Test 2 Integumentary system Flashcards
- Organ
a. Consists of tissues working together to perform certain function
- Skin (integument) and its appendages (sweat glands, oil glands, hairs and nails) considered an organ?
a. Yes
- What makes up the integumentary system?
a. Skin and its appendages – sweat glands, oil glands, hair and nails
b. Covering
- What is the largest of all organs?
a. Skin
b. Accounts for 7% of total body weight
c. Varies in thickness from 1.5 – 4 mm
- Skin’s two distinct region
a. Epidermis – thick epithelium
b. Dermis – fibrous connective tissue
- Epidermis and dermis are firlmy cement3ed together along?
a. An undulating border
- What happens if epidermis and dermis separates?
a. Results in a blister
- Where is hypodermis located?
a. Deep to the dermis
- Is hypodermis part of integumentary system?
a. No, but it shares some of the skin’s function
- Function of skin: integumentary system
a. Protect body from bumps scrapes and cuts
b. Screens out harmful UV rays from the sun
c. Metabolic duties…synthesis of vitamin D
d. Insulates/cushions underlying body tissues
e. Protects the body from water loss
f. Helps regulate body temperature
g. Excretes wastes (urea, salt)
h. Contains sense organs
- What are the four cell types found in the epidermis
a. Keratinocytes
b. Melanocytes
c. Merkel cells
d. Langerhans’ cells
- Keratinocytes
a. The most abundant epidermal cell
b. Connected to one another by desmosomes
- What is keratinocyte’s role?
a. To produce keratin
b. Produce antibiotics and enzymes that detoxify harmful chemicals
- Keratin
a. A tough fibrous protein that gives the epidermis its protective properties
- Melanocytes
a. Located in stratum basale
b. Spidershaped cells which make the dark skin pigment melanin
- Where is the melanin transferred to after the melanocytes makes them?
a. Transferred to nearby keratinocytes where it clusters on the superficial side of the cell
- Significance of position of melanin on light skinned people?
a. The melanin is digested by lysosomes a short distance above the basal layer
- Significance of position of melanin on dark skinned people?
a. No digestion occurs and melanin occupies keratinocytes throughout the epidermis
- Merkel cells
a. Located in stratum basale
b. Hemisphere-shaped cells that are associated with a disc-like sensory nerve ending and serves as a receptor for touch
- Langerhans’ cells - location
a. Stratum spinosum
b. Belong to a class of macrophages like cells
c. Part of the immune system
- Langerhans’ cells function
a. Police the outer body surface, using rece3ptor mediated endocytosis to take up foreign proteins (antigens) that have invaded the epidermis
- What does the Langerhans’ cells do after it has performed endocytosis on foreign antigens?
a. Leaves the skin and travel to a nearby lymph node, where they present the antigens to killer T lymphocytes, which proceed to attack all foreign cells that carry the antigen
- The layers of epidermis is composed of?
a. Avascular epithelium stratified squamous
- What are the four or five distinct layers of the epidermis?
a. Stratum basale (basal layer)
b. Stratum spinosum (spiny layer)
c. Stratum granulosum (granular layer)
d. Stratum lucidum (clear layer)
e. Stratum corneum (horny layer)
- Stratum basale
a. Basal layer
b. Deepest epidermal layer
c. Attached to the underlying dermis along an undulating borderline
- Stratum basale consists of?
a. A single row of cells, mostly stemcells representing the youngest keratinocytes
- Cells in stratum basale layer rapidly divide via?
a. Rapidly divide via mitosis
- Stratum spinosum
a. Spiny layer
b. Several cell layers thick
c. Mitosis occur here but less often than in the basal layer
- Stratum spinosum cells contains?
a. Thick bundles of intermediate filaments, called tonofilaments (tension filaments)
- Stratum granulosum
a. Granular layer
b. 1 to 5 layers of flattened keratinocytes
- What granules does stratum granulosum contain?
