Fundamentals of Anatomy, Physiology, and Cytology

Comprehensive vocabulary flashcards covering anatomical terminology, levels of biological organization, homeostatic feedback loops, chemical principles of life, organic macromolecules, and cellular transport mechanisms.

Anatomy

The study of internal and external body structures and their physical relationships among other body parts.

Physiology

The study of how living organisms perform their vital functions.

Principle of Complementarity of Structure and Function

The principle stating that all specific functions are performed by specific structures, and that the form of a structure relates directly to its function.

Gross Anatomy

Also called macroscopic anatomy; the examination of large structures visible to the naked eye.

Cytology

The microscopic study of the structure of cells.

Histology

The microscopic study of the structure of tissues.

Signs vs. Symptoms

Signs are objective disease indications observed by an examiner (such as a fever), whereas symptoms are subjective disease indications experienced by the patient (such as tiredness).

Levels of Organization

The six structural levels of the human body, proceeding from simplest to most complex: chemical level, cellular level, tissue level, organ level, organ system level (comprising 11 systems), and organism level.

Anatomical Position

The standard reference position where a person stands with hands at the sides, palms facing forward, and feet together.

Supine vs. Prone

Supine refers to lying down in the anatomical position face up, whereas prone refers to lying down face down.

Abdominopelvic Quadrants

Four divisions of the abdominopelvic cavity formed by two perpendicular lines intersecting at the umbilicus: Right Upper Quadrant (RUQ), Left Upper Quadrant (LUQ), Right Lower Quadrant (RLQ), and Left Lower Quadrant (LLQ).

Abdominopelvic Regions

Nine precise regional divisions of the abdominopelvic area: right hypochondriac, epigastric, left hypochondriac, right lumbar, umbilical, left lumbar, right inguinal, hypogastric (pubic), and left inguinal.

Sectional Planes

Two-dimensional slices through the body: frontal (coronal) plane dividing anterior from posterior, sagittal plane dividing right from left (midsagittal at midline; parasagittal offset), and transverse (horizontal) plane dividing superior from inferior.

Serous Membrane

A two-layered membrane lining closed body cavities consisting of a parietal layer lining the inner cavity wall and a visceral layer covering the internal organs, lubricated by serous fluid to reduce friction.

Mediastinum

A mass of connective tissue in the thoracic cavity separating the pleural cavities that stabilizes the trachea, esophagus, thymus, and major heart vessels, and contains the pericardial cavity.

Retroperitoneal

The anatomical position of organs located posterior to the parietal peritoneum against the back muscular body wall, including the pancreas and kidneys.

Homeostasis

The continuous physiological processes that maintain a relatively stable internal environment despite fluctuations in external or internal conditions.

Autoregulation vs. Extrinsic Regulation

Autoregulation is an automatic, local response to an environmental change made by a cell, tissue, or organ; extrinsic regulation involves broader responses coordinated by the nervous system (rapid, short-term) or endocrine system (slower, long-term).

Negative Feedback

(anything that opposes the original stimulus) A primary homeostatic mechanism in which the effector response opposes or negates the initial stimulus, maintaining physiological variables within a normal range (e.g., thermoregulation around a $37^\circ\text{C}$ set point).

Positive Feedback

(anything that enhances the original stimulus and feedback) A regulatory mechanism in which the initial stimulus produces a response that exaggerates or amplifies the change until a specific endpoint is reached, such as blood clotting.

Dynamic Equilibrium

A state of balance in which opposing processes or forces continuously adapt and adjust to changing conditions, keeping variables within acceptable ranges.

Isotope

Versions of the same element whose atoms contain the same number of protons but different numbers of neutrons, resulting in different mass numbers.

Radioisotope

An unstable isotope whose nucleus spontaneously decomposes via radioactive decay at a rate measured by its half-life.

Mole

A quantity of an element or compound with a weight in grams equal to its atomic or molecular weight, always containing Avogadro's number ($6.023 \times 10^{23}$) of units.

Valence Shell

The outermost electron shell of an atom; its degree of electron fullness determines the atom's chemical stability and reactivity.

Ionic Bond

bonds created by the attractions between negative and positive ions

Covalent Bond

Atoms share electrons. Can be polar (unequal) or nonpolar (equal).

Hydrogen Bond

A weak electrical attraction between a partially positive hydrogen atom in a polar covalent bond and a partially negative atom (such as oxygen or nitrogen) in another polar covalent bond.

Metabolism

All the chemical reactions occurring in the cells and tissues of the body at any given time.

Catabolism vs. Anabolism

Catabolism refers to decomposition reactions that break complex molecules down into simpler ones and release energy; anabolism refers to synthesis reactions that build larger molecules from smaller ones and require energy.

Hydrolysis

Are decomposition reactions (that involve water) that breaks chemical bonds through the addition of a water molecule ($\text{AB} + \text{H}_2\text{O} \rightarrow \text{AH} + \text{BOH}$).

Dehydration Synthesis

A condensation reaction that joins two smaller molecules into a larger compound accompanied by the removal of a water molecule ($\text{AH} + \text{BOH} \rightarrow \text{AB} + \text{H}_2\text{O}$).

Activation Energy

The amount of energy required to start a specific chemical reaction.

Enzyme

are catalyts that lower the activation energy of reactions and therefore speed up the reaction.

Exergonic vs. Endergonic Reaction

An exergonic reaction releases more energy than its activation energy requires, resulting in a net release of energy; an endergonic reaction requires more activation energy than is produced, resulting in net absorption of energy.

Electrolytes

Soluble inorganic substances whose ions dissociate in water and conduct an electricity in solution.

