intergumentary system

What organs are part of the integumentary system?

Skin, hair, and nails

What are the four main functions of the integumentary system?

1. Protection (bacteria, moisture, chemical)

2. Senses (pressure, pain, temperature)

3. Makes Vitamin D

4. Excretes water, waste, and salt

:What are the three main layers of the skin?

1. Epidermis – epithelium (stratified keratinized squamous), avascular

2. Dermis – main layer, contains sweat & sebaceous glands, hair follicles

3. Hypodermis – subcutaneous fat layer

What is the epidermis?

The top layer of the skin, like a plastic sandwich bag thick

Is the epidermis vascular or avascular?

Avascular (no blood vessels)

Does the epidermis have nerves?

No

What type of tissue makes up the epidermis?

Stratified squamous keratinized epithelium

What protein waterproofs the epidermis?

Keratin

How many layers thick is the epidermis?

4 or 5 layers thick

Where is thin skin found?

On most of the body

Where is thick skin found?

On the palms of the hands and soles of the feet

What is the mnemonic for the layers of the epidermis (superficial to deep)?

Come Let’s Get Sun Burned

What are the five layers of the epidermis (from top to bottom)?

1. Stratum corneum

2. Stratum lucidum

3. Stratum granulosum

4. Stratum spinosum

5. Stratum basale

What is the stratum corneum?

The outermost layer of the epidermis; protective cover made of keratinized dead cells

How many layers thick is the stratum corneum?

15–30 layers

 What is special about the stratum lucidum?

Found only in thick skin (palms and soles); clear layer

What happens in the stratum granulosum?

Cells flatten and stop dividing; begin producing keratin

How many layers thick is it?

 3–5 layers

What happens to cells in the epidermis as they move upward?

They die.

What is the stratum spinosum known as?

The “spiny” or “prickly” layer containing alive keratinocytes.

How thick is the epidermis?

5–15 layers thick.

What are Langerhans cells?

Immune cells/macrophages in the epidermis.

What does the stratum basale do?

Generates new skin cells for growth.

What attaches the epidermis to the dermis?

The stratum basale layer.

What are the 4 types of cells in the epidermis?

Langerhans cells, melanocytes, Merkel cells, keratinocytes.

What is the main skin cell in the epidermis?

Keratinocytes.

What does the dermis support?

The epidermis.

What kind of tissue is found in the dermis?

Connective tissue made of collagen and elastic fibers.

What gives skin elasticity?

Irregular connective tissue fibers.

 What accessory structures are found in the dermis?

 Hair follicles and sweat glands.

 What are the two types of sweat glands?

Merocrine (eccrine) and apocrine.

Where are apocrine glands found?

Darker areas like the perineum, axilla (armpit), and mammary regions.

What is the dermis rich in?

Blood vessels (very vascular) and sensory nerves.

What is the function of sebaceous glands?

They produce oil and can contribute to acne.

What does the arrector pili muscle do?

Causes hair to stand up when it contracts.

What connects the dermis to the underlying tissue?

 The hypodermis.

What type of tissue makes up the hypodermis?

Areolar and adipose tissue

What are the functions of the hypodermis?

Protection, insulation, and fat storage

What gives the hypodermis elasticity?

Collagen and elastic fibers

What does skin turgor measure?

 Hydration status.

What happens when the skin loses turgor?

It indicates dehydration.

Why do surgeons cut along cleavage lines?

To minimize scarring.

What are the three types of hair?

 Lanugo (embryonic), vellus (“peach fuzz”), and terminal (adult).

When does terminal hair develop?

During puberty under hormonal influence.

What are examples of terminal hair?

Hair on the head, eyebrows, and pubic area.

What is lanugo hair?

  Fine, unpigmented hair usually shed at birth.

 Where do nails grow from?

The root (proximal to distal direction).

 What are nails made of?

 Keratinized epidermal cells.

 What gives skin its color?

Melanin and carotene pigments.

What are the main melanin pigments?

Brown, yellow, and black.

Why do people have different skin colors?

 Due to different amounts of melanin produced.

 What gives skin a yellow-orange color?

Carotene (from foods like carrots and squash).

What pigment is related to vitamin A?

Carotenoid (important for eye health).

What causes freckles?

 Localized areas with more melanin.

What causes red skin?

Increased dermal circulation and oxygen in hemoglobin.

What are the ABCs of cancer detection?

A: Asymmetry, B: Border irregularity, C: Color variation, D: Diameter > pencil eraser, E: Evolving changes.

Which skin cancer is least common?

Squamous cell carcinoma.

Which skin cancer is most common?

 Basal cell carcinoma.

 Which skin cancer is most dangerous?

 Melanoma.

 What are the three types of burns?

First degree (redness), second degree (blisters), third degree (all skin layers damaged, may affect nerves).