Chapter 5: The Integumentary System Flashcards
Define integumentary system and explain functions
Skin, hair, oil, and sweat glands, nails, and sensory receptors
Functions: Regulate body temp, store blood, protect body from external environment, detect cutaneous sensations, excrete and absorb substances, synthesize vitamin D
What are the 2 components of the cutaneous memebnae?
aka skin consists of:
Epidermis: superficial thinner portion
Dermis: deeper connective tissue
Define the SubQ layer
aka hypodermis
Not a part of the skin but is anchored to the dermis and attaches to the connective tissue
_______ corpuscles in the subQ and sometimes dermis are sensitive to pressure
lamellated
aka pacinian corpuscle
The epidermis has 4 principle types of cells, describe them:
Keratinocytes
Melanocyte
Intraepidermal macrophages (langerhans cell)
Tactile epithelial cells
Keratinocytes (90%): arranged in 4-5 layers and produce keratin that helps protect the skin
Melanocyte (8%): develop from the ectoderm of a developing embryo and produce melanin which contributes to skin colour and absorbed UV light
Intraepidermal macrophages: arise from red bone marrow and participate in immune responses
Tactile epithelial cells: located in the deepest layer where they contact a sensory nuron called a tactile or Merkel disk
Thin vs. Thick skin
Thin skin is regions of the epidermis that has 4 strata (layers):
- straum basale, stratum spinosum, stratum granulosm, and stratum corneum
Thick skin is where friction is greatest and has 4 layers:
- all same layers +stratum lucidium
List & describe the layers of the epidermis (from deepest to most superficial)
Basale: single row of keratinocytes that include scattered kertain intermediate filaments (tonofilaments) which are tough and protect from injury
Spinosium: 8-10 layers of keratinocytes that increasingly become flattened the more superficial they are; provides strength and flexibility
Granulosum: 3-5 flattened layers of keratinocytes undergoing apoptosis; has keratohyalin (darkly staining granules) that assembled monofilaments into keratin; also have lamellar granules acting as sealant against water/particles
Lucidum (thick skin): 4-6 layers of flattened, dead keratinocytes that overlap like scales to prevent injury from friction (it is a thickening of the stratum corneum)
Corneum: 25-30 layers of flattened dead keratinocytes that are extremely thin and flat; constant exposure to friction results in a callus
As cells move from one epidermal layer to the next, they accumulate more and more keratin, a process called _________
keratinization
The whole process from basale to the surface and then being sloughed off takes about 4-6 weeks
What is psoriasis?
A skin disorder in which keratinocytes divide and more more quickly than normal and shred prematurely in as little as 7-10 days
They are abnormal keratin which forms flaky scales on the skin
The dermis can be subdivided into two portions. List and describe them:
Papillary region (superficial): consists of areolar connective tissue with thin collagen and fine elastic fibres; contains dermal ridged that house blood capillaries capillary loops), corpsucles of touch (tactile nerve endings), and free nerve endings (initiate sensation of temp, pain, itch, etc.)
Reticular region (deep): consists of dense irregular connective tissue with bundles of thick collagen and some coarse elastic fibers. Provides skin with extensibility and elasticity
What are epidermal ridges? When are they produced?
Produced during 3rd month of fetal development and they create a strong bond between epidermis and dermis at areas of high mechanical stress (Ex. found in the creases of a palm)
Sweat glands that open on the top of these ridges form fingerprints/footprints
What are epidermal ridges? When are they produced?
Produced during 3rd month of fetal development and they create a strong bond between epidermis and dermis at areas of high mechanical stress (Ex. found in the creases of a palm)
Sweat glands that open on the top of these ridges form fingerprints/footprints
What causes differences in skin colour? How about a mole?
Skin colour is due to the amount of pigment the melanocytes produce (not the overall number) - phenomelannnin (yellow to red) and eumelanin (brown to black)
A mole occurs when a patch of melanin accumulates and becomes raised due a localized overgrowth
_______ is a yellow-orange pigment that gives egg yolks/carrots their colour. Eating a lot of these foods can turn your skin orange
Carotene
Describe albinism and vitiligo
Albinism is the inherited inability of an individual to produce melanin, albinos have melanocytes that are unable to synthesize tyrosinase
Vitiligo is the partial or complete loss of melanocytes that produces irregular white spots - may be related to an autoimmune dysfunction
Skin colour can be used as a diagnostic tool - what do the following terms mean:
Cynotic
Jaundice
Erythema
Pallor
Cynotic: blue (lack of oxygen)
Jaundice: yellow (liver disease)
Erythema: redness (ergorement of capillaries - skin injury)
Pallor: pale (shock/anemia)
What is the function of hair?
Guards scale from injury/sun rays (limited protection)
Decreases heat loss
Protect eyes from foreign particles
Sensing light touch
Describe the following structures of hair anatomy:
Shaft Root Follicle Bulb Matrix Hair root plexus
Shaft: superficial portion that projects above surface
Root: potion deep to the shaft that penetrates into the dermis; comprised of medulla, middle, and cuticle
Follicle: surrounds the root
Bulb: base of each folic that contains a germinal layer of cells called the hair matrix - responsible for growth/production of hair
Hair root plexus: dendrites that surround each follicle to generate nerve poles if hair shafts are moved
Describe the 3 layers of the hair root:
Medulla (inner): 2-3 irregular shade cells that contain pigment granules that determines hair colour
Middle cortex: forms major part of shaft
Cuticle (outer): consist of thin, flat cells that are heavily keratinized
When under psychological or emotional stress the smooth muscle called the ___________ contracts causing goosebumps
arrestor pilli
What are the 3 stages of hair growth?
