Skin, Dermatology Flashcards
What is the Hypodermis made of?
What cells?
What is its function?
Adipose tissue Loose CT ( Fibroblasts, Mast cells, Macrophages, Fibres)
Energy store, Shock absorber, Insulation, Site of hormone production
In Men and Women, where is Hypodermis thickest?
Where is it thick common to both genders?
Men: Abdomen, Shoulders
Women: Hips, Thighs, Buttocks
Palms, Soles of feet
Thinning of which layers cause wrinkles?
Hypodermis
Dermis
Is the epidermis vascular or avascular?
What are the functions of the epidermis?
Avascular
- Prevent water loss
- Pathogen ingress
- Keratin synthesis
- Prevent Loss of underlying tissue
What are the layers of the epidermis?
Which layer is not found everywhere, where is it found, how thick is this layer?
Stratum Corneum Stratum Lucidum (Only palms and soles, One cell thick) Stratum Granulosum Stratum Spinosum Stratum Basale
Describe the Strateum Corneum
- What is it made of?
- Shedding
- Where is it thickest
- Squames (Dead keratinocytes)
- Always sheds
- Palms and soles
What is the Stratum Granulosum made of?
Sratified Squamous Epithelia Lamellar Granules (Make Tonofibrils and Keratin Fibres)
What is the Stratum Spinosum made of?
What structures are made here?
This is the first point where, WHICH structures are found?
3 layers of Cuboidal Epithelia held together by Desmosomes
Lamellar Granules
Golgi Bodies
What is the Stratum Basale made of?
What processes occurs here?
- Tall columnar Epithelial cells
- Tonofilaments
- Keratinocytes renewed by cell division, As cells differentiate they move towards S. Corneum
How is keratin made, how does it reach S. Corneum?
What happens in Psoriasis? How does this present?
What happens in Hyperkeratosis? What causes this?
- Made by keratinocytes, takes 28-40 days to reach S. Corneum
- Takes 2-3 days, presents as silvery scales
- Excess keratin on surface, Excessive Pressure, Inflammation, Irritation
How do the Dermis and Epidermis link together?
S. Basale interdigitates into Dermis
These are called Dermal Papillae
What are the dermis layers?
What are the functions of the Dermis?
Papillary
Reticular
- Thermoregulation, Give skin structure-> Body shape, Sensory Structures
What are the 9 main function of skin?
- Protection and Repair
- Thermoregulation
- Lubrication (Sebum release)
- Vitamin D Synthesis
- H20 and O2 absorption
- Excretion of waste products
- Lipid storage
- Sensation
- Aesthetics
Where are Melanocytes found, and what do they do?
Why do different people have different melanin levels?
Compare number of melanocytes in different people
Stratum Basale, Produce melanin.
Melanocytes produce different amounts of melanin in different people.
Melanocyte no. is same in all people.
What and where are Langerhans Cells?
What do they do?
- Dendritic cells in Stratum Basale
- Present antigens to T cells to cause an immune response
In which layer do keratinocytes undergo apoptosis, when moving to S. Corneum
Stratum Granulosum
What Structures are found in Dermis?
- Sebacous glands
- Hair follicles
- Sweat glands
- Arrector Pili Muscles
- Sensory Structures
What are 5 skin-associated structures?
- Hairs
- Nails
- Sebaceous Glands
- Sweat Glands
- Arrector Pili Muscles
Describe the structure of a nail, and what they’re made of
What are some functions of the nail?
Made of Alpha-Keratin, Consist of Nail Plate, Nail Matrix, Nail Bed
- Extended Precision Grip
- Enhanced Fingertip sensitivity
- Protection of Phalanx
What do Sebaceous Glands secrete? What does this do?
Where are they found?
- Sebum, an oily and waxy substance. Lubricates and waterproofs skin
- Found near hair follicles
What are Arrector Pili muscles, what do they do?
- Smooth muscle fibres attached to “Hair Bulb”
- Caus hair to ‘stand up’ and induce Sebum release
Where is the Hair Bulb (Base of hair follicle) found?
What are the functions of hair?
- Papillary Dermis
- Thermoregulation
- Sexual attraction (Pheromones)
- Sensation
- Protection (Eyelashes, nasal hair prevent dust and pathogen entry)
Compare the 3 types of hair
Which type replaces which?
Lanugo: On babies
Vellus: Short, thin, soft, light, Unconnected to Sebaceous glands
Terminal: Long, wide, dark, coarse (E.g in Nasal Passage)
Vellus replaces Lanugo
Compare the 2 types of skin
What are the exceptions?
Thick: Non-Hairy
Thin: Hairy
EX: Lips, External Genital region, Back of ear
