Integumentary System - midterm 2

Question 1

Integumentary system consists of: (6)

Answer 1

• skin
• hair
• nails
• glands (ex. sweat)
• sense receptors (nervous) ex. cold, hot, touch
• muscles (ex. cause hair to stand)

Question 2

What are the 2 skin layers

Answer 2

Epidermis (upper layer) & Dermis (lower layer) …….. (below skin = hypodermis

Question 3

Characteristics of Epidermis skin layer

Answer 3

• stratified squamous epithelium (from ectoderm….outside)
• avascular (lack of blood vessels)
• separated into 4-5 strata (sub-layers) based on cell types

Question 4

What are the Epidermis strata (sub-layers): (5)

Answer 4

• Stratum Basale
• Stratum Spinosum
• Stratum Granulosum
• Stratum Lucidum
• Stratum corneum
  (Bad Students Get Low C’s)

Question 5

Stratum Basale

Answer 5

• single row of cells
• 2 cell types:
  i) keratinocytes (90%)
  > undergo mitosis, make keratin (tough protein), migrate to surface as new cells produced in basale
  ii) melanocytes (10%)
  > produce pigment (melanin) for UV light protection. e.g.. sunburns, wrinkles (collagen damage), cancer (DNA damage)
  > skin colour. We all have 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 6

Stratum Spinosum

Answer 6

Limited cell division

Question 7

Stratum Granulosum

Answer 7

• contains dark staining granules

- thin dark line (anything above this layer is dead)

Question 8

Stratum Lucidum

Answer 8

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

- visible ONLY in thick skin

Question 9

Stratum Corneum

Answer 9

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

Question 10

What does the dermis contain + what are the 2 sublayers

Answer 10

• contains blood vessels, nerves, glands, hair follicles
• 2 sub-layers (CT - from mesoderm)
  > Papillary Layer (beneath epidermis) (top layer), areolar CT, Vascular, has projection into epidermis = dermal papillae (finger prints in thick skin)
  > Reticular Layer (bottom layer), most of dermis, dense irregular CT

Question 11

Hypodermis

Answer 11

NOT part of skin, below the skin
- = subcutaneous layer
- = superficial fascia
> fascia = CT layers that surround and support organs
- Adipose CT below skin
> store 1/2 of bodys adipose tissue (insulation)

Question 12

Thin skin

Answer 12

• lucidum not apparent

- Has hair follicles, sebaceous glands, arrector pili muscles

Question 13

Thick skin

Answer 13

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

Question 14

Epidermal Derivatives includes: (3)

Answer 14

• ALL derived (formed) from the epidermis
  1) Hair
  2) Nails
  3) Skin Exocrine glands

Question 15

Hair

Answer 15

• all dead cells
  parts:
  a) root = dead cells below the surface of the skin
  b) shaft = above the skin surface
  c) hair follicle - surrounds root

Question 16

Parts of hair follicle: (3)

Answer 16

i) epithelial root sheath = several epidermal layers extend into the dermis
ii) bulb = expanded region at base of root
iii) matrix (not the same as other matrix) = single layer of cells (derived from basale cells) - site of hair growth and melanin in hair colour

Question 17

Associated with hair follicle: (5)

Answer 17

a) outer CT sheath
b) hair papilla - contains blood supply for growing hair
c) root hair plexus (touch)
d) sebaceous (oil) gland
e) arrector pili muscle (smooth muscle) causes goosebumps

Question 18

Nails

Answer 18

-Very heavily keratinized epidermal cells
- consists of
nail root (buried in skin)
body (visible portion)
free edge

Question 19

Skin Exocrine glands: (4)

Answer 19

1) sebaceous glands (causes greasy hair because of sebum)
2) sudoriferous glands (sweat glands)
3) ceruminous glands (in ear canal produce ear wax)
4) mammary glands (produce milk)

Question 20

4 major types of cutaneous sense receptors

Answer 20

1) touch receptors
a. free nerve endings - in epidermis
b. root hair plexuses
c. meissners corpuscles- in demis papillae
2) pressure receptors
a. free nerve endings- in dermis
b. pacinian cormuscles - deep in dermis or hypodermis
3) thermoreceptors (temperature) - free
4) nociceptors (pain) - free

Question 21

Cutaneous sense receptors

Answer 21

Specialized cell that responds to stimuli.

Receptor = sensory neuron