Fox's Human Physiology, 16th Edition (Chapters 1–6) Comprehensive Flashcards

VOCABULARY flashcards covering the core concepts of Human Physiology (16th ed.) for Chapters 1 through 6, including physiological mechanisms, biochemistry, cellular structures, metabolism, and cell transport.

Physiology

The study of how living organisms function and how their parts work together to maintain life.

Homeostasis

The maintenance of a relatively stable internal environment despite external changes.

Claude Bernard

The individual who proposed the concept of the "internal environment."

Negative feedback

A control mechanism that reverses a change to restore normal conditions.

Regulation of body temperature

An example of negative feedback achieved through sweating and vasodilation.

Positive feedback

A mechanism that amplifies a response until a specific endpoint is reached.

Oxytocin release

An example of positive feedback that occurs during labor contractions.

Primary tissue types

The four categories classified as epithelial, connective, muscle, and nervous tissue.

Receptor

The structure in a feedback loop that detects changes in the environment.

Effector

The structure in a feedback loop that produces the corrective response.

Major elements in the body

Oxygen, carbon, hydrogen, and nitrogen.

Carbon

An element important for forming $4$ covalent bonds and serving as the backbone of organic molecules.

Covalent bond

A bond formed by sharing electrons.

Ionic bond

The attraction between oppositely charged ions.

Hydrogen bond

A weak attraction involving hydrogen atoms and electronegative atoms.

Water

Physiologically important substance serving as a solvent, transport medium, and temperature regulator.

pH

The negative logarithm of hydrogen ion concentration.

Neutral pH

A pH value equal to $7$.

Buffers

Substances that resist changes in pH.

ATP

Adenosine triphosphate, identified as the cell's primary energy currency.

Major classes of biological molecules

Carbohydrates, lipids, proteins, and nucleic acids.

Plasma membrane

The structure that surrounds the cell.

Fluid mosaic model

A model where the membrane consists of phospholipids with embedded proteins that move laterally.

Mitochondrion

The organelle that produces ATP; also known as the "powerhouse of the cell."

Ribosomes

Organelles that synthesize proteins and serve as the site for translation.

Rough ER

Endoplasmic reticulum dedicated to protein synthesis and modification.

Smooth ER

Endoplasmic reticulum dedicated to lipid synthesis and detoxification.

Golgi apparatus

The organelle responsible for modifying, packaging, and distributing proteins.

Lysosomes

Organelles containing digestive enzymes.

DNA

Deoxyribonucleic acid that stores genetic information.

Transcription

The synthesis of RNA from DNA, occurring in the nucleus.

Translation

The synthesis of proteins using mRNA instructions, occurring at the ribosomes.

Codon

A three-nucleotide sequence on mRNA coding for an amino acid.

Mutation

A change in DNA sequence.

Enzyme

A biological catalyst that speeds reactions by lowering activation energy.

Activation energy

The energy needed to initiate a chemical reaction.

Active site

The specific region of an enzyme where substrates bind.

Substrate specificity

The concept that enzymes act only on certain substrates.

Denaturation

The loss of enzyme structure and function, often caused by high temperatures or extreme pH.

Cofactors

Non-protein helpers required for enzyme activity.

Coenzymes

Organic cofactors, often vitamins.

Phosphorylation

The process of adding a phosphate group to a molecule.

ATP synthase

The specific enzyme that synthesizes ATP.

Cellular respiration

The process of extracting energy from nutrients to make ATP.

Glycolysis

The breakdown of glucose into pyruvate in the cytoplasm, which does not require oxygen.

Citric acid cycle

Also known as the Krebs cycle, this process occurs in the mitochondrial matrix.

Oxidative phosphorylation

ATP production that is linked to electron transport.

Electron transport chain

Located in the inner mitochondrial membrane, this is where oxygen accepts electrons at the end of the process.

Chemiosmosis

The generation of ATP using a proton gradient.

Fermentation

ATP production occurring without oxygen and involving the regeneration of $NAD^+$.

Glycogena

The major energy-storage carbohydrate in the body.

Gluconeogenesis

The specific metabolic process that forms glucose.

Lipolysis

The process involving the breakdown of triglycerides.

Beta-oxidation

The breakdown of fatty acids into $\text{acetyl-CoA}$.

Extracellular fluid (ECF)

Fluid outside cells that bathes tissues.

Intracellular fluid (ICF)

Fluid located inside cells.

Diffusion

The movement of substances from high to low concentration.

Simple diffusion

Passive movement directly through the membrane.

Facilitated diffusion

Passive transport using membrane proteins.

Osmosis

The diffusion of water across a membrane.

Active transport

Energy-requiring movement of substances against a concentration gradient.

Sodium-potassium pump

An ATP-dependent transport mechanism moving $3\,Na^+$ out and $2\,K^+$ into the cell.

Endocytosis

The process of uptake of substances into the cell.

Exocytosis

The process of releasing substances from the cell.

Receptor proteins

Proteins that bind signaling molecules to initiate a cellular response.

Signal transduction

The conversion of an extracellular signal into a cellular response.

Second messengers

Intracellular molecules, such as Cyclic AMP (cAMP), that relay signals.

G proteins

Regulatory proteins involved in receptor signaling.

Receptor down-regulation

A decrease in receptor numbers following prolonged stimulation.

Receptor up-regulation

An increase in receptor numbers following reduced stimulation.

Cell communication

A process essential for coordinating physiological responses and maintaining homeostasis.

Central theme of Chapters $1$-$6$

The dependence of homeostasis on coordinated cellular structure, metabolism, communication, and energy transfer.

Proteins

The macromolecule class that performs most enzymatic functions.