Skin (Exam II) Flashcards
What is the largest organ of the body?
Skin
What are the 4 main functions of skin?
- Protection
- Sensation
- Thermoregulation
- Metabolic functions
What are the 3 main layers of skin?
- Epidermis
- Dermis
- Hypodermis
The hypodermis may also be called:
Subcutis
What types of insult does the skin provide protection from? (4)
UV, Mechanical, chemical & thermal
Our skin has protective qualities that prevent ______; and provides a physical barrier to ______.
Prevents dehydration
Microoganisms
Our skin is the largest _____ organ of the body.
Sense
The skin contains receptors for: (4)
Touch, pressure, pain & temp
Skin thermoregulation functions via:
Insulation via hair & subcutaneous fat
Heat loss in skin occurs by:
Sweat glands & dermal capillary network
For metabolic function of skin, energy is stored in:
Subcutaneous fat
Energy is stored in subcutaneous fat primarily as:
Triglycerides
Vitamin D is synthesized in the skin via:
Sunlight waves
What type of cells occupy the epidermis?
Keratinized, stratified squamous epithelium
The cells of the epidermis are called:
Keratinocytes
The epidermis varies in thickness, and this difference is reflected in terms of:
Thick skin and thin skin
Epidermis made of a thick highly keratinized layer
Thick skin
Thick skin is restricted to:
Volar (soles)
Palmar (palms)
Thick skin lacks _____, so its termed _____.
Hair; Glabrous
Most of the body is covered in _____.
Thin skin
Epidermis lacks:
Blood vessels
Blood vessels do not penetrate the:
Basement membrane
Epidermis is supplied and nourished by blood vessels in the:
Underlying (sub adjacent) dermis
When epidermis and dermis are combined, where is skin the thickest?
Shoulders and back of neck
Composed of dense, irregular, collagen outs connective tissue, interspersed with elastic fibers
Dermis
What type of collagen is present in the collagenous connective tissue of the dermis?
Type 1 collagen
Progressive damage to the elastic fibers or the dermis from sunlight waves results in:
Aging/loss of skin tone
Aging is caused by damage to:
Elastic fibers
The dermis is highly ____ and contains many _____.
Vascular ; sensory receptors
What are the two layers of the dermis?
Papillary layer & reticular layer
The papillary of the dermis is ____ and the reticular layer of the dermis is _____.
Papillary= superficial
Reticular= deep
Relatively thin layer of the dermis that interdigitates with the epidermis
Papillary layer
______ increase surface area for attachment and prevent shear and mechanical abrasion within the dermis
Corrugations
Epidermal projections into the dermis:
Epidermal ridges (rate ridges)
Epidermal ridges may also be called:
Rete ridges
Dermal projections into the epidermis:
Dermal ridges
Dermal ridges may also be called:
Dermal papillae
Large dermal ridges in the skin are called:
Fingerprinted (dermatoglyphs)
Fingerprints/ dermatoglyphs are:
Unique to each individual
What prevents the epidermis from peeling off when you bump into something?
Corrugations
Deeper layer of dermis that is thicker and less cellular than papillary layer:
Reticular layer
The reticular layer of the dermis contains: (3)
Hair follicles, sweat glands, and sebaceous glands
The reticular of the dermis interdigitates with the underlying:
Hypodermis (subcutis)
Within the reticular layer of the dermis, thick collagen bundles & elastic fibers form:
Lines of tension (langer’s lines)
Skin incisions parallel to langer’s lines heal with:
Less scarring
Located below the dermis:
Hypodermis
Layer of loose, irregular connective tissue and adipose tissue
Hypodermis
What are all the different names for hypodermis? (3)
Subcutis, superficial fascia, panniculus adiposus
What are the 3 vascular plexi of the skin?
