Introduction to Physiology: Homeostasis, Feedback, and Body Fluids

Vocabulary flashcards covering core concepts from the physiology lecture notes, including homeostasis, feedback mechanisms, body fluids, and regulatory hormones.

Homeostasis

The body’s ability to maintain a relatively stable internal environment (set points) through regulatory mechanisms, primarily via negative feedback.

Negative feedback

A control mechanism that counteracts a deviation from a set point to return toward the baseline.

Positive feedback

A control mechanism that amplifies a deviation or drives a process toward a goal; can be beneficial (e.g., fever) or pathological when unregulated.

Set point

The target value for a regulated physiological variable that the body tries to maintain.

Detection system (sensor/receptor)

A component that monitors a variable and detects deviations from the set point, prompting a corrective response.

Pancreas

An organ that secretes insulin and glucagon to regulate blood glucose.

Insulin

Hormone that lowers blood glucose by promoting uptake of glucose into cells and storage as glycogen in liver and fat.

Glucagon

Hormone that raises blood glucose by stimulating glycogenolysis and gluconeogenesis in the liver.

Glycogen

A branched polymer of glucose stored mainly in the liver and skeletal muscle.

Glycogenesis

The synthesis of glycogen from glucose for storage.

Glycogenolysis

The breakdown of glycogen to glucose, releasing glucose into the bloodstream.

Blood glucose (blood sugar)

The concentration of glucose in the bloodstream.

Lipolysis

The breakdown of fats (triglycerides) in adipose tissue to release fatty acids for energy.

Lipogenesis

The synthesis and storage of fat from excess glucose or other substrates.

CHO (carbon, hydrogen, oxygen) & Organic molecule

Elements common to organic compounds; organic molecules contain carbon, hydrogen, and oxygen (CH O).

Organic molecule

A molecule that contains carbon and is typically found in living organisms.

Oxygen (O2)

Gas essential for cellular respiration; transported in blood and incorporated into organic molecules.

Carbon dioxide (CO2)

Waste gas produced by cellular respiration; transported in blood to lungs for exhalation.

Intracellular fluid (ICF)

Fluid contained inside the body's cells.

Extracellular fluid (ECF)

Fluid outside cells; includes plasma and interstitial fluid.

Plasma

The liquid component of blood; extracellular fluid within blood vessels.

Interstitial fluid (ISF)

Fluid between cells; part of the extracellular fluid that surrounds cells in tissues.

Platelets

Small blood cells essential for blood clotting (coagulation).

Troponin

Cardiac protein used as a biomarker of heart muscle injury; normally low in healthy individuals.

Clotting / Coagulation

Process of forming a blood clot to stop bleeding; part of hemostasis.

Hemostasis

The overall process that stops bleeding and maintains blood in a fluid state, involving platelets and clotting cascades.

Fever (positive feedback example)

Elevation of body temperature to fight infection; a form of positive feedback that can escalate if unchecked.

Lactation

Milk production driven by hormonal signals; suckling increases milk release (let-down reflex).

Labor contractions

Uterine contractions that intensify via positive feedback until birth occurs.

Water compartments in the body

Body fluids are divided into intracellular and extracellular compartments; extracellular includes plasma and interstitial fluid.