Anatomy and Physiology: Cellular, Chemical, and Tissue Fundamentals

Comprehensive vocabulary flashcards covering anatomical terminology, chemical bonding and energy, macromolecules, cytology, membrane dynamics, molecular genetics, the cell cycle, and histology.

Anatomy

The study of the structure of body parts and their relationships to one another.

Biology

The description and classification of living organisms.

Physiology

The study of the function of the body's structural machinery.

Cytology

The branch of anatomy focused on the study of the cell.

Histology

The microscopic study of tissues.

Embryology

The study of developmental changes of the body before birth.

Surface Anatomy

The study of internal structures as they relate to the overlying skin.

Systemic Anatomy

Gross anatomy of the body studied system by system.

Pathological Anatomy

The study of structural changes caused by disease.

Radiographic Anatomy

The study of internal body structures visualized by X-ray.

Molecular Biology

The study of anatomical structures at a subcellular level.

Levels of Structural Organization

The hierarchical organization of the human body: Chemical level (atoms combine to form molecules) -> Cellular level (cells made of molecules) -> Tissue level (similar cells) -> Organ level (different tissues) -> Organ System level (different organs working closely together) -> Organismal level (made up of organ systems).

Negative Feedback

A homeostatic control mechanism where the output shuts off the original stimulus to return the variable to a stable baseline (e.g., regulation of blood glucose levels).

Positive Feedback

A control mechanism where the output exaggerates or amplifies the original stimulus to push a biological process forward to completion (e.g., regulation of blood clotting).

Matter

Anything that has mass and takes up space.

Chemical Energy

Energy stored within the chemical bonds of substances, which can be released during reactions such as combustion.

Electrical Energy

Energy that results directly from the movement of charged particles.

Mechanical Energy

Energy directly involved in moving matter or producing motion, such as the action of actin and myosin.

Radiant Energy

Energy that travels in electromagnetic waves.

Isotopes

Structural variations of an atom that possess different numbers of neutrons but the exact same number of protons.

Atomic Weight

The average mass of an element found beneath its name on the periodic table, measured in $amu$ or $g\,mol^{-1}$.

Ionic Bonds

Relatively weak bonds formed when electrons are transferred between atoms, producing anions (which gain electrons) and cations (which lose electrons).

Covalent Bonds

Strong chemical bonds formed when atoms share electron pairs to produce molecules (can be single, double, or triple shared electron pairs).

Hydrogen Bonds

Weak attractive forces incapable of binding atoms into molecules, but essential for providing three-dimensional molecular shape and creating surface tension.

Polar Covalent Bond

A covalent bond characterized by the unequal sharing of electrons between atoms with differing electronegativities.

Non-Polar Covalent Bond

A covalent bond formed by the equal sharing of electrons between atoms.

Oxidation

A chemical reaction involving the loss of electrons (remembered by the acronym LEO: Lose Electrons Oxidation).

Reduction

A chemical reaction involving the gain of electrons (remembered by the acronym GER: Gain Electrons Reduction).

Exergonic Reaction

A chemical reaction that yields a net release of energy and causes its surroundings to become warmer.

Endergonic Reaction

An energy-absorbing chemical reaction whose products contain more energy than the reactants, causing the surroundings to become colder.

Enzymes

Chemically specific biological catalysts (typically ending in '-ase') that bind substrates and reduce the activation energy required to initiate chemical reactions.

Acid

A substance that acts as a proton donor by releasing $H^+$ into solution, corresponding to a pH range of $0 - 6.99$.

Base

A substance that acts as a proton acceptor by releasing $OH^-$ into solution, corresponding to a pH range of $7.01 - 14$.

Chemical Buffer

A chemical system that resists abrupt or large swings in body pH in order to maintain homeostasis.

Carbohydrates

Organic molecules composed of carbon, hydrogen, and oxygen that serve as a primary source of cellular energy; common examples include glucose, fructose, and glycogen.

Triglycerides

Lipid molecules composed of one glycerol molecule covalently bonded to three fatty acid chains.

Phospholipids

Modified lipids consisting of two fatty acid tails and a phosphorus-containing polar head group, serving as the main structural component of cellular membranes.

Proteins

Complex polymers composed of combinations of 20 different types of amino acids joined together by peptide bonds.

Primary Protein Structure

The linear sequence of amino acids in a polypeptide chain, strictly determined by the genetic code.

Deoxyribonucleic Acid (DNA)

The double-stranded genetic material housed in the nucleus, consisting of nucleotides composed of deoxyribose, phosphate, and the nitrogenous bases adenine, guanine, cytosine, and thymine.

Ribonucleic Acid (RNA)

A single-stranded nucleic acid found in both the nucleus and cytoplasm that contains ribose sugar and uses uracil in place of thymine.

Cell Theory

The fundamental concept stating that the cell is the basic structural and functional unit of life, organismal activity depends on individual and collective cell activity, cellular biochemical activities are dictated by subcellular structures, and continuity of life has a cellular basis.

Cytosol

The fluid portion of cytoplasm, largely composed of water with dissolved proteins, salts, sugars, and other solutes.

Mitochondria

Cytoplasmic membranous organelles that supply the majority of cellular ATP via aerobic cellular respiration.

Nucleus

The control center of the cell that houses genetic information (DNA) and directs protein production.