Subpapillary plexus
Cutaneous plexus
Subcutaneous plexus
The Subpapillary plexus is the most:
Superficial
The cutaneous plexus is located:
In between subpapillary plexus and subcutaneous plexus
The subcutaneous plexus is the most:
Deep
Arrange the vascular plexi of the skin in order of superficial to deep:
- Subpapillary plexus
- Cutaneous plexus
- Subcutaneous plexus
The subpapillary plexus is located at the junction of:
Papillary and reticular layers
Cutaneous plexus is located at the junction of:
Reticular layer and hypodermis
The subcutaneous plexus is located deep within:
Hypodermis
What vascular plexi is the largest?
Subcutaneous plexus
The vascular plexi of the skin are used in:
Thermoregulation
The vascular plexi of the skin are used in thermoregulation, especially in fingertips and ears, and are associated with _____ containing _____
AV shunts; glomus bodies
Thickened regions of smooth muscle in wall of arterioles, surrounded by connective tissue capsule
Glomus bodies
Bypass capillary bed, re-route blood from arterial to venous circulation
Glomus bodies
On winter day when outside our hands and feet get cold due to:
AV shunts and glomus bodies
Layer of skin that is continuously grown and replaced
Epidermis
It takes ~25-50 days for cells to travel from ______, mature, and be sloughed from _____.
Deep germinal layer ; superficial epidermis
In _____, keratinocyte maturation takes only ~1 week
Psoriasis
In psoriasis there is an absence of a ____ layer
Granular layer
In psoriasis we have abnormal: (2)
Keratohyaline & tonofibrils
Layers of the epidermis include:
- Stratum basale
- Stratum spinous
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
What is another name for stratum basale:
Stratum germinativum
What is the basal layer of the epidermis?
Stratum basale
Mitotic layer or cuboidal germinal cells in the epidermis are bound to the basement membrane by:
Hemidesmosomes
Hemidesmosomes attach to the underlying dermis via: (2)
Anchoring filaments and microfibrils
Prickle cell layer
Stratum spinosum
Layer of epidermis where the cells look spiny; and its thickest layer of epidermis in the skin
Stratum spinosum
Prominent cells within stratum spinosum
Polyhedral cells
Polyhedral cells within the stratum spinosum have prominent: (3)
Intercellular bridges (desomosomes), numerous cytoplasmic processes & lateral folding of cell membrane
Predominant cell product of the stratum spinosum:
Cytokeratin
Cytokeratin of the stratum spinosum forms ______ that aggregate into larger _____ and anchor onto desmosomes
Tonofilaments ; Tonofibrils
Epidermal layer that helps glue the cells of the epidermis together, and prevents sloughing or separating
Stratum spinosum
Anchor to desmosomes and provide increased support
Tonofibrils
What type of keratin do humans produce?
Alpha keratin
What type of keratin do birds and reptiles produce?
Beta keratin
What is the difference between alpha and beta keratin:
Beta keratin is more robust, thicker and stronger than alpha keratin
Granular cell layer of epidermis
Stratum granulosum
The stratum granulosum is characterized by cells containing basophilic, _________.
Keratohyaline granules
The keratohyaline granules of the stratum granulosum are:
Basophilic
Basophilic, Non-membrane bound, electron-dense granules within the stratum granulosum
Keratohyaline granules
In the stratum granulosum, the keratiniziation of cells represents the interaction between:
Keratohyaline granules & tonofibrils
The cells of the stratum granulosum have distinctive:
Stippled cytoplasmic staining
Keratiniziation is initiated by the release of:
Lysosomal enzymes
The release of lysosomal enzymes in keratiniziation, results int he rupture of ________ & polymerization of their contents
Keratinohyaline granules
During keratinization process, following the rupture of keratohyaline granules & polymerization of their contents, this forms a:
Matrix for tonofibrils of cytokeratin
During the keratinization process, the matrix formed for tonofibrils of cytokeratin leads to an amorphous mass of:
Mature keratin
In keratiniziation release of lysosomes causes what to happen to the cell?
Cell death
As the keratinocytes mature, the _____ and lose ____.
Die and lose nuclei
Cells of the granular layer contain membrane-bound, lamellar structure called:
Keratinosomes
_____ contain glycolipids which provide waterproofing coat for skin cells
Keratinosomes
Cells of what layer mature to form waterproof layer of keratinized cells, with glycolipid coating on surface of epidermis.
