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Home , Eponychium, Stratum lucidum, Subcutaneous tissue

LECTURE OUTLINE & REVIEW QUESTIONS: 25 - GUTHRIE

I. INTEGUMENTARY SYSTEM Stem cells > mitosis > new Components: Integument: outer covering of body Production of filaments Appendages: , nails, glands Progressive flattening of cells Increasing surface area II. INTEGUMENT Cells held together by desmosomes Components, superficial to deep: } = “” } Keratin filaments + keratohyaline granules > } } Integument keratin Hypodermis: } Lamellated granules: glycolipids > extracellular or superficial space Areolar c.t. Cell death Dead, flattened cells packed with keratin Skin averages about: 16% of body weight 2 square meters surface area Thin Skin vs. Thick Skin 2 mm thickness Refers to epidermal thickness Thin skin: A. EPIDERMIS Most of body Stratified squamous keratinized epithelium ~ 0.07-0.12mm thick (varies) Keratin = “soft” form Hairs 1. Cell Types: Thick skin: a. Keratinocytes Palms and soles Life Cycle: 0.4-0.6mm thick Mitosis of stem cells in basal layers glabrous (no hairs) Pushed toward surface by newer cells Keratin production & accumulation Thick skin: Progressive flattening All strata thicker. Lose nucleus and organelles May have an additional layer: Desquamate (~ 1 gram/day) Average Time: 28-30 days Between granulosum and corneum

Functional Layers of Epidermis, Thin skin: (deep to superficial): All strata thinner (germinativum) No stratum lucidum A25lectout.inegument.mguthrie 1 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

Melanocyte processes contact keratinocytes Epidermal functions: surrounding it. Stratum corneum Produce and release melanin (pigment) Keratinized cells protect against: Tyrosine >>> melanin > melanosomes > physical and chemical trauma keratinocytes bacterial and parasitic invasion dehydration and imbibition Types of melanin: Eumelanin: brownish pigment, ovoid Stratum granulosum melanosomes Final keratin processing Pheomelanin: red-orange pigment, round Glycolipid coating of keratinocytes melanosomes Initial steps in Vitamin D production often “clearer” than surrounding Stratum spinosum keratinocytes Keratin precursors Increase in cell surface area Melanin function: Cell-to-cell adhesion: desmosomes Protects DNA from potentially mutagenic UV radiation (especially 290-320nm wavelengths) Stratum basale Stem cell divisions Tanning reactions: Initial: Some common epidermal phenomena Increased release of existing melanosomes Calluses & corns from melanocytes Blisters Melanosomes darken; cluster between Mucocutaneous junctions nucleus and incoming radiation. Response is ephemeral. b. Langerhans Cells Subsequent Exposures: Dendritic or APC cells Increased melanosome production and Part of mononuclear phagocyte system (MPS) release. Phagocytize and present antigens Tan loss: Initial: reversal of darkening, clustering c. Melanocytes Secondary: lysosomal destruction of Located mostly at dermal-epidermal junction, melanosomes; desquamation of cells lower layers of epidermis Form - units:

A25lectout.inegument.mguthrie 2 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

Skin color (pigmentation): Inability of melanocytes to take up tyrosine or Three additive components: defective tyrosinase. Melanin Melanocyte ger  tyrosinase  golgi body  Carotenoids: yellowish pigment in tissues melanosome: tyrosine uptake; tyrosinase Hemoglobin: reddish pigment in blood catalyzes conversion of tyrosine to DOPA (1,3,4 Population and individual variations: dihydroxyphenalanine); DOPA  Darker complexions: dopaquinone  melanin Melanocytes more active > more melanosomes Melanomas Melanosomes: larger, tend remain unclustered in cell d. Merkel’s Cells persist through more layers of epidermis Tactile (touch) receptors Lighter complexions: Processes between surrounding keratinocytes Melanocytes less active > fewer Cell in contact with sensory ending melanosomes Melanosomes: B. DERMIS smaller, tend cluster in cell Between epidermis and hypodermis restricted to lower layers of epidermis Two layers: Superficial: papillary layer. Loose (areolar) ct Some phenomena due to melanocytes: Projections (“papillae”) interlock with undersurface of Freckles epidermis Moles Deep: reticular layer. Dense irregular ct Pregnancy: Abundant collagenous & elastic fibers Cloasma: increased melanin in cheeks, Arranged to withstand mechanical stresses forehead Directions vary with body region Linea nigra: increased melanin over linea alba Cleavage planes in abdomen Areola: increased melanin Contents: “Mongoloid spot” follicles & Arrectores pilorum mm. Bluish area of skin, usually in sacral region Sebaceous glands More common in Asian infants Sweat glands Melanin in deep dermis Eccrine Usually disappears with age Apocrine (axilla & only) Albinism Sensory receptors Melanin absence : Genetic: autosomal recessive A25lectout.inegument.mguthrie 3 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

