Unit 9: Organ Systems I. Integumentary System

Question 1

What is included in the integumentary system?

Answer 1

Skin, hair, nails, glands, muscles, sense receptors (nervous), hypodermis

Question 2

What are the 2 major layers of the skin?

Answer 2

1. Epidermis (superficial/outermost layer) and 2. Dermis (deep layer)

Question 3

What is the hypodermis?

Answer 3

Hypodermis is NOT part of the skin:
- is also called the subcutaneous layer
- is also called superficial fascia (fascia = CT layers that
surround and support organs)
- adipose CT below skin that stores 1/2 of body’s adipose
tissue (insulation)

Question 4

What are the 4-5 strata (sublayers) of the epidermis?
And what come beneath/after them?

Answer 4

They are based on cell types, and they include (bottom to top): stratum basale, spinosum, granulosum, lucidum, and corneum (Beautiful Skin Gets Lovely Compliments).
So it goes:
Surface
Stratum Corneum
Stratum Lucidum
Stratum granulosum (last layer of living cells)
Stratum spinosum (living)
Stratum basale (living)
Basement membrane (living)
Dermis (living)
Subcutaneous layer (beneath dermis) (living cells)

Question 5

Info on Stratum basale

Answer 5

= Single row of cells; 2 cell types (LIVING CELLS):
1. keratinocytes
- actively undergo mitosis
- make keratin (tough protein)
- pushed towards surface as new cells are produced in
basale
2. melanocytes
- produce pigment (melanin) for UV light protection
(sunburns, wrinkles = collagen damage, cancer = DNA
damage)
- skin colour = we all have same relative # of melanocytes,
but cells produce diff. amounts/shades of melanin
- blood (hemoglobin) - in dermis can give a pinkish tinge
to fair-skinned people

Question 6

Info on stratum spinosum

Answer 6

Low levels of mitosis (BUT LIVING CELLS)

Question 7

Info on stratum granulosum

Answer 7

NO MITOSIS
- contains granules that help produce keratin (strength) and start to produce waterproofing glycolipids (prevents water loss)
- LAST LAYER OF LIVING CELLS

Question 8

Info on stratum lucidum

Answer 8

NO MITOSIS
- flat, DEAD CELLS (too far from blood supply)

Question 9

Info on stratum corneum

Answer 9

• many layers of flat dead cells filled w/ keratin (tough protein)
• glycolipids btw. cells creates a waterproof layer (prevents water loss)
• shed and replaced from below

Question 10

What is the 2nd major layer of the skin?

Answer 10

The dermis.
- contains blood vessels, nerves, glands, hair follicles, arrector pili muscles (for warmth and shivering),

Question 11

What are the two subtypes of the dermis?

Answer 11

Both = CT:
1. Papillary layer (connected to epidermis)
- areolar CT, vascular
- has projection into epidermis = dermal papillae
- in thick skin these for epidermal ridges = fingerprints
(improve grip)
2. Reticular layer (btw. papillary layer and hypodermis)
- forms most of dermis
- dense irregular CT

Question 12

What is thin skin versus thick skin?

Answer 12

Thickness refers to epidermis (not dermis).

Thin characteristics:
- covers most of body
- LUCIDUM ABSENT (so just beautiful skin gets compliments)
- has hair follicles, sebaceous glands, arrector pili muscle

Thick characteristics:
- DOES NOT HAVE HAIR
- found on palm of hand and sole of feet
- LUCIDUM PRESENT (so beautiful skin gets lovely compliments)
- no hair follicles, sebaceous glands, or arrector pili muscles

Question 13

What are the epidermal derivatives?

Answer 13

1. Hair
2. Nails
3. Skin Exocrine glands

Question 14

Info on hair

Answer 14

All dead cells.
Parts:
a) Root = part of hair embedded w/in skin
b) Shaft = visible part of hair above skin surface
c) Hair follicle - surrounds root
i. epithelial root sheath = several epidermal layers extend
into the dermis
ii. bulb = expanded region at base of root
iii. matrix = single layer of cells (derived from basale cells) -
site of hair growth and melanin for hair colour)

Parts of each hair follicle:
a) outer CT sheath - holds follicle in place (formed from the dermis)
b) hair papilla - extends upward beneath matrix
- contains blood supply for growing hair
- formed from dermis
c) root hair plexus - free nerve ending (touch)
d) sebaceous (oil) gland - opens into follicle
e) arrector pili muscle (smooth muscle) - causes “goosebumps”

Question 15

Info on nails

Answer 15

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

Question 16

What are the 4 skin exocrine glands?

Answer 16

Sebaceous glands, sudoriferous glands, ceruminous glands, and mammary glands.

Question 17

Info on sebaceous glands

Answer 17

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

Question 18

Info on sudoriferous glands

Answer 18

• sweat glands
• secretory portions in dermis of thick and thin skin
• ducts open onto skin surface
• functions:
  
  • temp regulation - cool body
  • antibiotic action (due to sweat being acidic)
  • waste removal (e.g. urea)

Question 19

Info on ceruminous glands

Answer 19

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

Question 20

Info on mammary glands

Answer 20

• modified sweat glands
• produce milk

Question 21

What are cutaneous sense receptors, and what are the 4 types of them?

Answer 21

• sensory receptors are a sensory neuron (part of NS)
• specialized cell that responds to stimuli (touch, temp., pain)
• 4 major types:
  
  1. Touch Receptors = free nerve endings IN EPIDERMIS,
     root hair plexuses, and Tactile (Meissner’s) Corpuscles, in
     dermal papillae, corpuscle is a connective tissue capsule
     surrounding a nerve ending
  2. Pressure Receptors = free nerve endings IN DERMIS,
     Lamellar (Pacinian) corpuscles - deep in dermis or
     hypodermis
  3. Thermoreceptors = free nerve endings for temp.
  4. Nociceptors = free nerve endings for pain - 3rd degree
     burns destroy nociceptors, causing lack of pain sensation
     in affected areas