Granular layer
Layer of epidermis present only in thick skin:
Stratum lucidum
Homogenous compact layer of enucleate cells between stratum granulosum & stratum corneum
Stratum lucidum
What type of cells are present in the stratum lucidum?
Enucleate cells
Thin skin will not have what layer?
Stratum lucidum
Most superficial layer of epidermis:
Stratum corneum
What is the thickest layer of epidermis in thick skin?
Stratum corneum
Flattened, enucleate, dead cell remnants:
Squames
What type of cell is characteristic of stratum corneum:
Squames
The stratum corneum is composed primarily of:
Soft keratin
The soft keratin of the stratum corneum acts as a:
Hydrophobic barriers preventing dedication
The stratum corneum is continuously:
Exfoliation
The process of continuous exfoliation:
Desquamation
In females, ____ cervical ____ cells are routinely examined in PAP smear, to detect cervical cancer.
Exfoliated cervical epithelial cells
Cervical skin cells are prone to _____ which leads to cervical cancer
Dysplasia
Three common types of skin tumors:
Squamous cell carcinoma
Basal cell carcinoma
Melanoma
Squamous cell carcinoma and basal cell carcinoma are both derived from:
Melanoma is derived from:
Epithelial cells
Melanocytes
Healing from a clean (surgical), approximated incision
First intention healing
After a clean cut, the incision immediately:
Fills with blood & clots
In first intention wound repair, within 3-24hrs, neutrophils infiltrate the clot: (what phase is this)
Acute phase
During wound repair, the epithelial cells of the stratum basale being:
Mitosis
What cells being mitosis during fist intention healing in wound repair?
Epithelial cells of stratum basale
For first intention wound healing to occur, the cut has to reach the:
Dermis (not just epidermis)
In first intention healing during wound repair, why do the epithelial cells of the stratum basale undergo mitosis?
To reapproximate the edges of the skin
During first intention healing during wound repair, within 3-7 days the neutrophils are replaced by:
Macrophages
During first intention healing during wound repair, when the neutrophils begin to be replaced by the macrophages (~3-7 days) this marks the transition of:
Acute to subacute phase
During the subacute phase of first intention healing, what three things start to occur?
- Neovascularization
- Fibroplasia
- Re-epithelialization
During first intention healing during wound repair, neovascularization causes:
Growth of new blood vessels & repair of damage old vessels
During first intention healing during wound repair neovasuclarization, fibroplasia, & re-epithelization all lead to:
Production of granulation tissue
During first intention healing during wound repair, fibroplasia refers to the production of ____ by ____.
Collagen by fibroblasts
During first intention healing during wound repair, re-epithelization refers to:
Epithelial proliferation
During first intention healing during wound repair, around day 5, the incision is filled with:
Granulation tissue
During first intention healing during wound repair, during week 2, we are continued _____ and ______ leading to mature granulation tissue.
Fibroplasia and collagen accumulation
During first intention healing during wound repair during week 2, we have a progressive decrease in:
Inflammation
During first intention healing during wound repair, the presence of inflammatory cells and inflammatory cell products leads to:
Itching
During first intention healing during wound repair, around month 2, what should be be formed?
Connective tissue scar
During first intention healing during wound repair, around month 2, there should be no:
Inflammation
During first intention healing during wound repair, around month 2, the connective tissue scar should be covered by:
Intact epithelium
With deficiency in ____, collagen breaks down and the old scar can re-open and bleed.
Vitamin C
During the first 24hrs of second intention healing compared to first intention healing, the scab/ clot:
Is much larger
In second intention healing, inflammation is more intense because there is more _____, _____, and ______ to remove.
Necrotic debris
Exudate
Fibrin
In second intention wound healing, during the weeks following the initial injury, the wound requires larger amounts of _____ because of its larger defect
Granulation tissue
Second intention wound healing involves:
Wound contraction
Excess fibroplasia resulting in a raised, thickened, connective tissue scar>
Keloid
Keloid results from too much:
Collagen
What type of wound healing occurs with more extensive loss of tissue, where the wound edges DO NOT approximate.
