The Dermis and Accessory Structures Guided Notes
1. The color of your skin is due to an interaction between:
(1) ___________________ pigmentation
(2) dermal __________________
2. Two pigments present in the epidermis:
(1) ____________________ – orange-yellow pigment found in the stratum corneum layer and in the fatty
tissues in the dermis.
(2) ________________ – brown, yellow-brown, or black pigment produced by melanocytes
3. Melanocytes produce the pigment _________________. Melanin is transferred up through the layers via vesicles
called _______________________ until they are destroyed. In individuals with pale skin, the ______________________
are destroyed in the lower layers of the epidermis, and the cells of the more superficial layers lose their pigmentation.
In individuals with dark skin, the melanosomes are larger and the melanosomes are destroyed in the stratum
____________________ layer, making the pigment in the upper layers darker.
4. Melanin pigment in your skin protects you from _______________________. Large amounts of UV radiation can
damage ______, causing mutations and promoting the development of ____________________. In the keratinocytes,
melanin is concentrated around the __________________, thereby protecting your DNA from UV exposure.
5. Although melanocytes increase their __________________ and _________________ production when exposed to UV
radiation, the response is not rapid enough to prevent __________________ the first day of constant exposure.
Melanocyte activity peaks about _____ days after initial exposure. Chronic exposure to UV radiation can result in
premature ________________, leathery consistency to skin, and skin cancers.
6. Blood contains red blood cells that contain the pigment ____________________, that binds and transports oxygen
throughout the body. Hemoglobin is bright ______. If blood vessels are _________________, the red tones seen in light
colored individuals gives the skin a redder tone. ___________________ (blue skin) can occur due to a sudden drop in
__________ supply to the skin.
7. When exposed to small amounts of UV radiation, epidermal cells in the stratum basale and stratum spinosum convert
a cholesterol-related steroid into vitamin D3 (____________________). The liver then converts choleciferol into the
hormone ____________________, essential for the absorption of _________________ and phosphorus by the small
intestine. An inadequate supply of calcitriol leads to impaired _________ maintenance and growth.
8. There are two major components of the dermis:
(1) a superficial dermal ____________________ layer
(2) a deeper ________________ layer
9. The dermal papillary layer consists of _________________ tissue, and contains capillaries and sensory neurons that
supply the surface of the skin.
10. The reticular layer of the dermis is found beneath the _________________ layer and consists of dense irregular
tissue. Bundles of ______________ fibers extend beyond the reticular layer into the hypodermis below.
11. Although collagen fibers are strong and resist ____________________, they are easily ________ or twisted.
___________ fibers permit stretching but then return to their original length. Aging, hormones, and UV radiation
exposure reduce the amount of _____________ in the dermis, producing ___________________ and sagging
_________.
12. Distortion of the dermis over the abdomen during ________________________ or after substantial weight gain can
exceed the ___________________ capabilities of the skin. The resulting damage prevents it from recoiling to its original
size after delivery or weight loss. The skin wrinkles/creases, creating _______________ ____________.
13. Most of the collagen and elastic fibers are arranged in _____________ bundles. These bundles are aligned in
different directions to resist applied forces. The pattern of arrangement of these bundles are called ________ of
_______________.
These lines are significant, because a cut parallel to a cleavage line will remain
__________________, whereas a cut at right angles to the line will be pulled _________. Surgeons chose their
_____________ lines based on the lines of cleavage.
14. The dermis layer contains many ________________ receptors:
(1) sensitive to light touch (_______________________ corpuscles) that are located in the dermal papillae
(2) receptors sensitive to deep pressure and vibration (________________ corpuscles)
15. Hairs are produced from organs called hair _________________.
16. There are many different types of hair:
_______________ – extremely fine, unpigmented hairs that form after three months of embryonic development.
Lanugo is shed before ___________ and is replaced by:
(1) ______________ hairs – fine peach fuzz located throughout the body. _______________ causes some vellus
hairs to transition to terminal (airpit, groin, etc)
(2) ________________ hairs – heavy, deeply pigmented, sometimes curly hairs (head hair, eyebrows, and
eyelashes)
17. There are numerous functions of hair. Head hair protects the scalp from _______ radiation and
_________________ the head. Nasal hairs prevent entry of ________________ particles into the airway
(___________________ perform same function for eyes). A _______ ______ _______________ of sensory nerves
allows you to feel even slight movements of each hair shaft.
18. Ribbons of smooth muscle called _______________________ muscles pull on the hair follicles and force the hair to
stand erect.
19. Hairs grow and shed based on hair growth cycle. A scalp hair grows for ________ years, at a rate of about 0.33
mm/day. Collections of hair can be useful to assay for:
(1) ______ poisoning
(2) ____________ poisoning
(3) heavy metal poisoning
Healthy adults lose about ____ hairs/day from your head. In males, changing sex hormone leves can change terminal
hair to vellus hair, in a process called ________ ________________ __________________.
20. There are two types of exocrine glands:
(1) Sebaceous glands
(2) Sweat glands – consists of ______________ and _____________ glands
21. Sebaceous glands are _____ glands that discharge a waxy, oily secretion into hair follicles. They release sebum
(____________) that inhibit _____________ growth, _________________ keratin (hair/nails), and _________________
the skin.
22. During the last months of fetal development, the sebaceous glands are extremely active and produce secretions to
form a protective layer called the ___________ _________________. Why does this protective layer need to be
formed? ____________________________________________________________________________________
23. Apocrine glands are located in the _______________, around the nipples, and in the groin attached to hairs. They
produce sticky, cloudy, sometimes _________________ secretions.
The sweat is a nutrient source for
_______________, which intensify the odor. The apocrine glands begin secreting at _________________.
24. Merocrine/ecrine glands are more ___________________ and widely dispersed than sebaceous glands. The
_____________ and ___________ have the greatest number of ecrine sweat glands. These glands discharge secretions
directly onto __________.
25. Merocrine/ecrine glands function to:
1. Cool the skin through _____________________ cooling
2. Excrete __________ and electrolytes
3. Provide ______________________ to environmental hazards, by diluting harmful chemicals and discouraging
growth of __________________
26. Ceruminous glands are modified ____________ glands located in the passageway of the external ear canal. The
secretions are called __________________, or earwax. They work along with tiny _________ to trap foreign particles
and prevent them from reaching the eardrum.
27. Nails form on the _____________ surfaces of fingers and toes. They function to _________________ exposed tips
of fingers and toes, and limit their ______________________ when subjected to mechanical stress, like grabbing
objects.
28. Nail production occurs at the nail __________. The underlying blood vessels provide the nail bed with its
______________. There is a small white/pale colored moon called the ________________ found at the base of the nail.
29. Nails can also be used to indicate the general overall health of an individual. EX: _____________-- nails in
individuals with chronic respiratory disorders, thyroid disorders, or AIDS, ______________ nails as a result of psoriasis,
_______________ nails as a result of some blood disorders