Skin Structure and Epidermis Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which layer is the deepest layer of the epidermis?

Stratum basale (correct)

Stratum corneum

Stratum lucidium

Stratum spinosum

What is the main function of keratinocytes in the epidermis?

Production of melanin

Protection through keratin production (correct)

Sensation of touch

Immune responses

Which cell type in the epidermis is responsible for UV protection?

Keratinocytes

Langerhans cells

Merkel cells

Melanocytes (correct)

In which type of skin is the stratum lucidum present?

Thick skin Signup and view all the answers

Which of the following layers of the epidermis contains keratohyalin and lamellar granules?

Stratum granulosum Signup and view all the answers

What layer lies deep to the dermis and is often referred to as the subcutaneous layer?

Hypodermis Signup and view all the answers

What is the primary reason for the formation of a callus?

Constant friction on the skin Signup and view all the answers

Which type of cells in the epidermis is involved in immune responses?

Langerhans cells Signup and view all the answers

What is the primary function of sebaceous glands?

Secrete sebum to prevent dryness Signup and view all the answers

Which of the following best describes the structure of sweat glands?

Single long tubes with highly coiled ends lined by cuboidal epithelium Signup and view all the answers

What type of connective tissue is primarily found in the dermis?

Dense layer of irregular connective tissue Signup and view all the answers

Where do T lymphocytes undergo maturation?

In the thymus Signup and view all the answers

What is lymph primarily composed of?

Proteins, water, and white blood cells Signup and view all the answers

What are the secondary lymphoid organs?

Lymph nodes and spleen Signup and view all the answers

What type of gland is characterized by cells rupturing during secretion?

Holocrine glands Signup and view all the answers

Which part of the thymus is characterized by densely packed lymphocytes?

Peripheral cortex Signup and view all the answers

What type of cells primarily compose the central medulla of the thymus?

Epithelial reticular cells Signup and view all the answers

Which of the following hormones is secreted by epithelial reticular cells in the thymus?

Thymosin Signup and view all the answers

In the structure of lymph nodes, what region contains lymph nodules rich in B-lymphocytes?

Cortex Signup and view all the answers

What characterizes the red pulp of the spleen?

Made up of splenic sinuses Signup and view all the answers

Which type of epithelium covers the palatine tonsils?

Stratified squamous non-keratinized epithelium Signup and view all the answers

What is primarily derived from the somatic mesoderm?

Muscles and bone Signup and view all the answers

Which part of the somite is referred to as the sclerotome?

Ventro-medial part Signup and view all the answers

Which structure is characterized by the presence of Hassall's corpuscles?

Thymus Signup and view all the answers

What structure does the sclerotome primarily develop into?

Axial skeleton and annulus fibrosus Signup and view all the answers

Which of the following describes the formation of the limb buds?

Mesodermal core forms bones and connective tissues Signup and view all the answers

At what stage do the terminal portions of limb buds become flattened to form plates?

6th week of gestation Signup and view all the answers

What is Amelia?

Complete absence of a limb Signup and view all the answers

How do the upper and lower limbs rotate during the 7th week of gestation?

Upper limbs rotate laterally, lower limbs medially Signup and view all the answers

Which congenital anomaly is characterized by a sole of the foot turned medially and the foot being inverted?

Talipes equinovarus Signup and view all the answers

What is a likely cause of congenital limb anomalies such as meromelia?

Genetic and chromosomal abnormalities Signup and view all the answers

What does the myotome develop into?

Striated muscles of the trunk and girdles Signup and view all the answers

Study Notes

Skin Structure

Skin consists of two main layers: the epidermis and the dermis.
The epidermis is a superficial layer of stratified squamous epithelium.
The dermis is a deep layer of connective tissue, containing collagen and elastic fibers.
The hypodermis, also called the subcutaneous layer, is a layer of areolar and adipose connective tissue that lies deep to the dermis.
The hypodermis is not considered part of the skin.

