Lecture test 1 Short answer
which of the following is not an epidermal derivative
*sensory receptor*, sebaceous gland, hair, sweat gland
excessive secreation of androgens
...
function of arrector peli
...
how is skin manufactured
...
sebum provides
...
touch sensors
...
Important role of accerine sweat
...For most mammals, however, apocrine sweat glands secrete an oily (and eventually smelly) compound that acts as a pheromone, territorial marker, and warning signal. Being sensitive to adrenaline, apocrine sweat glands are involved in emotional sweating in humans (induced by anxiety, stress, fear, sexual stimulation, and pain). The apocrine gland secretes an oily fluid with proteins, lipids, and steroids that is odorless before microbial activity. mature during puberty
pigments of skin
...Melanin, Carotene, and hemoglobin
how does body regulate temperature
...The temperature of the body is regulated by neural feedback mechanisms which operate primarily through the hypothalmus. The hypothalmus contains not only the control mechanisms, but also the key temperature sensors. Under control of these mechanisms, sweating begins almost precisely at a skin temperature of 37°C and increases rapidly as the skin temperature rises above this value. The heat production of the body under these conditions remains almost constant as the skin temperature rises. If the skin temperature drops below 37°C a variety of responses are initiated to conserve the heat in the body and to increase heat production. These include Vasoconstriction to decrease the flow of heat to the skin. Cessation of sweating. Shivering to increase heat production in the muscles. Secretion of norepinephrine, epinephrine, and thyroxine to increase heat production In lower animals, the erection of the hairs and fur to increase insulation.
important role of eccrine sweat
...hey are active in thermoregulation by providing cooling from water evaporation of sweat secreted by the glands on the body surface and emotional induced sweating (anxiety, fear, stress, and pain)
which skin cancer developes from the youngest epidermal cells
Basal cell carcinoma develops from the youngest epidermal cells
Which epidermal cell is most numerous
Keratinocytes
how does UV radiation contribute to skin wrinkles
UV radiation degrades collagen and leads to loss of skin elasticity and water holding capacity
the product of this type of sweat gland includes protein and lipid substances that become odoriferous as a result of bacterial action
apocrine gland
you have just gotten a paper cut but it doesnt bleed, has the cut penetrated into the dermis?
because there is no bleeding, the cut has penetrated into the avascular epidermis only
skin color is determined by
blood, pigments, oxygenation of blood
although the anterior head and face represnet only a small percentage of the body, burns in this area are often more serious than those to the body trunk, why?
burns to the face are serious because damage to respiratory passageways can occur in such burns
an arrector pili muscle does what
can cause a hair to stand up straight
sebum does what?
consists of cell gragments and fatty substances, in excess may cause seborrhea, lubricates
what cyanosis and what does it indicate
cyan (deep blue) is a bluish cast of the skin that indicates that hemogglobin in the red blood cells in the dermal capillaries is poorly oxygenated
which cell functions as part of the immune system
dendritic cell
the rule of nine is helpful clinically in
estimating the extent of a burn
which tissue of the hypodermis makes it a good shock abosrober
fatty tissue in the hypodermis gives it insulating and schock absrobing properties
the healing of burns and epidermal regeneration is uually uneventful unless the burn is a third degree burn, what accounts for this difference
first and secound degree burns can heal uneventfully by regeneration of epidermal cells as long as infection does not occur. the third degree burns destroy the entire depth of skin and regeneration is not possible. infection and loss of body fluid and proteins are problematic
skin surface marking that reflect points of tight dermal attachment to underlying tissues are called
flexur lines
what is the difference between heat induced sweating and a cold sweat and which veriety of sweat gland is involved
heat induced sweating occures all over the body when we are overheated. a cold sweat is emotionally induced sweating that begins on the palms, soles, and armpits and then spreads to other body areas. both types of sweating are produced by the eccrine sweat glands, but activity of apocrine sweat glands is also likily during a cold sweat
when anothong returned home from a run in 85 degree weather, his face was dripping in sweat, why?
his sympothetic nervous system activated his eccrine sweat glands and caused heat induced sweating in order to cool the body
which is not true statement about the papillary layer of the dermis
it is most responsible for the toughness of the skin
which alteration in skin color may indicate a liver disorder
juandice or a tellow cast to the skin due to the deposit of yellow bile pigments in body tissues may indicate a liver disorder
the epidermis provides a physical barrier due largely to the presence of
keratin
what change in the skin leas to cold intolerance in the elderly
loss of subcutanous fat, common in the elderly leads to cold intolerance seen this group of people
why are nails so hard
nails are hard beause the keratin they contain is the hard keratin veriety
which cutaneous glands are associated with hair follicles
sebaceous oil glands and apocrine glands are associated with the hair follicles
principle role of melanin
shield the nucleus from damage by ultraviolet radiation.
how is sunlight important to bone health?
sunlight causes the skin to produce a precursor of vit. D from cholesterol. Vit D is essential for bone synthesis
layers of epidermis
superficial to deepest would be the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale
what name is given to the rule of recognizing the signs of melanoma
the ABCD rule helps on to recognize sings of melanoma
whay is the role of an arrector pili muscle
the arrector pili muscles pull the hair (normally slanted) to the upright position (when cold or scared)
the sensation of touch and pressure are picked up by receptors located in
the dermis
which epidermal cells play a role in body immunity?
the epidermal dendritic cells play a role in body immunity
what is the function of the hair papilla
the hair papilla contains a knot of capillaries that supplies nutrients to cells of the hair bulb
what chemicals produced in the skin help provide barriers to bacteria? list at least three and explain how the chemicals are protective
the low pH of skin secreation (acid mantle) inhibits division of bacteria, and many bacteria re killed be bactericidal substance in sebum or by natural antibiotics called defensins. damaged skin secretes cathelicidins that are effective agains a certain stran of strep bacteria
why is the lunule of a nail white instead ofpink like the rest of the nail
the lunule of the nail is white because the thick nail matrix that underlies it blocks the rosy color of the dermal blood supply from showing throught
sabaceous glands are not found in thick sking. why is their absence in those body regions desirable
the palms of the hands and soles of the feat are thick skin areas, it would be dangerous to have oily soles, and oily palms would decrease the ability of the handsto hang onto things
which layer of the dermis is responsible for producing fingerprint patterns
the papillary layer of the dermis gives rise to fingerprint patters
what are the concentrig region of a hair shaft, from outside in
the regions of the hair from outside in are the cuticle, cortex and medulla
how does the skin contrubte to body metabolism
the skin carries out chemical conversaions that supplement some of the protective conversions carried out by the liver, convert some chemicals ino carcinogens, activate some steroid hormons and synthesisize vitamin D precursor
why are the desmosomes connection the keratinocytes so important
the skin is subjected to a lot of abrasion and physical truma. the Desmosomes, which are connecting junctions, help to hold the cells together during such stress
stratum basale (stratum germinativum) function
the stratum basale undergoes almost continuous mitosis to replace cells lost be abrasion
given that epithelia are avascular, which layer would you expect to have the best nourished cells
the stratum basale, which abuts the dermis where blood supply is, has the best nourished cells
melanin and carotene are two pigments that contribute to skin color, what is the third and where is it found
the third pigment contributing to skin color is hemoglobin, the pigment contain in red blood cells found in blood vessels of the dermis
why is having your hair cut painless
there are no nerves in hair, so cutting hair is painless
what is the source of vernix caseosa that covers the skin of the newborn baby?
vernix caseosa is a product of sebaceous glands
