Cellular Physiology Chapter 1

Study Notes

Volume and Composition of Body Fluids

Body fluids are divided into two main compartments: intracellular fluid (ICF) and extracellular fluid (ECF).
Major ions in ECF include sodium (Na+) as the primary cation, and chloride (Cl-) and bicarbonate (HCO3-) as main anions.
Major ions in ICF consist of potassium (K+) and magnesium (Mg2+) as cations, and phosphate and protein as anions.
Solute concentrations are measured using various units: millimoles per liter (mmol/L) for concentration, milliequivalents per liter (mEq/L) for charged solutes, and milliosmoles per liter (mOsm/L) for osmolarity.
Electroneutrality principle dictates that concentrations of positive charges (cations) must equal negative charges (anions) in body fluid compartments.
Resting membrane potential is influenced by potassium ion movement, while action potentials are related to sodium ion concentration differences across cell membranes.
Calcium (Ca2+) pumps in erythrocyte membranes prevent rigidity by extruding calcium ions.

Characteristics of Cell Membranes

Cell membranes consist primarily of a phospholipid bilayer which provides fluidity and flexibility.
Membrane proteins are categorized as integral, transmembrane, or peripheral, and perform various functions such as transport and cell signaling.
Integral and transmembrane proteins include ligand-binding receptors, transport proteins, and ion channels, facilitating selective passage of molecules.
Peripheral proteins assist with cell adhesion and GTP-binding activities.

Transport Across Cell Membranes

Simple diffusion occurs along a concentration gradient and is influenced by partition coefficients, diffusion coefficients, membrane thickness, and surface area.
Facilitated diffusion employs carrier proteins to enhance the movement of solutes; however, saturation occurs at high concentrations.
Primary active transport involves the movement of solutes against their concentration gradient using ATP, with key pumps such as Na-K ATPase and Ca2+ ATPase.
Secondary active transport relies on coupling the transport of multiple solutes, classified as co-transport (symport) and anti-transport (counter transport).
Osmosis is the movement of water through a semipermeable membrane driven by solute concentration differences.

Description

This quiz focuses on Chapter 1 of Cellular Physiology, emphasizing the understanding of body fluid composition, membrane characteristics, and ion distribution in cell membranes. Learners will explore the mechanisms of communication between neurons and muscles, including resting and action potentials.