أسئلة المحاضرة الـ 13 هستولوجي (قبل التعديل)
26 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which layer of the epidermis is primarily responsible for the synthesis of melanin?

  • Stratum corneum
  • Basal cell layer
  • Prickle cell layer (correct)
  • Reticular layer

What type of connective tissue is found in the thinner, superficial layer of the dermis?

  • Elastic tissue
  • Dense connective tissue
  • Adipose tissue
  • Loose connective tissue (correct)

Which receptor is primarily associated with touch sensation in the skin?

  • Krause end bulbs
  • Pacinian corpuscles
  • Meissner corpuscles (correct)
  • Ruffini corpuscles

How many layers are typically found in areas of thick skin, such as the palms and soles?

<p>4-8 layers (B)</p> Signup and view all the answers

Which statement correctly describes the characteristics of the papillary layer of the dermis?

<p>Forms dermal papillae and is more vascular (B)</p> Signup and view all the answers

What type of epithelium is found in the non-hairy skin areas like the palms and soles?

<p>Stratified squamous keratinized epithelium (A)</p> Signup and view all the answers

Which type of cell is responsible for pigmentation in the skin?

<p>Melanocytes (A)</p> Signup and view all the answers

Which layer of the epidermis is known for its granular appearance due to keratohyaline granules?

<p>Granular layer (A)</p> Signup and view all the answers

What is the primary function of the cells in the basal cell layer of the epidermis?

<p>Regeneration of keratinocytes (B)</p> Signup and view all the answers

Which layer of the epidermis contains dead, flattened cells that shed continuously?

<p>Horny layer (D)</p> Signup and view all the answers

Which structure is NOT a part of the skin according to the histology content?

<p>Subcutaneous adipose tissue (A)</p> Signup and view all the answers

Which statement correctly describes the function of keratinocytes?

<p>They regenerate and replace other skin cells. (D)</p> Signup and view all the answers

Which feature distinguishes the clear layer (Stratum Lucidum) of the epidermis?

<p>Thin, wavy, and homogenous appearance (A)</p> Signup and view all the answers

What distinguishes the dermal papillae found in the papillary layer of the dermis?

<p>Presence of thick ridges and grooves (B), Formation of a network of loose connective tissue (C)</p> Signup and view all the answers

Which of the following cells in the epidermis serves as antigen-presenting cells?

<p>Langerhans cells (B)</p> Signup and view all the answers

What is a distinguishing feature of the thicker skin found in areas like the palms and soles compared to thinner skin?

<p>More numerous epidermal layers (D)</p> Signup and view all the answers

In the context of skin histology, which type of connective tissue is predominant in the reticular layer of the dermis?

<p>Dense irregular connective tissue (A)</p> Signup and view all the answers

Which sensory receptor is primarily associated with detecting deep pressure and vibration in the skin?

<p>Pacinian corpuscles (A)</p> Signup and view all the answers

What type of cells primarily make up the basal cell layer of the epidermis?

<p>Keratinocytes (C)</p> Signup and view all the answers

What is the composition of the clear layer (Stratum Lucidum) of the epidermis?

<p>Dead non-nucleated flattened cells (C)</p> Signup and view all the answers

Which layer contains granules that help in waterproofing the skin?

<p>Stratum Granulosum (D)</p> Signup and view all the answers

What type of granules are responsible for the skin's barrier against foreign bodies?

<p>Keratohyaline granules (C)</p> Signup and view all the answers

What is the primary function of the Langerhans cells in the skin?

<p>Immune response activation (D)</p> Signup and view all the answers

Which statement correctly describes the squames found in the outermost layer of the skin?

<p>They are non-nucleated, flattened cells continuously shed. (D)</p> Signup and view all the answers

Which of the following best describes the cells in the prickle cell layer (Stratum Spinosum)?

<p>Branched cells with rounded bodies connected by cytoplasmic processes (A)</p> Signup and view all the answers

What characteristic is used to identify the stratum spinosum under a microscope?

<p>Branched cells with central rounded nuclei (B)</p> Signup and view all the answers

Flashcards

Layers of epidermis

The epidermis has five layers; basal, prickle, granular, lucid, and corneum.

Keratinocytes

The most abundant skin cells (85%), responsible for producing keratin, a protein that makes skin tough.

Melanocytes

Skin cells that produce melanin, a pigment that gives skin its color.

Stratum Corneum

The outermost layer of the epidermis; made of dead, flattened cells that slough off.

Signup and view all the flashcards

Subcutaneous tissue

Fatty tissue beneath the skin; it is not part of the skin structure

Signup and view all the flashcards

Stratum Granulosum

Layer of the epidermis containing granules that waterproof the skin

Signup and view all the flashcards

Langerhans cells

Immune cells in the epidermis that help fight infection.

Signup and view all the flashcards

Merkel cells

Sensory receptors in the epidermis that detect touch.

Signup and view all the flashcards

What are the layers of the epidermis?

The epidermis has five layers from the deepest to the most superficial: stratum basale (basal layer), stratum spinosum (prickle cell layer), stratum granulosum (granular layer), stratum lucidum (lucid layer), and stratum corneum (horny layer).

Signup and view all the flashcards

Where are melanocytes found?