Autonomic > smooth m., glands Vascular Supply: Somatic > sensory receptors : Blood vessels Rete cutaneum: dermis-hypodermis junction Rete subpapillare: reticular-papillary junction Dermal – Epidermal interlocking Capillary loops into dermal papillae Thick skin: : Basic pattern: Rete cutaneum: dermis-hypodermis junction Dermal ridge projects into undersurface of Rete subpapillare: reticular-papillary junction epidermis Plexus in middle of reticular layer Epidermal ridge projects into primary groove A-V Shunts: Direct - connections running length of dermal ridge. Thermoregulation: Papillae project from dermal ridge into epidermis Cold temperature exposure: A-V shunts dilate > Epidermal ridges project into furrows between less blood to outer skin capillaries > minimizes dermal ridges heat loss Sweat glands open into primary groove Hot temperature exposure: A-V shunts constrict > Functions: more blood to outer skin capillaries > maximizes Mechanical support heat loss Blood supply Blushing, , and blanching Dermatoglyphs Palmar and plantar surfaces C. HYPODERMIS Surface grooves and ridges; reflect interlocking Aka: superficial fascia, subcutaneous tissue pattern Finger prints Superficial layer: Loops, whorls, arches White Palm prints, foot prints, toe prints Paniculus adiposus Genetics + environmental factors Lobulated or loculated Function: Increased friction Amount varies with age, sex, diet, health Functions: Flexion creases and expansion folds Insulation Cushioning Thin Skin: Lipid storage Interlocking less complex and extensive: Body contours “Peg” and “Socket” Secondary sexual characteristics Regional surface patterns

A25lectout.inegument.mguthrie 4 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

Brown fat (adults) Follicle Structure & Terminology: Small amounts in limited areas Layers (external to internal) Dermal or sheath III. APPENDAGES Glassy membrane Hairs, nails, glands External } essentially stratum basale. All are epidermal derivatives Internal root sheath } spinosum, granulosum of the follicle (lower part of follicle only) A. HAIRS Bulb (bottom of follicle) Types: Coarse (terminal): scalp, axilla, pubic Small “hill” of epidermal cells Vellus (fine): most of body Mitosis of cells generates hair Lanugo (woolly): fetus Dermal papilla Dermal connective tissue Downgrowth of epidermis into dermis Invaginates bottom of hair bulb Stratum corneum disappears Capillaries: vascular supply to matrix cells Follicle associated structures: Hair bulge Arrectores pilorum muscles (sing. = arrector pili) Located in upper follicle wall, near sebaceous Bands of smooth muscle gland duct Angle from follicle wall up to skin Cluster of stem cells Attachments: Migrate to hair matrix Lower end: ct of upper part of follicle Initiate hair growth Upper end: dermis just below epidermis Genetic control: nFAT gene ? Functions: Hair Structure & Terminology Hair follicles set at an angle to skin surface Essentially composed of concentric cylinders of dead Contraction of arrectores pilorum muscles keratinized cells produced by hair matrix cells. Decreases follicle angle (hairs “stand up”) Cuticle Pull surrounding skin down (“goose bumps”) Outermost cylinder of overlapping cells Occurs in response to cold, fear, excitement “Hard” keratin Thermoregulation: Traps insulating layer of air next to skin Inside cuticle Protection against assault: Thickness varies Animal looks “bigger” and “tougher” “Hard” keratin Harder to get a good “bite” (most coarse hairs) Sebaceous glands Inside cortex Located in angle between follicle and arrector pili “Soft” keratin Ducts open into follicle A25lectout.inegument.mguthrie 5 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

