Hair Structure Quiz

Questions and Answers

What cell type is primarily responsible for producing keratin in the skin?

Merkel cells

Langerhans

Keratinocytes (correct)

Melanocytes

Which layer of the epidermis is most actively engaged in mitosis?

Stratum Basale (correct)

Stratum Corneum

Stratum Granulosum

Stratum Spinosum

What component gives color to the skin and protects against UV radiation?

Collagen

Elastin

Melanin (correct)

Keratin

Which layer contains Langerhans cells that play a role in the immune response?

Stratum Spinosum Signup and view all the answers

How many layers of cells are typically found in the Stratum Spinosum?

8-10 layers Signup and view all the answers

What is the role of the hair matrix?

To produce new hairs via mitosis Signup and view all the answers

Which layer of the hair is highly structured and contains hard keratin?

Middle cortex Signup and view all the answers

What happens when the outer cuticle of the hair becomes worn out?

A split end occurs Signup and view all the answers

What structure contains blood vessels that nourish the hair follicle?

Hair papilla Signup and view all the answers

What is the function of arrector pili muscles?

To cause hair to stand up Signup and view all the answers

Which component of the epithelial root sheath attaches tightly to the hair root?

Inner component Signup and view all the answers

What is the primary characteristic of the hair shaft?

It projects from the surface of the skin Signup and view all the answers

What does the dermal root sheath do?

Separates the hair follicle from the dermis Signup and view all the answers

What is the primary function of the reticular layer of the dermis?

It strengthens the dermis and protects deeper layers. Signup and view all the answers

What happens to elastic fibers in the skin during extreme stretching?

They may tear, forming stretch marks. Signup and view all the answers

What do epidermal ridges primarily function to enhance?

The gripping ability of the hands and feet. Signup and view all the answers

What type of connective tissue primarily makes up the reticular layer of the dermis?

Dense irregular connective tissue. Signup and view all the answers

Which structure is NOT found in the reticular layer of the dermis?

Epidermal cells. Signup and view all the answers

What are cleave lines or tension lines formed by?

Indentations between bundles of collagen fibers. Signup and view all the answers

What is found within the hair follicle that contributes to hair production?

A root where keratinization occurs. Signup and view all the answers

What is the primary structural composition of hair?

Dead keratinized cells. Signup and view all the answers

What is the main function of eccrine sweat glands?

Thermoregulation and excretion of sweat through pores Signup and view all the answers

Where are apocrine sweat glands primarily located?

Armpits and groin Signup and view all the answers

What is contained in sweat released by eccrine glands?

Water, salts, and metabolic wastes Signup and view all the answers

What is the role of ceruminous glands?

Secrete earwax to lubricate the eardrum Signup and view all the answers

Which statement about apocrine sweat glands is accurate?

Sweat produced is odorless until metabolized by bacteria. Signup and view all the answers

What area does the lunula represent on the nail?

The area where keratin accumulates Signup and view all the answers

Which of the following glands produces milk?

Mammary gland Signup and view all the answers

What is a characteristic of eccrine sweat glands compared to apocrine glands?

They are functional at birth and cover most of the body. Signup and view all the answers

What is the primary method used to estimate the extent of a burn?

Rule of Nines Signup and view all the answers

Which degree of burn is characterized by damage to the epidermis and part of the dermis, accompanied by pain and blistering?

Second-degree burns Signup and view all the answers

What symptom is NOT associated with third-degree burns?

Blistering Signup and view all the answers

Which of the following is a characteristic of full-thickness burns?

Dry and leathery appearance Signup and view all the answers

What percentage of body burned deems a second-degree burn critical?

Over 30% Signup and view all the answers

What is the most common type of skin cancer characterized by carcinomas of keratinocytes?

Basal Cell Carcinoma Signup and view all the answers

What potential consequence does a severe burn lead to concerning body fluids?

Loss of body fluids Signup and view all the answers

Which statement about skin tumors is false?

All tumors are benign. Signup and view all the answers

Study Notes

Hair Structure

Composed of three layers: inner medulla, middle cortex, outer cuticle.
Inner medulla contains large cells and soft keratin; found primarily in thick hair.
Middle cortex consists of flattened cells and hard keratin, highly structured.
Outer cuticle is the most superficial layer, composed of overlapping keratinized cells; wear leads to split ends.

Hair Components

Shaft projects from skin surface; contains dead cells.
Root is embedded in the dermis, consisting of living hair cells.
Hair papilla nourishes hair follicles with blood vessels; located at the base of the hair bulb.
Hair bulb includes the root and papilla, enclosing new hair growth areas.
Hair matrix, at the bulb's base, produces new hairs through mitosis.
Hair follicle surrounds the root; contains nerve endings and blood supply.
Epithelial root sheath has outer and inner components; supports and attaches hair to the dermis.
Dermal root sheath separates the follicle from the dermis.
Arrector pili muscles cause piloerection by contracting, making hair stand up.

Epidermis

Stratum Basale (Germinativum) is the deepest layer; highly mitotic, containing keratinocytes and melanocytes for melanin production.
Keratinocytes regenerate skin by pushing dead cells upwards; essential due to daily cell loss.
Stratum Spinosum appears spiky, with several layers of living keratinocytes, Langerhans, and melanocytes; thickest epidermis layer.

Dermis Structure

Reticular layer is the deepest dermal layer composed of dense irregular connective tissue; contains collagen and elastic fibers.
Elastic fibers allow skin to regain shape; stretching can lead to permanent stretch marks.
Rich in receptors, blood vessels, sweat glands, and sensory neurons; contains Pacinian corpuscles sensitive to pressure.

Skin Markings

Interaction between dermis and epidermis creates skin markings on palms and soles, enhancing grip.
Epidermal ridges increase gripping ability; contain sweat pores leading to fingerprints.
Cleavage lines indicate the direction of collagen fiber bundles; deep creases are flexor lines.

Skin Appendages

Hair or pili consists of dead keratinized cells; produced by hair follicles.
Nails are bordered by skin folds; contain hyponychium and lunula.
Exocrine glands include sweat glands and others.
Types of sweat glands: eccrine (thermoregulation, widespread) and apocrine (located in specific areas, produce body odor).

Burn Classification

Estimated using the Rule of Nines, dividing body into areas representing 9% of total body surface area.
Burns categorized by degree:
- First-degree: impacts the epidermis; red, painful, no blisters.
- Second-degree: affects epidermis and part of dermis; red, blistered, painful.
- Third-degree: full thickness, severe damage; requires skin grafts, painless in burned areas.
- Fourth-degree: extends into deeper tissues; complete loss, may require amputation.

Skin Cancer

Common disease caused by DNA mutations disrupting cellular control; leads to tumors that may metastasize.
Basal Cell Carcinoma is the most prevalent, arising from stratum basale keratinocytes; often forms nodules and ulcers in areas exposed to UV radiation.

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Description

Test your knowledge on the anatomy of hair, focusing on its three main layers: the inner medulla, middle cortex, and outer cuticle. This quiz covers the characteristics and functions of each layer, including the types of keratin present. Perfect for students studying biology or cosmetology.