a. Keratohyaline granules
b. Lamellated granules
- Keratohyaline granules function
a. Form keratin in the higher strata
- Lamellated granules
a. Contain a waterproofing glycolipid that is secreted into the extracellular space and plays a major role in slowing water loss
- Cells above what layer are dead?
a. Stratum granulosum
- Stratum lucidum
a. Clear layer
b. Occurs only in thick skin
c. Consists of few rows of flat dead keratinocytes
- Stratum corneum
a. Horny layer
b. Most external part of the epidermis
- Stratum corneum is composed of?
a. Many layers of dead keratinocytes…which resembles flat sacs filed with keratin because their nuclei and organelles disintegrated upon death
- Function of keratin and thickened plasma membrane of cells?
a. Protect the skin against abrasion and penetration
- How much skin does a person shed in a lifetime?
a. 40 lbs
- Dermis
a. Second major layer of the skin
b. Strong, flexible connective tissue
- Function of dermis
a. Binds the entire body together like a body stocking
b. It is your “hide” and corresponds to animal hides that are used to make leather products
- Cells and fibers of the Dermis: a strong flexible CT
a. Cells: fibroblasts, macrophages, mast cells and white blood cells
b. Fibers: collagen, elastic, and reticular
- The dermal blood vessels consists of?
a. Two vascular plexus – a network of convering and diverging vessels
b. 1. Cutaneous plexus
c. 2. Subpapillary plexus
- Cutaneous plexus
a. Deep
b. Located between the hypodermis and the dermis
c. Nourishes the hypodermis and the structures located within the deeper portions of the dermis
- Subpapillary plexus
a. Superficial
b. Located just below the dermal papillae
c. Supples the more superficial dermal structures – the dermal papillae and the epidermis
- The vascular plexuses plays a role in?
a. Thermal regulation
- What are the two layers of dermis?
a. Papillary layer
b. Reticular layer
- Papillary layer
a. Superficial 20% of the dermis
b. Composed of areolar connective tissue (think collagen/reticular fiber)
- Within the papillary layer is the dermal papillae, what is it?
a. Fingerlike projection that extend into the overlying epidermis
- What functions do the dermal papillae perform?
a. Holds epithelial cells tightly together
b. Increase surface area for nutrients
- Where is the dermal papillae located specifically?
a. On the palm and soles, where they lie atop larger mounds called dermal ridges, which elevate the overlying epidermis into epidermal ridges
- What are the epidermal ridges?
a. Fingerprints, palmprints, and footprints
b. Sweat pores open along the crests of the epidermal ridges, which leave distinc fingerprints (“sweat films”)
- What function does the epidermal ridges provide?
a. To grip things
b. Increase friction
- The second layer of the dermis is?
a. Reticular layer which is a “network” of collagen fibers deep to the papillary layer
- Reticular layer
a. 80% of thickness of dermis
b. The deepest skin layer composed of dense irregular connective tissue
- The ECM of reticular layer contains?
a. Thick bundles of interlacing collagen and elastic fibers, where most fibers run parallel to the skin surface
- Function of the collagen fibers of the dermis
a. Gives skin its strength and resilience
- Function of the elastic fibers in the dermis
a. Provide the skin with stretch-recoil properties
- Extreme stretching of the skin (obesity and pregnancy) can tear the collagen in the dermis which cause slivery white scars called?
a. Striae
- Hypodermis
a. Not part of skin
b. Deep to the skin
c. Also called superficial fascia and subcutaneous layer
- Hypodermis contains
a. Areolar and adipose connective tissue
- Hypodermis function
a. Anchors skin to underling structures mostly to muscles
b. Helps insulate the body (stores fat) because fat is a poor conductor of heat, it prevents the heat loss from the body
- The epidermis thickens with weight gain
a. In female – subcutaneous fat accumulates first in the thighs and breasts
b. In males it first accumulates in the anterior abdomen (beer belly)
- What are the three pigments that contribute to skin color?
