Anatomy and Physiology I LAB - Integumentary System

What type of membrane is the skin?

CUTANEOUS membrane ——> type of epithelial membrane

What are the functions of the skin? (5)

1. Protect against mechanical/chemical damage, bacterial invasion

2. Insulate against heat/cold, dissipates heat

3. Cushions body tissue

4. Prevents water loss/excretes wastes (urea, salts, water)

5. Site for vitamin D synthesis

What is the superficial region of the skin called?

EPIDERMIS

What are the 5 major layers of the epidermis? Order from outermost to innermost:

1. Stratum corneum

2. Stratum lucidum

3. Stratum granulosum

4. Stratum spinosum

5. Stratum basale

Crazy Lab Got Some Bones

Stratum Corneum

Outermost layer that accounts for bulk of epidermal thickness

Stratum Lucidum

Very thin clear layer that only exists in THICK skin, not thin skin

Stratum Granulosum

Thin layer containing granules that provide waterproofing and support

Stratum Spinosum

Layer of several cells, with lower layer cells getting nutrients and undergoing cell division

Stratum Basale

Innermost layer only one cell layer thick, with cells undergoing mitotic division

What is the connective tissue region under the epidermis?

DERMIS

What is the hypodermis/superficial fascia?

Layer composed of adipose tissue that lies underneath the dermis

What are the 2 layers of the dermis?

1. Papillary Layer (TOP)

2. Reticular Layer (BOTTOM)

Dermis: Papillary Layer

Superficial layer composed of areolar connective tissue

• Has pain receptors (free nerve endings)

• Meissner’s corpuscles (touch receptors in hairless skin)

Dermis: Reticular Layer

Deepest skin layer composed of dense irregular connective tissue

• Contains arteries, veins, sweat, sebaceous glands

• Pacinian corpuscles (pressure receptors)

What does the color of skin depend on?

• Melanin

• Carotene

• Oxygenation of blood

Skin color: Hypertension

Flushed skin

Skin color: Anemia

Pale skin

Skin color: Asphyxiation / Lung Disease

Cyanosis - blueish skin

Skin color: Liver Disease

Jaundice - yellow skin

Skin color: Addison’s disease

Hyposecretion from adrenal cortex —→ bronze skin