Lecture Exam - The Integumentary System

1. What is a burn?

a Tissue damage inflicted by intense heat, electricity, radiation, or certain chemicals, all of which kill cells in the affected areas

1. What types of cells are found in the epidermis? Which of these is the primary cell type?

a Tissue type: keratinized stratified squamous epithelium b Keratinocytes (primary cell type) c Melanocytes d Langerhans' cells e Merkel cells

1. The inherited condition of albinism is most often associated with an inability to synthesize what enzyme? What is the direct effect of a deficiency of this enzyme?

a Tyrosinase; results in an inability to synthesize melanin

1. Where do the ducts of most sebaceous glands terminate?

a Upper part of the hair follicle and sometimes skin surface

Epidermal growth factor

a peptide that causes cells to undergo mitosis in the stratum basale

jaundice

a yellow discoloration most obvious in the sclerae, or whites, of the eyes; when liver isn't working properly so bilirubin is not eliminated

1. The ABCDE mnemonic is a way to remember the key detection points of melanoma. What does each letter of the mnemonic represent?

a) Asymmetry b) Border irregularity - indentations c) Color - several colors (blacks, browns, tans, and sometimes blues and reds) d) Diameter - larger than 6 mm e) Evolution

alopecia

absence of hair on the body where it would normally occur; partial or complete baldness

superficial fascia

another word for subcutaneous layer

erythema

redness of the skin; because of embarrassment, fever, inflammation, or allergy

cyanosis

skin blueness because hemoglobin poorly oxygenated, especially in mucous membranes and nail beds; sign of respiratory or cardiovascular problems

blanch

skin looking pale or white because blood diverted from the skin to internal organs; caused by low blood pressure and anemia

What are the five layers of the epidermis? (Know them in order from deep → superficial)

(Bitch Sam Gets Lit Constantly) a Stratum basale b Stratum spinosum c Stratum granulosum d Stratum lucidum e Stratum corneum

1. What are the primary tissue types in the hypodermis?

a Areolar tissue and adipose tissue

1. What are the differences between basal cell carcinoma, squamous cell carcinoma, and melanoma?

a Basal cell carcinoma - least malignant, most common; stratum basale cells proliferate, invading the dermis and subcutaneous tissue; lesions on sun-exposed areas of the face and are shiny, dome-shaped nodules that develop a central ulcer with a pearly, beaded edge; slow-growing, barely ever metastasizes; 99% cure with surgery b Squamous cell carcinoma - 2nd most common; arises from keratinocytes of the stratum spinosum; lesions are scaly reddened papule that arises most often on the head (scalp, ears, and lower lip) and hands; grows rapidly and metastasize if not removed; cure chances are good if caught early a surgery/radiation c Melanoma - cancer of melanocytes; most dangerous because highly metastatic and resistant to chemotherapy; 1% skin cancers but most skin cancer deaths; begins anywhere where there is pigment; most appear spontaneously but one-third develop from preexisting moles; spreading brown to black patch that spreads quickly to lymph and blood vessels; key is to catch it early; advanced cases include surgery then therapy (chemo, gene, etc)

1. What organs/structures are located in the dermis?

a Blood vessels, nerve fibers, sensory receptors, major portions of hair follicles, and sebaceous & sweat glands, lymphatic vessels

1. What effects does chronic exposure to UV radiation have on the skin?

a Causes elastic fibers to clump, resulting in leathery skin; temporarily depresses the immune system; can alter DNA of skin cells, leading to skin cancer

1. What causes arrector pili contraction?

a Cold temperatures and fear

1. What is the hypodermis? Where is it located?

a Deep to the dermis b Main function: it anchors the skin to the underlying organs; other functions: shock absorber, insulation of the deeper body tissues, contains blood vessels that supply the skin

1. What is the primary tissue type in the dermis? What type of connective tissue fibers does it contain? What types of cells are commonly found in the dermal layer?

a Dense irregular connective tissue b Mostly collagen fibers with smaller amounts of elastic and reticular fibers c Are fibroblasts, macrophages, and sometimes mast cells and white blood cells

