Lecture 18: Skin structure and function Flashcards
What are the 3 layers of skin called?
Epidermis (outermost layer)
Dermis
Hypodermis (innermost layer)
What makes up the hypodermis?
Mainly adipose tissue
Loose connective tissue
Give some functions of the hypodermis.
Provide energy store (generate heat) Muscle insulator Shock absorber Connects skin to muscle and bone Make hormones (leptin)
Which layers of the skin contribute to skin wrinkling and hypothermia?
Hypodermis
Dermis
How does the hypodermis differ between men and women?
Men’s hypodermis is thickest in abdomen and shoulders.
Women’s hypodermis is thickest in hips, thighs and buttocks.
However, both sexes have thick hypodermis in palms of hands.
What other name is given to the dermis?
Corium
epidermis + dermis = cutis
What are the 3 structures of the dermis?
Papillary
Reticular
Dermal papillae
Give the functions of the middle layer of skin.
Dermis…
contains hairs + sweat glands (thermoregulation)
Sensory structures (touch)
Structure to the skin (body shape)
What does “Come Let’s Get Sun Burnt” mean in terms of skin?
These are the 5 different layers of the epidermis.
- Stratum Corneum
- Stratum Lucidum
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
Describe the structure of the epidermis.
Can have 4 layers (thin skin- without Stratum Lucidum) or 5 layers (thick skin)
Held laterally by adherens junctions
Held basal-apically by desmosomes
Avascular
Some terminal nerve endings
Give 3 functions of the skin.
Prevent pathogen entry Thermoregulation Water-proof lipid layer barrier Keratin syn. Prevents underlying tissue from abrasion Sensation
How is the stratum corneum’s structure related to its function?
Made up of dead squames so that they can protect the underlying tissue from abrasion.
Keratin tends to be thicker on palms and soles of feet.
How is the stratum lucidum’s structure related to its function?
This is a subunit of the stratum corneum where keratinisation occurs. SL contributes to the thickening of skin only on the palms and soles of feet.
Describe the stratum granulosum’s structure.
A line of stratified squamous epithelium consisting of lamellar granules and tonofibrils.
What are tonofibrils and what do they contribute to the stratum granulosum?
They are bundles of keratin filaments and keratohyalin granules from the lamellar bodies. Their function is to secrete lipids to make the epidermis a water-proof barrier.
