Podcast
Questions and Answers
What type of cells primarily make up the epidermis?
What type of cells primarily make up the epidermis?
Which layer of the epidermis is responsible for cell renewal?
Which layer of the epidermis is responsible for cell renewal?
What is the primary characteristic of thick skin?
What is the primary characteristic of thick skin?
Langerhans cells are found predominantly in which layer of the epidermis?
Langerhans cells are found predominantly in which layer of the epidermis?
Signup and view all the answers
What is the thickest layer of the epidermis in thick skin?
What is the thickest layer of the epidermis in thick skin?
Signup and view all the answers
Which layer contains cells that are described as having a 'prickly appearance'?
Which layer contains cells that are described as having a 'prickly appearance'?
Signup and view all the answers
What type of epithelium is the epidermis classified as?
What type of epithelium is the epidermis classified as?
Signup and view all the answers
Which of the following is NOT part of the epidermis?
Which of the following is NOT part of the epidermis?
Signup and view all the answers
The epidermis receives its nutrition mainly through which process?
The epidermis receives its nutrition mainly through which process?
Signup and view all the answers
Which component is observed in the Stratum Basale of the epidermis?
Which component is observed in the Stratum Basale of the epidermis?
Signup and view all the answers
Study Notes
Skin Structure
- Skin is composed of two primary layers: the epidermis and the dermis.
- The epidermis is the outer, epithelial layer derived from ectoderm.
- The dermis is the thicker, deep connective tissue layer derived from mesoderm.
- The hypodermis, while located beneath the skin, is not considered part of it.
Types of Skin
- Skin is classified into thick and thin skin based on the thickness of the epidermis.
- Thick skin, also known as non-hairy skin, features a thick epidermis (400-1400 µm) with a prominent horny layer.
- Thick skin is found in the palms and soles, composed of both the epidermis and dermis.
The Epidermis
- The epidermis is a keratinized stratified squamous epithelium that varies in thickness, being greater in the soles than the palms.
- It is an avascular layer, receiving its nutrition by diffusion from the underlying dermis.
- The epidermis contains free nerve endings and is comprised of keratinocytes and non-keratinocytes.
Keratinocytes
- Keratinocytes constitute 85% of the cells in the epidermis.
- They undergo continuous division, differentiation, and keratin formation as they progress upwards.
- Superficial layers of the epidermis are constantly shed off.
- The epidermis is divided into 5 layers based on keratinocyte maturation:
Stratum Basale (Basal Cell Layer)
- A single layer of low columnar or cuboidal cells resting on a wavy basement membrane.
- The cells have basophilic cytoplasm with large, oval nuclei.
- Intense mitotic activity occurs in this layer, responsible for epidermal renewal.
- Melanocytes and Merkel's cells are found in this layer.
Stratum Spinosum (Prickle Cell Layer)
- Contains 4-8 layers of polyhedral cells located above the stratum basale.
- Cells possess less basophilic cytoplasm compared to the stratum basale.
- Central rounded nuclei are present within the cells.
- Cell borders appear separated by spaces traversed by fine spine-like processes (desmosomes), giving the layer a prickly appearance.
- Langerhans cells are found within this layer.
Malpighian Layer
- This layer encompasses both the stratum basale and stratum spinosum.
Stratum Granulosum (Granular Cell Layer)
- Composed of layers of spindle-shaped cells situated above the spinous cell layer.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