1. What is the significance of the dermal papilla? of the epidermal ridges?

a Dermal papilla are projections on the upper surface of the papillary layer that indent into the epidermis and have a high surface area for oxygen to diffuse into the epidermis and for a strong anchoring between the dermis and epidermis b Dermal ridges are the mounds that dermal papilla lay on (on palms of hands and soles of feet); they cause the epidermis to protrude to from epidermal ridges c All the ridges together form friction ridges, which enhance gripping and sense of touch; the ridges are unique for everyone=fingerprints d Papillary layer

1. Which type of sudoriferous gland secretes into hair follicles? into ducts that open in a pore on the skin's surface?

a Eccrine - ducts b Apocrine - hair follicles

1. To what functional class does each of the above glands (sudoriferous glands) belong?

a Eccrine - merocrine b Apocrine - merocrine c sebaceous - holocrine

1. Describe the secretions produced by each of the glands above (sudoriferous glands).

a Eccrine - sweat; hypotonic filtrate of the blood that passes through the secretory cells of the sweat glands and is released by exocytosis; 99% water with some salts, traces of metabolic wastes, and a microbe-killing peptide called dermcidin; pH between 4 and 6 b Apocrine - Same as sweat except for has fatty substances and proteins; viscous and sometimes has a milky or yellowish color; odorless but when bacteria on the skin decompose its organic molecules, it takes on a musky and unpleasant odor, body odor

1. What are the two main types of sudoriferous glands (sweat glands) associated with the skin?

a Eccrine and apocrine

1. Name the two layers of the skin.

a Epidermis b dermis

1. Identify the 3 classes of burns. Describe the general characteristics of each class.

a First-degree burns - only epidermis damaged; localized redness, swelling, and pain; heal in 2-3 days without special attention; ex is sunburn; partial-thickness; ex. sunburn b Second-degree burn - injure epidermis and upper region of the dermis; same symptoms as 1st degree with blisters; skin regeneration with little to no scarring in 3-4 weeks if infection prevented; partial-thickness c Third-degree burns: involve full thickness of the skin; burned area is gray-white, cherry red, or blackened, and initially there is little to no edema; nerve endings destroyed so not painful; can't wait for skin regeneration because of fluid loss and infection to skin grafting is advised

1. Describe the location and function of the hair follicle itself, the papilla and matrix of the follicle, the root hair plexus, and the arrector pili muscle.

a Hair follicle location: fold down from the epidermal surface into the dermis (and sometimes the subcutaneous tissue); deep end expands to form hair bulb b Hair follicle function: anchors the hair into the skin c Papilla location: protrudes into the hair bulb d Papilla function: has a knot of capillaries that supplies nutrients to the growing hair and signals it to grow e Matrix location: adjacent to the hair papilla f Matrix function: it is the dividing cells in the bulb of the follicle g Root hair plexus location: wraps around each hair bulb h Root hair plexus function: a knot of sensory nerve endings; acts as touch receptors i Arrector pili muscle location: attaches to the base of a hair follicle at one end and to dermal tissue on the other end j Arrector pili muscle function: contraction pulls the hair follicle upright and dimples the skin surface to produce goose bumps in cold temperatures or fear; contractions force sebum out of hair follicles to the skin surface where it acts as a skin lubricant

1. What is the function of keratin? of melanin?

a Keratin - makes epidermis water resistant and protective b Melanin - Protects keratinocytes from UV radiation; 2 kinds: brown-black and pink-red; amount and type of melanin produced is controlled by genes that operate under incomplete dominance i UV exposure hurts fibroblasts in the skin, which impairs maintenance of the dermis, causes premature aging, and induces nuclear damage (skin cancer)

