Chapter 6

Lecture chapter 6 book review questions

What is the major histological difference between thick and thin skin? Where on the body is each type of skin found?

The major histological difference is that thick skin has a thicker stratum corneum and lacks hair follicles, while thin skin has a thinner stratum corneum and contains hair follicles 1. Thick skin is found on the palms and soles, whereas thin skin covers the rest of the body

How does the skin help to adjust body temperature?

The skin helps adjust body temperature through cutaneous vasoconstriction and vasodilation, altering blood flow to release or retain heat

List the five cell types of the epidermis. Describe their locations and functions.

The five cell types of the epidermis are keratinocytes (most abundant, produce keratin), melanocytes (produce melanin), tactile cells (touch receptors), dendritic cells (immune response), and stem cells (precursors to keratinocytes)

List the five layers of epidermis from deep to superficial. What are the distinctive features of each layer? Which layer is often absent?

The five layers of the epidermis from deep to superficial are stratum basale (stem cells), stratum spinosum (living keratinocytes), stratum granulosum (keratohyalin granules), stratum lucidum (only in thick skin), and stratum corneum (dead keratinized cells) 11, 15. The stratum lucidum is often absent in thin skin

What are the two layers of the dermis? What type of tissue composes each layer?

The two layers of the dermis are the papillary layer (areolar tissue) and the reticular layer (dense irregular connective tissue)

Name the pigments responsible for normal skin colors and explain how certain conditions can produce discolorations of the skin.

Melanin and carotene are responsible for skin color; conditions like UV exposure can increase melanin production, leading to darker skin

List the functions of the skin and relate them to its structure

The epidermis is a keratinized stratified squamous epithelium, avascular, with five layers including the stratum corneum. The dermis is a connective tissue layer rich in collagen and elastic fibers, housing blood vessels and glands. The subcutaneous tissue, or hypodermis, consists mainly of adipose tissue, providing insulation and energy storage

Describe the normal and pathological colors that the skin can have, and explain their causes

Skin color variations arise from melanin and carotene; conditions like UV exposure can darken skin. Pathological colors include jaundice (yellow) from liver issues and cyanosis (blue) from oxygen deficiency

Distinguish between three types of hair

• Lanugo: Fine unpigmented hair found on fetuses during the last trimester.

• Vellus Hair: Fine, pale hair that replaces lanugo at birth; predominant in women and children.

• Terminal Hair: Coarser, pigmented hair found on the scalp, eyebrows, and after puberty in axillary and pubic regions.

describe the histology of a hair and its follicle

• Hair consists of a shaft (above skin) and root (below skin).

• The follicle includes a bulb with a dermal papilla for nourishment and a hair matrix for growth.

• Hair has three layers: medulla (core), cortex (bulk), and cuticle (outer layer)

discuss some theories of the purposes served by various kinds of hair

• Hair consists of a shaft (above skin) and root (below skin).

• The follicle includes a bulb with a dermal papilla for nourishment and a hair matrix for growth.

• Hair has three layers: medulla (core), cortex (bulk), and cuticle (outer layer)

describe the structure and function of nails.

• Nails are hard derivatives of the stratum corneum, composed of dead keratinized cells.

• Structure includes the nail plate (visible part), nail bed (underlying skin), and nail matrix (growth zone).

• Functions include enhancing sensitivity, improving grooming, and providing a counterforce for fingertip manipulation

What is the difference between vellus hair and terminal hair?

Vellus hair is fine, pale, and unpigmented, covering most of the body, while terminal hair is coarser, darker, and pigmented, found on the scalp, eyebrows, and after puberty in certain areas

State the functions of the hair papilla, hair receptors, and arrector muscle

• Hair Papilla: Provides nutrients to the hair follicle and supports hair growth.

• Hair Receptors: Detects movement and sensations, alerting the body to potential threats like parasites.

• Arrector Muscle: Causes hair to stand up (goosebumps) and helps in thermoregulation by trapping air for insulation

State some reasonable theories for the different functions of hair of the eyebrows, eyelashes, scalp, nostrils, and axilla

• Eyebrows and eyelashes protect eyes from debris and enhance facial expressions 28.

