Flashcards
Structure & Function of the Skin
Cards in this deck (23)
- 1What are the 3 layers that make up the skin?1. Epidermis
2. Dermis
3. Hypodermis - 2Features of the 3 layers of skin1. Epidermis
• avascular epithelium
• undergoes proliferation
• synthesises keratin
2. Dermis
• vascular & tough layer
• contains blood vessels, lymphatics & cutaneous nerves - sensory
• comprised of collagen & elastic fibres which are not replaced with age
3. Hypodermis
• superficial fascia which varies in thickness
• contains blood vessels, lymphatics & nerves
• contains adipose tissue
• contains skin ligaments which determine the mobility of skin implicated in scarring & incision - 3What are the functions of the skin?Protection
Homeostasis
Provision of sensory info - 4What does the skin protect against & how does it do this?UV - via melanin
Organisms - via immune cells
Chemicals / water / mechanical stress - via keratin - 5What homeostatic controls does the skin provide?Metabolic - vitamin D & fat stores
Temp. regulation - vasodilation, sweating, fat stores & hair
Internal - water, electrolytes & macromolecules - 6What forms of sensory information can the skin receive?Sensation:
Pain - Temperature - Touch - Pressure - Vibration
Psycho-social signals:
Visual - Chemicals - 7What are the layers of the epidermis?S. Corneum - S. Lucidum - S. Granulosum - S. Spinosum - S. Basale
- 8Describe the stratum basale layerInterface with the dermis
• hemi-desmosomes anchor basal cells to the basal lamina
• Collagen 7 binds the epidermis to the dermis - 9What may occur when collagen 7 is mutated?Dystrophic epidermolysis bullosa - blistering
• link between BM & cells is weakened - 10Describe the stratum spinosum layerStratum spinosum are linked between cells via desmosomes & to the BM by hemi-desmososmes
Expression of keratin k1/k1 - 11Function of: Filaggrin & Pro-filaggrin• Maintain optimal skin barrier
• Main components in KERATOHYALINE granules in S. granulosum
• Aids keratin filament aggregation
• Inhibits water loss - filaggrin is cleaved into amino acids - 12IcthyosisA group of disorders of keratinisation characterised by dry, scaly skin
- 13Melanocytes are..• derived from neural crest cells which originate near the developing nervous system & spread into the embryo
• found in the basal layer of epidermis
• cells which synthesis & release, via exocytosis, melanin - which is then transferred to keratinocytes - 14Langerhans cells: Derived from? Location? Function?1. Monocytes
2. Most present in the S. spinosum
3. Antigen processing & presentation
Activated in the skin then migrate to the lymph nodes where they express langerin which degrades viruses (e.g. HIV) in Birbeck granules - 15Properties of the dermisDermo-epidermal junction -
• complex to prevent shearing
• Papillae flatten with age causing the skin to become more vulnerable
Papillary dermis -
• comprised of fine collagen + elastic fibres & small blood vessels + nerves
Reticular dermis -
• comprised of coarser collagen + elastic fibres & larger blood vessels + nerves - 16Function of: HypodermisSupports: deepest part of the hair follicle & eccrine + apocrine glands
Responsible for vitamin D production - 17Describe the 2 types of sweat glandsEccrine -
• simple coiled tubular glands which secret watery fluid
• lie in the dermis & superficial fascia - open onto the skin surface
• under sympathetic NS control
• important in thermo-regulagtion
Apocrine -
• found in the axillae & genital regions
• open into the hair follicles
• release milky secretions containing pheromones - 18Structure of hair folliclesCylindrical, epithelial structures anchored in the hypo-dermis. The hair shaft, comprised of keratin, grows from the bulb.
- 19What gland is the hair follicle shaft associated with?Sebaceous gland - which secretes sebum to lubricate the hair follicle & adjacent skin
- 20How is hair made to 'stand'?Arewctor pilli muscle, which is attached to the papillary dermis & to the sheath of the follicle, contracts
NOTE --> this is under Sympathetic NS control - 21What makes up the PILOSEBACEOUS UNIT?Hair follicle + Sebaceous gland + Hair shaft + Arrector pili
- 22What other skin appendages exits?Mammary glands - modified apocrine sweat glands
Nails - nail plate is formed of keratin & growth occurs from the nail root which passes into the dermis
Teeth - tooth enamel develops from epithelium, dentine, pulp & periodontal membrane (which is mesodermal) - 23Sense organs for: Pain Temperature Touch Pressure Vibration1. Nocio-receptors on free nerve endings
2. Free nerve endings
3. Meissners corpuscles
4. Pacinian corpuscles
5. Meissners & Pacinian corpuscles
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- MD2001 Flashcards on Structure & Function of the Skin, created by Lareyna Mcmenemy on 16/07/2018.
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- Lareyna Mcmenemy
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