1. What is the general function of each of the four cell types listed above (#13)?

a Keratinocytes (primary cell type) - produce keratin to make epidermis water resistant and protective; arise from deepest layer of epidermis, and they create desmosomes and tight junctions with adjacent keratinocytes; as cells get pushed towards the surface as new cells are synthesized, they make keratin and become dead b Melanocytes - highly branched spider shaped cells which produce melanin in the deep layer of the epidermis; have lots of projections touching 35-40 keratinocytes, which send signals to tell it how much melanin to make (and controls melanocyte replication too); melanin is made and packaged in melanosomes and when they are filled, they get moved along to keratinocytes where it accumulates in the superficial parts of keratinocytes to cover the nucleus of the cell with melanin to protect it from UV radiation; 10 days for peak melanin synthesis=slow c Langerhans' cells - a type of fixed macrophage located in deeper layers of epidermis; protect against bacterial invasion by phagocytosis and activation of the immune system; originate in red blood marrow and migrate to the epidermis d Merkel cells - specialized epithelial cells which serve as sensory receptors for touch; are between keratinocytes in the deepest layer; activated by compression, which activates sensory neuron and neural fibers called Merkel discs; only touch receptors in epidermis; in hairless skin areas

1. How does sunlight affect melanocytes?

a Keratinocytes secrete chemicals that simulate melanocytes with sun exposure. Sun exposure causes melanin buildup, which helps protect the DNA of skin cells from UV radiation by absorbing the rays. This causes the skin to darken in all but the darkest skin ppl.

1. What are the potential life-threatening systemic effects of severe burns?

a Loss of body fluids containing proteins and electrolytes, which leads to dehydration and electrolyte imbalance then renal failure (kidney shutdown) and circulatory shock (inadequate blood volume)

1. Describe the function(s) of the hypodermis.

a Main function: it anchors the skin to the underlying organs; other functions: shock absorber, insulation of the deeper body tissues, contains blood vessels that supply the skin

1. What pigments determine skin color?

a Melanin (made from amino acid tyrosine by the enzyme tyrosinase; pink/red and brown/black form determined by genes; skin color based on amount and form of melanin b Carotene (derived from diet; source is carotenoids found in fruits and vegetables; yellow/orange pigment that accumulates in the stratum cornuem and is most obvious in palms and soles) c Hemoglobin (reddish pigment in red blood cells; oxygen carrying component; ppl with low amounts of melanin have a pink-hue from hemoglobin; bluish-white color of hypodermis tempers RBC color in fair skinned ppl; red color more prominent when dermal arterioles dilate)

1. Generally describe the process through which epidermis is renewed & maintained.

a Mitosis creates new cells in the deepest layers (stratum basale mostly and stratum spinosum a little), which then get pushed towards the body's surface/superficial layers as new cells are made. At the stratum corneum, these cells are sloughed off.

1. In which epidermal layer does most mitosis occur? Beyond which layer does no mitosis occur?

a Most=statrum basale b No more mitosis after=stratum spinosum

1. Describe the structure and function of sebaceous glands.

a Oil glands; simple branched alveolar glands all over the body except thick skin of the palms and soles b Secrete sebum

1. Describe the composition and functions of sebum.

a Oily lipids b soften and lubricate the hair and skin, prevent hair from becoming brittle, and slows water loss from the skin, and it's bactericidal

1. In what body areas is thick skin located?

a Palms of hands and soles of feet

1. Which dermal layer is composed primarily of areolar connective tissue? which of dense irregular connective tissue?

a Papillary layer - areolar b Reticular - dense irregular CT

1. Which of the above class(es) is/are considered partial-thickness? full-thickness?

a Partial thickness is 1st and 2nd degree burns b Full thickness is 3rd degree burns

1. What are the functions of the integumentary system?

a Protection i Physical, chemical, and biological b Thermoregulation c Excretion d Cutaneous sensation e Vitamin D synthesis f Blood reservoir

1. What is the cause of pressure injuries?

a Result from a loss of or restricted blood flow to the tissue, most commonly at bony prominences / bedsores b Problems with dermal circulation affect the dermis and epidermis because the epidermis relies on diffusion from the dermis for blood because it lacks vessels - caused by blood vessels of the dermis