2nd intention healing
An infarct, ulcer, or abscess would require what type of wound healing?
2nd intention
During second intention wound healing, following the initial clot formation, the epithelial cells of the _____ migrate from the edges of wound at ~0.5mm per day.
Stratum basale
In 2nd intention healing, around how long does it take to fill a 1 cm wide cut?
~3 weeks
During second intention wound healing, in haired skin, migration of cells from ______ of hair follicles augments re-epithelialization
External root sheath
During second intention wound healing simultaneous _____/______ of keratinocytes behind the migrating front slowly restore the multilayered stratified epidermis.
Proliferation/maturation
During second intention wound healing, as the keratinocytes are migrating to fill in the gap, the cells of the stratum basale mature in a:
Vertical process
During second intention wound healing, it takes on average ~25 days for cells to mature from the stratum basale to the stratum corneum in the process of:
Keratinization
During second intention wound healing, the keratinization of new cells = the _____ and _____ of scab from periphery after ~ 3 weeks
Desquamation and lifting
During second intention wound healing, after the scab falls off (from the edges first), this is followed by _____ due to _____.
Wound contraction due to myofibroblasts
During second intention wound healing wound contraction is performed by what type of cell?
Myofibroblasts
During second intention wound healing, in full thickness abrasion, or third degree burns, re-epithelialization is limited by:
Size of wound
What is so special about myofibroblasts?
They produce collagen and have contractile properties
A burn that only involves the epidermis:
1st degree burn
Burn involving both epidermis and dermis
2nd degree burn
Burn involving epidermis, dermis, and hypodermis (loss of all 3 layers)
3rd degree burn
Neuroectodermal dendritic cells present in the epidermis
Melanocytes
What is the origin of melanocytes?
Neural crest origin
Melanocytes comprise a small # of cells, usually restricted to the:
Basal layer
melanocytes have extensive ______ that may extend into the _____.
Cytoplasmic processes; stratum spinosum
Melanin is released in melanocytes from organelles called:
Melanosomes
Melanin is released by melanosomes & taken up by surrounding:
Epidermal cells
In determining a melanocyte in an H&E stain, you look for a nucleus with a _____ in the basal layer
Halo
What are the. Two types of melanin?
Eumelanin and pheomelanin
Dark brown black pigment that presents in dark haired individuals
Eumelanin
Red/yellow pigment that presents in individuals with red or blonde hair
Pheomelanin
There are ___ #’s of melanocytes in all individuals, but ____ rates of melanin production & degradation by lysosomal enzymes
Equal #’s ; variable rates
Lighter-skinned individuals produces less___ or digest _____ at a faster rate.
Pigment
Darker skinned individuals ____ & _____ more pigment longer
Produce & retain
Autoimmune disease leading to the destruction of melanocytes which leads to depigmentation
Vitiligo
Melanin synthesis is under the control of pituitary hormone:
Melanocytes stimulation hormone (MSH)
Color due to the arrangement of small structures or particles- seen in iridescent hummingbirds or insects
Structural color
To produce melanin, ____ precursor is first oxidized to _____ by _______ .
Tyrosine ; DOPA; tyrosinase
The tyrosine precurser is first oxidized to DOPA by tyrosinase located in organelles called:
Premelanosomes
The initial steps of melanin production are followed by conversion of DOPA to ____ in _____.
Melanin in melanosomes
Albinos lack _____, so DOPA and Melanin are NOT formed.
Tyrosinase
In albinos, ____ form but do not mature.
Premelanosomes
_____ can be used as a marker, to differentiate melanocytes from keratinocytes continuing phagocytosed melanin
Tyrosinase
Using tyrosinase as a marker to differentiate melanocytes from keratinocyte containing phagocytosed melanin can by used in distinguishing:
Tumor types
Melanin is important because it serves as a ____ to protect the nucleus and inhibit ____.