Epidermis

The epidermis has layers, from deep to superficial: basale, spinosum, granulosum, lucidum (in thick skin only), and corneum.
Stratum basale (germinativum) is the deepest layer, where continuous cell division occurs, producing the other layers.
Stratum spinosum is the layer above basale, with 8-10 layers of keratinocytes.
Stratum granulosum contains keratohyalin and lamellar granules.
Stratum lucidum is only present in thick skin (palms, soles, fingertips).
Stratum corneum is composed of many layers of flat, dead keratinocytes called corneocytes. These cells are continuously shed and replaced.

Epidermal Cells

Keratinocytes (90%): Produce keratin, a tough fibrous protein for protection.
Melanocytes: Produce melanin for protection against UV radiation.
Langerhans cells: Involved in the immune response, originate from red bone marrow.
Merkel cells: Function in the sensation of touch, along with adjacent tactile discs.

Types of Skin

Thick skin: Found on palms, soles, and corresponding surfaces of fingers and toes. It contains all five epidermal strata and is hairless.
Thin skin: Covers most of the body, has a thinner stratum corneum, and lacks stratum lucidum. It has only four epidermal strata.

Dermis

The dermis is a dense layer of irregular connective tissue containing collagen and elastic fibers.
It varies in thickness.
It's rich in nerves, blood vessels, hair follicles, sebaceous glands, and sweat glands.
Contains hair follicles, arrector pili muscles, sebaceous glands, and sweat glands.

Hair

Hairs are filaments arising from hair follicles, which are modified parts of the stratum corneum.
Arrector pili muscles attach the follicle to the superficial dermis.

Sebaceous Glands

Sebaceous glands are holocrine glands, where cells rupture during secretion.
Secrete sebum to prevent dryness.

Sweat Glands

Sweat glands are tubular structures, with a highly coiled end, lined by cuboidal epithelium.
Typical sweat glands are merocrine glands (watery secretion secreted by exocytosis).

Fascia

Fascia is a collection of connective tissues.
Two types of fascia are superficial and deep fascia.

Lymphatic System

The lymphatic system is a combination of cells, tissues, and organs that protect the body from invasions from foreign cells, microbes, viruses, and parasites.
Lymph is a colorless fluid derived from body tissues.

Lymphoid Organs

Primary lymphoid organs are where antigen-dependent proliferation and differentiation of lymphocytes occur.
- Thymus: centrally located, behind the sternum. Functions in maturation of T lymphocytes.
- Bone Marrow: site of B lymphocyte maturation.
Secondary lymphoid organs are where functional lymphocytes eventually reach (final destination).
- Lymph nodes
- Spleen
- Tonsils
- Peyer's patches

Spleen

The spleen is covered by a connective tissue capsule with trabeculae extending inward.
It is composed of white pulp (lymphoid nodules containing B lymphocytes) and red pulp (splenic cords and sinuses, containing all types of white blood cells).

Tonsils

Tonsils are incompletely encapsulated lymphoid nodules.
Palatine tonsils are located in the oral cavity, covered by stratified squamous non-keratinized epithelium; crypts and underlying connective tissue barrier exist.
Pharyngeal tonsils (adenoids) are centrally located and have ciliated pseudostratified columnar epithelium; no crypts.

Limb Development

Upper limb buds appear before lower limb buds.
Limb buds develop opposite specific spinal cord segments.
Limb buds initially have a core of mesenchymal tissue derived from somatic mesoderm, which will give rise to bones and connective tissues—covered by a layer of ectoderm.
A circular constriction separates the hand and foot plates from the proximal segment.
The limb buds rotate in the 7th week of gestation.

Congenital Anomalies

Amelia is a condition of complete absence of a limb, developing during the early 4th week.
Meromelia is a condition of partial limb absence, related to differentiation and growth disturbances during the 5th week.
Causes can be genetic, chromosomal abnormalities, or environmental factors like thalidomide.
Congenital clubfoot (Talipes equinovarus) is a condition where the foot is turned medially and inverted, more common in males. The cause is multifactorial.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the structure of skin, focusing on the various layers of the epidermis and its functions. Understand the differences between the epidermis, dermis, and hypodermis, and learn about the unique features of each skin layer. This quiz will solidify your understanding of skin anatomy.