Case 1 - healthy skin Flashcards
what are the functions of the skin? (simple, basic)
It keeps things out - protects internal organs from UV light etc
It prevents loss
It keeps things in
It regulates
It is part of psychology and reproduction
It makes things
It talks to the brain
what does the skin keep out?
Skin reduces the entry of unwanted molecules, microbes and radiation
Skin provides the structure and means to create a network of antigen presenting cells that monitor and guard/protect the region
what does the skin do?
Makes Vitamin D3
Prevent fluid loss
Regulate heat loss
Relays information about the outside world to the brain – e.g vibration, touch,
pressure
Why is the outer skin keratinized while internal epithelial surfaces (like inside the mouth/”inner skin”) are non-keratinized?
Keratinized epithelium (e.g., outer skin) provides protection from abrasion, dehydration, and pathogens by forming a tough, waterproof layer of dead cells filled with keratin.
Non-keratinized epithelium (e.g., inside the mouth, esophagus, vagina) lacks this keratin layer, allowing it to stay moist and flexible for functions like swallowing or speaking.
The difference is due to environmental exposure and functional needs: dry, protective barrier vs. moist, flexible lining.
what do you know about stratum corneum?
The stratum corneum is the outermost layer of the skin, made of dead keratinocytes. It acts as a protective barrier and helps prevent water loss.
what do you know about stratum lucidum?
this is present in thick skin only (like the soles of feet and palms of hands)
cells begin to die here
what do you know about stratum granulosum?
cells are flattened, organelles are deteriorating, cytoplasm is full of granules
[* Too far from blood supply so change morphology
* Flatten and become dense
* Become granular with keratin granules
* Lose nuclei]
what do you know about stratum spinosum?
cells contain thick bundles of intermediate filaments made of pre-keratin
* Escalator of Daughter Keratinocyte cells
* Older cells at top
* Patrolled by Langerhans Cells (DCs)
what do you know about stratum basale?
stem cells are actively dividing; some newly formed cells become part of the more superficial layers
* Epithelial layer (each cell not called epithelia but keratinocyte)
with basal lamina and hemidesmosomes anchors into dermis
* Highly proliferative
what is the epidermis made up of? (4 words)
Keratinsed stratified
squamous epithelium
what does the dermis layer consist of?
papillary layer and reticular layer
what is contained in the papillary layer of the dermis?
The papillary layer of the dermis contains:
Dermal papillae (ridges)
Capillaries
Sensory nerve endings (like Meissner’s corpuscles)
Fibroblasts
Loose connective tissue
what is contained in the reticular layer of the dermis?
The reticular layer of the dermis contains:
Dense irregular connective tissue
Collagen and elastin fibers
Blood vessels
Sweat and sebaceous glands
Hair follicles
Pacinian corpuscles (pressure sensors)
what does the dermis consist of (list)?
ECM (extracellular matrix) consists of: Elastin Fibres, Glycosaminoglycans (GAGs), Collagens
Fibrocytes, Macrophages, dendritic cells, Mast cells
Hair, glands and nerve endings
Blood supply and Lymphatic drainage
what does the subcutaneous layer have?
Subcutaneous layer has loose Connective Tissue, is rich in/mainly made up of of adipose tissue and is anchored to the skeletal muscle underneath
what are the functions of adipose tissue?
An effective heat insulator
Food storer
shock absorber
what is the adipose tissue in the subcutaneous tissue separated by?
The adipose tissue in subcutaneous tissue is separated by fibro-collagenous septa and contains the main blood vessels and nerves from which the overlaying dermis is supplied.
tell me about the skin pigmentation
Melanocytes (in or just superior to the stratum basale) are the cells that make the melanin and once the melanin is synthesised, it’s stored inside the melanosomes (melanosomes are located immediately above the nuclei in the keratinocytes of the stratum basale and stratum spinosum). The melanosomes are the vesicles that contain melanin, and these melanosomes are transferred from the melanocytes to the surrounding keratinocytes in the epidermis