Nucleoli

Dark-staining spherical bodies located inside the nucleus responsible for assembling ribosome subunits.

Endoplasmic Reticulum

An extensive membranous network surrounding the nucleus; exists as Rough ER (studded with ribosomes; produces and packages proteins) and Smooth ER (lacks ribosomes; functions in lipid metabolism, drug detoxification, and calcium storage).

Ribosomes

Non-membranous cytoplasmic granules composed of protein and ribosomal RNA (rRNA) that serve as the sites of protein synthesis.

Golgi Apparatus

A stack of membranous sacs that modifies, concentrates, and packages proteins and lipids received from the rough ER, routing them to destinations via vesicles.

Lysosomes

Membranous digestive organelles produced by the Golgi apparatus that degrade nonfunctional organelles, bacteria, viruses, toxins, and bodily tissues.

Peroxisomes

Membranous sacs derived from the ER containing oxidases and catalases to detoxify harmful substances and neutralize free radicals.

Fluid Mosaic Model

A model describing the plasma membrane as an extremely thin, flexible bilayer of lipids (phospholipids, cholesterol, glycolipids) containing embedded floating proteins.

Lipid Rafts

Specialized outer-membrane microdomains composed of sphingolipids and cholesterol (occupying ~20% of the surface) that serve as concentrating platforms for cell-signaling molecules.

Osmosis

The passive diffusion of a solvent (water) across a selectively permeable membrane when solute concentrations differ on opposite sides.

Osmolarity

The measure of total concentration of solute particles within a given solution.

Hypertonic Solution

A solution possessing a greater solute concentration than the cytosol, pulling water out of cells and causing them to shrink.

Hypotonic Solution

A solution possessing a lesser solute concentration than the cytosol, causing water to enter cells and making them swell.

Tight Junctions

Impermeable junctions that form continuous seals around adjacent cells, preventing molecules from passing through intercellular spaces.

Desmosomes

Anchoring junctions scattered along cell sides that act like mechanical rivets to distribute mechanical tension and resist pulling forces.

Gap Junctions

Hollow communicating cylinders (nexuses) between adjacent cells that allow ions and small molecules to pass directly, enabling rapid intercellular communication.

Purines

Two-ring nitrogenous bases found in nucleic acids, specifically Adenine ($A$) and Guanine ($G$).

Pyrimidines

Single-ring nitrogenous bases found in nucleic acids, specifically Cytosine ($C$), Thymine ($T$), and Uracil ($U$).

Transcription

The enzymatic transfer of genetic information from a DNA gene base sequence into a complementary strand of messenger RNA (mRNA).

Translation

The process of converting the language of nucleic acid codons in mRNA into the specific amino acid sequence of a polypeptide chain at the ribosome.

Polypeptide Chain Elongation

A cyclic translation process where aminoacyl-tRNA binds the ribosome's A site, a peptide bond forms, the ribosome translocates shifting tRNAs ($A \rightarrow P \rightarrow E$), and the uncharged tRNA is released from the E site.

RNA Polymerase

The primary transcription enzyme that untwists the DNA helix, aligns complementary ribonucleoside triphosphates, links RNA nucleotides together, and terminates at a stop signal.

Introns

Non-coding intervening sequences within pre-mRNA that are excised and discarded before the molecule leaves the nucleus.

Exons

Amino-acid-specifying coding segments of pre-mRNA that are spliced together to form the functional mRNA transcript.

Interphase

The metabolic phase of the cell cycle between divisions, divided into $G_1$ (growth and metabolism), $S$ (DNA replication), and $G_2$ (final preparation for division).

$G_0$ Phase

A non-dividing quiescent state in which cells permanently or temporarily exit the active cell cycle.

DNA Helicase

An enzyme that unwinds and untwists the double-stranded DNA molecule during replication to expose single-stranded template chains.

DNA Polymerase

The enzyme that synthesizes new DNA strands by matching complementary deoxynucleotides to the parent template in the $5' \rightarrow 3'$ direction.

Semiconservative Replication

The mechanism of DNA replication in which each newly produced double helix contains one original parent strand and one newly formed complementary daughter strand.

Cyclin-Dependent Kinases (Cdks)

Protein kinases that drive the cell cycle forward by phosphorylating specific intracellular target proteins once activated by binding cyclins.

Cyclins

Regulatory proteins whose concentrations fluctuate throughout the cell cycle, serving as activating switches for cyclin-dependent kinases (Cdks).

Epithelial Tissue

Avascular sheets of tightly bound cells covering body surfaces, lining internal cavities, and forming glands.

Endocrine Glands

Ductless glands that secrete hormones directly into surrounding interstitial fluid to enter the bloodstream.

Exocrine Glands

Glands that secrete chemical products onto body surfaces or into body cavities via epithelial ducts.

Ground Substance

The unstructured material of the extracellular matrix containing interstitial fluid, cell adhesion proteins (fibronectin, laminin), and proteoglycans, acting as a molecular sieve between blood vessels and cells.

Connective Tissue Classification

Major structural categories of connective tissue including loose connective tissue (cushions organs), dense regular (tendons), dense irregular (joint capsules), hyaline cartilage (costal cartilage), elastic cartilage (external ear), fibrocartilage (intervertebral discs), and bone.