 22

Branched acinar glands usually connected to hair follicles. Secretes an oily protective substance called sebum.

Question 23

Sudoriferous glands

Answer 23

Sweat glands. Divided into eccrine and apocrine based on structure and type of secretion.

Question 24

Eccrine sweat glands

Answer 24

Simple coiled tubular. Distributed through most of the body. Main function is help regulate temperature. Also helps eliminate waste. Also release sweat in response to stress.

Question 25

Apocrine sweat glands

Answer 25

Coiled tubular gland with larger duct and lumen than eccrine. Mainly in axilla, groin, breasts, bearded region. Sweat Appears milky or yellowish. Does not play a role in thermoregulation.

Question 26

Ceruminous glands

Answer 26

Modified glands in the ear. Produce cerumen (ear wax).

Question 27

Nails

Answer 27

Tightly packed hard, dead keratinized epidermal cells.

Question 28

Components of nails proximal to distal

Answer 28

Root
Eponychium
Lunule
Nail bed
Nail plate
Hyponychium
Free edge.