Human Physiology: Fluid Compartments, Organic Compounds, Cell Membrane, and Transport Mechanisms

Vocabulary practice flashcards covering fluid compartments, organic/inorganic chemistry, plasma membrane structure, passive/active transport, and electrical membrane potentials based on lecture text.

Solute

The dissolved substances in a solution, which in the human body include proteins, lipids, carbohydrates, and electrolytes.

Solvent

The liquid in which solutes are dissolved; water is considered the universal solvent in biological systems.

Electrolyte

A mineral dissociated from a salt that carries an electrical charge, such as sodium ions ($\text{Na}^+$) and chloride ions ($\text{Cl}^-$).

Intracellular Fluid (ICF) Compartment

The body fluid compartment that includes all fluid enclosed within cells by their plasma membranes.

Extracellular Fluid (ECF) Compartment

The fluid compartment that surrounds all cells in the body, composed primarily of plasma and interstitial fluid.

Plasma

The fluid component of blood that travels in blood vessels and transports cells, proteins, electrolytes, nutrients, gases, and wastes.

Interstitial Fluid (IF)

The major component of extracellular fluid that surrounds all body cells not located within blood vessels.

Intracellular Fluid Volume Percentage

The proportion of total body water contained within the ICF compartment, accounting for approximately $60\%$ of total body water.

Adult Male ICF Volume

The average total volume of intracellular fluid in an average-sized adult male, which equals approximately $25\,\text{liters}$.

ECF Plasma Percentage

The proportion of extracellular fluid found specifically within the blood plasma, accounting for approximately $20\%$ of the ECF.

Cerebrospinal Fluid

A specialized water-based extracellular fluid that bathes and cushions the brain and spinal cord within the skull and vertebral column.

Synovial Fluid

A lubricating extracellular fluid found in joint cavities that reduces friction during body movements.

Pleural Fluid

An extracellular fluid located within the pleural cavities that enables the lungs to expand and recoil smoothly during respiration.

Pericardial Fluid

An extracellular fluid contained within the cardiac sac that surrounds and protects the heart.

Peritoneal Fluid

An extracellular fluid within the abdominal cavity that minimizes friction between adjacent abdominal organs.

Aqueous Humor

The watery extracellular fluid located within the eye.

Inorganic Compound

A substance that does not contain both carbon and hydrogen atoms, such as water ($\text{H}_2\text{O}$) or hydrochloric acid ($\text{HCl}$).

Infant Body Water Percentage

The relative proportion of body mass made up of water in infants, which is approximately $75\%$.

Adult Body Water Percentage

The proportion of body mass made up of water in healthy human adults, ranging from $50\%$ to $60\%$.

Old Age Body Water Percentage

The proportion of body mass made up of water in old age, which can drop as low as $45\%$.

Heat Sink

A substance or object that absorbs and dissipates heat without experiencing a corresponding large increase in its own temperature.

Evaporative Cooling

The process by which heat is carried away from the body as sweat released by sweat glands evaporates into the surrounding air.

Mixture

A physical combination of two or more substances where each constituent maintains its own chemical identity without forming new chemical bonds.

Solution

A liquid mixture composed of a solvent that evenly dissolves one or more solutes into individual distributed molecules.

Colloid

A liquid mixture containing tiny clumps of molecules large enough to make the mixture opaque by scattering light, such as milk or thyroid colloid.

Suspension

A liquid mixture in which a heavier substance is temporarily suspended in a liquid but settles out over time.

Homogeneous Solution

A state of a solution in which solute particles are distributed evenly throughout the solvent.

Universal Solvent

A designation given to water because of its abundance and ability to dissolve polar and ionic compounds required for biological chemical reactions.

Polar Molecule

A molecule containing regions of partial positive and partial negative electrical charge resulting from unequal electron sharing.

Hydrophilic

Refers to 'water-loving' compounds, such as ionic or polar covalent substances, that readily dissolve in water.

