Cellular Physiology - Chapter 1

Vocabulary flashcards covering core concepts from cellular physiology, homeostasis, membrane transport, and epigenetics.

Anatomy

The study of the structure and description of the human body; contrast with physiology.

Physiology

The study of biological functions and processes of the human body under normal (basal) conditions.

Cellular physiology

The study of biochemical and biophysical processes occurring within cells.

Systemic physiology

The study of regulation of physiological processes within the body by homeostatic reflexes.

Homeostasis

The dynamic constancy of the internal physiological environment despite external changes.

Receptor

Sensor that detects changes in a controlled variable.

Afferent pathway

Input information pathway from receptor to the control center.

Control center

Component that processes information and determines the response.

Efferent pathway

Output information pathway from the control center to the effector.

Effector

Organ or tissue that responds to restore homeostasis.

Negative feedback

A response that opposes or reduces the original stimulus to return to homeostasis.

Positive feedback

A response that amplifies the original stimulus, pushing the system away from homeostasis until a set outcome is reached.

Baroreceptors

Receptors in the carotid arteries that detect changes in blood pressure and help regulate it.

Temperature regulation (negative feedback)

A homeostatic process where a temperature change is detected and responses counteract to restore normal temperature.

Blood pressure regulation (negative feedback, example)

Example where baroreceptors detect pressure changes and trigger effectors to adjust vascular tone and heart rate.

Childbirth (positive feedback)

A process where cervical stretch leads to oxytocin release, increasing contractions until birth occurs.

Blood coagulation (positive feedback)

A cascade in which initial clotting activity enhances subsequent steps until a clot forms.

Plasma membrane

The external cell barrier that is selectively permeable.

Phospholipid bilayer

The membrane boundary made of two layers of phospholipids; amphipathic.

Amphipathic

Molecule having both hydrophilic and hydrophobic regions.

Hydrophilic head

Phospholipid region attracted to water.

Hydrophobic tail

Phospholipid region repelled by water.

Simple diffusion

Passive movement of substances down their concentration gradient without proteins.

Channel-mediated diffusion

Facilitated diffusion through protein channels forming hydrophilic tunnels for small polar molecules and ions.

Carrier-mediated diffusion

Facilitated diffusion via carrier proteins that shuttle substances across the membrane.

Facilitated diffusion

Passive transport aided by membrane proteins to move substances down their gradient.

Active transport

Movement of substances against their concentration gradient, requiring energy.

Primary active transport

Direct use of cellular energy (ATP) by pump proteins to move substances against their gradient.

Secondary active transport

Energy from a downhill gradient drives uphill transport of another molecule; indirect energy use.

Vesicular transport

Bulk transport via vesicles into or out of the cell.

Endocytosis

Uptake of substances by engulfing them with the plasma membrane to form vesicles.

Phagocytosis

“Cell eating”; engulfment of large particles into a phagosome.

Pinocytosis

“Cell drinking”; ingestion of extracellular fluid and solutes in vesicles.

Exocytosis

Release of substances from the cell by vesicle fusion with the plasma membrane.

Osmosis

Net movement of water across a selectively permeable membrane toward higher solute concentration.

Hypotonic solution

Solution with lower solute concentration and higher water concentration relative to another solution.

Hypertonic solution

Solution with higher solute concentration and lower water concentration relative to another solution.

Isotonic solution

Solution with equal solute and solvent concentrations on both sides of the membrane; no net water movement.

Tonicity

Measure of the osmotic pressure gradient between two solutions separated by a semipermeable membrane.

Epigenetics

Study of how lifestyle and environmental signals modify gene activity without changing DNA sequence.

Proteins and DNA in physiology

Proteins expressed by DNA carry out cellular functions; DNA serves as the template, not the active executor.

Genetics vs epigenetics in health

Approximately 20% of health and aging is due to genetics; about 80% is influenced by epigenetic changes from lifestyle and environment.