Melanocytes are found in the stratum basale (basal layer) of the epidermis and produce melanin, the pigment that gives skin its color.

Signup and view all the flashcards

Dermal papillae

Dermal papillae are small projections of the dermis that extend into the epidermis, creating a wavy border.

Signup and view all the flashcards

What are the two layers of the dermis?

The dermis has two layers: the papillary layer, which is thin and superficial, and the reticular layer, which is thicker and deeper.

Signup and view all the flashcards

What are the types of receptors found in the dermis?

The dermis contains various sensory receptors, including Meissner corpuscles (light touch), Pacinian corpuscles (deep pressure), Krause end bulbs (temperature), and Ruffini corpuscles (stretch).

Signup and view all the flashcards

What is the difference between hairy and non-hairy skin?

Hairy skin covers most of the body and contains hair follicles and sebaceous glands, while non-hairy skin is found on the palms and soles and lacks these structures.

Signup and view all the flashcards

What is the deepest layer of the epidermis?

The stratum basale, also known as the basal cell layer, is the deepest layer of the epidermis. It's responsible for producing new keratinocytes.

Signup and view all the flashcards

What are Keratohyaline granules?

Keratohyaline granules are basophilic granules found in the cytoplasm of cells in the stratum granulosum (granular layer) of the epidermis. They play a role in the formation of keratin.

Signup and view all the flashcards

What are Lamellar granules?

Lamellar granules are found in the stratum granulosum of the epidermis. They contain phospholipids that help waterproof the skin.

Signup and view all the flashcards

What is the stratum lucidum?

The stratum lucidum is a thin, clear layer of the epidermis found only in thick skin. It is made of dead cells that contain eleidin.

Signup and view all the flashcards

What is the function of melanocytes?

Melanocytes are pigment-producing cells found in the stratum basale. They produce melanin, a pigment that gives skin its color and protects against UV radiation.

Signup and view all the flashcards

Where are langerhans cells found?

Langerhans cells are immune cells found in the epidermis. They help protect the skin from pathogens.

Signup and view all the flashcards

What are Merkel cells?

Merkel cells are sensory cells found in the stratum basale of the epidermis. They detect touch.

Signup and view all the flashcards

What layer is the melanocyte found?

Melanocytes are situated in the stratum basale, which is the deepest layer of the epidermis.

Signup and view all the flashcards

What are the characteristics of Langerhans cells?

Langerhans cells are branched, central, phagocytic, and antigen-presenting cells, often found in the upper prickle cell layer and blood monocytes. These cells are crucial for the immune response.

Signup and view all the flashcards

What are the functions of Merkel cells?

Merkel cells are located in the basal cell layer of the epidermis and act as receptors for touch sensations.

Signup and view all the flashcards

What is the difference between papillary and reticular dermis?

The papillary dermis is the thin, superficial layer made of loose connective tissue, while the reticular dermis is the thicker, deeper layer composed of dense connective tissue.

Signup and view all the flashcards

Study Notes

Skin Histology

  • Skin is classified as thick or thin
  • Thick skin: Found on palms and soles, non-hairy
  • Thin skin: Covers most of the body, hairy

Layers of Skin

  • Epidermis: Stratified squamous keratinized epithelium
  • Dermis: Connective tissue
  • Hypodermis: Subcutaneous adipose tissue; not part of the skin

Epidermal Cell Types

  • Keratinocytes: 85% of epidermal cells
  • Melanocytes: Produce melanin
  • Langerhans cells: Phagocytic and antigen-presenting cells (APCs)
  • Merkel cells: Receptors for touch sensation

Keratinocyte Layers

  • Malpighian layer (2 layers):
    • Basal cell layer: Single layer of columnar cells
    • Prickle cell layer (Stratum Spinosum): 4-8 layers of polyhedral cells
  • Granular layer (Stratum Granulosum) : Diamond-shaped flattened cells
    • Contains keratohyaline and lamellar granules
  • Clear layer (Stratum Lucidum): Thin transparent layer of dead cells, only present in thick skin
  • Horny layer (Stratum Corneum): Many layers of flattened, dead keratinocytes (squames)

Dermal Layers

  • Papillary layer: Loose connective tissue, more vascular, forms dermal papillae which contain Meissner corpuscles
  • Reticular layer: Dense connective tissue, less vascular, containing Pacinian corpuscles, Krause end bulbs, and Ruffini corpuscles

Differences Between Thick and Thin Skin (Epidermis)

Feature Thick Skin Thin Skin
Epidermal layers 4-8 2-4
Stratum lucidum Present Absent
Surface ridges/grooves Present (fingerprints) Absent

Differences Between Thick and Thin Skin (Dermis)

Feature Thick Skin Thin Skin
Dermal papillae Regular Irregular, fewer
Sweat glands More numerous Less numerous
Hair follicles Absent Present
Sebaceous glands Absent Present
Arrector pili muscle Absent Present

Studying That Suits You

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

Quiz Team

Related Documents

More Like This

Layers of the Epidermis
18 questions
Histology of the Skin Overview
8 questions
Skin Histology Overview
10 questions

Skin Histology Overview

DelicateConstellation avatar
DelicateConstellation
Use Quizgecko on...
Browser
Browser