• Scalp hair provides insulation and protects against UV rays 28.

• Nostril hair filters out dust and particles, while axillary hair may play a role in pheromone signaling 28.

1. Describe what happens in the anagen, catagen, and telogen phases of the hair cycle.

• Anagen: Active growth phase where hair follicles produce new hair 28.

• Catagen: Transitional phase where hair growth slows and the follicle shrinks 28.

• Telogen: Resting phase where hair is shed and the follicle remains inactive before starting a new growth cycle

Define or describe the nail plate, nail fold, eponychium, hyponychium, and nail matrix

• Nail Plate: The hard, visible part of the nail .

• Nail Fold: Skin surrounding the nail plate, providing protection 34.

• Eponychium: The cuticle, a narrow zone of dead skin at the nail's base 34.

• Hyponychium: The skin beneath the free edge of the nail 34.

• Nail Matrix: The growth zone at the proximal end of the nail, responsible for nail formation

1. name two types of sweat glands, and describe the structure and function of each

• Apocrine Sweat Glands: Located in the groin, anal region, axilla, and areola. They have ducts that lead to hair follicles and produce a milky sweat containing fatty acids. These glands become active at puberty and are associated with stress and sexual stimulation 38.

• Eccrine (Merocrine) Sweat Glands: Found throughout the body, especially on palms, soles, and forehead. They are simple tubular glands that produce a watery sweat to help cool the body through evaporation

1. describe the location, structure, and function of sebaceous and ceruminous glands

• Sebaceous and Ceruminous Glands:

  • Sebaceous Glands: Located near hair follicles, these flask-shaped glands secrete sebum, an oily substance that keeps skin and hair moisturized 38.

  • Ceruminous Glands: Found in the external ear canal, these modified apocrine glands produce cerumen (earwax), which protects the ear by waterproofing the canal and trapping debris 38.

1. discuss the distinction between breasts and mammary glands, and explain their respective functions.

Breasts vs. Mammary Glands:

• Breasts are external structures composed of adipose and glandular tissue

• Mammary glands are specialized glands within the breasts that produce milk. Mammary glands develop during pregnancy and lactation, providing nourishment to infants

How do eccrine and apocrine sweat glands differ in structure and function?

• Differences between Eccrine and Apocrine Sweat Glands:

  • Eccrine Sweat Glands: These are the most numerous sweat glands, found all over the body, especially on the palms, soles, and forehead. They are simple tubular glands that produce a watery sweat primarily for thermoregulation 38.

  • Apocrine Sweat Glands: Located in specific areas like the groin and axilla, these glands have ducts that lead to hair follicles and produce a thicker, milky sweat containing fatty acids. They become active at puberty and are associated with stress and sexual stimulation 38.

What other type of gland is associated with hair follicles? How does its mode of secretion differ from that of sweat glands

• Gland Associated with Hair Follicles:

  • Sebaceous Glands are associated with hair follicles. They secrete sebum through a holocrine mode of secretion, where the entire cell disintegrates to release its contents, unlike sweat glands that use merocrine or apocrine secretion methods [38](#38].

What is the difference between the breast and mammary gland?

• The breast refers to the external structure composed of adipose and glandular tissue, while the mammary gland is the functional gland within the breast that produces milk during pregnancy and lactation .

1. describe the three most common forms of skin cancer

• Basal Cell Carcinoma (BCC): This is the most common type of skin cancer, originating from the basal cells in the epidermis. It typically appears as a small, shiny bump with a central depression and beaded edges. BCC is the least dangerous form as it seldom metastasizes and has high survival rates if detected early 43.

• Squamous Cell Carcinoma (SCC): Arising from keratinocytes in the stratum spinosum, SCC usually presents as raised, reddened, scaly lesions that can develop into concave ulcers. While it has a good recovery rate with early detection, it can metastasize to lymph nodes and may become lethal if not treated 43.

• Malignant Melanoma: This type accounts for less than 5% of skin cancers but is the most dangerous due to its potential to metastasize rapidly. It originates from melanocytes and is characterized by irregularly shaped moles or dark spots. Early detection is crucial for successful removal, as it is often fatal if it spreads

Describe the three classes of burns and the priorities in burn treatment.

