The epidermis is the outermost layer of the skin. The dermis is the deeper layer beneath it, and the hypodermis (subcutaneous layer) lies below the dermis.
Category: Chapter 5
Question 2
Keratinocytes are the most abundant cell type in the epidermis.
Correct Answer
True
Keratinocytes make up about 90% of epidermal cells. They produce keratin, a tough fibrous protein that gives skin its protective properties.
Category: Chapter 5
Question 3
Melanin is produced by cells called fibroblasts.
Correct Answer
False
Melanin is produced by melanocytes, which are found in the stratum basale of the epidermis. Fibroblasts are found in the dermis and produce collagen and other connective tissue fibers.
Category: Chapter 5
Question 4
The stratum basale is the deepest layer of the epidermis.
Correct Answer
True
The stratum basale (basal layer) is the deepest epidermal layer, attached to the dermis. It contains stem cells that continuously divide to produce new keratinocytes.
Category: Chapter 5
Question 5
Thick skin is found on the palms of the hands and soles of the feet.
Correct Answer
True
Thick skin has all five epidermal layers including the stratum lucidum and has a much thicker stratum corneum. It is found on the palms and soles where extra protection is needed.
Category: Chapter 5
Question 6
Sebaceous glands produce sweat.
Correct Answer
False
Sebaceous glands produce sebum, an oily substance that lubricates and waterproofs the skin and hair. Sudoriferous (sweat) glands produce sweat.
Category: Chapter 5
Question 7
The dermis contains blood vessels, but the epidermis does not.
Correct Answer
True
The epidermis is avascular (contains no blood vessels) and receives nutrients by diffusion from blood vessels in the dermis below.
Category: Chapter 5
Question 8
Hair grows from a structure called the hair follicle.
Correct Answer
True
Hair follicles are structures in the dermis from which hair grows. The base of the follicle (hair bulb) contains the matrix cells that divide to produce the hair shaft.
Category: Chapter 5
Question 9
First-degree burns damage the epidermis and dermis.
Correct Answer
False
First-degree burns (superficial burns) damage only the epidermis, causing redness and pain. Second-degree burns extend into the dermis. Third-degree burns destroy both layers.
Category: Chapter 5
Question 10
Vitamin D synthesis begins in the skin when exposed to UV radiation.
Correct Answer
True
UV radiation triggers the conversion of a cholesterol precursor (7-dehydrocholesterol) in the skin to vitamin D3 (cholecalciferol), which is then modified by the liver and kidneys.
Category: Chapter 5
Question 11
The arrector pili muscle causes goosebumps when it contracts.
Correct Answer
True
The arrector pili is a small smooth muscle attached to each hair follicle. When it contracts (usually in response to cold or fear), it pulls the hair upright, creating goosebumps.
Category: Chapter 5
Question 12
The hypodermis is considered a true layer of the skin.
Correct Answer
False
The hypodermis (subcutaneous layer) lies deep to the dermis but is not considered a true part of the skin. It anchors the skin to underlying structures and contains adipose tissue.
Category: Chapter 5
Question 13
Eccrine sweat glands are found over nearly the entire body surface.
Correct Answer
True
Eccrine glands are the most numerous sweat glands and are distributed over most of the body surface. They produce a watery sweat important for thermoregulation.
Category: Chapter 5
Question 14
The stratum corneum consists of living keratinocytes filled with keratin.
Correct Answer
False
The stratum corneum is the outermost layer of the epidermis and consists of dead, flattened keratinocytes filled with keratin. These dead cells are continuously shed (desquamation).
Category: Chapter 5
Question 15
Nails are composed of hard keratin.
Correct Answer
True
Nails are made of a hard type of keratin produced by the nail matrix. They protect the distal tips of fingers and toes and assist with grasping small objects.
Category: Chapter 5
Question 16
Apocrine sweat glands become active at puberty.
Correct Answer
True
Apocrine glands are found mainly in the axillary and genital areas. They become active at puberty and produce a thicker secretion that can produce body odor when broken down by bacteria.
Category: Chapter 5
Question 17
The papillary layer of the dermis creates fingerprints.
Correct Answer
True
The papillary layer contains dermal papillae that form ridges on the skin surface, creating the unique patterns known as fingerprints (friction ridges).
Category: Chapter 5
Question 18
Cyanosis is a bluish skin color caused by excess melanin production.
Correct Answer
False
Cyanosis is a bluish discoloration caused by inadequate oxygenation of the blood (low oxygen in hemoglobin). It is not related to melanin production.
Category: Chapter 5
Question 19
Burns that cover a large body surface area can be life-threatening due to fluid loss.
Correct Answer
True
Severe burns destroy the skin's barrier function, leading to massive fluid loss, electrolyte imbalance, infection risk, and potentially fatal dehydration and shock.
Category: Chapter 5
Question 20
The skin is the largest organ of the body.
Correct Answer
True
The skin covers approximately 1.5 to 2 square meters in adults and accounts for about 15% of total body weight, making it the largest organ by surface area and weight.
Category: Chapter 5