Intro to integumen

Question 1

Describe the formation of the epicermis

Answer 1

• Formed from ectoderm
• Basal layer divides forming the PERIDERM
• Further basal cell divisions form intermediate layers
• Half way through pregnancy the basal layers form STRATIFIED SQUAMOUS EPITHELIUM and PERIDERM IS LOST

Question 2

Describe the formation of the dermis

Answer 2

• Formed from mesoderm
• Mesenchymal mesoderm cells differentiation and form connective tissues e.g. COLLAGEN/ ELASTIN
• The denser CT is deeper than the looser CT.

Question 3

What does the Hypodermis do?

Answer 3

is it a layer of LOOSE CT than is below the dermis and ANCHORS it to underlying structures

Question 4

How is hair formed?

Answer 4

Epidermal basal cells proliferate and form the PEG (hair bud)

• Mesenchymal cells aggregate around the bud to form the DERMAL PAPILLA
• Epidermal cells grow around the papilla forming the HAIR BULB

Question 5

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

Answer 5

Sweat and sebaceous

Question 6

What are the functions of the integument?

Answer 6

• Protection
• Sensory
• Glandular secretions
• Thermoregulation
• Immunity