Integumentary System and Pathophysiology Quiz

Integumentary System and Pathophysiology

• A membrane is a thin sheet or layer of pliable tissue that serves as a covering or envelope of a part, as the lining of a cavity, as a partition, or to connect two structures.
• Three types of membranes:
  • Cutaneous (skin): the largest organ; accounts for 7% of body weight; surface area 18-20 sq ft; thickness 1.5-4mm; divided into epidermis and dermis; has accessory structures and subcutaneous layer (hypodermis).
  • Mucous: lines hollow organs that open to the body surface, an epithelial sheet underlain with lamina propria.
  • Serous: slippery membranes; simple squamous epithelium lying on areolar connective tissue; line closed cavities (pleural, peritoneal, and pericardial).

Functions of the Integumentary System

• Cushions and insulates deeper organs.
• Protects the body from abrasion, trauma, chemicals, pathogens, temperature extremes, and UV rays.
• Excretion and secretion.
• Contains sensory receptors associated with nerve endings (sensation).
• Synthesis and storage of nutrients (vitamin D3).
• Thermoregulation.
• Absorption.

Integumentary Structures

• Components: epidermis, dermis, and subcutaneous layer (hypodermis).
• Structures: hair shaft, pore of sweat gland duct, epidermal ridge, dermal papilla, sebaceous gland, arrector pili muscle, sweat gland duct, touch and pressure receptors, hair follicle, artery, vein, sweat gland, nerve fibers, and fat.

Skin Structures

• Epidermis: stratified squamous epithelium (keratinized); several distinct cell layers; thick skin-five layers on palms and soles; thin skin-four layers on the rest of the body (absent of stratum lucidum).
• Layers of epidermis: stratum corneum (most superficial layer, dead, flattened keratinocytes, abundant keratin, protects skin against abrasion and penetration); stratum lucidum (clear layer, only in thick skin, palms and soles, composed of dead keratinocytes); stratum granulosum (cells are flattened, organelles deteriorating, contain keratohyaline and lamellated granules, contain thick bundles of intermediate filaments); stratum spinosum (cells are actively mitotic stem cells, some newly formed cells become part of the more superficial layers); stratum basale (forms the base of the epidermis, composed of actively mitotic stem cells).
• Appendages:
  • Nerves
  • Meissner's corpuscle
  • Pacinian corpuscle
  • Hair follicle receptor (root hair plexus) -Sensory nerve endings
• Other components: cutaneous vascular plexus, adipose tissue.

Classification of Burns

• By depth (first-degree, second-degree, third-degree, fourth-degree).
• By surface area of skin burnt (TBSA - Rule of Nines or Sevens).

Aging of the Skin

• Major Age-Related Changes: Injury and infection increase; immune cells decrease; sun protection diminishes; skin becomes dry, scaly; hair thins, grays; sagging, wrinkles occur; heat loss decreases; repair slows.

Skin and Thermoregulation

Mechanisms controlling body temperature:

• Sweating: increases body heat loss by increasing sweat evaporation.
• Shivering: produces heat by involuntary movement of muscle.
• Vasodilation: for heat loss from body (hot weather).
• Vasoconstriction: conserves body heat (cold weather).

Skin Infection

• Few species of bacteria commonly invade intact skin.
• Skin and soft Tissue Infections (SSTI): - Inflammatory microbial invasion of the epidermis, dermis, and subcutaneous tissues - Classification based on - Depth of infection -Superficial: impetigo, erysipelas, folliculitis
• Deep localised: furunculosis, hidradenitis
• Deeper: necrotizing fasciitis, myonecrosis
• Hair follicle infections are commonly self-limiting.

Hair Follicle Infections

• Commonly self-limiting, but can progress to severe or life-threatening in some instances
• Example: folliculitis (staphylococcal origin can spread within body.)

Symptoms

• Folliculitis: small red bump/pimple at hair follicle site; hair may be pulled; may involve pus; often self-limiting.
• Furuncle: Infection extends from follicle to adjacent tissue; localized redness, swelling, severe tenderness, and pain. Lesion is a furuncle.
• Carbuncle: cluster of boils; connected area of infection under the skin.

Causative Agent

• Most furuncles and carbuncles (as well as many cases of folliculitis) are caused by Staphylococcus aureus.
• S. aureus is identified by its ability to produce coagulase, a protein that reacts with blood clots.

Risk of Infection

• Host factors (e.g., diet, age, chronic illness, medications, impaired immunity).
• Battle ground factors wound(e.g. ischemia, necrosis, gangrene, decrease in WBC and Abs).

Summary of Integumentary System Disorders

• General superficial infections (easily treatable): impetigo, erysipelas, folliculitis, and non-purulent infections.
• Deep localized infections (often require hospitalization): furunculosis, hidradenitis, skin abscesses
• Deeper infections (demand urgent treatment) - necrotizing fasciitis, and myonecrosis
• Important considerations include: systemic antibiotics (for cellulitis); emergent surgery (for necrotizing fasciitis); and rapid surgical debridement (for myonecrosis).

Skin Cancer

• Types of skin cancer: basal cell carcinoma, squamous cell carcinoma, melanoma.

Disorders of the Integumentary System (Continued)

• Disorders: cellulitis, chloasma (melasma), cleft lip or cleft palate, contact dermatitis, eczema, fungal skin infections, skin cancer, acne vulgaris, sebaceous cyst, skin lesions

Integumentary System (Continued)

• Acne: caused by increased oil secretion related to increased hormones during puberty.
• Albinism: inherited disorder in which melanin isn't produced.
• Alopecia: loss of hair.
• Athlete's foot: contagious fungal infection of the foot.

Test your knowledge on the integumentary system, including its membranes, functions, and pathophysiological aspects. This quiz covers various types of membranes such as cutaneous, mucous, and serous, along with their roles in human biology. Perfect for students studying anatomy or physiology.