2. Integumentary system

Question 1

the integumentary system consists of

Answer 1

skin
hair,nails,glands
sense receptors (nervous)
muscles

Question 2

Skin has two layers:

Answer 2

epidermis -upper layer

dermis - lower layer

Question 3

hypodermis

Answer 3

below skin

Question 4

epidermis subtype

Answer 4

stratified squamous epithelium (from ectoderm)

Question 5

is the epidermis vascular?

Answer 5

it is avascular

Question 6

the epidermis is separated into 4-5 strata (sublayers) based on cell types:

Answer 6

-stratum basale
-stratum spinosum
-statrum granulosum
-stratum lucidum
-stratum corneum
(bad students get low Cs)

Question 7

stratum basal

Answer 7

• single row of cells

- 2 cell types: keratinocytes (90%) and melanocytes (10%)

Question 8

keratinocytes

Answer 8

undergo mitosis
make keratin (tough protein)
migrate to surface as new cells produced in basale

Question 9

melanocytes

Answer 9

• produce pigment (melanin) for UV light protection
  (eg. sunburns, wrinkles (collagen damage), cancer (DNA damage)
• skin colour:
• we all ave the same relative number of melanocytes, but cells produce different amounts/shades of melanin
• albinos=no melanin
• blood (hemoglobin) - in dermis can give a pinkish tinge to fair skinned people

Question 10

stratum spinosum

Answer 10

limited cell division

Question 11

stratum ganulosum

Answer 11

contains dark staining granules

Question 12

stratum lucidum

Answer 12

• flat, dead cells (too far from blood supply)

- visible only in thick skin

Question 13

stratum corneum

Answer 13

• 20-30 layers of flat dead cells filled with keratin (tough protein), surrounded by waterproofing glycolipid (prevents water loss)
• shed and replaced from below

Question 14

dermis

Answer 14

• contains blood vessels, nerves, glands, hair follicles
• 2 sublayers (CT- from mesoderm):
• papillary layer
• reticular layer

Question 15

papillary layer

Answer 15

beneath epidermis
areolar CT
vascular
has projection into epidermis = dermal papillae
*in thick skin these form dermal ridges=fingerprints (improve grip)

Question 16

reticular layer

Answer 16

• most of dermis

- dense irregular CT

Question 17

hypodermis

Answer 17

not part of skin
-subcutaneous layer
-superficial fascia
(fascia= CT layers that surround and support organs)
-adipose CT below skin
(stores 1/2 of body’s adipose tissue (insulation)

Question 18

thin vs thick skin

Answer 18

refers to epidermis (not dermis)

Question 19

thin skin

Answer 19

• lucidum not apparent

- has hair follicles, sebaceous glands, arrector pili muscles

Question 20

thick skin

Answer 20

• found on the palm of the hand and the sole of the foot
• lucidum visible
• no hair follicles, sebaceous glands, or arrector pilli muscles

Question 21

epidermal derivatives

Answer 21

• all derived (formed) from the epidermis

- includes: hair, nails, skin exocrine glands,

Question 22

hair

Answer 22

• all dead cells

- parts: root, shaft, hair follicle

Question 23

hair root

Answer 23

dead cells below the surface of the skin

Question 24

hair shaft

Answer 24

above the skin surface

Question 25

hair follicle

Answer 25

surrounds root - epithelial root sheath= several epidermal layers extend into dermis - bulb= expanded region at base of root - matrix=single layer of cells (derived from basale cells) - site of hair growth and melanin for hair colour

Question 26

associated with each hair follicle (5)

Answer 26

- outer CT sheath - hair papilla - root hair plexus - sebaceous (oil gland) - arrector pilli muscle (smooth muscle)

Question 27

outer CT sheath

Answer 27

holds follicle in place (formed from the dermis)

Question 28

hair papilla

Answer 28

extends upward beneath matrix - contains blood supply for growing hair - formed from dermis

Question 29

root hair plexus

Answer 29

free nerve ending (touch)

Question 30

sebaceous (oil) gland

Answer 30

open into follicle

Question 31

arrector pili muscle

Answer 31

smooth muscle | -causes goosebumps

Question 32

nails

Answer 32

very heavily keratinized epidermal cells | -consists of : nail root (buried in skin), body (visible portion), free edge

Question 33

skin exocrine glands

Answer 33

- sebaceous glands - sudoriferous glands - ceruminous glands - mammary glands

Question 34

sebaceous glands

Answer 34

- connected mainly to hair follicles - secretes sebum (oily-mix of fats, salts, proteins) * softens, lubricates hair and skin, prevents drying out, antibiotic

Question 35

sudoriferous glands

Answer 35

- sweat glands - secretory portions in dermis of thick and thin skin - ducts open onto skin surface - act to: cool the body, antibiotic (acidic), remove wastes (urea)

Question 36

ceruminous glands

Answer 36

- modified sweat glands - in ear canal - produce ear wax- prevents insects etc. from entering

Question 37

mammary glands

Answer 37

produce milk | modified sweat glands

Question 38

cutaneous sense receptors

Answer 38

- receptor= sensory neuron (part of NS) - specialized cell that responds to stimuli (touch, temp, pain) - 4 major types : touch receptors, pressure receptors, thermoreceptors, nociceptors

Question 39

touch receptors

Answer 39

-free nerve endings (in epidermis) -root hair plexuses -meissner's corpuscles ( in dermal papillae,) corpuscle = connective tissue capsule surrounding nerve ending

Question 40

pressure receptors

Answer 40

- free nerve endings (in dermis) | - pacinian corpuscles (deep in dermis or hypodermis)

Question 41

thermoreceptors

Answer 41

free nerve endings for temperature

Question 42

nociceptors

Answer 42

- free nerve endings for pain | - 3rd degree burns-no pain b/c nociceptors destroyed