Tissue Foundations & Overview
What two main tissue types make up the integument?
→ Epithelial tissue and connective tissue
What are the five strata of the epidermis in order from deep to superficial?
→ Basale, spinosum, granulosum, lucidum, corneum
What are the two layers of the dermis?
→ Papillary and reticular
Which vitamin is synthesized in the skin when exposed to sunlight?
→ Vitamin D3
What protein makes up hair and nails?
→ Keratin
What distinguishes a first-degree burn from a second-degree burn?
→ First-degree = epidermis only; Second-degree = epidermis + part of dermis
Which tissue type is responsible for covering surfaces and forming glands in the integumentary system?
→ Epithelial tissue
Which cell type in the stratum basale produces melanin?
→ Melanocytes
Which type of connective tissue is found in the papillary layer of the dermis?
→ Areolar connective tissue
What integumentary structure provides protection against microbes and toxins?
→ The epidermis
Which type of sweat gland is most numerous and functions in thermoregulation?
→ Eccrine (merocrine) sweat glands
Which type of burn damages the epidermis and part of the dermis?
→ Second-degree burn
Which tissue type provides strength and structural support in the dermis?
→ Connective tissue
What makes the stratum lucidum unique compared to other strata?
→ Only found in thick skin; filled with eleidin
What is the function of dermal papillae?
→ Anchor epidermis, supply nutrients, provide sensation
Which skin function involves vasodilation and vasoconstriction?
→ Thermoregulation
What is the function of sebaceous glands?
→ Secrete sebum for lubrication and waterproofing
Why are third-degree burns considered life-threatening?
→ Destroy all skin layers, risk of fluid loss, infection, thermoregulation failure
Why is the skin considered the largest organ in the body?
→ Because it covers the entire external surface and has multiple integrated structures
Why do keratinocytes in the stratum spinosum appear “spiny”?
→ Shrinkage and desmosome junctions give a spiny look
How does the reticular layer differ structurally from the papillary layer?
→ Dense irregular connective tissue vs. areolar connective tissue
How does the integument act as a barrier to water loss and water entry?
→ Keratinized cells resist water passage but are selectively permeable
How do arrector pili muscles affect hair?
→ Cause hair to stand up (“goosebumps”)
How do physicians estimate the total surface area affected by a burn?
→ Rule of nine
Compare how epithelial tissue and connective tissue contribute differently to the integument.
→ Epithelial covers/protects, forms barrier; connective provides support, strength, vascular supply
Explain the process of keratinization in the stratum granulosum.
→ Keratinocytes produce large amounts of keratin, organelles disintegrate, cells die
Explain why the dermis contains blood vessels while the epidermis does not.
→ Dermis provides nutrients since epidermis is avascular
Explain how sensory receptors in the skin help protect the body from injury.
→ Detect touch, pressure, pain, temperature → trigger avoidance responses
Compare the roles of eccrine and apocrine sweat glands.
→ Eccrine = thermoregulation; Apocrine = scent, pubertal activation
Explain why fluid loss is a major concern after severe burns.
→ Skin barrier destroyed → rapid dehydration and electrolyte imbalance
Explain why nervous tissue is essential to integumentary function even though it is not a primary tissue type in the skin layers.
→ Nervous tissue provides sensory input and reflex protection
Compare the functions of tactile (Merkel) cells and dendritic cells in the epidermis.
→ Merkel = touch sensation; dendritic = immune defense
Compare the functions of the dermis and the subcutaneous layer in protecting the body.
→ Dermis = support, sensation, blood supply; subcutaneous = insulation, padding
Compare the role of sweat secretion and sebum secretion in maintaining homeostasis.
→ Sweat = thermoregulation & excretion; Sebum = lubrication & water resistance
Explain how nail structure supports their protective function.
→ Hard keratin provides defense for fingertips/toes
Compare the healing process of a superficial burn with that of a deep burn.
→ Superficial heals quickly via stratum basale; deep requires grafting/slow regeneration
Predict what would happen if epithelial tissue failed to regenerate properly at the stratum basale.
→ Wounds would not heal, infections increase, barrier compromised
Predict what would happen to skin health if melanocytes were destroyed.
→ No melanin → loss of UV protection, risk of cancer, albinism-like condition
Predict the effects of losing most subcutaneous fat on temperature regulation.
→ Reduced insulation → rapid heat loss
Predict the consequences of impaired epidermal dendritic cell function on the immune system.
→ Higher risk of infection, reduced immune surveillance
Predict the effects of absent sebaceous gland activity on skin health.
→ Dry, cracked skin prone to infection
Predict how loss of sweat glands and sebaceous glands in burn tissue affects long-term skin function.
→ Impaired thermoregulation, dry skin, increased infection risk
Analyze how the four major tissue types (epithelial, connective, muscle, nervous) interact to allow the integumentary system to function as an organ system.
→ Epithelial (barrier), connective (support), muscle (arrector pili), nervous (sensation) integrate for full function
Analyze how the structural differences among epidermal strata allow for both protection and regeneration of skin.
→ Deep layers regenerate, upper layers provide keratinized barrier
Analyze how the papillary, reticular, and subcutaneous layers work together to stabilize the skin and support integumentary function.
→ Papillary = anchors & nourishes; reticular = strength; subcutaneous = stability, energy, insulation
Analyze how the integument simultaneously balances multiple functions such as protection, absorption, secretion, and thermoregulation.
→ All occur at once: barrier & immunity, sweat/sebum, vit D synthesis, water balance
Analyze how hair, nails, and glands contribute together to integumentary protection and homeostasis.
→ Nails = defense; hair = insulation/sensation; glands = secretion & lubrication
Analyze how burn treatment must address not only tissue repair but also thermoregulation, fluid balance, and immune defense.
→ Burns compromise multiple functions → treatment must restore skin barrier + fluids + immune support