- Growth stage - cells of the hair matrix divide and are added and pushed upwards and become keratinized and eventually die
- Regression stage - cells of the matrix stop dividing the hair follicle shrinks
- Resting stage - no growth, resting (then growth stage begins)
_________ is the partial or complete loss of hair that may occur genetically, due to aging, or due to a disorder/disease
alopecia
Differentiate between the following types of hair:
Lanugo
Terminal
Vellus
Lanugo: fine non-pigmented hairs that cover the body of a fetus
Terminal: eventually replace lanugo of eyebrows, armpits, pubic regions, eyelashes, and scalp and are heavily pigmented
Vellus: replace lanugo elsewhere on the body (peach fuzz)
The following hair colours contain mainly which type of keratin:
Brown/black
Blonde/red
Grey
Brown/black: eumelanin
Blonde/red: phenomelanin
Grey: lack of melanin production
What are the general differences between sebacous, sudiferous, and ceruminous gland?
Sebaceous (oil): secrete oily substances called serum that coats the surface of the hairs and helps them from becoming dry and brittle
Sudiferous (sweat): release sweat/perspiration through pores (2 types)
Ceruminous (ear): produce waxy lubricating secretion called cerumen or earwax
Acne is the inflammation of ________ glands
sebaceous
What are the 2 different types of sudiferous (sweat glands)? List their functions
Eccrine (most common): coiled tubular
- Functions in thermoregulation (homeostatic regulation of body temp) via thermoregulatory sweating
- sweat can be insensible, sensible, and emotional
Apocrine: simple oiled that have larger ducts and lumens
- simulated during emotional stress/sexual excitement
- sweat appears milky/yellowish
What is the difference between insensible & sensible perspiration, and emotional sweating (cold sweat)
Insensible: sweat that evaporates before it is perceived as moisture
Sensible: seat that is exerted in larger amounts and is seen as moisture
Emotional sweating (cold sweat): released in repsonse to emotional stress (both eccrine and apocrine involvement)
Nails are plates of highly packed, hard, dead, keratinized epidermal cells. Describe the following components:
Nail body (plate) Free edge Hyponcychium Eponychium (cuticle) Nail root Lunula Nail matrix
Nail body (plate): visible portion of the nail
Free edge: edge that projects past the finger/toe
Hyponcychium: secures nail to the fingertip
Eponychium (cuticle): stratum corneum of the epidermis
Nail root : portion that is buried in a fold of skin
Lunula: moon shaped white part at bottom nail
Nail matrix: epithelium proximal to the nail root - contains dividing cells which produces new nail cells
Describe how the skin contributes to following functions:
Thermoregulation Blood reservoir Protection Cuteanous sensations Excretion and absorption Synthesis of vitamin D
Thermoregulation : liberates sweat at its surface and adjusts the flow of blood in the dermis depending on temperature
Blood reservoir: carries 8-10% of total blood flow
Protection: prevents damage, dehydration, and shields against UV
Cuteanous sensations: nerve endings throughout the skin that detect sensations
Excretion and absorption
Synthesis of Vit. D: requires activation of a precursor molecule in the skin by UV rays (produce calcitrol, active form of vit. D)
Outline the steps involved in epidermal wound healing
Epidermal wound healing is restricting to the epidermis
- Basal cells surrounding the wound break contact with the basement membrane and the cells then enlarge and migrate across the wound
- Once they merge, they stop migrating due to contact inhibition
- As the cells migrate, epidermal growth factor (hormone) stimulates stem cells to divide and replace the ones that have moved into the wound
Outline the 4 steps involved in deep wound healing
Inflammatory: blot clot forms in the wound and loosely unites the wound edges
Migratory: clot becomes a scab and the epithelial cells migrate beneath to bridge the wound - tissue following the wound is called granulation tissue
Proliferative: extensive growth of epithelial cells, decomposition by fibroblasts, and continued growth of blood vessels
Maturation: Scab sloughs off and the epidermis returns to normal thickness
Would you expect an epidermal wound to bleed?
No - the epidermis is avascular
_____ refers to the process of scar tissue formation. What are the 2 different types?
Fibrosis
Hypertrophic: scar remains in the boundaries of original wound
Keloid/cheloid: scar extends beyond the boundaries into normal surrounding areas
Outline the details in the following disorders:
Skin cancer
Burn
Pressure ulcer
Skin cancer: ultraviolet radiation (UVA & UVB) affect the health of the skin and are responsible for skin damage
- 3 common types are basal cell carcinoma (tumors arise in stratum basale), squamous cell carinoma (tumors arise in stratum spinosum), and malignant melon (most deadly)
Burn: UVB rays, excessive heat/electricity/chemical that destroys the skins homeostasis
Pressure ulcer (bedsores): caused by deficiency of blood flow to tissues
