Integumentary System

Question 1

What is functions of the skin?

Answer 1

-Thermoregulation
-Secretion
-Cutaneous sensation
-Prevent moisture loss
-Absorption
-Reduces effects of harmful UV radiation
-Physical protection
-Vitamin D synthesis
- Social perception

Question 2

Describe the Epidermis

Answer 2

●Most superficial (top/outer) layer of the skin

●Composed of stratified keratinised squamous epithelium ( mainly keratinocytes)

●Has no blood vessels ( avascular), but the deeper layers of the epidermis are bathed in interstitial fluid, which provides oxygen and nutrients and drains away as lymph

●Has several layers from germinative layer (deepest) to stratum corneum (superficial).

●Process of keratinisation & differentiation as cells move towards the surface

Question 3

Describe Skin colour

Answer 3

●MELANIN - pigment derived from tyrosine & secreted by MELANOCYTES in the Stratum basale.

●Protects from harmful UV exposure

●Colour determined by

●number of size of melanosomes.

●Haemoglobin and circulating blood

●Genetics

●UV radiation

●Hormonal influences

Question 4

Dermis

Answer 4

●Formed from connective tissue, containing collagen and elastic fibres

●Cells in the dermis are fibroblasts, macrophages and mast cells

●The dermis contains blood and lymph vessels, sensory nerve endings, sweat glands, hairs, arrector pili muscles and sebaceous glands
The sensory nerves end in receptors, which are sensitive to touch, temperature, pressure and pain:

●Light pressure - Meissner’s corpuscle

●Deep pressure - Pacinian corpuscle and Ruffini’s corpuscle

Question 5

Cells of the dermis

Answer 5

Fibroblasts
–> Synthesise collage ( 70) elastin and viscious gel and surrounding these structures
- provide strength and elasticity

• contain chemical which act on small blood vessels
• part of the inflammatory and immune response.