Hair root & shaft (cuticle) = fold of epidermis at proximal Root anchored to follicle walls end of plate. Shaft free of follicle walls, exits at skin surface = attachment of undersurface of plate Hair growth cycles to epidermis of digit; just proximal to “free” or distal Active follicle end of the plate Hair bulge stem cells > matrix (“little moon”) = whitish area of plate just Dermal papilla invades matrix distal to eponychium Matrix cells divide mitotically to produce hair Most noticeable on pollex Hair bulb is prominent Varies on other digits Quiescent follicle Development & Growth: Dermal papilla recedes Epidermis folds into dermis overlying proximal Matrix cell mitosis ceases phalanx. Hair bulb shrivels Stratum corneum disappears Hair root looses connections with follicle cells Epidermal cells form nail bed and matrix Called a “club hair” because of its microscopic Matrix cells divide mitotically appearance. Produce sheets of dead cells filled with hard Hair “falls out” keratin. Hair color Melanin (eumelanin and/or pheomelanin) C. GLANDS Melanocytes in hair matrix Melanosomes “injected” into hair cells 1. SEBACEOUS (oil) GLANDS Trapped air bubbles Class: exocrine Hair form Structure: simple branched alveolar “Kinky, wavy, or straight” Location: dermis Cross-sectional shape: flat, oval, round Absent in palms, soles, and sides of feet “Heavy, coarse, fine” Duct termination: Cross-sectional diameter Most > hair follicles, but on , glans penis, glans clitoridis, and areola of B. NAILS > skin surface Terminology: Density: ~100/cm2 over most of body Nail plate = body of nail ~400-900/cm2 on scalp, forehead, face Nail root = proximal part of plate embedded in Secretion: sebum epidermis Mode: holocrine Lateral nail folds (walls) = ridges of epidermis Content: triglycerides, cholesterol, waxes, cell flanking lateral edges of plate debris Lateral nail grooves = grooves between folds and plate Start: puberty A25lectout.inegument.mguthrie 6 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

Hormonal regulation: Content: water, sodium chloride, urea, uric acid, testosterone (males) ammonia ovarian and adrenal androgens (females) Filtrate of blood plasma produced by secretory Function: unit cells and modified by duct cells. Lubrication of skin and hair Start: shortly after birth Softness & flexibility Functions: Antibacterial / antifungal actions? Primary: thermoregulation Evaporation at skin surface : result of bacterial activity Exothermic (heat loss) Works in tandem with vasoconstriction of A-V Meibomian (tarsal) glands shunts Located in tarsus of Secondary: excretion Tarsus = curved plate of dense ct. Some electrolytes & nitrogenous waste products Stiffens lids Neural control: cholinergic autonomic nerves Maintains lid curvature Ducts terminate at free edges of lids 3. APOCRINE SWEAT GLANDS Chalazion: an impacted tarsal gland due to duct Class: exocrine clogging. Structure: simple coiled tubular Duct: stratified cuboidal 2. ECCRINE SWEAT GLANDS Secretory unit: simple cuboidal or columnar (SUDODIFEROUS)GLANDS Diameter: ~ 3mm Class: exocrine Myoepithelial cells surround secretory unit cells Structure: simple coiled tubular Location: dermis of axillary and perineal regions Duct: stratified cuboidal epithelium Duct termination: hair follicles Secretory unit: simple cuboidal or columnar (Apocrine glands develop as outgrowths of hair Diameter: ~0.4 mm follicles.) Cell types: Secretion: Clear cells Mode: Merocrine Dark cells Start: puberty Myoepithelial cells surround secretory unit cells Content: Pheromones ? Location: dermis and hypodermis Glands resemble those that produce sexual Duct termination: skin surface via “sweat pore” attractants in other animals. Channel between epidermal cells Odor is produced by bacterial actions on Numbers: 2-4 million secretion. Secretion: sweat Neural control: adrenergic autonomic nerves Mode: merocrine Hormonal influence: A25lectout.inegument.mguthrie 7 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