Hydrophobic

Refers to 'water-fearing' compounds, such as nonpolar molecules, that do not readily dissolve in water.

Average Blood Glucose Concentration

The concentration of glucose in the bloodstream of a healthy adult, which averages about $100\,\text{mg/dL}$.

Molarity

A unit of solute concentration expressed as moles ($\text{M}$) of solute molecules per liter ($\text{L}$) of solution.

Sedimentation

The process by which suspended heavy particles separate from a liquid suspension and settle to the bottom over time.

Sedimentation Rate Test

A clinical blood test measuring how rapidly red blood cells settle out of blood plasma in a test tube over a specified duration.

Dehydration Synthesis

A chemical reaction in which two monomers covalently bond together, releasing a molecule of water as a byproduct.

Hydrolysis

A chemical reaction that breaks the covalent bond between monomers by adding a hydrogen atom to one part and a hydroxyl group ($\text{OH}^-$) to the other, requiring one water molecule.

Monomer

A basic individual subunit that links with other similar units to build larger chemical polymers.

Polymer

A large molecule formed by two or more chemically bonded monomer subunits.

Salt

A substance formed by ionic bonding that dissociates in water into ions other than $\text{H}^+$ or $\text{OH}^-$.

Ionic Bond

A chemical bond formed when one atom transfers electrons to another, creating oppositely charged ions that attract each other.

Bile Salts

Salts produced by the liver that act to break apart and emulsify dietary fats.

Calcium Phosphate Salts

Inorganic mineral salts that form the hard structural component of human teeth and bones.

Acid

A chemical substance that releases hydrogen ions ($\text{H}^+$) when dissolved in aqueous solution.

Base

A substance that releases hydroxyl ions ($\text{OH}^-$) or accepts existing $\text{H}^+$ ions when dissolved in solution.

Homeostatic pH

The closely regulated physiological pH level maintained across body cells and fluids, approximately equal to $7.4$.

Buffer

A chemical compound that stabilizes solution pH by releasing or binding hydrogen ions in body fluids.

Organic Compound

A chemical substance produced by living organisms that typically contains carbon atoms covalently bonded to hydrogen.

Hydrocarbon

A chemical structure composed exclusively of carbon and hydrogen atoms.

Carbon Skeleton

A interconnected chain of covalently bonded carbon atoms forming the molecular core of organic compounds.

Functional Group

A specific group of covalently bonded atoms that reacts as a single unified unit in chemical reactions.

Macromolecule

Any large complex organic molecule, often constructed from linked monomer subunits.

Carbohydrate

An organic compound composed of carbon, hydrogen, and oxygen, usually maintaining a $2:1$ ratio of hydrogen to oxygen.

Monosaccharide

The basic monomer subunit of carbohydrates, consisting of single sugar molecules.

Hexose Sugars

Monosaccharides containing exactly six carbon atoms, including glucose, fructose, and galactose.

Glucose

A hexose monosaccharide that serves as the primary energy source for human cells, and the exclusive energy source for neurons and red blood cells.

Fructose

A dietary hexose monosaccharide sugar.

Galactose

A hexose monosaccharide that combines with glucose via dehydration synthesis to form lactose.

Pentose Sugars

Monosaccharides that contain five carbon atoms, including ribose and deoxyribose.

Ribose

A pentose sugar monomer present in RNA and ATP molecules.

Deoxyribose

A pentose sugar monomer found in DNA that contains one less oxygen atom than ribose.

Disaccharide

A carbohydrate composed of two monosaccharide monomers joined together by dehydration synthesis.

Sucrose

Common table sugar; a disaccharide composed of one glucose molecule and one fructose molecule.

Maltose

Malt sugar; a disaccharide formed by the covalent bonding of two glucose monosaccharides.

Lactose

Milk sugar; a disaccharide composed of one galactose molecule and one glucose molecule.

Polysaccharide

A complex carbohydrate polymer made of hundreds to thousands of monosaccharide monomers.