• First-Degree Burns: These burns affect only the epidermis, causing redness, slight edema, and pain. They typically heal within a few days without scarring 43.

• Second-Degree Burns: Also known as partial-thickness burns, these involve the epidermis and part of the dermis. They may appear red, tan, or white, are blistered, and can be painful. Healing can take from two weeks to several months and may result in scarring 43.

• Third-Degree Burns: These full-thickness burns extend through the entire dermis and often affect deeper tissues. They may appear white, charred, or leathery and usually require skin grafts for healing. Treatment focuses on fluid replacement, infection control, and supplemental nutrition 43.

• Priorities in Burn Treatment: Immediate priorities include ensuring airway safety, controlling bleeding, and preventing infection. Fluid resuscitation is critical for severe burns, along with pain management and wound care

What types of cells are involved in each type of skin cancer?

• Basal Cell Carcinoma (BCC): Involves basal cells from the stratum basale of the epidermis 43.

• Squamous Cell Carcinoma (SCC): Arises from keratinocytes in the stratum spinosum 43.

• Malignant Melanoma: Originates from melanocytes, the pigment-producing cells in the skin 43.

Which type of skin cancer is most dangerous? What are its early warning signs?

• Malignant Melanoma is the most dangerous type of skin cancer. Early warning signs include irregularly shaped moles, changes in color, and asymmetry

What are the differences between first-, second-, and third-degree burns?

• First-Degree Burns: Affect only the epidermis, causing redness and pain, healing within days 43.

• Second-Degree Burns: Involve the epidermis and part of the dermis, causing blisters and longer healing times 43.

• Third-Degree Burns: Extend through the dermis and deeper tissues, often requiring skin grafts and extensive healing 43.

What are the two most urgent priorities in treating a burn victim? How are these needs addressed?

• The two most urgent priorities are ensuring airway safety and fluid resuscitation. These needs are addressed by monitoring the airway for obstruction and administering intravenous fluids to prevent shock and dehydration

Cells of the _______ are keratinized and dead.

Statum corneum

The epidermal water barrier is formed at the point where epidermal cells

Pass form stratum spinosum to stratum granulosum

Which of the following skin conditions or appearances would most likely result from liver failure?

Jaundice

4. All of the following interfere with microbial invasion of the body except

a. the acid mantle.

b. melanization.

c. dendritic cells.

d. kcratinization.

e. scbum.

b Melaniazation

The hair on a 6 year old is what kind of hair?

Versalus

6. Which of the following terms is least related to the rest?

a. lunule

b. nail plate

c. hyponychium

d. free edge

e. cortex

e. cortext

7. Which of the following is a scent gland?

a. cccrine gland

b. sebaccous gland

c. apocrine gland

d. ceruminous gland

e. eccrine gland

c. apocrine gland

__________are skin cells with a sensory role.

a. Tactile cells

b. Dendritic cells

c. Stem cells

d. Melanocytes

e. Keratinocytes

a. Tactile cells

Which of the following glands produce the acid mantle?

a. eccrine sweat glands

b. apocrine sweat glands

c. mammary glands

d. ceruminous glands

e. sebaccous glands

a. eccrine sweat glands

10. Which of the following skin cells alert the immune system to pathogens?

a. fibroblasts

b. melanocytes

c. keratinocytes

d. dendritic cells

e. tactile cells

d. dendritic cells

________ is sweating without noticeable wetness of the skin.

Insensible perspiration

A muscle that causes a hair to stand on and is called a _________.

arrector muscle

The process of moving burnt skin from a patient is called _________.

debridement

Blueness of the skin and mucous membranes due to low oxygen concentration in the blood is called__________.

cyanosis

Projections of the dermis toward the skin surface are called ___________.

dermal papillac

Cerumen is more commonly known as _________.

earwax

The holocrine glands that secrete into hair follicle are called __________.

sebaceous glands

Hair grows only during the _______ phase of the hair cycle.

anagen

A hair is nourished by blood vessels in a connective tissue projection called the ___________.

dermal papilla

A ____________ burn destroys the entire dermis.

Third degree burn