Axillary apocrine glands undergo size and High in antibodies (immunoglobulins) cytological changes during menstrual period. Breast Structure & Terminology 4. MODIFIED (APOCRINE) SWEAT GLANDS Location: anterior thorax A. Mammary Glands Overlies Pectoralis major m. Location: breast Separated from muscle by fascial plane Class: exocrine : epidermis + elevated cone of dermis Structure: compound tubuloalveolar Contains: 15-20 independent lobes enveloped by ct terminations of 15-20 lactiferous ducts containing variable amounts of white fat parallel bands of smooth muscle Each lobe is subdivided into lobules. sebaceous glands that empty directly onto Each lobe is drained by a lactiferous duct. surface Duct empties at apex of nipple Areola: pigmented area around nipple Lactiferous sinus = dilatation of duct Dermis contains: near its termination. lactiferous ducts (and sinuses ?) Duct system: smooth muscle Smaller ducts: simple cuboidal to columnar radial fibers Larger ducts: stratified cuboidal to columnar circular fibers around base of nipple Surrounded by myoepithelial cells contractions cause nipple erection and Non-lactating breast: wrinkling of areola in response to cold, Duct system only tactile stimulation, or emotion Undergoes some cyclic changes with Suspensory ligaments: menstrual cycle. Bands of dense ct separating lobes and their Lactating breast: enveloping . Duct system + secretory units Run from deep fascia over Pectoralis major to Secretion: dermis underlying epidermis Mode: apocrine Contents: water (~88%); protein, primarily B. Ceruminous glands casein (~1.3%); carbohydrates, primarily Location: external acoustic meatus (auditory lactose (~6.5%); lipids (~3.3%); electrolytes canal) (Na, K, Cl); minerals (Fe, Mg, Ca); Class: exocrine immunoglobulins A and E; fragments of Structure: simple coiled tubular secretory unit cells Duct termination: skin surface or hair follicle Colostrum: Secretion: cerumen (“ear wax”) First few days of lactation Yellow-brown to grayish waxy material Less fat and more protein than later milk. A25lectout.inegument.mguthrie 8 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

May be either “wet and sticky” or “dry and 2. Encapsulated flaky” a. Some correlations between wax type and Dermis, hypodermis incidence of breast cancer Touch, pressure, vibration Functions: b. End of Ruffini Waterproofing (?) Dermis, hypodermis (especially of foot) Protection against infection (?) Continuous touch, pressure, tension Insect repulsion (?) c. End Bulb of Krause Papillary layer of dermis C. Glands of Moll Conjunctiva, genitals Location: eyelids between hair (eyelash) follicles Touch, temperature ? Class: exocrine d. Meissner’s Corpuscles Structure: simple coiled tubular Dermal papillae of glabrous skin Duct termination: hair (eyelash) follicle Palmar surface of , plantar surface of Function: Secretion may foot, , lips, genitals Help lubricate (?) Touch, light pressure, two point discrimination Combine with sebum from eyelid sebaceous glands (glands of Zeis and Meibomian or 3. Merkel’s Discs tarsal glands) to retard evaporation of tears (?) Lower epidermis Usually in groups called Iggo domes IV. INNERVATION Merkel’s cells + keratinocytes Cutaneous branches of spinal and some cranial nerves. Continuous touch, pressure

A. Autonomic nerves (adrenergic & cholinergic) Glands; arrectores pilorum muscles, smooth muscle in REVIEW QUESTIONS blood vessels 1. The most superficial layer of the integument is the _?_. (a) B. Somatic sensory (afferent) nerves to sensory receptors hypodermis (b) dermis (c) epidermis (d)superficial fascia (e) Cutaneous receptors: deep fascia 1. Free or naked nerve endings a. Between epidermal cells 2. The epidermis is a keratinized _?_ epithelium. (a) stratified Pain, temperature, (response to histamine), columnar (b) stratified cuboidal (c) stratified squamous (d) pseudostratified columnar (e) none of these tickle b. Hair end organ Around bulb of hair follicle Touch (motion) A25lectout.inegument.mguthrie 9 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

3. The epithelial cells of the epidermis are called _?_. (a) 11. The stratum corneum protects against: (a) dehydration (b) keratinocytes (b) fibrocytes (c) melanocytes (d) Langerhans cells chemical and physical damage (c) bacterial invasion (d) all of (e) none of these these (e) none of these.