a. Melanin
b. Carotene
c. Hemoglobin
- Melanin
a. Made from an amino acid called tyrosine
b. Present in several varieties: yellow, reddish, brown, black
c. Made in melanocytes, which contain an enzyme called tyrosinase
- Melanin passes from melanocytes to keratinocytes in the?
a. Stratum basale of the epidermis
- What are localized accumulation of melanin called?
a. Freckles
b. Pigmented moles
- Freckles
a. Melanin is restricted to the basal layer of the epidermis and form as the result of exposure to the sun
- Moles
a. Clusters of melanocytes transform into melanin-containing cells and accumulate in the basal layer of the epidermis and the top layers of the dermis. Not formed by exposure to the sun
- Carotene
a. A yellow orange pigment that the body obtains from vegetable sources such as carrots and tomatoes
- Carotene accumulates in the?
a. Stratum corneum of the epidermis and in the fat of the hypodermis
- Hemoglobin
a. The crimson-color of oxygenated hemoglobin
- What is another factor influencing skin color?
a. Vitamin D – a vital hormone requir3ed for the uptake of calcium from the diet and essential for healthy bones
- How is vitamin D produced
a. By UV rays stimulating the deep epidermis
- What is the trade-off between protection from the harmful effects of UV radiation and production of Vitamin D?
a. The selective pressure behind the evolution of skin coloration as early humans moved away from the tropics
- Appendages of the skin: two categories of the cutaneous glands
a. Subaceous glands and sweat glands
- Subaceous glands
a. Greasy
b. Occurs over entire body, except palms and soles
c. The body’s oil glands
d. Most are associated with a hair follicle
- Subaceous glands are made up of?
a. Simple alveolar glands with several alveoli opening into a single duct
b. The alveoli are filled with cells (no lumen) that make oily lipids
- Function of sebaceous glands
a. Secrete sebum: an oily substance that acts as a lubricant to keep skin soft an moist and to keep the hair from becoming brittle
b. Collects dirt, prevents water loss, and kills bacteria
- When are sebaceous glands mostly active?
a. During puberty because of homrones/androgen, making the skin very oily
- What are blackheads
a. Accumulations of dried sebum and bacteria in the oil duct
- What are acnes?
a. Active infection of the sebaceous glands
- Sebum is made via a process called?
a. Holocrine secretion…whole cells break up to form the produce
- Sweat glands
a. Sudoriferous glands
b. Widely distributed on body
c. A blood filtrate released via exocytosis
- How much sweat do we normally produce in one day?
a. 500 ml
b. On hot days or vigorous exercise: 12 L
- Sweat glands
a. Only mammals have sweat glands
b. Used for thermoregulation
c. Humans have the most sweat glands
d. Hair usually interferes with the evaporation of sweat and ability to cool the body so the need for temperature regulatioin through sweating led to a reduction of hairness
- Sweat
a. The filtrate of blood that passes through the secretory cells of the sweat glands and is released by exocytosis
b. Acidic so it retards the growth of bacteria on the skin
- True sweat
a. 99% water
b. 1% salts (NaCl) metabolic wastes (urea, ammonia, uric acid)
- Two types of sweat glands:
a. Eccrine
b. Apocrine
- Eccrine glands
a. More numerous type and produce true sweats
b. Abundant on palms, soles, and forehead
c. Coiled simple tubular gland
d. The coiled secretory base lies in the deep dermis and hypodermis
- Apocrine glands
a. Confined to axillary, anal, and genital areas
b. Produces a special kind of sweat
c. Larger in size
d. Milky or yellow color sweat consisting of fatty substances and proteins (odorless), but organic molecules are decomposed by bacteria on skin which gives body odor
- When does apocrine glands begin to functioin?
a. At puberty under the influence of androgens
b. Enlarge and recede with phase of a woman’s menstrual cycle
c. Activity increases with sexual foreplay
d. Analogous to the sexual scent glands of other animals
- Hair vs hair follicles
a. Hair: long filaments
b. Hair follicle: tubular invaginations of the epidermis from which the hair grows
- What is the function of hair for humans?