UV shield; mutagenesis
Exposure to UV stimulates:
Melanin synthesis
Melanin is necessary for:
Normal neural development
Fixed tissue macrophage- phagocytic antigen presenting cells:
Langerhans cells
Langerhans cells contain distinctive ___ visible on EM.
Birbeck granules (tennis racket)
Where are langerhans cells located?
Within stratum spinosum
What cells are involved in contact allergic dermatitis?
Langerhan’s cells
Cells within the stratum spinosum that contain abundant cytoplasmic extensions
Langerhans cells
Embryological outgrowths of epidermis
Skin appendages
Hair, nails, sebaceous glands, sweat glands, and horns are all examples of:
Skin appendages
Coarse hair on scalp, axillae and pubis known as:
Terminal hair
Hair shaft consists of outer ____ and inner ____
Cortex ; medulla
Shaft covered by thin ___ of overlapping keratin plates, prevent matting
Cuticle
Hair shaft is produced by hair ____.
Follicles
Cylindrical down growths of epithelium surrounded by collagen sheaths
Hair follicle
Hair growth occurs within deep terminal expansion of follicle:
Hair bulb
The hair bulb is synonymous with:
Hair root
The hair bulb is lined with actively dividing ____ cells.
Epithelial
In a hair bulb, the actively dividing epithelial cells are homologous to:
The stratum basale
At the base of the hair is a vascular core called the :
Dermal papilla
The finger-like invagination of dermis contains blood vessels
Dermal papilla
As the epithelial cells lining the hair bulb mature, they fill with hard _______ arranged in ____ bundles.
Keratin filaments ; parallel bundles
Melanocytes are located ___ to the hair follicle and produce melanin that becomes incorporated into the _____.
Adjacent; cortex
The developing hair is surrounded by and protected by:
Internal and external root sheath
What lines the hair follicle?
Internal & external root sheath
Modified basement membrane that separates the hair bulb from the surrounding dermis
Glassy membrane
Hair aids in ____ & ______; and is absent on the skin of palms and soles of feet.
Protection and thermoregulation
Describe nucleus of arrector pili:
Elongated
What type of cell s comprise the arrector pili:
Smooth muscle cells
Arrector pili usually run ____ to hair shaft
30 degrees oblique
Bundles of smooth muscle cells that attach hair to follicle sheath and insert on epidermal ridges:
Arrector pili muscle
When arrector pili contract, they:
Raise hair
What phenomenon are arrector pili associated with:
Goosebumps
The proper name for goosebumps:
Piloerection
Piloerection is caused by _____ stimulation due to cold/fear/aggression.
Sympathetic
Where do arrector pili attach? Insert?
Attach: hair follicle sheath
Insert: on epidermal ridge
Hair growth is NOT:
Continuous
Hair: growth phase:
Anagen
Hair: involuting phase (loss of blood supply) : signals to end active growth
Catagen phase
Hair: inactive resting phase:
Telogen phase
Hair: shedding of old hair shaft- cells have stopped dividing:
Exogen phase
What phase of hair growth do we see baldness occur:
Exogen phase
Fine body hair in children:
Vellus hair
At puberty, vellus hair is replaced by:
Terminal hairs
Most common form of hair loss, affecting 30-40% of adults
Androgenic alopecia
Androgenic alopecia is both: _____ & _____ dependent
Genetic and androgen dependent
Individuals affected with Androgenic alopecia have high levels of:
5-alpha-reductase
5-alpha-reductase is the enzyme responsible for the conversion of:
Testosterone to dihydroxy testosterone
The conversion of testosterone to dihydroxytestosterone results in:
Follicular atrophy
Hair length is determined by the ____ phase relative to the _____ phase.
Growth phase relative to the resting phase
Flattened nails are unique to:
Primates
Nails consist of a flattened ______
Nail plate
The nail plate rests on the _____ of the nail bed.
