Epidermis Layers

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Questions and Answers

What is the primary function of the layer of skin that acts as insulation to protect internal organs and muscles?

Protection from shock and temperature changes (correct)

Production of sebum

Sweat secretion

Sensation and thermoregulation

What determines the color of an individual's skin?

Amount of carotene

Activity of melanocytes (correct)

Number of melanocytes

Presence of hemoglobin

What is the function of arrector pili muscles?

To relax and push the hair follicle

To secrete sebum

To contract and pull the hair follicle (correct)

To regulate body temperature

What is the primary function of eccrine sweat glands?

To regulate body temperature Signup and view all the answers

What is the function of sebaceous glands?

To secrete sebum Signup and view all the answers

Where are the sensory receptors for touch found in the skin?

In the Merkel cells Signup and view all the answers

What is the first step in the process of tissue repair?

Inflammation Signup and view all the answers

How is the percentage of the body affected by a burn calculated?

Using the rule of nines Signup and view all the answers

What is the primary function of keratin in the epidermis?

To provide protection from abrasion and penetration, and act as a barrier for biological, chemical, and physical assaults Signup and view all the answers

What is the function of melanocytes in the epidermis?

To synthesize melanin and protect DNA Signup and view all the answers

What is the function of desmosomes in the epidermis?

To ensure that cells in organs and tissues that don't stretch remain connected and unbroken Signup and view all the answers

What is the function of the papillary layer of the dermis?

To contain touch and pain receptors and make up fingerprints Signup and view all the answers

What determines the dermal ridges that produce our fingerprints?

The arrangement of papillary ridges Signup and view all the answers

What is the function of the hypodermis?

To absorb drugs and be highly vascular Signup and view all the answers

What is the function of Langerhans cells in the epidermis?

To help activate the immune system Signup and view all the answers

What is the function of epithelial stem cells in the epidermis?

To allow for regeneration of the epidermis Signup and view all the answers

Study Notes

Skin Structure

The skin consists of three main layers: epidermis, dermis, and hypodermis
Epidermis: outer layer, no blood vessels, keratinized squamous epithelium with 5 major layers
Dermis: deeper layer, highly vascularized
Hypodermis: subcutaneous tissue, absorbs drugs, highly vascular

Epidermal Layers

Stratum corneum: outermost protective layer
Stratum lucidum: only found in thick skin, composed of dead keratinocytes
Stratum granulosum: cells undergoing change, lamellated granules
Stratum spinosum: several cell layers thick, keratinocytes, melanin granules, most Langerhans cells
Stratum basale: site of mitosis (cell replication)

Epidermal Cell Functions

Keratinocytes: main cell type that produces fibrous protective protein
Melanocytes: epithelial cells that synthesize pigment melanin (protects DNA)
Merkel cells: sensory nerve endings for touch
Langerhans cells: macrophages that help activate the immune system
Epithelial stem cells: allow for regeneration of the epidermis

Keratin Function

Protection from abrasion and penetration
Water resistance
Barrier against biological, chemical, and physical assaults

Cell Junctions

Desmosomes: ensure cells in organs and tissues that don't stretch remain connected and unbroken

Dermis Layers

Papillary: superficial layer containing touch and pain receptors, makes up fingerprints
Reticular: 80% of thickness in dermis, contains sweat, oil glands, and pressure receptors

Subcutaneous Layer

Acts as a layer of insulation to protect internal organs and muscles from shock and temperature changes
Composition: loose connective tissue with fat cells, collagen, and elastin fibers

Skin Color Factors

Melanin
Hemoglobin
Carotene

Hair Functions and Types

Functions: sensation, protection, thermoregulation, and communication
Types:
- Vellus: pale, fine body hair of children and adult females
- Terminal: coarse, long hair of eyebrows, scalp, axillary, and pubic regions
- Lanugo: fine and unpigmented fetal hair

Hair Composition

Keratin
Lipids
Minerals
Pigments

Arrector Pili Muscles

Small muscles attached to hair follicles
Function: to stand hair upright (e.g., goosebumps)

Sweat Glands

Eccrine: open directly onto the skin surface, found over most of the body
Apocrine: open into the hair follicle and lead to skin surface
Function: regulate body temperature and eliminate waste products

Sebaceous Glands

Microscopic glands found in hair follicles that secrete sebum (oil)
Function: lubricate and protect skin

Other Glands

Ceruminous glands: secrete ear wax
Mammary glands: female produces milk after giving birth

Sensory Receptors

Found in Merkel cells connected to nerves, compressed during touch, sending information to attached receptors

Tissue Repair

Steps:
1. Inflammation: release inflammatory chemicals, blood vessels, and clotting occurs
2. Organization: restores blood supply
3. Regeneration and fibrosis: epithelium thickens, underlying area of scar tissue

Burn Classifications

Classified into 1st, 2nd, and 3rd degree burns based on severity

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Description

Learn about the five layers of the epidermis, the outermost layer of the skin, including their structure and function. From Stratum corneum to Stratum spinosum, test your knowledge of the skin's anatomy.