Unit 3: Integumentary System Study Guide

What are the two main layers of the skin? Which layer is not technically part of the skin?

Epidermis and Dermis

The hypodermis is not technically part of the skin (made of adipose/fat tissue to connect the skin)

What is the relationship between melanocytes and skin color?

- all humans have an equal amount of melanocytes

- skin color depends on two causes:

1. type of melanin produced

2. how much melanin produced

What is the function of the acid mantle?

Slows bacterial growth

What is the relationship between UV rays and Vitamin D?

When exposed to UV rays, our skin helps produce vitamin D (which helps the digestive tract in absorbing muscle)

Texture of hair vs. shape of hair follicle

- Straight = Round hair follicle

- Wavy = Oval hair follicle

- Curly = flat hair follicle

What are considered the skin appendages?

- sweat glands

- oil glands

- hair

- nails

What percent of your body weight consists of skin?

15% (2.2 square meters)

What are the two layers of the dermis?

Papillary layer & reticular layer

Papillary Layer

Superficial, thin layer of the dermis (top 1/5)

- Dermal papillae

- Meissner's corpuscles

- Capillary loops

- Free nerve endings

Reticular Layer

Deeper, thick layer of the dermis (bottom 4/5)

- Hair follicle

- Arrector pili muscle

- Sebaceous gland

- Sudoriferous gland

- Pacinian corpuscle

Hypodermis

subacutaneous layer

- adipose tissue

- sensory nerve

- motor nerve

- blood vessels

Dermal Papillae

"skin nipples"

bumps that bind epidermis and dermis

creates fingerprints

Meissner's corpuscle

sense light touch

Capillary loops

where oxygen and nutrients are dropped off in the dermis (shared with epidermis)

where CO2 and waste are removed from the dermis

Free Nerve Endings

sense pain, heat, cold, itching, and tickling

Hair follicle

tunnel where the hair grows from

Arrector pili muscle

contracts to raise hair on end

Sebaceous gland

oil glands

oil is called sebum

Pacinian corpuscle

sense heavy touch (pressure/vibration)

Adipose tissue

adheres skin to underlying muscle (anchored loosely enough to allow skin to slide)

insulates heat

absorbs shock

Sensory nerve

sends messages from the merkel cells, meissner's corpuscles, free nerve endings, and pacinian corpuscles to the brain

Motor nerve

sends messages from the brain to the arrector pili muscles, sebaceous glands, sudoriferous glands

Blood vessels

delivers blood to and from the skin

artery: drops off blood with oxygen and nutrients

vein: takes away blood with CO2 and waste

Which epidermis layers contain dead keratinocytes?

Stratum corneum and lucidum

Which epidermis layer contains cells undergoing mitosis?

Stratum basale

Which layer appears spiny and why?

Stratum spinosum because keratinocytes are connected by desmosomes

What is the function of merkel cells?

sense light touch

What is the function of langerhan cells?

ingest foreign substances and activate the immune system

Which cells are formed in the bone marrow?

langerhan cells

What is the most common epidermal cell?

Keratinocytes

Which cells are stimulated by friction?

keratinocytes

What is the function of lamellar bodies?

secretes lipids that cause skin to be water resistant and prevent water loss

What type of tissue is the epidermis made of?

stacked epithelial tissues

What type of tissue is the dermis made of?

connective tissue filled with collagen and elastin fibers

Which epidermal cell has squamous anucleate cells, and what does that mean?

The stratum corneum has 20-30 layers of these cells, meaning there is no nucleus

What structure contracts to raise hair on the end?

arrector pili muscle

What structure creates fingerprints?

dermal papillae

What structure absorbs shock?

adipose tissue

What structure is the tunnel where hair grows from?

hair follicle

What structure senses heavy touch?

pacinian corpuscle

What structure senses pain?

free nerve endings

What are two ways that your skin responds to cold to maintain body warmth?

1. Blood vessels constrict

2. Blood vessels deepen to trap heat

What is the function of the sebum?

- Soften and lubricate the hair/skin

- prevent water loss

- bactericidal action (kills bacteria)

How is the skin a physical barrier?

- epidermis = stratified and keratinized

- lipids secreted by lamellar bodies cause skin to be water resistant and prevent water loss

How is the skin a chemical barrier?

- our skin's surface teems with bacteria, so the skin secretes an acid mantle, which slows bacterial growth

- sweat and sebum have ingredients that kill bacteria

- melanin acts as a shield over epidermal cells to prevent UV ray damage

How is the skin a biological barrier?

- langerhans cells ingest foreign invaders and notify the immune system, calling in other immune cells and triggering an immune response

3 Types of Skin Cancer

- Basal cell carcinoma (BCC)

- Squamous cell carcinoma (SCC)

- Melanoma

Basal Cell Carcinoma (BCC)

- The most common type, originating in basal cells at -- Often looks like a small, shiny, skin-colored or pink bump, a sore that doesn't heal, or a reddish patch.

- Slow-growing and rarely spreads.

Squamous Cell Carcinoma (SCC)

- The second most common type, developing in squamous cells of the epidermis.

- May appear as a firm, red bump or a scaly, rough patch.

- Can grow more quickly and has a higher likelihood of spreading than BCC if not treated.

Melanoma

- Develops in melanocytes, the cells that produce skin pigment.

- Often looks like a mole but can be asymmetrical, have irregular borders or multiple colors, and changes over time.

- The most dangerous form, as it can spread rapidly to other organs.