Colloid vs. Suspension

A colloid is a solution containing large dispersed molecules that stay permanently in solution (e.g., blood plasma), whereas a suspension contains large particles that settle out if left undisturbed (e.g., whole blood).

pH

The negative logarithm of the hydrogen ion concentration ($[\text{H}^+]$) in moles per liter, where pure water is neutral at $7.0$, values below $7.0$ are acidic, values above $7.0$ are basic/alkaline, and human blood is maintained between $7.35$ and $7.45$.

Buffer

compounds that stabalize PH by neutralzing added acid or base

Carbohydrates

Organic macromolecules containing carbon, hydrogen, and oxygen generally in a $1:2:1$ ratio ($\text{C}:\text{H}:\text{O}$) that serve as primary cellular energy sources.

Glycogen

A highly branched polysaccharide composed of repeating glucose molecules, manufactured and stored in liver and muscle cells as an energy reserve.

Fatty Acids

Lipid monomers consisting of long hydrocarbon chains with a carboxyl group ($-\text{COOH}$) at one end; categorized as saturated (no double carbon bonds) or unsaturated (one or more double bonds producing kinks).

Eicosanoids

Lipids derived from dietary arachidonic acid, including leukotrienes (active in immune/injury responses) and prostaglandins (local tissue chemical messengers).

Triglycerides

Neutral fats composed of a glycerol molecule joined to three fatty acid chains via dehydration synthesis, serving in energy storage, thermal insulation, and physical cushioning.

Steroids

Lipid molecules characterized by a four-ring carbon framework, including cholesterol, sex hormones (estrogen, testosterone), corticosteroids, calcitriol, and bile salts.

Micelles

Spherical droplets formed when amphipathic phospholipids and glycolipids disperse in water, orienting their hydrophilic heads outward toward water and hydrophobic tails inward.

Amino Acid Structure

The monomer subunit of proteins consisting of a central carbon atom bound to a hydrogen atom, an amino group ($-\text{NH}_2$), a carboxyl group ($-\text{COOH}$), and a variable side chain ($\text{R}$ group).

Peptide Bond

A covalent bond formed via dehydration synthesis between the carboxyl group of one amino acid and the amino group of another.

Protein Structural Complexity Levels

The four structural tiers of proteins: primary (amino acid sequence), secondary (spirals such as alpha helices or beta sheets via hydrogen bonding), tertiary (three-dimensional folding from $\text{R}$ group interactions), and quaternary (assembly of multiple polypeptide subunits).

Denaturation

A change in the tertiary or quaternary structure of a protein caused by extreme temperature or $\text{pH}$, resulting in the permanent loss of biological function.

Nucleotide Structure

The monomer building block of nucleic acids, consisting of a pentose sugar (ribose or deoxyribose), a phosphate group, and a nitrogenous base (purine or pyrimidine).

Purines vs. Pyrimidines

Purines are double-ring nitrogenous bases comprising adenine (A) and guanine (G); pyrimidines are single-ring bases comprising cytosine (C), thymine (T, found in DNA only), and uracil (U, found in RNA only).

Adenosine Triphosphate (ATP)

A high-energy nucleotide containing adenosine, ribose, and three phosphate groups linked by high-energy covalent bonds whose hydrolysis yields adenosine diphosphate ($\text{ADP}$) and releases usable cellular energy.

Plasma Membrane Composition

The cell boundary consisting of approximately $42\%$ lipids (phospholipid bilayer, cholesterol), $55\%$ proteins (integral and peripheral), and $3\%$ carbohydrates (glycocalyx).

Integral vs. Peripheral Proteins

Integral proteins span the bilayer and cannot be removed without disrupting the membrane; peripheral proteins are loosely attached to inner or outer surfaces and can detach without cell damage.

Glycocalyx

A superficial carbohydrate layer formed by membrane glycolipids and glycoproteins that functions in lubrication, protection, anchoring, specificity in binding, and immune cell recognition.

Ligand

Any specific extracellular molecule (such as a hormone or nutrient like insulin) that binds to a designated receptor protein on the plasma membrane.

Extracellular Fluid (ECF) vs. Intracellular Fluid (ICF)

ECF has high $\text{Na}^+$, low $\text{K}^+$, and a positive relative charge; ICF (cytosol) has high $\text{K}^+$, low $\text{Na}^+$, stores proteins and carbohydrates, and carries a net negative relative charge.

Diffusion

The passive movement of solute particles down their concentration gradient from an area of higher concentration to an area of lower concentration until equilibrium is reached.

Osmosis

The passive net movement of water molecules across a selectively permeable membrane toward the higher solute concentration.

Osmotic Pressure vs. Hydrostatic Pressure

Osmotic pressure is the force of water movement across a membrane driven by solute concentration; hydrostatic pressure is the opposing mechanical fluid force resisting that flow.

Sodium-Potassium Exchange Pump

The primary active transport carrier mechanism that expels $3\,\text{Na}^+$ ions from the cell in exchange for bringing in $2\,\text{K}^+$ ions, consuming approximately $40\%$ of total cellular $\text{ATP}$.

Endocytosis vs. Exocytosis

Endocytosis is vesicular transport packaging extracellular materials into internal vesicles for uptake; exocytosis is the discharge of vesicle contents into the extracellular space via membrane fusion.

Phagocytosis

A form of endocytosis termed 'cell eating,' wherein a cell engulfs large particulate matter or bacteria into a vesicle called a phagosome for intracellular destruction.

Pinocytosis

A form of endocytosis termed 'cell drinking,' wherein the plasma membrane invaginates to bring droplets of extracellular fluid into pinosomes or endosomes for nutrient absorption.