Starches

Plant-derived glucose polymers occurring as amylose or amylopectin chains that serve as digestible food sources.

Amylose

An unbranched, long-chain polymer form of plant starch.

Amylopectin

A branched-chain polymer form of plant starch.

Glycogen

A highly branched glucose polymer stored in animal tissues, particularly within skeletal muscle and the liver.

Cellulose

An indigestible plant polysaccharide (fiber) that forms plant cell walls and supports human gastrointestinal health.

Glycoprotein

A conjugated molecule formed by bonding carbohydrate groups to proteins, present in plasma membranes.

Glycolipid

A conjugated molecule formed by bonding carbohydrate groups to lipids, located in the outer cell membrane.

Lipid

A highly diverse group of organic compounds composed mostly of nonpolar hydrocarbons, rendering them hydrophobic.

Emulsion

A temporary mixture formed when nonpolar hydrophobic lipids are dispersed in a polar liquid like water.

Triglyceride

A common dietary lipid (fat) formed from a glycerol backbone attached to three fatty acid chains via dehydration synthesis.

Glycerol

A three-carbon organic backbone molecule that binds fatty acid chains to form triglycerides and phospholipids.

Fatty Acids

Long hydrocarbon chains featuring a carboxyl group at one end and a methyl group at the opposite end.

Carboxyl Group

An acidic functional group ($\text{COOH}$) located at one end of a fatty acid and in all amino acids.

Methyl Group

A functional group ($\text{CH}_3$) located at the omega end of a fatty acid chain.

Saturated Fatty Acid

A straight, rigid fatty acid chain with no double carbon bonds, containing the maximum possible number of hydrogen atoms.

Monounsaturated Fatty Acid

A fatty acid chain containing exactly one double carbon bond, creating a kink that keeps it liquid at room temperature.

Polyunsaturated Fatty Acid

A fatty acid chain containing two or more double carbon bonds.

Omega-3 Fatty Acids

Beneficial unsaturated fatty acids with their first double bond at the third carbon from the methyl end, found in cold-water fish.

Trans Fatty Acids

Harmful chemically altered fats created by partially hydrogenating unsaturated oils.

Adipose Tissue

Fat tissue in the body that stores triglycerides for long-term energy reserves, insulation, and organ protection.

Fat-Soluble Vitamins

Nonpolar essential micronutrients (vitamins A, D, E, and K) that require dietary fats for absorption and transport.

Lipoprotein

A transport complex composed of hydrophobic triglycerides surrounded by a protein envelope for circulation in body fluids.

Phospholipid

An amphipathic lipid composed of a diglyceride, a phosphate group, and a charged head region.

Diglyceride

A molecule consisting of a glycerol backbone attached to two fatty acid chains.

Phosphate Group

A charged, polar phosphorus-containing group that forms the hydrophilic head of phospholipids and components of nucleotides.

Amphipathic

Describing a molecule that contains both a hydrophilic region and a hydrophobic region within its structure.

Steroid

A lipid compound built upon a foundation set of four interconnected hydrocarbon rings.

Cholesterol

A sterol synthesized by the liver that modulates membrane fluidity and acts as a precursor for bile acids and steroid hormones.

Prostaglandins

Signaling molecules derived from unsaturated fatty acids that regulate inflammation, blood pressure, and pain sensation.

NSAIDs

Nonsteroidal anti-inflammatory drugs that reduce pain and inflammation by inhibiting prostaglandin effects.

Protein

An organic macromolecule made of amino acid monomers linked by peptide bonds, containing carbon, hydrogen, oxygen, nitrogen, and often sulfur.

Keratin

A structural protein present in the epidermis of the skin that protects underlying tissue.

Collagen

A durable fibrous protein present in skin dermis, bones, and meninges that acts as structural scaffolding.

Peptide Bond

A covalent bond formed between two amino acids through dehydration synthesis.