BIO 206 Lab 5: Integumentary System, Thermoregulation, and Lab Exam 2 Review

Comprehensive vocabulary flashcards covering the Integumentary System, thermoregulatory mechanisms, the 8 steps of feedback loops, and Lab Exam 2 guidelines for BIO 206.

Integumentary System

The organ system consisting of the skin and its accessory structures (hair follicles, nails, sweat glands, and sebaceous glands) responsible for protection, sensation, thermoregulation, and vitamin D synthesis.

Calcitriol

The active steroid hormone form of vitamin D, produced after enzymatic conversion of skin-synthesized vitamin $D_3$ in the liver and kidneys, required for absorption of calcium and phosphorus from the digestive tract.

Meissner Corpuscle

A encapsulated touch receptor located in the upper dermis that detects light touch and low-frequency vibrations.

Pacinian Corpuscle

A deep cutaneous mechanoreceptor that detects deep pressure and high-frequency vibrations.

Nociceptors

Free nerve endings embedded in various tissue layers that detect pain by sensing chemicals released by damaged cells.

Peripheral Thermoreceptors

Free nerve endings located in the skin and internal organs (such as the stomach) that detect temperature and send sensory information to the central nervous system via sensory neurons.

Central Thermoreceptors

Temperature-sensing neurons located within the hypothalamus that monitor the core temperature of blood circulating through the brain.

Hypothalamic Thermoregulatory Center

A subnucleus of the hypothalamus that serves as the primary integrating center for processing body temperature data and activating effectors to restore homeostasis.

Normal Core Temperature Set-Point

The ideal baseline human body temperature maintained by homeostatic negative feedback loops, specified as 37^\\text{circ}\text{C} (98.6^\\text{circ}\text{F}).

Hyperthermia

A physiological condition in which body temperature rises above the normal set-point of 37^\\text{circ}\text{C} (98.6^\\text{circ}\text{F}).

Hypothermia

A physiological condition in which body temperature drops below the normal set-point of 37^\\text{circ}\text{C} (98.6^\\text{circ}\text{F}).

Stimulus (Feedback Loop)

The initial physical or chemical deviation of a physiological variable away from its ideal set-point.

Sensor (Feedback Loop)

A specialized cell or receptor structure that detects a deviation of a regulated variable from its set-point.

Afferent Pathway (Feedback Loop)

The communication pathway (typically sensory neurons or interneurons) that conveys sensory data from the sensor to the integrating center.

Integrating Center (Feedback Loop)

The organ or neural structure that analyzes sensory input, compares it to the set-point, and determines the appropriate response.

Efferent Pathway (Feedback Loop)

The communication route (such as autonomic neurons, somatic motor neurons, or hormones) carrying output signals from the integrating center to the effector.

Effector (Feedback Loop)

A target organ, muscle, or gland in the body capable of altering physiological activity to modify the stimulus.

Effector's Action (Feedback Loop)

The sequence of biological steps or physiological behaviors carried out by an effector to achieve the goal of a feedback loop.

Response (Feedback Loop)

The ultimate outcome or goal of a feedback loop that directly counteracts or alters the initial stimulus.

Negative Feedback Loop

A homeostatic regulatory pathway that acts to oppose, remove, or negate a stimulus that deviates either above or below the set-point.

Positive Feedback Loop

A biological feedback mechanism that amplifies and drives a variable further away from the set-point until an outside factor intervenes to terminate the cycle (e.g., labor contractions or lactation).

Radiant Heat Exchange

Heat transfer between the body and the external environment via electromagnetic waves without physical contact (such as absorbing heat from the sun or radiating heat into a cold room).

Conductive Heat Exchange

Heat transfer occurring via direct physical contact between the body and a warmer or cooler object (e.g., holding a hot mug or wearing wet clothes).

Convective Heat Exchange

Heat transfer driven by the circulation of air or fluid across the body surface (e.g., a breeze, air conditioning, or immersion in water).

Evaporative Heat Loss

A cooling mechanism in which sweat secreted onto the skin absorbs heat energy and transitions into vapor, dissipating heat away from the body.

Cutaneous Vasodilation

The widening of blood vessels in the dermis in response to elevated body temperature, routing more warm blood toward the surface to enhance radiant heat dissipation.

Cutaneous Vasoconstriction

The narrowing of dermal arterioles mediated by sympathetic adrenergic neurons, reducing blood flow to the skin and extremities to conserve core heat during cold exposure.

Shivering Thermogenesis

Involuntary contractions of skeletal muscle triggered by somatic motor neurons that hydrolyze ATP to produce metabolic heat and raise body temperature.

Lab Exam 2 (BIO 206)

The practical examination covering the entirety of Labs 5, 6, 7, and 8, administered during the first hour of the scheduled lab session.