Epidermis and Hair Structure Quiz

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Questions and Answers

What is the function of the arrector pili muscle?

To facilitate the movement of hair follicles during growth

To erect the hair shaft and cause goosebumps (correct)

To produce sweat when stimulated

To support the sebaceous glands in producing oil

Which glands are associated with the labia minora and glans?

Tyson glands (correct)

Montgomery glands

Fordyce spots

Meibomian glands

What type of muscle makes up the arrector pili muscle?

Skeletal muscle

Smooth muscle (correct)

Cardiac muscle

Striated muscle

How does the arrector pili muscle achieve its function?

By contracting and pulling on the hair follicle from above Signup and view all the answers

What is produced at the site where the arrector pili muscle inserts?

Goosebumps on the skin's surface Signup and view all the answers

What is the primary role of the Huxley Layer in the hair follicle?

Acts as a middle plate in the internal root sheath. Signup and view all the answers

Which layer separates the hair follicle from the dermis?

External Root Sheath Signup and view all the answers

What features characterize the Internal Root Sheath?

It contains eosinophilic granules and prominent pores. Signup and view all the answers

Which component is NOT a part of the hair shaft?

Epidermis Signup and view all the answers

What describes the characteristics of the External Root Sheath?

It has a glassy membrane layer and is distinct from connective tissue. Signup and view all the answers

Which type of hair is characterized as lanugo?

Soft, fine hair present on the fetus. Signup and view all the answers

What distinguishing feature does the Huxley Layer have?

It consists of single or double layers of flattened cells. Signup and view all the answers

Where is melanin pigment primarily present in the hair structure?

In the germinative layer of the hair bulb. Signup and view all the answers

What is the primary characteristic of the hair cortex?

Contains cuboidal cells that differentiate into keratin-filled cells. Signup and view all the answers

What is a distinguishing feature of vellus hairs compared to terminal hairs?

Vellus hairs are fine and light-colored with a narrow hair shaft. Signup and view all the answers

During which phase of hair growth is mitotic activity and growth most active?

Anagen phase. Signup and view all the answers

Which statement is true regarding the characteristics of the medulla in hair?

The medulla contains large vacuolated cells only in thick hairs. Signup and view all the answers

Which statement accurately describes vellus hairs?

Vellus hairs are often replaced by terminal hairs. Signup and view all the answers

What is the primary reason that humans do not shed hair synchronously?

Hair follicles operate as independent units. Signup and view all the answers

Which of the following is NOT a characteristic of terminal hairs?

Always dark in color. Signup and view all the answers

What characterizes the hair cuticle?

It surrounds the medulla and cortex. Signup and view all the answers

What is the role of the nail matrix in nail growth?

It serves as the site for nail growth through epithelial proliferation. Signup and view all the answers

Which part of the nail apparatus is directly covered by the cuticle?

Nail root Signup and view all the answers

Which of the following is NOT a component of the nail apparatus?

Eccrine sweat glands Signup and view all the answers

What is the function of the hyponychium in the nail structure?

It forms a protective barrier between the nail and the underlying skin. Signup and view all the answers

Which term also refers to the nail matrix?

Germinal matrix Signup and view all the answers

Where does the nail plate extend from in the nail structure?

Nail matrix Signup and view all the answers

What is the primary tissue type that comprises the nail matrix?

Epithelial tissue Signup and view all the answers

What is the relationship between the proximal nail fold and the nail structure?

It protects the nail root and contains the cuticle. Signup and view all the answers

Which areas of the body are primarily associated with thick skin?

Palms of hands and soles of feet Signup and view all the answers

What characterizes the thickness of the epidermis in thick skin?

It is considerably increased compared to thin skin. Signup and view all the answers

Which of the following features is NOT present in thick skin?

Pilosebaceous units Signup and view all the answers

What is the composition of the intima layer in the small arteries of the dermis?

Endothelial cells and an internal elastic lamina Signup and view all the answers

Which statement about nerve endings in the skin is correct?

Both efferent and afferent nerve supplies are present. Signup and view all the answers

Which of the following correctly describes thin skin?

Includes pilosebaceous follicles. Signup and view all the answers

What is true about the walls of veins compared to arteries?

They are generally thinner and less clearly divided into layers. Signup and view all the answers

In the dermis, what is the function of the arterioles?

To provide oxygen and nutrients through blood supply. Signup and view all the answers

Study Notes

Growth of the Epidermis

The Huxley Layer is a granular epithelium stratum, consisting of a single or double layer of flattened cells that contribute to the internal root sheath in hair follicles.
The external root sheath separates the hair follicle from the dermis and has a glassy membrane, covering the internal root sheath and extending to the epidermis, merging with the sebaceous gland's epidermis.
The internal root sheath is characterized by prominent pores and eosinophilic (keratohyalin) granules, surrounding the initial hair structure but degenerating above the sebaceous glands.

Hair Shaft Structure

The hair shaft contains melanin pigment within the germinative layer of the hair bulb and consists of the cuticle, cortex, and medulla.
The hair cuticle is a thin layer surrounding the cortex and medulla, while the cortex contains cuboidal cells that differentiate into keratin-filled cells.
The medulla serves as the central part of the hair shaft and includes large vacuolated cells found only in thick hairs.

Types of Hair

Lanugo: Fetal or newborn hair, characterized by fine texture, replaced by vellus and terminal hairs.
Vellus: Fine, light-colored hair with a narrow hair shaft and thin inner root sheath, rooted in the papillary or reticular dermis.
Terminal Hairs: Coarse, thick hair that is typically dark, except in blond individuals.

Stages of Hair Growth

Hair growth occurs cyclically with individual follicles operating independently; humans do not shed hair synchronously.
Anagen Phase: Active growth phase lasting 2 to 6 years, marked by significant mitotic activity.

Arrector Pili Muscle

Each hair follicle contains arrector pili muscle fibers, smooth muscle bundles that insert into the follicle and dermal papillae.
Controlled by the autonomic nervous system, contraction of this muscle causes hair to erect and creates "goosebumps," producing small bumps on the skin's surface.

Nail Structure

The nail apparatus comprises the nail plate, proximal nail fold, nail matrix, nail bed, and hyponychium.
The nail root, covered by the proximal nail fold (cuticle/eponychium), is where the nail matrix is formed, initiating nail growth through epithelial proliferation and differentiation.

Eccrine and Apocrine Glands

Eccrine and apocrine glands have secretory and excretory portions; eccrine glands are involved in sweat secretion.

Thick Skin Characteristics

Thick skin is found on the palms and soles, notable for its considerable epidermis thickness, abundant sweat glands, and lack of pilosebaceous units.
Prominent grooves and ridges stem from tall dermal papillae, along with numerous arteriovenous anastomoses.

Thin Skin Characteristics

Thin skin covers most body regions, has a thinner epidermis, smaller numbers of sweat glands, and contains pilosebaceous follicles.
Features a smooth surface without prominent grooves or ridges and fewer arteriovenous anastomoses compared to thick skin.

Blood Vessel Structure

Arteries possess three layers: intima (endothelial cells), media (collagen, elastic fibers, and smooth muscle), and adventitia (fibrocytes and fibers).
Veins generally have thinner walls compared to arteries and lack clearly defined three layers.

Nerve Endings

Both efferent and afferent nerve supplies are present in the skin, including free nerve endings for sensory perception.

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Description

Test your knowledge on the growth of the epidermis and the structure of hair. This quiz covers various layers of hair follicles, including the Huxley Layer and the composition of the hair shaft. Perfect for students studying anatomy or dermatology.