Lecture 27: Integument II

Question 1

Sebaceous glands

Answer 1

Holocrine, branched acinar glands with short ducts; found everywhere except palms and soles; continuously produce sebum - growth stimulated by sex hormones at puberty

Question 2

Merocrine Sweat (suderiferous) glands

Answer 2

Coiled, simple tubular secretory portions lined by simple epithelium; apical dark secretory cells secrete glycoproteins, basal clear cells secrete water and electrolytes; contain myoepithelial cells; cholinergic endings

Question 3

Apocrine Sweat (suderiferous) glands

Answer 3

Found in labia majora, areola, axillary and anal regions; secretions thicker and more viscous than merocrine types; excretory duct opens into hair follicle; adrenergic innervation; inactive until puberty

Special types: ceruminous glands, Glands of Moll

Question 4

Components of hair follicle

Answer 4

Root, free shaft, hair follicle; developed from epidermis as elastic, keratinized threads

Question 5

Hair bulb

Answer 5

expanded lower part of hair follicle with mitotically active matrix (hair growth) and vascularized dermal papilla

Question 6

Internal root sheath of hair follicle

Answer 6

Contains Henle’s layer, Huxley’s layer, Cuticle (which interlocks with cuticle of hair shaft)

Question 7

External root sheath of hair follicle

Answer 7

Down growth of epidermis with layers that mimic epidermis

Question 8

Hair shaft

Answer 8

Contains the following layers: medulla (innermost), cortex, cuticle - the overlap of follicle and shaft cuticles keep hair from falling out

Question 9

Keratinocyte stem cells

Answer 9

Re-establish epidermis in severely burned patients
Migration pathways: bulb-epidermis, bulb-sebaceous, bulb-hair stem cell
Signaling pathways: Wnt and Notch