4. Select the incorrect statement. Epidermal cells _?_. (a) are 12. Calluses and corns _?_. (a) are thickenings of the stratum produced by mitosis of stratum basale cells (b) take 20-30 days to granulosum (b) are epidermal responses to increased pressure reach the skin surface (c) produce and accumulate soft keratin as and friction (c) are due to increased mitosis in the stratum they progress to the surface (d) are held together by desmosomes corneum (d) all of these (e) none of these until they desquamate (e) die after they flake off the skin surface 13. The Langerhans cells of the skin are _?_. (a)sensory receptors for 5. Which sequence best indicates the epidermal strata through touch (b) dividing keratinocytes (c) of the MPS which a skin cell passes on its way to the surface ? (a) (d) inactive melanocytes (e) defective keratinocytes corneum, lucidum, granulosum, spinosum, basale (b) basale, spinosum, granulosum, lucidum, corneum (c) basale, 14. Select the incorrect statement. Melanin _?_. (a) is produced by granulosum, spinosum, lucidum, corneum (d) basale, lucidum, melanocytes (b)is a pigment derived from the amino acid glycine granulosum, spinosum, corneum (e) none of these (c)is packaged as structures called melanosomes (d)protects the DNA of skin cells from damage by ultraviolet radiation (e) 6. The terms "thick” and "thin” skin refer to the relative thicknesses occurs in two forms: eumelanin and pheomelanin of the _?_. (a) hypodermis (b) dermis (c) epidermis (d) stratum corneum (e) none of these 15. Melanocytes _?_. (a) are equally distributed in all areas of the skin (b) develop from mesenchymal cells (c) form units 7. Thick skin _?_. (a) is characteristic of the palms and soles (b) is consisting of one melanocyte in contact with several normally glabrous (c) has a more complex epidermal-dermal keratinocytes (d) all of these (e) none of these interlocking than thin skin (d) all of these (e) none of these 16. Compared to lighter skinned individuals, darker skinned 8. The stratum _?_ is usually present in thick skin, but absent in individuals tend to have _?_. (a) larger melanin granules (b) thin skin. (a) corneum (b) lucidum (c) granulosum (d) melanin granules that are more widely scattered inside the cell spinosum (e) basale (c) melanin granules that are more widely distributed through 9. Stratum granulosum cells _?_. (a) produce and accumulate the epidermis (d) all of these (e) none of these keratohyalin (b) produce and secrete lamellar granules containing lipids (c) are involved in vitamin D synthesis (d) all of these (e) 17. Skin color is due to _?_. (a) hemoglobin in blood vessels (b) none of these carotenoids in skin connective tissues (c) melanin in melanocytes and keratinocytes (d) all of these (e) none of these 10. Select the incorrect statement. Stratum corneum cells _?_. (a) have no nuclei or organelles (b) are coated with lipids (c) have a 18. The initial tanning reaction is not due to _?_. (a) exposure to UV much smaller surface area than stratum basale cells (d) are radiation (b) increased release of existing melanin granules from packed with keratin (e) normally desquamate at the rate of about melanocytes (c) increased melanin production (d) darkening of 1-2 grams per day. existing melanin granules (e) clustering of existing melanin granules around the nuclei of keratinocytes A25lectout.inegument.mguthrie 10 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

