Lab#4 Integumentary System

Question 0

Layers of the epidermis

Answer 0

-Thin skin: has hair
-Thick skin: hairless areas subject to abrasion
Ex: Palms, fingertips, soles of feet.

• stratum basale
• stratum spinosum
• stratum granulosum
• stratum Lucidum
• stratum corneum

Question 1

Functions of integumentary system

Answer 1

The largest system of the body “skin”

Two parts:

1. Cutaneous membrane “skin”
   - Outer epidermis: epithelial tissue
   - Inner dermis: connective tissue
2. Accessory structures: start in dermis
   - Extend->through epidermis to skin surface
   - ex: hair, nails and exocrine glands

Question 2

Stratum Germinativum

Answer 2

Germinating layer– Basal layer

• Deepest epidermal layer
• single row of actively mitotic stem cells
• continually renewing cell population with youngest keratinocytes

Question 3

Stratum Corneum

Answer 3

A.k.a. Horny layer (Cornu=horn)

• Dead-anucleate (no nucleus) cells
• 20-30 cell layers thick
• durable/protective top layer for abrasion
• flat ingredients socks filled with keratin

Question 4

Characteristics/locations of thick skin

Answer 4

Hairless skin w/additional layers of cells

Palms of hands and soles of feet.

Has skin ridges/ friction ridges for gripping / sense of touch

Question 5

Characteristics/location of thin skin

Answer 5

Skin with hair

20-30 layers of keratinocytes

Question 6

Description of Microscopic view of thin and thick skin

Answer 6

Thick skin - epidermal ridges

Thin skin- hair follicles

Both have eccrine sweat glands

Question 7

Reasons for differences in skin color

Answer 7

Evolutionary Variations in three pigments

 - melanin (reddish yellow / brownish black)
 - carotene (yellow to orange)
 - hemoglobin (red blood cells)

Question 8

Describe microscopic view of pigmented nonpigmented skin

Answer 8

Melanocytes of darker skinned people, produce many more and darker melanosomes than those of fair skinned individuals and their keratinocytes retain it longer.

Question 9

Recognize papillary dermis

Answer 9

Areolar connective tissue

 - fine interlacing collagen and elastic fibers 
 - very invested with small blood vessels

Question 10

Reticular dermis

Answer 10

• Reticular layer made up of dense irregular connective tissue
• Majority of the dermis layer
• Irregularly arranged dense fibrous connective tissue
• Contains the cutaneous plexus (blood vessel network)

Question 11

Recognize sweat glands

Answer 11

(AKA) Eccrine glands

(Coiled/knotted) gland within rerticular layer

Question 12

Describe the distribution in the body of: Sebaceous glands, Sudoriferous glands and Pili follicles

Answer 12

All within the reticular layer of the dermis

Question 13

Keratin

Answer 13

Fibrous proteins that helps give the epidermis it’s protective properties

-kera = horn in Greek

Question 14

Keratinocytes

Answer 14

• Makes keratin (protective protein)
• most epidermal cells are keratinocytes
• Millions of dead keratinocytes rub off every day giving us a new epidermis every 25 to 45 days

Question 15

Basal lamina

Answer 15

A layer of extracellular matrix secreted by the epithelial cells, on which the epithelium sits. It is often confused with the basement membrane.

Question 16

Functions of the skin

Answer 16

• Protects us (against bacteria)
• Agent against excretion (water/ salts/organic wastes)
• Maintenance of body temperature (insulation/evaporation)
• Production -Melanin and Keratin (lubrication)
• Synthesis -vitamin D3
• Storage -lipids
• Sensory -touch, pressure, pain, temperature

Question 17

Sudoriferous glands

Answer 17

Sweat glands

• Eccrine/Merocrine Glands
• Apocrine glands (odored sweat)
• Abundant on palms and soles of feet and forehead
• Coiled tubular glands that secretes sweat to pore on skin surface

Question 18

Sebaceous glands

Answer 18

Oil glands

• secrete Subum (oily substance)
• All over the body except in the thick skin of the palms and soles
• Attached to hai follicle

Question 19

Pili and follicles

Answer 19

Hair and hair follicles

-Consist largely dead hard keratinized cells
-connected to follicle is the hair root, the arrector pili muscle, Sabaceous oil gland
Most and I couldn’t sweat
-External Hair = hair shaft

Question 20

Epidermis

Answer 20

• Keratinized stratified squamous epithelium
• Outermost protective shield of the body
• Contains four cell types:
  - Keratinocytes
  - Melanocytes
  - Dendritic cells
  - Tactile cells
• Contains four/five layers:
  - stratum basale
  - stratum spinosum
  - stratum granulosum
  - stratum lucidum (thin only)
  - stratum corneum

Question 21

Dermis

Answer 21

Contains Papillary and Reticular layers

Below Epidermis above Hypodermis

Question 22

Hypodermis

Answer 22

Subcutaneous (below blood vessels)

AKA superficial fascia

Mainly adipose cells (fatty)

Technically not part of the skin

Question 23

Arrector pili muscle

Answer 23

Tiny smooth muscles connecting hair follicle to papillary layer

Contracts to pull hair upright when cold, scared, amazed!

Question 24

Dermal papilla

Answer 24

Peg-like projections from papillary layer

Indent the overlying epidermis

Question 25

Epidermal ridge

Answer 25

Epidermal ridge lies above dermal ridges within thick skin of palms and soles of feet.

These are skin ridges/ friction ridges… For grip and sense of touch

Question 26

Germinative/stem cells

Answer 26

Actively mitotic stem cells within Stratum Basale

Newly formed cells with rapid devision.

Question 27

Melanocytes

Answer 27

• Site of melanin synthesis
• Deepest layer of epidermis
• Forms on top of keratinocytes (UV Protection)

Question 28

Melanin

Answer 28

• Pigment found only in deeper layers of epidermis
• A polymer made of tyrosine amino acids
• ranges in color from reddish yellow to brownish black

Question 29

Dendritic cells

Answer 29

Star shaped cells that come from bone marrow and migrate to the epidermis

They ingest find substances and are key activators to our immune system

Question 30

Tactile cells

Answer 30

A.k.a. Merkel cells

Present at epidermal/dermal junction

Associated with a sensory nerve ending

Functions as a sensory receptor for touch