Integumentary System

Question 1

What are the functions of integument?

Answer 1

• protection (keratinized stratified squamous epithelium)
• excretion of salt, water, and organic wastes (sudoriferous glands -sweat glands)
• systhesis of vitamin D3 for Ca absorption (skin cells)
• detection of touch, pressure, pain, and temperature (nerve endings)

Question 2

What is the S&F of the epidermis?

Answer 2

• tissue: keratinized stratified squamous epithelium
• cell division and renewal because its the deepest layer closest to capillaries and nutrients
• new cells push older cells to surface where they shed

Question 3

What is the most common cell type in the skin?

Answer 3

-keratinocytes

Question 4

How many days does it take from division to shedding?

Answer 4

• 30-56 days

- varies in age and response to injury

Question 5

What are the characteristics of epidermis in thin skin?

Answer 5

• thin stratum corneum, few layers of ells
• 4 sublayers
• 20-30 layers of cells

Question 6

What are the characteristics of epidermis in thick skin?

Answer 6

• think stratum corneum (many layers of dead cells)
• 4 sublayers and stratum lucdium
• 30-60 layers of cells

Question 7

Name the layers in thin skin

Answer 7

Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale

Question 8

Name the layers in thick skin

Answer 8

Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale

Question 9

What is the S&F of the stratum corneum?

Answer 9

• 15-30 layers of dead keratinized cells
• connected by desmosomes, tight junctions
• shed ofter approx. every 2 weeks
• water resistant but NOT water proof

Question 10

What is the S&F of the stratum lucidum?

Answer 10

• only in think skin (fingertips, palms, soles)

- clear layer of flattened, densely packed keratinized cells

Question 11

What is the S&F of the stratum granulosum?

Answer 11

• 3-5 layers of keratinocytes
• make strong fibrous keratin protein = fills and flattens cells
• nuclei and organelles degenerate
• cells have granules that release lipids onto the surface, blocking water and preventing dehydration
• cells above lipid barrier are dying, dead

Question 12

What is the S&F of the stratum spinosum?

Answer 12

• 5-10 layers of living, dividing keratinocytes
• produce vitamin D in response to UV –> vitamin D required for Ca absorption in intestine
• dendritic cells

Question 13

What is the S&F of the stratum basale?

Answer 13

-one layer of cells attached to the basement membrane
-closest to diffusing nutrients
basal (stem) cells divide to replenish keratinocytes
-Markel cells
-Melanocytes

Question 14

What are Markel cells?

Answer 14

• touch receptors

- stimulate nerve endings

Question 15

What are dendritic cells?

Answer 15

-patrol and defend pathogens eg. skin cancer

Question 16

What are melanocytes?

Answer 16

• turn amino acid tyrosine into melanin pigment –> protects against UV
• packed into vesicles = melanosomes
• melanosomes transferred to keratinocytes
• keratinocytes pigmented until melanosomes fuses with lysosome

Question 17

What is skin colour?

Answer 17

-depends on number, size, and distribution of melanosomes, and type of melanin pigment

Question 18

What is the papillary layer?

Answer 18

• the top 20% of the dermis
• aereolar connective tissue
• contains: capillaries, sensory neurons, Meissener’s corpuscle, dendritic cells and other WBC
• dermal papillae

Question 19

What is dermal papillae and how do they create fingerprints?

Answer 19

• in papillary layer of dermis
• increase SA in contact with epidermis
• in thick skin dermal papillae lie on top of mounds called “dermal ridges”
• dermal ridges cause epidermis to form epidermal ridges
• epidermal ridges with sweat pores cause fingerprint
• fingerprint ridges increase friction/grip

Question 20

What is the reticular layer?

Answer 20

• bottom 80% of the dermis
• dense irregular connective tissue
• fills space, provides strength and resiliency
• accessory organs: blood, lymph vessels, nerve fibres
• collagen extends into papillary and subcutaneous layers to anchor

Question 21

What is the hypodermis?

Answer 21

• subcutaneous layer=superficial fascia

- not part of the integument

Question 22

What two tissues make up the hypodermis?

Answer 22

• aereolar connective tissue: stabilizes, binds skin to underlying muscle
• adipose tissue: insulates, stores energy

Question 23

What layer do drug users inject into?

Answer 23

• hypodermis
• arteries, veins act as blood reservoir
• subcutaneous injections allow drugs to enter blood stream

Question 24

What are the accessory organs of the integumentary system?

Answer 24

-hair, sebaceous glands, sudoriferous glands, Meissner’s corpuscle, Lamellated corpuscle, ceruminous glands, mammary glands, nails

Question 25

What are the three types of hair on our bodies?

Answer 25

1) lanugo: fine, unpigmented hair covering fetus in 3rd trimester 2) vellus: fine, unpigmented hairs on newborns, kids body hair, 2/3 of female body hair, 1/10 male body hair 3) terminal hair - long, course, pigmented on scalp, eyebrows, eyelashes, body hair post puberty

Question 26

What are sebaceous glands?

Answer 26

- oil glands! - holocrine, simple branched alveolar - arrector pili muscle - secrete sebum

Question 27

What is the function of sebum?

Answer 27

- lubricates and protects the keratin - conditions hair and skin - inhibits bacterial growth * *activated during puberty

Question 28

What is the arrector pili muscle?

Answer 28

-contractions erects hair and squeezes waxy oil (sebum) onto hair follicle

Question 29

What are the two kinds of suderiferous glands?

Answer 29

- merocrine sweat gland | - apocrine sweat gland

Question 30

What are merocrine sweat glands?

Answer 30

- small - watery - secrete onto skin

Question 31

What are aprocrine sweat glands?

Answer 31

- big - milky - onto hair follicle

Question 32

What is perspiration?

Answer 32

- when you may not feel like you are sweaty | - 500mL

Question 33

What is diaphoresis?

Answer 33

-noticeably sweaty up to 1L/hour

Question 34

What is the S&F of sweat?

Answer 34

- 99% water - electrolytes (sodium, chloride) - waste products - antibacterial proteins 4-6 pH - reduces body temp. - reduces bacteria growth

Question 35

What is Meissner's corpuscle?

Answer 35

- located in papillary layer of dermis | - nerve ending wrapped in a bit of connective tissue detects light touch

Question 36

What is the Lamellated corpuscle?

Answer 36

- located in reticular layer of dermis | - nerve endings wrapped in many layers of connective tissue detect deep pressure, vibrations

Question 37

What are ceruminous glands?

Answer 37

- modified sweat glands in ear passageway - secretion and sebum = cerumen = earwax - traps: particles/debris, reduce bacteria growth, moisturize eardrum

Question 38

What are mammary glands?

Answer 38

- shedding the apical layer - apocrine secretion (only one) - secretes milk

Question 39

What is the nail plate?

Answer 39

- iron deficiency causes flat or concave nails | - long term hypoxia eg. congenital heart defects causes clubbing of nails

Question 40

What is the free edge of the nail?

Answer 40

- expands beyond the end of your finger | - scrub well, under to remove dirt and pathogens

Question 41

What is the nail groove?

Answer 41

-groove where nails fold meets nail plate | -

Question 42

What is the nail root?

Answer 42

-located deep and proximal to eponychium cell division and nail growth occurs here

Question 43

What is the eponychium of the nail?

Answer 43

-cuticle