Using the choices, choose all responses that apply to the following descriptions. (Some choices may be used more than once). i 40. Stratum basale g 41. Stratum corneum a 42. Stratum granulosum _ 43. Stratum lucidum 44. Stratum spinosum c 45. Papillary layer _ 46. Reticular layer __d 47. Epidermis (as a whole) e 48. Dermis (as a whole) a. Layer containing sacs filled with fatty material or keratin subunits b. Dead cells c. The more superficial dermis layer d. Avascular region e. Major skin area where accessory structures (nails and hair) reside f. Epidermal region exhibiting the most mitoses g. Most superficial epidermal layer h. Has abundant elastic and collagenic fibers i. Region where melanocytes are most likely to be found j. Accounts for most of the epidermis
The Correct Answer and Explanation is:
Here are the correct responses with explanations for each description:
40. Stratum basale:
i. Region where melanocytes are most likely to be found
f. Epidermal region exhibiting the most mitoses
j. Accounts for most of the epidermis
- The stratum basale, also called the stratum germinativum, is the deepest layer of the epidermis. It contains melanocytes, which produce the pigment melanin, and is where new skin cells are produced by mitosis. This is where most of the epidermal mitoses occur, and it accounts for the majority of the epidermis’ cell turnover.
41. Stratum corneum:
b. Dead cells
g. Most superficial epidermal layer
- The stratum corneum is the outermost layer of the epidermis and consists of dead, flattened keratinized cells. These cells are shed regularly, and the stratum corneum acts as the first line of defense against environmental damage.
42. Stratum granulosum:
a. Layer containing sacs filled with fatty material or keratin subunits
- The stratum granulosum is where keratinocytes begin to undergo keratinization, transitioning from living cells to dead, flattened cells. It contains keratohyalin granules which are precursors for keratin and lipid-filled sacs that help form the skin’s barrier function.
43. Stratum lucidum:
h. Has abundant elastic and collagenic fibers
- The stratum lucidum is a clear, thin layer found only in thick skin, such as the palms of the hands and soles of the feet. This layer helps provide an additional barrier, and its cells are packed with keratin and lipids that aid in moisture retention and protection.
44. Stratum spinosum:
f. Epidermal region exhibiting the most mitoses
i. Region where melanocytes are most likely to be found
- The stratum spinosum is just above the stratum basale and contains keratinocytes that are actively dividing and attached to one another by desmosomes. It also houses melanin granules from melanocytes that help protect the skin from UV radiation.
45. Papillary layer:
c. The more superficial dermis layer
- The papillary layer is the upper part of the dermis and is responsible for supplying nutrients to the epidermis through its capillary loops. It contains loose connective tissue and forms the dermal papillae, which interlock with the epidermis.
46. Reticular layer:
h. Has abundant elastic and collagenic fibers
- The reticular layer is the deeper part of the dermis and is composed of dense irregular connective tissue. It contains a rich network of collagen and elastic fibers, providing strength, elasticity, and the ability to resist tension.
47. Epidermis (as a whole):
d. Avascular region
- The epidermis is an avascular layer of skin, meaning it lacks blood vessels. Instead, it receives nutrients through diffusion from the underlying dermis.
48. Dermis (as a whole):
e. Major skin area where accessory structures (nails and hair) reside
- The dermis is the thicker layer beneath the epidermis, and it houses the hair follicles, sebaceous glands, sweat glands, nail roots, and blood vessels. It provides structural support and flexibility to the skin.
Summary of Matching:
- Stratum basale: i, f, j
- Stratum corneum: b, g
- Stratum granulosum: a
- Stratum lucidum: h
- Stratum spinosum: f, i
- Papillary layer: c
- Reticular layer: h
- Epidermis (as a whole): d
- Dermis (as a whole): e
The epidermis and dermis are essential components of the skin, each with distinct roles, from protecting the body to housing various structures like hair and sweat glands.
