INTEG 1 Flashcards
What is the Primary Function of Skin?
Barrier against Physical/Chemical and Biological Agent
State 3 other Functions of Skin?
Homeostatic (Temp & Water), Sensation, Secretory/Nutritional (Vit. D Production), Insulation, Cosmetic, Camouflage
State the 3 Basic Layers of Skin
Epidermis, Dermis, Hypodermis (Subcutaneous Tissue)
What is the Epidermis?
Everything down to Stratum Basale, varies in thickness
What is the Dermis?
Contains the Vessels and Nerves, between Stratum Basale and Adipose Tissue
What is the Hypodermis?
Connective/Adipose Tissue
State the Structure of the Epidermis and their Function
Stratum Corneum – Form Layers of Cells that cause the Outer Layer to Pull Away, Forms Soft Keratin (Has Lipids in it)
Stratum Granulosum – Granular Leaking (Precursor to Keratin). Keratinocytes then die and form Sheets of Keratin. Contains Keratohyalin (Keratin) and Lamellar (Adipose) Cells
Stratum Spinosum – Lots of Strong Desmosomes (Holds Cytoskeleton together)
Stratum Basale – Stem Cells that Divide to form Cells above them Flatten to form Horny Layer
What is a Friction Blister?
Constant Friction, cells burst forms clear liquid. Forms a Lump as Osmolality Vessels leak to balance this
What is Psoriasis?
Turnover of Horny Layer is too Rapid. Skin becomes Hardened and Sensitive
What is the Stratum Lucidum?
The Clear Layer found in Thick Skin contains immature Keratin (Eleidin)
State the types of Melanocyte?
Eumelanin (Brown/Black) and Pheomelanin (Red/Yellow)
What is Vitiligo?
Destruction of Melanocytes, could be Autoimmune or Infection
What are Langerhan Cells? Give an Example of how this can go wrong.
APCs – Mobile, present Ags to Lymph. Eczema/Skin Allergy
What are Merkel Cells?
Appear to be Sensory Cells. Mechanoreceptors? Modulate Nerve Sensitivity?
State 3 Facts about Hair.
Hard Keratin (No Lipids), have a Muscle Attached, Pubes grow in Tubular Cone
State the difference between the 2 types of Sweat Gland
Apocrine – Smell Bacteria Metabolise Secretions and under Adrenergic Control Ltd. Distribution
Eccrine – Just Sweat and Cholinergic Everywhere
What are Sebaceous Glands?
Produce Sebum that Lubes and Protects Hair
State 3 facts about Nails.
Hard Keratin, Nail Matrix forces Growth, Grows 3mm/month, Nail Bed (under nail) very sensitive
What is the Advantage of Goose Pimples? How does it happen?
Muscle on Hair Contracts, Hair Stands on End, Traps Layer of Air for Insulation
Why is Vit. D Production Important and how do we get it?
Ca2+/PO42- Metabolism, Prevention of Rickets, 90% formed in Skin & rest from Diet
Why is Vasculature in the Skin important?
Temp. Regulation
Outline the Adaptations and Advantages of Skin Vasculature.
2 Plexuses offering Deep Dermal and Capillary Control, allows different degrees of shutting off blood flow
Outline the Common Types of Nerve Fibres in Skin
Pain, Temp, Pressure/Mechanical
State the Different Types of Innervation in Skin and their Function
- Free Nerve Endings (Heat/Pain/Pressure), Hair Follicle Receptor (Mechanoceptors)
- Ruffini Endings/Corpuscles (Slowly-Adapting Mechanoceptors)
- Meissner Corpuscles on Hairless Skin (Sense Stretch of Incorporated Collagen Fibres)
- Pacinian Corpuscles lots in Fingertips (Rapidly Adapting Mechanoceptors)
- Merkel Cells (Slowly Adapting Mechanoceptors)
What is the difference between Insults and Integuments?
Integument – Skin, Hair or Nails
Insults – Stresses e.g. Dehydration or Infection
State 5 Insults.
Dehydration, Heat Loss (Hypo/Hyperthemia), Infection, Protein/Electrolyte Loss, CO, Renal Failure, Radiation/UV, Allergens, irritants, Microbes, Physical Trauma (Burns, Friction, Pressure)
State 5 features designed to protect against Insults and how they’re adapted to do so.
- Drying (Waterproof Epidermis & Oil from Sebaceous Glands)
- Friction/Impact (Nails, Thick Reforming Keratin, Basement Membrane for Anchorage
- Collagen Fibres in Dermis), Heat (Sweating & Vasodilation)
- Cold (Subcut. Fat, Hair & Adaptable Blood Supply)
- Burns/Injury (Thick Regenerating Epidermis) –
- Radiation/Sunlight (Melanin & Thick Epidermis)
- Infections (Resident Immune System),
How does Protection against UV occur?
Melanocytes secrete Melanin which is taken up by neighbouring cells. Melanocytes are arranged in Cap to Protect against DNA Damage
What is tanning and why is it significant?
Increased Melanocyte Activity increased Skin Thickening caused by DNA Damage
How can we protect ourselves against Microbes?
Dendritic Cells, Langerhan Cells Present Ags and Form Immunity Network in Epidermis
What is Lichenification?
Extreme Hyperkeratosis –> Excessive Rubbing/Scratching
What type of UV penetrates the Skin and how does it cause Damage?
UVA, Radiation Burn Blister, Inflammation, Cell Death/DNA Damage & Increased Risk of Cancer
What is Polymorphic Light Eruption?
Allergy to the Sun
What is Solar Elastosis?
Loss of Elasticity due to the Sun
What is a Naevus? (Naevi plural)
Benign Proliferation of Melanocytes - Increased Risk of Melanoma
What is Ephelides?
Freckles – Strong Genetic Link – Sun-Exposed Areas
What are Solar Lentigos? Who is more likely to get them?
Liver Spots, the Elderly
What are Solar Keratoses?
Dysplastic Growth of Keratinocytes – Early Sign of Cancer
What are the different types of Skin Cancer? What Cell Types do they affect
Melanoma (Melanocytes), Non-Melanoma (Keratinocytes)
What are the different types of Non-Melanoma Skin Cancer?
Squamous Cell Carcinoma & Basal Cell Carcinoma
What are the different types of Dermatitis and which is more common?
Irritant Contact (Common) & Allergic Contact (Rare)
Describe Irritant Dermatitis.
Hyperexposure of a Substance - Decrease Usage, Redness, Itching, Blisters/Scratching
Describe Allergic Dermatitis.
Allergy to Something (Sensitation can occur over a long or short period), Tiny amount may be sufficient
- Sensitisation – Langerhans present Ag to Lymphocyte
- Delay Hypersensitivity – Memory T Cells remember for the next time contact occurs
What are Dermal Papillae?
Where Vessels try to Reach the Surface
What are Rete Ridges?
Where Dermis and Epidermis are forced together
Why does Skin wrinkle in Water?
Granular Layer is where we make the Keratin & Lipids Hydrophobic. Outer Cells absorb Water but it cannot go anywhere. Outer Cells are fixed at one end and must therefore Wrinkle to expand with Water
State the Types of Glands
Erocrine – Vesicles Fuse with the Membrane and Leaves
Apocrine – Pinches off Vesicles
Holocrine – Makes loads of Secretions until the Cell Explode
