What are the five types of glands associated with the skin?
Eccrine sweat glands
Apocrine sweat glands
What does the eccrine gland secrete?
found on palms, soles of feet and forehead. Opens onto skin and is used to regulate body temp.
What does the Apocrine sweat gland secrete?
found in axillary and anogenital areas. Open into hair follicles, contains true sweat plus a fatty additive - function not sure; perhaps analogous to sexual scent glands of other animals
What does the sebaceous gland secrete?
found everywhere but thick skin (soles and palms). Small on body trunk and limbs, larger on face, neck and upper chest. Protect skin and hair.
Explain the advantage and disadvantage of cerumen associated with the ear?
a. Adv. - block entry of foreign material into ear canal that could damage eardrum and impair hearing
b. Disadv. - if accumulates can block sound waves from reaching eardrum and decrease hearing.
What are the benefits of sebum?
a. Lubricate skin and hair
b. Slows water loss from skin
c. Kills bacteria
What is the most common cause of acne or acne vulagaris?
Bacterial inflammation of the sebaceous glands ; pores become blocked due to high production of sebum as a result of hormone production.
4. What is the difference in a whitehead and a blackhead?
Whitehead - pore blocked by sebum; Blackhead - sebum in blocked pore has oxidized and turned black
How does hair grow?
Chemical signals from the hair papilla reach the hair bulge causing the cells to migrate toward the papilla and go thru mitosis. As the new hair cells are produced by the matrix, the older part of the hair is pushed upward, fuses and dies.
What causes goosebumps?
The arrector pili muscle contracts and pulls the hair upright. This pushes the skin back on the surface creating a "goosebump". The hair standing upright creates a layer of air insulation next to the skin increasing the skin's ability to retain heat.
7. Is hair growth stimulated by frequent cutting, shaving or death? Explain.
No It may give the appearance of growing due to dehydration and shrinkage of the skin after death or by comparing the layer of the hair to previously cut hair. Hair may only grow from the cells of the matrix and require ATP to do so.
- body hair of adult males; darker and coarser, also found in axillary and pubic regions of both sexes
Why do your eyebrows not grow as long as your hair on your head?
Hair cells only remain active for three to four months and then enter a dormant phase.
11. Which grows faster - fingernails or toenails? Nails on longer digits or shorter digits?
Fingernail, Longer the digit faster it grows - they are worn thru use and must grow faster to provide protection
12. What are some substances which are absorbed thru the skin? Why are they easily absorbed?
a. Lipid soluble substances - O2, CO2, Fat soluble vitamins i.e. A,D,E,K
b. Resin of certain plants - poison oak and poison ivy
c. Organic Solvents - acetone, dry cleaning solvent, paint thinner
d. Salts of heavy metals - lead, mercury, arsenic
e. Penetration Enchancers - aid drugs in moving across the membranes
13. How does vasoconstriction and vasodilation help maintain a constant body temperature?
As our body heats up, your blood vessels dilate (vasodilation) so the amount of blood near the surface of your skin is increased. This increases the rate of heat transfer to the skin. The opposite occurs when the body temp. drops due to vasoconstriction.
14. What germ layer does the epidermis come from? The dermis?
Epidermis comes from the ectoderm; the dermis comes from the mesoderm
15. What are the risk factors for skin cancer?
a. Skin Type - fair skin at higher risk
b. Sun Exposure - outdoor occupations, high altitutdes, areas with many sunlit days
c. Family History - rate of skin cancer occurrence
d. Age - older people more prone
e. Immunological Status - individual that are immunosuppressive or take immunosuppressive drugs have a higher incidence
17. List and define the ABCD(E) of skin cancer detection.
a. Assymetry - spot is not symmetrical
b. Border - border is notched, indistinct, scalloped or indented
c. Color - uneven coloration, several colors
d. Diameter - greater than 6mm (a pencil eraser)
e. Elevation - how far above the skin's surface does the spot extend
What is a burn and how is it caused?
Tissue damage inflicted by intense heat, electricity, radiation or chemicals which denature cell proteins and cause cell death
19. How is the seriousness or degree of a burn determined?
Seriousness is determined by the depth of the burn, the amount of the area involved, person's age and general state of health.
20. What is the Rule of Nines and how is it used to estimate burned surface area? When would it be used?
Used in emergencies and to determine fluid loss - body is divided into 11 areas, most counting for 9%.
9% each arm, 9% anterior and posterior surface of head and neck, 18% each leg, 36% trunk and buttocks, 1% perineum
21. What is the Lund Browder method and when would it be used?
Estimates the surface area affected by the burn as compared to total surface area. This is more accurate and used when patient is stable
First Degree Burn (Definition Characteristics Recovery Time Percent of Body Involved for Critical Condition)
Involves only epidermis Mild pain; redness 3 - 6 days
Second Degree Burn
Destroys portion of epidermis and some dermis Redness, blisters for, edema (swelling and fluid retention, pain) 3 - 4 weeks 25%
Third Degree Burn
Destroys portions of epidermis, dermis and assoc. structures such as nerves, muscles, hair White to dark brown in color, edema, numbness and lack of pain Slow if at all, grafting may be required as basal cells are destroyed
occurs as a sign of another disorder due to skin inflammation. Characterized by bumps, blisters and crusts
overactive sebaceous glands of scalp create pink lesions (scales) that become yellow and brown and are shed
partial or complete lack of hair in a localized area due to genetics, aging or a skin disorder
inflammation of hair follicles and sebaceous glands in which an infection has spread to the underlying hypodermis. Usually caused by bacterial infection
skin disorder caused by loss of melanocytes resulting in unpigmented skin regions (light spots) surrounded by normally pigmented areas. Possible autoimmune in origin.
inherited condition; melanocytes do not produce melanin. Skin is pink, hair pale or white, irises unpigmented ( pink from seeing bld vessels behind iris) or lightly pigmented (blue)
Porphyria, what myth did this lead to?
- lack enzymes necessary to form hemoglobin in blood. Side characteristics include gum degeneration creating prominent teeth. Thought to give rise to vampire myths.
25. Cortisone is a steroid that is applied to the skin to reduce inflammation. Cortisone acts on cells within the dermis and can travel through unbroken epidermis to reach cells in the dermis. If the epidermis is such a good barrier, how can cortisone easily travel through it?
Cortisone must be lipid soluble so it can easily diffuse through the cell membrane
Explain how dandruff is formed.
This is psoriasis of the scalp - kereatinocytes divide and migrate very quickly. The young keratin is scaly and thick.
27. Identify the epidermal layer(s) in which the following cancers arise:
a. Basal Cell Carcinoma - stratum basale
b. Malignant Melanoma - melanocytes in stratum spinosum
c. Squamous Cell Carcinoma - keratinocytes of stratum spinosum
As we age, our skin wrinkles due to changes in collagen and elastic fibers in the dermis and a decrease in their production. Explain why topical applications of collagen and elastic fibers would not eliminate wrinkles
Collagen is absorbed into the epidermis but not the dermis which is where the collagen and elastic fibers are - they would have to be injected into the dermis for even a temporary change to occur.