Stratified squamous epithelium
Another term for nail bed is:
Hyponichium
Proximal end of the nail=
Nail root
Nail root extends into dermis, attaches to the periosteum of the:
Distal phalanx
Nail root extends into the dermis and attaches to the _____ of distal phalanx
Periosteum
Nail growth occurs by _____ & _____ of epithelium at nail root in ______ zone of nail matrix
Proliferation and differentiation ; germinative zone
The germinal root of nail matrix is where what occurs:
Nail growth
______ underlies the white crescent at the base of the nail
Nail matrix
The white crescent at the base of the nail is called:
Lunula
The lunula is covered by a superficial cuticle also known as:
Eponychium
As epithelial cells mature, fill with keratin and die, this forms:
Nail plate
Consists of densely packed, parallel, ______ filaments embedded in amorphous matrix.
Hard keratin
The nail plate slides over the underlying nail bed epithelium as it:
Grows
Alveolar and holocrine glands are classified as what type of glands:
Sebaceous glands
Glands consisting of branched acini:
Sebaceous glands
In this type of gland, by definition, the entire cell is secreted:
Sebaceous glands
One or more ____ glands are associated with each hair follicle, and develop as outgrowths of external root sheath
Sebaceous glands
Type of gland that looks foamy, almost like adipose tissue:
Sebaceous glands
Sebaceous gland products are very:
Thick and viscous
Sebaceous glands secrete oily _____ via _____ canal
Oily sebum, via pilosebaceous canal
Sebum is high in ____ & cell debris
Lipid
What is sebum used for?
Waterproofing and moisturizing skin and hair
Sebaceous glands can also be found on non-haired ______ skin, and they secrete directly onto skin surface here.
Transitional skin
Excessive secretion of sebum
Seborrhea
Hair follicle + associated arrector pili + sebaceous gland =
Pilosebaceous unit
When sebaceous glands are hypertrophic, this results in:
Acne
Acne occurs when the products of sebaceous glands are so thick and viscous that canal gets blocked with dried products and ____ get trapped in the sebaceous glands
Bacteria
Simple, coiled, tubular glands, surrounded by myoepithelial cells; assist in secretion
Sweat glands
What are the two types of sweat glands?
Merocrine/eccrine
Apocrine
What is another name for follicle mites?
Démodéx
Sweat glands that by definition secrete only product:
Merocrine (eccrine)
Merocrine (eccrine) glands can be made of:
Columnar or cuboidal epithelium
In humans, Merocrine (eccrine) glands are distributed all over most of the body surface except for:
Lips and genitalia
Unbranched, coiled, tubular glands, with 1-2 layers of cuboidal or columnar epithelium with excretory ducts:
Merocrine glands (eccrine)
What type of ducts do Merocrine (eccrine) glands have?
Excretory
Merocrine (eccrine) glands secrete sweat onto skin surface via ____ on _____
Sweat pore on epidermal ridge
Sweat contains a hypotonic solution of: (4)
Salts, ammonia, urea, and uric acid
Sweat is important in what functions?
Thermoregulation & evaporative cooling
Body loses on average around 600ml per day of sweat through:
Evaporation from lungs, skin & mucous membranes
Thermoregulatory sweating is:
Cholinergic
Thermoregulatory, cholinergic sweating occurs by:
Parasympathetics
Thermoregulatory/cholinergic sweating occurs first where and then where?
First: axillae, forehead, & scalp
Second: hands & feet
Emotional sweating is _______.
Adrenergic
Emotional, adrenergic sweating is due to:
Sympathetics
Emotional/adrenergic sweating begins on:
The palms & soles
Sweat glands that by definition secrete product + some cytoplasm
Apocrine sweat glands
Coiled, tubular glands with large dilated lumina:
Apocrine sweat glands
Describe the lumina of apocrine sweat glands
Dilated
Apocrine sweat glands are located in the _____ & _____ , and develop at puberty.
Axillae & groin
Sweat glands made of secretory, cuboidal epithelium that are 2-3 cell layers thick & surround large glandular lumen.
Apocrine sweat glands
Apocrine glands discharge thick, viscid secretions into the:
Hair follicle
The thick, viscid secretions of Apocrine glands contain: (5)
- Proteins
- Carbs
- Ammonia
- Lipids
- Organic products
Originally, the secretions of apocrine glands are ____ when secreted, but bacterial breakdown results in _____.
