Physiology 261 Lab Notes

Vocabulary flashcards created for Physiology 261 Lab notes review.

Extracellular fluid

Fluid found outside of cells that contains water, electrolytes, proteins, and nutrients.

Cell membrane

A selectively permeable barrier that encloses the cell, controlling the movement of substances in and out.

Osmosis

The movement of water across a selectively permeable membrane in response to solute concentration gradients.

Tonicity

Describes the relative concentration of solutions that determine the direction and extent of osmotic movement.

Isotonic

Solutions that have the same osmotic pressure as the cell's internal environment, causing no net movement of water.

Hypertonic

A solution with a higher concentration of solutes compared to another solution, leading to water moving out of the cell.

Hypotonic

A solution with a lower concentration of solutes compared to another solution, leading to water moving into the cell.

Facilitated diffusion

Passive transport of molecules across the cell membrane through protein channels without energy expenditure.

Active transport

Movement of molecules against their concentration gradient, requiring energy, usually in the form of ATP.

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Electrochemical gradient

The combined effect of the concentration gradient and the electrical gradient across a membrane.

Vesicular transport

Transport of materials via vesicles, including endocytosis and exocytosis.

Endocytosis

The process by which cells internalize substances from their external environment via vesicle formation.

Exocytosis

The process of vesicles fusing with the membrane to release their contents outside the cell.

Aquaporin

A type of channel protein in cell membranes that facilitates the rapid transport of water.

Total body water

The total amount of water in the body, influenced by age and sex.

Resting membrane potential

The voltage difference across the cell membrane when the cell is not actively sending signals.

Nernst equation

Mathematical equation used to calculate the equilibrium potential for a particular ion.

Sodium-Potassium pump

An active transport mechanism that moves sodium out of the cell and potassium into the cell.

Homeostasis

The maintenance of stable internal conditions within an organism.

Chemical disequilibrium

Condition where the concentration of different ions is not equal inside and outside the cell.

Transport maximum

The maximum rate of transport achieved by a transporter when all binding sites are occupied.

Glucose transporter (GLUT)

A type of transport protein that facilitates the transport of glucose across cell membranes.

Osmolarity

The measure of solute concentration per unit of solvent, important for understanding tonicity.

Pinocytosis

A form of endocytosis where the cell engulfs small amounts of extracellular fluid.

Phagocytosis

A form of endocytosis in which a cell engulfs large particles or cells.

Receptor-mediated endocytosis

Endocytosis initiated by the binding of a substance to a specific receptor in the membrane.

Lipid bilayer

A double layer of phospholipids that constitutes the cell membrane.

Selectively permeable membrane

A membrane that allows certain substances to pass while restricting others.

Membrane permeability

A measure of how easily substances can cross the cell membrane.

Fick’s law of diffusion

Describes how the rate of diffusion is proportional to the concentration gradient and surface area.

Ion channel

A protein that enables the passage of ions across the cell membrane.

Uniport carriers

Transport proteins that move a single type of substrate across the membrane.

Cotransporters

Transport proteins that move two or more substrates either in the same direction (symport) or opposite directions (antiport).

Electrochemical forces

The combination of chemical (concentration) and electrical gradients that influence ion movement.

Homeostatic imbalance

A state where homeostasis is disrupted, potentially leading to disease.

Insulin secretion

The process by which the pancreas releases insulin in response to glucose levels.

Epithelial transport

Transport processes that occur across epithelial cells, such as absorption and secretion.

Glucose-sodium cotransporter

A transport protein that uses the sodium gradient to help transport glucose into the cell.

K+ leak channels

Ion channels that allow K+ ions to flow out of the cell, contributing to resting membrane potential.

Voltage-gated channels

Ion channels that open or close in response to changes in membrane potential.

Chemical gradient

The gradient resulting from differences in the concentration of solute molecules.

Concentration gradient

A difference in the concentration of a substance across a space.

Transporting epithelia

Specialized epithelial cells that facilitate the movement of substances in and out of the tissues.

Apical membrane

The surface of an epithelial cell that faces the lumen or external environment.

Basolateral membrane

The surface of an epithelial cell that faces the interstitial fluid.

Chemical signaling

Communication between cells through the release and binding of signaling molecules.

Endocrine signaling

Type of signaling involving hormones that are secreted into the bloodstream.

Neurotransmitter

Chemical messengers that transmit signals across a synapse from one neuron to another.

Hormonal regulation

Control of physiological processes by hormones that bind to receptors and induce changes.

Signal transduction

The process by which a cell converts an external signal into a functional response.

Phosphorylation

The addition of a phosphate group to a protein or other organic molecule, often used to regulate activity.

Dephosphorylation

The removal of a phosphate group from a protein, often leading to a change in its activity.

Caveolae

Small invaginations in the membrane involved in endocytosis and signaling.

Tight junctions

Connections between epithelial cells that prevent substances from passing between cells.

Interstitial fluid

Fluid that surrounds tissue cells, providing a medium for nutrient and waste exchange.

Plasma membrane

Another term for the cellular membrane that encloses the cytoplasm.

Cytoplasm

The material within a living cell, excluding the nucleus.

Fluid mosaic model

A model describing the structure of cell membranes as a mosaic of various proteins that float in or on the fluid lipid bilayer.

Clathrin

A protein that plays a major role in the formation of coated vesicles.