16 Questions
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
What determines the color of an individual's skin?
Activity of melanocytes
What is the function of arrector pili muscles?
To contract and pull the hair follicle
What is the primary function of eccrine sweat glands?
To regulate body temperature
What is the function of sebaceous glands?
To secrete sebum
Where are the sensory receptors for touch found in the skin?
In the Merkel cells
What is the first step in the process of tissue repair?
Inflammation
How is the percentage of the body affected by a burn calculated?
Using the rule of nines
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
What is the function of melanocytes in the epidermis?
To synthesize melanin and protect DNA
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
What is the function of the papillary layer of the dermis?
To contain touch and pain receptors and make up fingerprints
What determines the dermal ridges that produce our fingerprints?
The arrangement of papillary ridges
What is the function of the hypodermis?
To absorb drugs and be highly vascular
What is the function of Langerhans cells in the epidermis?
To help activate the immune system
What is the function of epithelial stem cells in the epidermis?
To allow for regeneration of the epidermis
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:
- Inflammation: release inflammatory chemicals, blood vessels, and clotting occurs
- Organization: restores blood supply
- Regeneration and fibrosis: epithelium thickens, underlying area of scar tissue
Burn Classifications
- Classified into 1st, 2nd, and 3rd degree burns based on severity
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.
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