determing the direction of surgical incisions (d) have different 19. Which of the following is not related to melanocytes ? (a) the orientations in different parts of the body (e) affect the size and cloasma and linea nigra of pregnancy (b) psoriasis (c) albinism appearance of scar formation (d) the “mongoloid spot” of some infants (e) melanomas 28. The _?_ is also called the superficial fascia or subcutaneous tissue. (a) hypodermis (b) hypophysis (c) hyponychium (d) 20. The entrance to the _?_ is not a mucocutaneous junction. (a) hypothalamus (e) none of these oral cavity (b) ear canal (c) (d) anal canal (e) vagina 29. The paniculus adiposus is a regionally variable accumulation of 21. The dermis _?_. (a) lies between the epidermis and the fat located in the _?_. (a) dermis (b) deep fascia (c) epidermis hypodermis (b) contains blood vessels, nerves, and cutaneous (d) hypodermis (e) corium nerve receptors (c) contains hair follicles, sweat glands and sebaceous glands (d) all of these (e) none of these 30. The adipose tissue of the paniculus adiposus _?_. (a) provides thermal insulation (b)provides protective padding over bony 22. The superficial layer of the dermis _?_. (a) is called the reticular prominences (c)is responsible for the differing body contours of layer (b) forms dermal papillae that interlock with the epidermis males and females (d) all of these (e) none of these (c) is a sheet of dense irregular ct. (d) all of these (e) none of these 31. The skin moves loosely over the body wall because there is a layer of areolar tissue between the _?_. (a) epidermis and dermis 23. The deep layer of the dermis _?_. (a)is called the papillary layer (b) dermis and hypodermis (c) hypodermis and deep fascia (d) (b)consists of areolar c.t. (c)is thinner than the superficial layer of deep fascia and muscles (e) none of these the dermis (d) all of these (e) none of these 32. Nails _?_. (a) are epidermal derivatives (b) are plates of stratified 24. Dermal papillae _?_. (a) contain capillaries that supply the squamous keratinized cells (c) contain "hard" keratin (d) are epidermal cells (b) contain sensory receptors (c) are more essentially sheets of stratum corneum (e) all of these. complex in thick skin than in thin skin (d) all of these (e) none of these 33. _?_ is the anatomical name for the cuticle of a nail. (a) hyponychium (b) lunula (c) eponychium (d) nail matrix (e) 25. The patterns of ridges on the palmar surfaces of the and lateral nail wall the plantar surfaces of the feet are called _?_. (a) mucocutaneous junctions (b) flexion lines (c) dermatoglyphs (d) cleavage planes 34. The crescent-shaped white area visible on some nails just distal (e) none of these to the eponychium is called the _?_. (a) lunula (b) hyponychium (c)nail bed (d)nail matrix (e)lateral nail wall 26. Dermatoglyphs _?_. (a) are genetically determined (b) reflect dermal-epidermal interlocking patterns (c) increase skin surface 35. The white area on the distal end of the nail plate marks the friction (d) all of these (e) none of these attachment of the _?_ to the undersurface of the nail. (a) lateral nail wall (b) hyponychium (c)eponychium (d) lunula (e)none of 27. Select the incorrect statement. Cleavage planes _?_. (a) reflect these the orientation of the collagenous and elastic fibers in the dermis (b) are also referred to as flexion creases (c) are important in A25lectout.inegument.mguthrie 11 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

36. During growth, cells are added to the nail plate from the _?_. (a) vascularity of the dermal papilla increases (c) hair matrix cells nail bed (b) nail matrix (c) hyponychium (d) eponychium (e) divide mitotically (d) all of these (e) none of these lunula 46. Which factor does not affect hair color ? (a) eumelanin (b) 37. The fine hairs covering most of the adult body are called _?_. (a) pheomelanin (c) reflective properties of trapped air (d) vellus (b)lanugo (c)coarse (d)terminal (e) club orientation and shape of the follicle

38. The hairs of the scalp, axilla, pubic area, and eyelashes are _?_. 47. Sebaceous glands _?_. (a) mostly empty into hair follicles (b) are (a) vellus (b)lanugo (c) terminal (d) club (e) none of these. simple coiled tubular glands (c) are merocrine (d) all of these (e) none of these 39. The outermost layer of a hair shaft is the _?_. (a) cuticle (b) medulla (c) cortex (d) external root sheath (e) internal root 48. Sebaceous glands in the skin of the _?_ open directly onto the sheath skin surface. (a) glans penis and clitoridis (b) lips (c) areola of the breast (d) all of these (e) none of these 40. Most vellus hairs lack a _?_. (a) cortex (b) medulla (c) cuticle (d) (e) 49. Select the incorrect statement. Sebaceous gland secretions _?_. (a) are called sebum (b) consist of lipids and cellular debris (c) 41. Hair follicles _?_. (a) ) are epidermal derivatives (b) are located begin to be produced immediately after birth (d) lubricate the in the dermis of thin skin (c)undergo active and quiescent phases skin and hair (e) may have some antibacterial actions (d) all of these (e) all of these 50. Select the incorrect statement. Arrectores pilorum muscles _?_. 42. Which sequence best describes the layers of a hair follicle from (a) are bands of smooth muscle (b) attach to the connective outermost to innermost ? (a) ct sheath, external root sheath, tissue sheath of a hair follicle and the dermis just beneath the glassy membrane, internal root sheath (b) ct sheath, glassy epidermis (c) are attached only to the follicles of vellus hairs (d) membrane, external root sheath, internal root sheath (c) internal may help to express sebum from sebaceous glands (e) contract in root sheath, external root sheath, glassy membrane, ct sheath (d) response to cold or fear, causing “goose bumps” of the skin and none of these erection of the hairs