1. What are the layers of the dermis? Which of these two layers is more superficial?

a Reticular layer (more deep and thick layer) (stretch marks/striae caused by tearing of fibers here) b Papillary layer (more superficial, thin layer) c Layers anchor cells to the basement membrane

1. Distinguish between the root and shaft of an individual hair.

a Root - part embedded in the skin b Shaft - part that projects above the skin's surface

1. What forms the lines of cleavage?

a Separations between collagen bundles within the tissue of the reticular layer b Tearing of fibers causes stretch marks / striae

1. Which layer contains most of the melanocytes?

a Stratum basale

1. How do the epidermal layers differ from each other in terms of appearance and function?

a Stratum basale - single row of keratinocytes connected tightly by desmosomes and to underlying tissue by hemidesmosomes; cells highly mitotic stem cells (one daughter cells stays in stratum basale for mitosis and the other moves towards body's surface); melanocytes and merkel cells are present b Stratum spinosum - cells slightly mitotic; 8-10 cell layers thick, cells slightly flattened and irregularly shaped; web-like thick cytoskeleton of keratinocytes that contain bundles of intermediate filaments called tonofilaments which are composed of prekeratin-they attach to desmosomes on opposite sides of a cell to resist pulling and stretching from multiple directions c Stratum granulosum - relatively thin layer consisting of flattened cells which have begun to die; 3-5/4-6 cell layers; when they die, the nuclei disintegrate; grainy appearance because cytoplasmic granules (keratohyalin granules and lamellar granules); plasma membrane thickens because proteins and glycolipids accumulate; keratinization begins d Stratum lucidum - only in 'thick skin' areas; cells are dead, tightly-packed, flattened; thick plasma membrane; organelles disintegrated forming a clear appearance under the microscope; tonofilaments (here and in stratum corneum) are converted to keratin; keratin only component left; 2-3 layers e Stratum corneum - horny layer; outermost and thickest layer; contains 20-30 layers of shingle-like dead cells remnants completely filled with keratin; cells continuously shed and replaced by cells pushed up from deeper layers; protects deeper cells from the environment, prevents water loss, abrasion, and mechanical stress, and acts as a barrier against biological, chemical, and physical assaults; takes 2 weeks for cells to get to the stratum corneum & 2 more weeks to get to the outer layer when they are sloughed off

1. In which epidermal layer do you first expect to see significant amounts of keratin (rather than pre-keratin)?

a Stratum granulosum

1. In which layer do cells contain keratohyalin and lamellar granules? What is the functional significance of each of these granule types?

a Stratum granulosum b Keratohyalin granules - involved in the formation of keratin; promote the cross-linking of pre-keratin & converting it to keratin c Lamellar granules - contain a glycolipid that, when secreted, helps to waterproof the superficial layers of the epidermis; water-resistant glycolipid in the extracellular space to slow water loss

1. In which layer do the cells begin to die? Why do they die?

a Stratum granulosum; die because they are far from the capillary blood supply, so not getting nutrients and oxygen

1. Which layer is not present in thin skin?

a Stratum lucidum

1. In which epidermal layer do the keratinocytes take on a spiny appearance?

a Stratum spinosum

1. In which epidermal layer do tonofilaments first become evident?

a Stratum spinosum

1. What are the two basic types of glands in the integumentary system?

a Sweat glands and sebaceous glands

male pattern baldness

hair loss in an adult male due to changes in levels of circulating sex hormones and genetic predisposition

lamellated (Pacinian) corpuscles

in the deeper dermis or subcutaneous tissue; alert us to bumps or contacts involving deep pressure; cutaneous sensory receptor

photosensitivity

increased skin's sensitivity to UV radiation (caused by chemicals in antibiotic drugs and perfume)

ceruminous gland

modified apocrine glands found in the lining of the external ear canal; helps create cerumen or earwax

fibrosis

the thickening and scarring of connective tissue, usually as a result of injury.

rule of nines

used to estimate the percentage of body surface burned; divides body into 11 areas which are each 9% of total body area with an extra 1% for genitals

hirsutism

when females develop coarse terminal hairs in a masculine distribution