Fluid Compartments, Homeostasis, and Cell Physiology

Vocabulary flashcards covering body fluid compartments, homeostatic mechanisms, and mitochondrial cellular respiration based on the lecture material.

Intracellular fluid (ICF)

The fluid located inside the cell, making up two-thirds of total body water.

Extracellular fluid (ECF)

The fluid located outside the cells, consisting of plasma and interstitial fluid, which serves as the body's internal environment.

60-40-20 Rule

A rule indicating that total body water is $60\text{\%}$ of body weight, with ICF accounting for $40\text{\%}$ ($\frac{2}{3}$) and ECF accounting for $20\text{\%}$ ($\frac{1}{3}$).

Plasma Osmolarity

A measurement of different solutes in the plasma, with a normal adult reference range of $280-295\,mOsm/L$.

Osmolality

The concentration of a solution expressed as the number of osmoles per kilogram of water ($mOsm/kg\,H_2O$).

Isotonic saline

An intravenous fluid solution composed of $154\,mM\,NaCl$ ($0.9\,g\%$).

Insensible water loss

Evaporative water loss occurring through the lungs and skin, distinct from sweat.

Effective osmole

A solute confined to a particular compartment (such as sodium in the ECF) that creates an osmotic force to attract water.

Homeostasis

The maintenance of a dynamic steady state within the body's internal environment.

Homeostatic Control System

An interconnected network of body components that detects deviations, integrates information, and makes adjustments to maintain factors relatively constant.

Negative Feedback

A homeostatic control principle where a change in a controlled variable triggers a response that drives the variable in the opposite direction of the initial change.

Positive Feedback

A control mechanism that amplifies an initial change, moving the system further away from the set point.

Pathophysiology

The abnormal functioning of the body associated with disease.

Matrix

The interior gel-filled cavity of a mitochondrion.

Cristae

The folds of the inner mitochondrial membrane.

Adenosine Triphosphate (ATP)

The primary energy molecule used by cells for cellular work, storing energy in high-energy bonds.

Cellular Respiration

The set of metabolic reactions consisting of glycolysis, the citric acid cycle, and oxidative phosphorylation that consumes $O_2$ and produces $CO_2$ to synthesize ATP.

Glycolysis

An anaerobic metabolic process in the cytosol involving 10 sequential reactions that breaks down glucose into two pyruvate molecules, yielding a net of $2\,ATP$.

Krebs (Citric Acid) Cycle

An aerobic cycle of 8 biochemical reactions in the mitochondrial matrix that processes acetyl CoA to yield $2\,ATP$, $CO_2$, and hydrogen carriers (NADH and FADH_2).

Oxidative Phosphorylation

The synthesis of ATP at the inner mitochondrial membrane using energy released by electrons as they are transferred to $O_2$.

Electron Transport System

An aerobic group of proteins at the inner mitochondrial membrane that extracts electrons from $H^+$ to create a gradient, producing a net yield of $28\,ATP$.

ATP Synthase

An enzyme structure at the end of the electron transport chain that utilizes potential energy from moving $H^+$ to synthesize ATP.