Unit 1.3: Integumentary System

Chapter 6

What are the primary functions of the Integumentary System?

Provides a barrier, vitamin D synthesis, sensation, thermoregulation

What are the Epidermis sub-layers in order?

Stratum corneum

Stratum lucidum

Stratum granulosum

Stratum spinosum

Stratum basale

What are the Dermis sub-layers in order?

Papillary layer

Reticular layer

What are keratinocytes?

Mostly found in the epidermis where keratin is produced, stem cells ins stratum basale make more keratinocytes

What are melanocytes?

Found in the stratum basale of the epidermis where synthesis of melanin(brown/black pigment) occurs, and contained in melanosomes

What protects the skin from UV rays?

Keratinocytes, phagocytose, melanosomes are used as protection.

More UV exposure, the more melanin produced (tanning)

What are Dendritic cells?

Found in the epidermis: stratum spinosum and stratum granulosum; and act as immune cells

What are Tectile cells

Found in the epidermis: stratum basale and are sensory receptors

Life of a Keratinocyte includes?

1. Stratum basale: stem cells divide to make copies that differentiate into keratinocytes

2. Stratum spinosum: new cells from below push older cells further up (this continuously occurs)

3. Stratum granulosum: keratinization begins, cells die

4. Stratum lucidum: present only in thick skin

5. Stratum corneum: compact layers of dead keratinocytes

6. Cells flake off, cycle restarts

Explain the dermis sublayers

Papillary layer: closest to epidermis, loose areolar tissue

Reticular layer: thickest, dense irregular connective tissue

What is Thermoregulation and what does it involve?

Altering blood flow through the cutaneous plexus(network-like) in the reticular layer

What is Vasoconstriction?

Occurs when body temperature is below normal (shivering), blood vessels constricts and there is less blood flow

What is Vasodilation?

Occurs when body temperature is above normal (sweating), blood vessels expand in diameter and there is more blood flow

What are the two types of sweat glands in the skin?

Eccrine sweat gland & Apocrine sweat gland

What is the Eccrine sweat gland?

Found all over the body, important for thermoregulation.

Regular sweat (NaCl & H2O)

What is the Apocrine sweat gland?

Found in armpits, privates

Smelly Sweat (NaCl, H2O, bacteria)

What is the Sebaceous gland?

Produces oil (sebum), helps lubricate and waterproof skin/hair.

Largely on the face, chest, neck, and back