Criado por Emma Allde
aproximadamente 8 anos atrás
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Questão | Responda |
What are the skin appendages? | Sweat glands, hair follicles, arrector pilli muscle, sebaceous glands |
What type of gland are sweat glands? | Exocrine and merocrine (unbranched and tubular) |
What are sweat glands important for? | Thermoregulation (evaporation of sweat) |
Sweat glands are innervated by what? | Sympathetic nervous system |
Describe the secretory portion of sweat glands: | * Highly coiled * Singe layer of cuboidal cells + layer of myoepithelial cells |
Where is the secretory portion of sweat glands located? | at junction of dermis and hypodermis |
What does the secretory portion of sweat glands produce? | isotonic fluid |
Describe the excretory duct | * Straight course through dermis * Corkscrew through epidermis * Stratified cuboidal cells |
What is the role of excretory duct? | Absorbs NaCl to produce hypotonic sweat |
Where are apocrine sweat glands found? | Axilla (armpit) and genital regions |
Apocrine sweat glands discharge into where? | Hair follicles |
What do the apocrine sweat glands discharge? | Sticky, milk fluid that becomes odiferous by microbial action |
When do the apocrine sweat glands come functional? | During puberty |
What is the mode of secretion for apocrine sweat glands? | Release of membrane-bound vesicles rich in lipid |
What are the modified apocrine sweat glands? | Mammary glands |
Where do sebaceous glands discharge into? | middle portion of hair follicles |
What do the sebaceous glands secrete? | Sebum |
What is sebum | Lipid rich secretion that maintains suppleness of skin |
What kind of gland are sebaceous glands? | Exocrine, holocrine glands |
What are arrector pili muscle? | Bundle of smooth muscle that inserts into the connective tissue sheath around the hair follicle and into the papillary layer of dermis |
What is the role of arrector pili muscle? | * Raising hair * Vestigial importance in man > goosebumps |
Hair follicles arise as what? | down growth of epidermis |
Keratinocytes of the hair bulb differ from the other keratinocytes in that? (2) | * They follow different differentiation pathways * Concentric rings or cells with different morphologies |
Describe the structure and location of Central medulla (hair follicle): | * Location * Centre of the hair only in thick hair * Lightly keratinised, large cells |
Describe the structure and location of Cortex (hair follicle): | * Location * Outer, third layer, surrounds the cortex * Very heavily keratinised scales |
Describe the structure and location of Inner root sheath (hair follicle): | * Location * Surrounds the hair, towards base of hair follicle * Degenerates at level of sebaceous glands, forms a space into which sebum is discharged |
Describe the structure and location of Outer root sheath (hair follicle): | * Location * Surrounds inner root sheath * Doesn't take part in hair formation; continuous with epidermis and contains reservoir of stem cells able to regenerate the epidermis |
Describe the structure and location of Glassy membrane (hair follicle): | Layer of connective tissue that surrounds the base of the hair follicle, connecting it to the dermis |
What is key to the differences between layers of the hair follicle? | Hair papilla |
What are hair papilla? | Specialised aggregation of connective tissue cells |
What is the role of hair papilla | Inductive role in directing hair formulation |
When do hair papilla form AND what happens if they are destroyed? | * Forms only one during development * If destroyed, hair cannot grow back |
Hair growth should be described as what? | Intermittent |
Growth phase for scalp? | Years |
Quiescence phase for scalp? | 3 months |
What is a quiescent follicle? | Club hair |
Growth phase for body hair? | Months |
Quiescence phase for body hair? | Years |
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