Odorless; acrid odor
Body odor is due to bacterial breakdown of:
Apocrine sweat gland products
In mammals, the acrid odor resulting from bacterial breakdown of apocrine secretions, is used as a:
Pheromone
Secretions from apocrine glands considered:
Adrenergic
Modified apocrine glands in the external auditory meatus (ear canal)
Ceruminous glands
Cerumen =
ear wax
Glands that develop along paired epidermal ridges & extend from axillae to groin:
Mammary glands
Mammary ridges and milk lines are also names for:
Epidermal ridges
In humans, only the ___ pair of gland along milk line develops
First
Mammary glands are highly modified _____ glands; identical in male & female until puberty
Sweat glands
In females, mammary glands develop under the influence of ___ & ____ hormones
Pituitary & Ovarian
In females, when do the pituitary and ovarian hormones influence the mammary glands to produce milk to feed young?
Following pregnancy
At menopause, the mammary glands:
Atrophy & involute
Mammary glands composed of mainly dense, irregular, collagenous connective tissue, interspersed with adipose tissue, & occasional smooth muscle
Inactive mammary gland
A mammary gland is composed of ____ glands organized into ___.
Tubulo-acinar glands organized into secretory lobules
Mammary glands are drained by:
Terminal ducts
After the mammary glands drain into the terminal ducts, they further drain into larger:
Lactiferous ducts
The lactiferous ducts of mammary glands empty into:
Lactiferous sinus
The lactiferous sinus is located in the region of the:
Nipple
Pigmented region of epidermis surrounding the nipple
Areola
What type of epithelium makes up the areola? (What else does it contain as well)
Stratified squamous epithelium with deep dermal ridges
Mammary glands contain numerous ____ glands, including ______ & ______ glands
Areolar glands, merocrine glands sebaceous glands
During ____, mammary glands enlarge due to hypertrophy of secretory cells & accumulation of secretory product.
Lactation
The first few days after birth, mammary glands secrete:
Colostrum
Alkaline, yellowish secretion, with high protein & salt content, that is low in lipids & carbs
Colostrum
Colostrum contains large amounts of _____, important in transfer of passive immunity to offspring
Antibodies
_____ production is both merocrine & apocrine
Milk
In milk production, ______ secretion is primarily merocrine & the _____ fraction is primarily apocrine
Protein; lipid
Mechanoreceptors/touch receptors in dermal ridges of papillary layer:
Meissner’s corpuscles
Where are Meissner’s corpuscles located?
Dermal ridges of papillary layer
Meissner’s corpuscles are prominent in:
Hands, feet, lips, genitalia
Shape of Meissner’s corpuscles?
Cylindrical
In a Meissner’s corpuscle, there are _____ nerve fibers associated with minimally modified ____ cells.
Afferent nerve fibers; schwann
Large Ovoid mechanoreceptors located in the dermis and hypodermis?
Pacinian corpuscles
Pacinian corpuscles are prominent in:
Fingertips and around joints
What type of pressure do Pacinian corpuscles detect?
Mechanical and vibratory
Pacinian corpuscles consist of what type of nerve fibers surrounded by highly modified ______ cells?
Afferent ; schwann
The afferent nerve fibers surrounded by highly modified schwann cells form _____ separated by fluid filled spaces.
Concentric lamellae
Small dermal mechanoreceptors especially common in soles of feet:
Ruffini corpuscles
Most numerous sensory receptor, present in epidermis and papillary dermis and surround most hair follicles:
“Free” N endings
“Free” nerve endings lack:
- Connective tissue capsules
- Associated schwann cell
“Free” nerve endings serve multiple sensory modalities including:
Heat/cold, touch, pain, movement
Epidermal cells derived from neural crest
Merkel cells
Cells that look like melanocytes; located in stratum basale, contain dense core granules, and store serotonin
Merkel cells
Pressure-sensitive mechanoreceptors, associated with free afferent nerve endings and merkel discs:
Merkel cell
