Integumentary System and Cell Membrane Transport Review

Comprehensive practice flashcards covering skin layers, appendages, sensory mechanoreceptors, wound healing, scar types, burn classifications, skin lesions, body fluid compartments, diffusion mechanisms, and tonicity.

What percentage of total body weight does the skin typically account for in humans?

About $16\%$ of the body weight.

What are the three primary layers that structure human skin?

The epidermis, the dermis, and the hypodermis (or subcutaneous tissue).

From deep to superficial, what are the four primary layers of the epidermis?

Stratum basale, stratum spinosum, stratum granulosum, and stratum corneum.

What specific epithelium composes the epidermis layer?

Keratinized stratified squamous epithelium.

How thick can the epidermis be on the soles of the feet compared to the eyelids and face?

Up to $1.5\,mm$ on the soles of the feet, and as little as $0.05\,mm$ on the eyelids and face.

Which two cell types are dispersed within the stratum basale?

Merkel cells (sensory touch receptors) and melanocytes (melanin producers).

What is the function of Langerhans cells found in the stratum spinosum?

They function similarly to macrophages by engulfing bacteria, foreign particles, and damaged cells.

In which specific regions of the body is the stratum lucidum layer present?

In the thick skin of the palms of the hands and the soles of the feet.

How frequently should a bedridden patient and a wheelchair-bound patient be repositioned to prevent bed sores?

A bedridden person's position should be changed at least every $2\,hours$, and someone in a wheelchair should shift every $15\,minutes$.

What two protein fibers compose the dermis to provide the skin with strength and elasticity?

Collagen and elastin.

Where are tactile corpuscles (Meissner corpuscles) located, and what do they detect?

They are found in the dermal papillae of hairless skin and detect light touch and low-frequency vibrations.

What structure connects the hypodermis to underlying muscles and organs?

Fascia.

What muscle attaches to a hair follicle and contracts to cause goosebumps?

The arrector pili muscle.

What is the key functional distinction between eccrine and apocrine sweat glands?

Eccrine glands are widely distributed and release a watery secretion directly onto the skin for thermoregulation; apocrine glands are in armpits and genital areas and produce a thicker, odor-causing fluid when mixed with bacteria.

Which specific bacterium trapped in clogged hair follicles contributes to the pathogenesis of acne?

Propionibacterium acnes.

Which antimicrobial peptide ingredient in sweat helps deter microbes on the skin surface?

Dermcidin.

Which mechanoreceptors located deep in the dermis sense deep pressure and high-frequency vibrations?

Pacinian corpuscles.

What are the specialized free nerve endings that serve as pain receptors in the skin called?

Nociceptors.

What are the five cardinal signs of inflammation?

Pain (Dolor), Heat (Calor), Redness (Rubor), Swelling (Tumor), and Loss of function (Functio laesa).

What is the name of the collagen-rich tissue produced by fibroblasts during wound repair?

Granulation tissue.

How does a keloid scar differ from a normal scar regarding fibroblastic activity and apoptosis?

In keloids, the fibroblastic phase continues unchecked with increased proliferative activity, persistence, lower rates of apoptosis, and overproduction of collagen.

What characterizes an atrophic scar, and what conditions commonly cause it?

An indented scar that heals below the normal layer of skin tissue due to the inability to regenerate tissue; commonly caused by severe acne or chickenpox.

How are burns categorized under the modern depth-based classification system?

Superficial (epidermis damaged), Partial-thickness (outer two layers damaged with blisters), Full-thickness (extends through all skin layers into fatty tissue), and Fourth-degree (extends to muscles, nerves, and bones).

What surgical emergency occurs when pressure builds up within deep fascia-bound muscle compartments, restricting blood flow?

Compartment syndrome.

How are papules and nodules differentiated by size?

Papules are raised solid lesions measuring less than $5\,mm$ in diameter, whereas nodules are solid raised lumps measuring at least $5\,mm$ in diameter.

How are petechiae and ecchymosis differentiated by size?

Petechiae are purpura lesions less than $3\,mm$ in size, while ecchymosis lesions are greater than $3\,mm$.

What is the structural difference between a laceration and an incision?

A laceration is a deep cut or tear with jagged, irregular edges, while an incision is a clean, straight cut made intentionally with a sharp instrument like a scalpel.

What two fluid compartments are separated by the cell membrane?

Intracellular Fluid (ICF) and Extracellular Fluid (ECF).

What are the two main subdivisions of Extracellular Fluid (ECF)?

Interstitial fluid and plasma.

What is the key distinction between simple diffusion and facilitated diffusion?

Simple diffusion moves molecules directly down the concentration gradient without transport proteins, whereas facilitated diffusion uses carrier or channel proteins to transport substances without ATP.

In what direction does water move across a semipermeable membrane during osmosis?

Water moves from an area of lower solute concentration to an area of higher solute concentration.

What happens to a cell placed in a hypotonic solution versus a hypertonic solution?

In a hypotonic solution, water enters the cell causing it to swell and potentially burst; in a hypertonic solution, water leaves the cell causing it to shrink.

Identify the tactile receptor depicted in this image that resides in the dermal papillae of hairless skin.

Tactile corpuscle (Meissner corpuscle).

Identify the three structural layers of the hair shaft labelled in this diagram.

Cortex, medulla, and cuticle.

What muscular action is depicted here when responding to nerve impulses to pull the hair shaft upright?

Contraction of the arrector pili muscle.