a. Sensory
b. Sense things that lightly touches the skin
- The function of hair is?
a. Main function is To sense things that lightly touches the skin
b. The hair on scalp protects the head against direct sunlight in summer and against heat loss on cold days
c. Eyelashes shield the eyes, and nose hairs filter large particles such as insects and lint from inhaled air
- Hair is composed of?
a. Dead, keratinized cells
- Hard keratin in hairs vs soft keratin in typical epidermal cells
a. Hard keratin is tougher and more durable
b. The cells of hard keratin do not flake off
- What are the chief parts of hair?
a. Root: the part of the hair embedded within the skin
b. Shaft: the part that projects above the skin surface
- The hair is composed of three concentric layers of keratinized cells
a. Medulla
b. Cortex
c. Cuticle
- Medulla
a. Central core that consists of large cells and air spaces
- Cortex
a. Surrounds medulla consisting of several layers of flattened cells
- Cuticle
a. Outermost layer
b. A single layer of cells that overlap one another from below like shingles on a roof
- What happens when you get split ends?
a. Cuticle breaks off
b. Cuticle provide strength and keeps inner layers tightly compacted
- Hair pigment is made by?
a. Melanocytes at the base of the hair follicle and is transferred to the cells of the hair root
- Different proportions of two types of melanin
a. Black brown and yellow rust combine to produce all the common hair colors…black, brown, red, and blond
- Graying or whitening of hair results from?
a. A decrease in the production of melanin and from the replacement of melanin by colorless air bubbles in the hair shaft
- Hair follicles
a. Tubular invaginations of epidermis that extend from the epidermis to the dermis
- Hair bulb vs root plexus
a. Hair bulb: deep, expanded end of the hair follicle
b. Root plexus: knot of sensory verves around hair blub, bending of the hair stimulates nerve endings
- The wall of the hair follicle is composed of?
a. An outer connective tissue root sheath (derived from the dermis) an inner epithelial root sheath (derived from the epidermis)
- Arrector pili muscle
a. Bundle of smooth muscle that runs from the most superficial part of the dermis to a deep lying hair follicle
b. Relaxed hairs lie at an angle
c. Contracted hairs stand erect and skin forms dimples
d. For animals insulating layer of air
- Nails
a. Scalelike modification of the epidermis made up of hard keratin
- Each nail has?
a. Distal free edge
b. A body
c. A proximal root
- Nail rests on a bed of epidermis called?
a. The nail bed, which contains only the deeper layers of the epidermis (the nail itse3lf corresponds to the superficial keratinized layers
- Why does nails look pink?
a. Because of the rich network of capillaires in the underlying dermis
- Where does the bed thickens to form the nail matrix?
a. At the root and promixal end of the nail body
b. The actively growing part of the nail
- What is lunula
a. A white crescent “little moon”
b. We see a lunula instead of pink beause the matrix is so thick in the proximal region that the pink dermis cannot show through it
- Nail folds
a. The skin folds overlapping The lateral and proximal borders of the nail
- Eponychium
a. Cuticle
b. The proximal nail fold
- Burn
a. Tissue damage inflicted by heat, electricity, radiation, extreme friction k or certain harmful chemicals
- What is the immediate threat to life from serious burns?
a. The loss of body fluids (water) and salts
b. Dehydration leads to fatal circulatory shock (inadequate blood circulations)
c. Also…infection becomes the main threat
- Burns are classified by?
a. Their severity (depth)
b. 1st degree burn – 2nd degree burn – 3rd degree burns
- First degree burns
a. Partial thickness burn
b. Only the epidermis is damaged
- 2nd degree burn
a. Partial thickness burn
b. Injury to the epidermis and upper part of the dermis
- Third – degree burn
a. Full thickness burns
b. Consume the entire thickness of the skin
c. Skin is usually grafted onto the burned area
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