Chapter 5: Integumentary System

The integument is?

the skin that covers your body

What is the integument also known as?

cutaneous membrane

The integumentary system is?

the skin and its derivatives

What are the two layers of the integument?

• epidermis 

• dermis 

What is the epidermis?

superficial layer

What kind of tissue is the epidermis made up of?

stratified squamous epithelium

What is the dermis?

deeper layer of skin

What kind of tissue is the dermis made up of?

areolar and dense connective tissue

Is the subcutaneous layer part of the skin?

no

Where is the subcutaneous layer located?

under dermis

What is the subcutaneous layer made up of?

areolar and adipose tissue

Label figure 1.

integument

Label figure 2.

epidermis

Label figure 3.

dermis

Label figure 4.

subcutaneous layer

Label figure 5.

reticular layer

Label figure 6.

papillary layer

Label figure 7.

hair follicle

Label figure 8.

tactile (sensory) receptors

Label figure 9.

areolar connective tissue

Label figure 10.

sensory nerve fiber

Label figure 11.

adipose connective tissue

Label figure 12.

artery

Label figure 13.

vein

Label figure 14.

merocrine sweat gland

Label figure 15.

sweat gland duct 

Label figure 16.

sebaceous (oil) gland

Label figure 17.

arrector pili muscle

Label figure 18.

dermal papilla

Label figure 19.

epidermal ridge

Label figure 20.

sweat pore

Label figure 21.

hair shaft 

What are the functions of the integument?

• protection

• prevention of water loss and gain

• temperature regulations 

• metabolic regulation

• immune defense

• sensory reception

• secretion

Are certain substances absorbed into the integument? Why?

yes because of selective permeability

Why is skin water-resistant but not completely waterproof?

due to transepidermal water loss (TEWL)

What falls under transepidermal water loss (TEWL)?

• insensible perspirations (non-visible sweating)

• sensible perspiration (visible sweating)

How does the integument regulate temperature?

dilation of dermal vessels release heat, constriction conserves heat 

How is the integument involved in metabolic regulation?

• vitamin D3 produced by skin cells and converted into calcitriol by kidneys

• calcitriol is a hormone involved in calcium homeostasis

How is the integument involved in immune defense?

epidermal dendtritic cells help initiate immune response 

How is the integument involved in sensory reception?

skin receptors help detect changes in temperature, touch

What are tactile cells?

stimulate nerve endings in response to touch

How is the integument involved in secretion?

sweating; lubrication of hair and skin with sebum

the epithelium of the skin is the ?

epidermis

What are some characteristics of the epidermis?

• avascular

• composed of several layers (strata)

What are the 5 epidermal strata? in order of superficial to deep

1. stratum corneum

2. stratum lucidum

3. stratum granulosum

4. stratum spinosum

5. stratum basale

What strata is only found in thick skin?

stratum lucidum

Label figure 1.

stratum corenum

Label figure 2.

stratum lucidum

Label figure 3.

stratum granulosum

Label figure 4.

stratum spinosum

Label figure 5.

stratum basale

Label figure 6.

dermis

What is the arrangement/ cell type in stratum basale?

• single layer of cells

• cuboidal to low columnar 

• cells attached to basement membrane and adjacent to dermis

What are the cell types present in stratum basale?

• keratinocytes

• melanocytes

• tactile cells 

what is the most abundant cell in stratum basale?

keratinocytes

What are keratinocytes?

cells that produce keratin

______________________ predominate main cell of stratum basale; divide to replace keratinocytes shed at epidermal surface

kertinocyte stem cells

What are melanocytes?

produce pigment melanin

What does melanin do?

absorbs UV light to prevent DNA damage

melanin packed into _____________ for incorporation into keratinocytes

melanosomes

tactile cells are sensitive to?

touch

What is the arrangement/ cell type in stratum spinosum?

several layers of polygonal keratinocytes

What cell types are found in stratum spinosum?

• daughter cell of stratum basale → specialized keratinocytes

• epidermal dendritic cells

• immune cells 

How do keratinocytes in stratum spinosum attach to each other?

via desmosomes

immune cells act as _________ to fight infection and initiate immune response

phagocytes

What is the arrangement/ cell type in stratum granulosum?

three to five layers of keratinocytes undergoing keratinization 

What occurs during keratinization?

• cytoplasm fills w/ keratin degrading filaments

• organelles begin to degrade

What are the types of keratin granules in cells of stratum granulosum?

• keratohyalin granules

• lamellar granules

What granules are involved in the keratinization process?

keratohyalin granules

what granules release contents (primarily lipids) into extracellular space; help form water barrier?

lamellar granules 

What is the arrangement/ cell type in stratum lucidum?

thin, translucent region, two to three cell layers thick

In stratum lucidum, the cell lack organelles and are filled with?

eleidin

What is the arrangement/ cell type in stratum corneum?

thickness varies from 20-30 layers of corneocytes

What are corneocytes?

dead, scaly, interlocking keratinized cells

The cells in stratum corenum are?

anucleate (lack nucleus) and tightly packed

About how long do cells take to migrate from stratum basale to stratum corneum?

2 weeks

How long do cells remain in stratum corneum to protect deeper layers?

2 weeks 

what happens to cells in stratum corenum?

eventually shed from epidermal surface 

Thick skin contains how many layers and which layer specifically does it include?

five layers including stratum lucidum

Where is thick skin typically found?

palms and soles of feet

Does thick skin contain hair follicles or sebaceous glands?

no

How many layers does thin skin have, what does it exclude?

4 layers, excludes straum lucidum

Where is thin skin found?

covers most of body

about how thick is the epidermis?

0.4-0.6 mm thick

skin color is determined by what pigments?

1. hemoglobin

2. melanin

3. carotene

hemoglobin

blood pigment

melanin

pigment produced by melanocytes

carotene

yellow-orange pigment from foods such as carrots; it builds up in the skin

appearance of skin due to melanin is influenced by what?

• hereditary 

• exposure to UV light

what are the subtypes of melanin?

• eumelanin

• pheomelanin

T/F all people have about the same number of melanocytes?

true

what is also known as a mole?

nevus

what is a mole?

localized overgrowth of melanocytes

what are freckles?

yellow or brown spots of high melanocyte activity

What are folds of epidermis and dermis on fingers, palms, soles and toes; increase friction for grasping?

friction ridges 

what are the types of friction ridges?

• arch

• whorl

• loop

where is the demis located?

deep to the epidermis

about how thick is the dermis?

0.5 mm to 3.0 mm

what is the dermis composed of?

areolar and dense irregular connective tissue

What are the two layers of the dermis?

• papillary layer

• reticular layer