Chapter 5

How many layers does the dermis contain?

2

The hair matrix contains _____.

A layer of basal cells

Sebaceous glands _____.

Are associated with hair follicles

Eccrine sweat glands _____.

Are present in the skin throughout the body and produce watery sweat

Bedsores _____.

Are preventable by eliminating pressure points

Cells of the epidermis derive from stem cells of the stratum basale. Describe how the cells change as they become integrated into the different layers of the epidermis.

As the cells move into the stratum spinosum, they begin the synthesis of keratin and extend cell processes, desmosomes, which link the cells. As the stratum basale continues to produce new cells, the keratinocytes of the stratum spinosum are pushed into the stratum granulosum. The cells become flatter, their cell membranes thicken, and they generate large amounts of the proteins keratin and keratohyalin. The nuclei and other cell organelles disintegrate as the cells die, leaving behind the keratin, keratohyalin, and cell membranes that form the stratum lucidum and the stratum corneum. The keratinocytes in these layers are mostly dead and flattened. Cells in the stratum corneum are periodically shed.

If you cut yourself and bacteria enters the wound, which of the following cells would help get rid of the bacteria? A. Merkel cells B. Keratinocytes C. Langerhans cells D. Melanocytes

C. Langerhans cells

Which of the following are NOT considered a touch receptor? A. Merkel cells B. Meissner corpsucles C. Langerhans cells D. Pacinian corpsucles

C. Langerhans cells

An individual using a sharp knife notices a small amount of blood where he just cut himself. Which of the following layers of skin did he have to cut in order to bleed? A. Stratum corneum B. Stratum basale C. Papillary dermis D. Stratum granulosum

C. Papillary dermis

Which of the following is NOT a function of the hypodermis? A. Protects underlying organs B. Helps maintain body temperature C. Source of blood vessels in the epidermis D. A site to long-term energy storage

C. Source of blood vessels in the epidermis

The papillary and reticular layers of the dermis are composed mainly of ______.

Connective Tissue

Which of the following is FALSE regarding the skin? A. It makes up approximately 16% of an adult human's body weight B. It is the largest organ system in the human body C. It's functions include protection and support D. All of the above are true

D. All of the above are true

Which of the following is NOT a function of hair? A. Thermoregulation B. Communication C. Sensory Input D. Structural Support

D. Structural Support

Which of the following is FALSE regarding sebaceous glands? A. They generate and secrete a substance called sebum B. Most sebaceous glands are associated with hair follicles C. They help to lubricate skin and hair D. These glands are more active during childhood

D. These glands are more active during childhood

Which aspect of the integumentary system contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands.

Dermis

Explain the differences between eccrine and apocrine sweat glands.

Eccrine sweat glands - Secrete through pores on the skin. This is a merocrine secretion. Responsible for thermoregulation.Apocrine swear glands - Secrete into the hair follicle. Produce a smelly odor. Mammary, ceruminous, and ciliary glands are all modified apocrine glands. Found in the axillary and anogenital regions. Only active after puberty occurs.

An individual has spent too much time sun bathing. Not only is his skin painful to touch, but small blisters have appeared in the affected area. This indicates that he has damaged which layers of his skin?

Epidermis and dermis

Which layer of the skin plays an important role in fat storage and insulation?

Hypodermis

Squamous cell carcinomas are the second most common of the skin cancers and are capable of metastizing if not treated. This cancer affects which cells?

Keratinocytes of the stratus spinosuM

Describe the structure and composition of nails.

Nails are composed of densely packed dead keratinocytes. They protect the fingers and toes from mechanical stress. The nail body is formed on the nail bed, which is at the nail root. Nail folds, folds of skin that overlap the nail on its side, secure the nail to the body. The crescent-shaped region at the base of the nail is the lunula.

Why do scars look different from surrounding skin?

Scars are made of collagen and do not have the cellular structure of normal skin. The tissue is fibrous and does not allow for the regeneration of accessory structures, such as hair follicles, and sweat or sebaceous glands.

Langerhans cells are commonly found in the _______.

Stratum Spinosum

Why do people sweat excessively when exercising outside on a hot day?

Sweating cools the body when it becomes warm. When the body temperature rises, such as when exercising on a hot day, the dermal blood vessels dilate, and the sweat glands begin to secrete more sweat. The evaporation of the sweat from the surface of the skin cools the body by dissipating heat.

Explain your skin's response to a drop in body core temperature.

The errector pilli muscle pushes up this casues hair to stand up closing off the pores of the skin. This helps to hold in the heat of the body.

What determines the color of skin, and what is the process that darkens skin when it is exposed to UV light?

The pigment melanin, produced by melanocytes, is primarily responsible for skin color, carotene(yellow/orange), and hemoglobin(red/pink) are also skin pigments. Melanin comes in different shades of brown and black. Individuals with darker skin have darker, more abundant melanin, whereas fair-skinned individuals have a lighter shade of skin and less melanin. Exposure to UV irradiation stimulates the melanocytes to produce and secrete more melanin, thus causing you to get darker.

A _____ degree burn fully extends into the epidermis and dermis, destroying the tissue and affecting the nerve endings and sensory function.

Third

In humans, exposure of the skin to sunlight is required for ____.

Vitamin D Synthesis

In response to stimuli from the sympathetic nervous system, the arrector pili ______.

are responsible for goose bumps

In general, skin cancers _____.

can be reduced by limited exposure to the sun

After a skin injury, the body initiates a wound-healing response. The first step of this response is the formation of a blood clot to stop bleeding. Which of the following would be the next response? A. Increased production of melanin by melanocytes B. Increase production of connective tissue C. An increase in Pacinian corpsucles around the wound D. An increased activity in the stratum lucidum

Increase production of connective tissue

At the base of the nail, a thick layer of epithelium over the nail matrix forms a crescent-shaped region called the -_____.

Lunula

Which structure overlaps the nail on the sides, helping to anchor the nail body?

Nail fold

The absence of sun exposure can lead to a lack of vitamin D in the body, leading to a condition called ______.

Rickets

Why do teenagers often experience acne?

Sebaceous glands cause acne, these glands produce sebum. Sebum creates blockages, thus resulting in a infection. Sebaceous glands become active when puberty starts. Hormones that are especially active during puberty stimulate the release of sebum, thus giving teenagers more acne.

______ is a cancer that affects the keratinocytes of the stratum spinosum and presents as lesions commonly found on the scalp, ears, and hands.

Squamous cell carcinoma

As you are walking down the beach, you see a dead, dry, shriveled-up fish. Which layer of your epidermis keeps you from drying out?

Stratum Corneum

The papillary layer of the dermis is most closely associated with which layer of the epidermis?

Stratum basale

Collagen lends _____ to the skin.

Structure

One of the functions of the integumentary system is protection. Which of the following does not directly contribute to that function? A. Stratum lucidum B. Desmosomes C. Folic acid synthesis D. Merkel cells

Folic acid synthesis

Similar to the hair, nails grow continuously throughout our lives. Which of the following is furthest from the nail growth center? A. Nail bed B. Hyponychium C. Nail root D. Eponychium

Hyponychium