Human Anatomy and Physiology Study Flashcards

A set of vocabulary flashcards covering key terms and concepts across histology, cell biology, biochemistry, and anatomical orientation.

Basal Lamina

A non-cellular layer at the basal surface of epithelial cells, composed of glycoproteins and collagen fibers, serving as the apical portion of the basement membrane.

Reticular Lamina

A layer of extracellular matrix deep to the basal lamina that belongs to the underlying connective tissue, reinforcing the epithelial sheet.

Tight Junctions

Specialized lateral contacts between adjacent epithelial cells that join cell membranes together to form a water-tight seal.

Desmosomes

Anchoring cell junctions composed of cadherins, protein plaques, and keratin filaments that hold adjacent cells together to resist mechanical stretch.

Cutaneous Membrane

The dry membrane covering the body surface (the skin), consisting of keratinized stratified squamous epithelium (epidermis) attached to a thick connective tissue layer (dermis).

Mucous Membrane (Mucosae)

Moist epithelial membranes that line body cavities open to the exterior, resting over an areolar connective tissue layer called the lamina propria.

Serous Membrane (Serosae)

Moist membranes lining closed ventral body cavities, composed of simple squamous epithelium (mesothelium) resting on thin areolar connective tissue.

Parietal Serosa

The portion of a serous membrane that lines internal body cavity walls.

Visceral Serosa

The portion of a serous membrane that covers the external surfaces of organs within closed body cavities.

Merocrine Glands

Glands that secrete their products by exocytosis without causing loss or damage to the cell.

Holocrine Glands

Glands that accumulate secretory products internally until the entire cell ruptures, releasing secretions along with dead cell fragments.

Fibroblasts

Immature, mitotically active cells in connective tissue proper that synthesize and secrete the extracellular matrix components.

Mesenchyme

An embryonic connective tissue from which all adult connective tissues originate.

Glycocalyx

A sticky, sugar-rich area at the cell surface formed by the carbohydrate portions of glycolipids and glycoproteins, functioning in cell recognition.

Isotonic Solution

A solution containing the same concentration of non-penetrating solutes as the cytosol, causing no net movement of water into or out of the cell.

Hypertonic Solution

A solution with a higher concentration of non-penetrating solutes than the cell cytosol, causing water to leave the cell and leading to cell shrinkage (crenation).

Hypotonic Solution

A solution with a lower concentration of non-penetrating solutes than the cell cytosol, causing water to enter the cell and leading to cell swelling or bursting.

Primary Active Transport

The movement of solutes across a cell membrane against their concentration gradient, directly driven by energy from ATP hydrolysis.

Secondary Active Transport

The movement of solutes across a cell membrane against their concentration gradient, powered indirectly by energy stored in ionic concentration gradients (such as the $Na^+$ gradient).

Phagocytosis

A type of endocytosis ('cell eating') in which a cell engulfs large or solid particles by forming pseudopods around them.

Pinocytosis

A type of endocytosis ('cell drinking') in which a cell engulfs droplets of extracellular fluid containing dissolved solutes.

Mitochondria

Double-membrane organelles that generate ATP through aerobic cellular respiration and possess their own DNA, RNA, and ribosomes.

Rough Endoplasmic Reticulum

A ribosome-studded membranous organelle responsible for synthesizing secreted proteins, integral membrane proteins, and phospholipids.

Smooth Endoplasmic Reticulum

A membranous organelle continuous with the rough ER that functions in lipid metabolism, cholesterol and steroid hormone synthesis, and calcium ion ($Ca^{2+}$) storage and release.

Central Dogma

The fundamental biological process describing the flow of genetic information from DNA to RNA (via transcription) to Protein (via translation).

Transcription

The process of synthesizing an mRNA strand from a DNA template catalyzed by RNA polymerase.

Translation

The process in which mRNA codons are read by ribosomes and tRNA to assemble a specific sequence of amino acids into a protein.

Dehydration Synthesis

A chemical reaction in which two monomers are covalently linked together with the removal of a water molecule ($H_2O$).

Hydrolysis

A chemical reaction that breaks covalent bonds between monomers by adding a water molecule ($H_2O$).

Triglycerides

Neutral fats composed of a glycerol backbone bound to three fatty acid chains, functioning in energy storage, insulation, and protection.

Phospholipids

Amphipathic lipid molecules composed of a glycerol backbone, two nonpolar fatty acid tails, and a polar phosphate head, forming the primary structure of cell membranes.

Steroids

Lipids characterized by a carbon skeleton consisting of four interlocking rings, with cholesterol serving as the structural precursor for all body steroids.

Enzyme

A protein biological catalyst that accelerates chemical reactions by lowering the activation energy required.

Activation Energy

The initial amount of energy required to break bonds and trigger a chemical reaction.

Adenosine Triphosphate (ATP)

The immediate energy currency of cells, consisting of adenine, ribose, and three high-energy phosphate groups.

Homeostasis

The state of relative constancy maintained by body control systems despite continuous changes in the external environment.

Negative Feedback

A homeostatic control mechanism in which the output response reduces or shuts off the original stimulus, returning the variable toward its initial set point.

Positive Feedback

A control mechanism in which the output response enhances or exaggerates the original stimulus, driving the variable further away from its initial value.

Afferent Pathway

The signal pathway that carries sensory input from a receptor toward the control center.

Efferent Pathway

The signal pathway that carries motor output commands away from the control center to an effector organ.

Superior (Cranial)

Directional term meaning toward the head end or upper part of a structure or the body; above.

Inferior (Caudal)

Directional term meaning away from the head end or toward the lower part of a structure or the body; below.

Proximal

Directional term meaning closer to the origin of a body part or point of attachment of a limb to the body trunk.

Distal

Directional term meaning farther from the origin of a body part or point of attachment of a limb to the body trunk.