Integumentary System

Question 1

Functions of the Integumentary system

Answer 1

Protection (proteins, lipids, glandular secretions, melanin pigment), blood reservoir (specifically dermis), thermoregulation (sweat, vasoconstriction/vasodilation, adipose in hypodermis), Cutaneous sensation, Excretion/secretion and absorption (sweat, oil, vitamin D synthesis)

Question 2

Composition of Integumentary system

Answer 2

3 layers (epidermis, dermis, and subcutaneous layer). Layers include sweat and oil glands, hair follicles, hair root, and adipose

Question 3

Layers of Epidermis (from superficial to deep)

Answer 3

Corneum, Lucidum (only present in thick skin), Ganulosum, Spinosum, Basale. (Come, Let’s Get Sun-Burned)

Question 4

Stratum Basale

Answer 4

single layer of round/alive cells, multiple types of cells. creates new cells that move superficially

Question 5

Stratum Spinosum

Answer 5

Numerous layers of keratinocytes, some retain ability to divide

Question 6

Stratum granulosum

Answer 6

transition layer –> some cells are alive, some are undergoing apoptosis

Question 7

Stratum Lucidum

Answer 7

thick skin only, ~3-5 cell layers thick, composed of dead keratinocytes

Question 8

Stratum Corneum

Answer 8

Variably thick layer of dead, flattened keratinocytes

Question 9

Psoriasis

Answer 9

a chronic skin disorder where keratinocytes divide and are produced more quickly and move up superficially faster than in a typical individual. This forms plaque which will appear white and scaly and there can be redness and inflammation.

Question 10

What type of tissue makes up the epidermis?

Answer 10

keratinized stratified squamous epithelial tissue

Question 11

Types of cells in epidermis

Answer 11

Mostly keratinocytes (produce keratin and lamellar granules), also include melanocytes, Langerhans cells, and Merkel cells

Question 12

Melanocytes

Answer 12

produce melanin, and have extensions that go between keratinocytes allowing melanin to move into those cells.

Question 13

Langerhans cells

Answer 13

very large cells that engulf/ingest microbes from within the epidermis. (part of immune response)

Question 14

Merkel cells

Answer 14

a touch receptor important from fine touch (texture/shape)

Question 15

Dermis

Answer 15

Middle layer of skin, includes mostly fibroblasts (create collagen) but also macrophages (engulf microbes) and adipocytes (fat cells).

Question 16

2 divisions of dermis

Answer 16

Papillary region: (~20%) projects into epidermis (creates fingerprints)
Reticular region: (~80%) lower region and contains most components of dermis ( such as muscle, glands, corpuscle, etc) and collagen and elastic fibers are organized into lines of cleavage (tension lines)

Question 17

Lines of Cleavage (Tension Lines)

Answer 17

the collagen and elastic fibers of the dermis are organized into lines. These lines play a big role in how wounds heal. (parallel injuries have a better chance of healing with only a fine scar)

Question 18

Hypodermis (subcutaneous layer)

Answer 18

Deepest layer of skin(although not a part of skin proper), contains mostly adipose, is well vascularized, and is important for thermoregulation and energy storage

Question 19

Melanin Production

Answer 19

produced by melanocytes in stratum basale, where it moves through extensions to protect the nuclei and DNA or keratinocytes. Synthesized from tyrosine.

Question 20

Melanin function

Answer 20

absorbs UV radiation, prevents damage to DNA in keratinocytes, neutralizes free radicals (cancer-causing agents). Affects skin, hair, and iris color

Question 21

Melanin clinical considerations

Answer 21

Sunburn (when amount of UV surpasses amount of melanin produced), freckles (accumulation of melanin), moles (accumulations of molanasides), skin cancer (basal cell carcinoma - ~78% starts in stratum basale and less serious, squamous cell carcinoma - ~20% originates in stratum spinosum and intermediate seriousness, malignant melanoma - ~20% originate in melanocytes will spread and highest mortality.

Question 22

Gland

Answer 22

Epithelial tissue that secretes something, can be endocrine (releases secretion within body) or exocrine (released onto a surface (skin or oral cavity))

Question 23

Sebaceous gland

Answer 23

releases oil(sebum), typically associated with hair follicle. during puberty they become larger and secrete more, infections lead to acne

Question 24

Sudoriferous glands

Answer 24

releases sweat. most common: eccrine (important for thermoregulation). Also can be apocrine which is sweat in armpit, beard, and external genitalia, has an odor, and secretes during sexual excitement and nervousness.