43. Hair growth occurs at a part of the follicle known as the _?_. (a) 51. Both eccrine and apocrine sweat glands are _?_. (a) simple coiled cuticle (b) matrix (c) cortex (d) c.t. sheath (e) internal root tubular (b) merocrine (c) exocrine (d) all of these (e) none of sheath these

44. When a hair follicle becomes quiescent _?_. (a) the blood supply 52. Eccrine sweat glands _?_. (a) open into hair follicles (b) are to the matrix decreases (b) the hair bulb shrinks in size (c) the involved primarily in thermoregulation and secondarily in non-growing hair becomes a club hair, loosens in the follicle, and excretion (c) are less numerous than apocrine sweat glands (d) eventually falls out (d) all of these (e) none of these. are activated at puberty (e) none of these

45. When a hair follicle shifts from quiescent to active _?_. (a) stem cells migrate from the hair bulge to the hair matrix (b) A25lectout.inegument.mguthrie 12 LECTURE OUTLINE & REVIEW QUESTIONS: INTEGUMENTARY SYSTEM ANATOMY 25 - GUTHRIE

53. Apocrine sweat glands _?_. (a) are located in the axilla and perineum (b) usually empty into hair follicles (c) are activated 62. If the arteriovenous shunts of the skin constrict, then _?_ blood only at puberty (d) probably produce pheromones (e) all of these flows to the integument; if they dilate, then _?_ blood flows to the integument. (a) more, less (b) less, more 54. Acne is a problem with the secretions of _?_ glands. (a) eccrine sweat (b) apocrine sweat (c) ceruminous (d) mammary (e) 63. If the environmental temperature drops, the arteriovenous shunts sebaceous of the integument _?_; if the temperature rises, then the arteriovenous shunts _?_. (a) constrict, dilate (b) dilate, constrict 55. The female breast consists of __?__. (a) fatty tissue (b) (c) dilate, dilate (d) constrict, constrict (e) none of these tissue (c) an areola (d) a nipple (e) all of these 64. When an individual blushes, the AV shunts in the integument 56. The mammary glands __?__. (a) are compound tubuloalveolar _?_. (a) dilate (b) constrict glands (b) are modified sweat glands (c) are divided into 15 to 25 lobes which are subdivided into lobules (d) all of these (e) 65. The glands, arrectores pilorum muscles, and smooth muscle in none of these blood vessels are controlled by _?_. (a) autonomic nerves (b) somatic nerves 57. Lactiferous ducts __?__. (a) are the excretory ducts of mammary gland lobes (b) have dilations called lactiferous sinuses just 66. Which somatic sensory nerve endings are pain and temperature below the areola (c) open on the tip of the nipple (d) all of these receptors ? (a) bulbs of Krause (b) free nerve endings wrapped (e) none of these around hair follicles (c) free nerve endings between epidermal cells (d) Meissner’s corpuscles (e) Ruffini corpuscles 58. The areola __?__ of the breast. (a) surrounds the nipple (b) is more darkly pigmented than the surrounding skin (c) contains 67. Meissner’s corpuscles ? (a) are touch and light pressure receptors large sebaceous glands opening directly onto the surface (d) all of (b) located in dermal papillae (c) very numerous in the skin of these (e) none of these the fingertips (d) all of these (e) none of these

59. A non-pregnant, post-pubertal female's breast does not contain 68. Which cutaneous receptors are motion sensors ? (a) Merkel’s __?__. (a) mammary gland ducts (b) fat (c) mammary gland discs (b) free nerve endings wrapped around hair follicles (c) free secretory units (d) a connective tissue stroma (e) an areola nerve endings between epidermal cells (d) Meissner’s corpuscles (e) Pacinian corpuscles 60. The arterial plexuses of the skin _?_. (a) supply the components of the integument with nutrients (b) are involved in 69. Which encapsulated cutaneous receptor responds to deep thermoregulation (c) are located at the hypodermal-dermal and pressure ? (a) Meissner’s (b) Ruffini (c) Pacinian (d) Krause (e) reticular-papillary junctions (d) all of these (e) none of these none of these

61. Arteriovenous shunts _?_. (a) directly connect arteries and veins (b) by-pass capillary beds (c) control the amount of blood flowing to the outer parts of the integument (d) all of these (e) none of these A25lectout.inegument.mguthrie 13