Anatomy, Physiology, Cells, and Tissues Review

Comprehensive vocabulary flashcards covering introductory anatomy and physiology, anatomical positions and directional terms, cellular structures and processes, and tissue classification.

Cytology

The study of cellular structure and function.

Plasma Membrane

The outer barrier separating the inside and outside of a cell that controls the flow of substances, helps identify cells, and participates in intracellular signaling.

Amphipathic

Having both polar (hydrophilic) and nonpolar (hydrophobic) regions, allowing molecules such as phospholipids to interact with water and lipids.

Integral Proteins

Membrane proteins that extend into or through the lipid bilayer among the fatty acid tails and are firmly embedded in it.

Peripheral Proteins

Membrane proteins attached to the polar heads of membrane lipids or to integral proteins at the inner or outer surface of the membrane without being firmly embedded.

Glycocalyx

The sugary coating surrounding the cell membrane, formed by the carbohydrate portions of glycolipids and glycoproteins.

Concentration Gradient

The difference in the concentration of a chemical between one side of the plasma membrane and the other.

Electrochemical Gradient

The combined influence of the concentration gradient and the electrical gradient on the movement of a particular ion.

Simple Diffusion

A passive process where substances move freely through the lipid bilayer of plasma membranes without the help of membrane transport proteins.

Osmosis

The net movement of a solvent through a selectively permeable membrane from an area of higher solvent concentration to an area of lower solvent concentration.

Hypotonic Solution

A solution with a lower solute concentration than the cytosol, causing water to enter the cell and leading to cell swelling or lysis (hemolysis in red blood cells).

Primary Active Transport

A transport process in which energy derived from the hydrolysis of ATP directly changes the shape of a carrier protein to pump a substance across a plasma membrane against its concentration gradient.

Secondary Active Transport

A transport process that uses energy stored in a sodium ($\text{Na}^+$) or hydrogen ($\text{H}^+$) concentration gradient to drive other substances across the membrane against their own concentration gradients.

Phagocytosis

A form of endocytosis in which a cell engulfs large solid particles, such as worn-out cells, whole bacteria, or viruses.

Pinocytosis

A form of endocytosis, also known as bulk-phase endocytosis, in which tiny droplets of extracellular fluid are taken up into the cell.

Transcytosis

A transport mechanism combining endocytosis and exocytosis, where vesicles undergo endocytosis on one side of a cell, move across the cytoplasm, and undergo exocytosis on the opposite side.

Cytosol

The fluid portion of the cytoplasm surrounding organelles, constituting about $55\%$ of total cell volume, composed of $75\text{--}90\%$ water along with dissolved solutes and suspended particles.

Microfilaments

The thinnest elements of the cytoskeleton, composed of actin and myosin, which generate movement and provide mechanical support.

Microtubules

The largest cytoskeletal components, consisting of long, unbranched hollow tubes composed mainly of tubulin that contribute to cell shape and movement.

Centrosome

An organelle consisting of a pair of centrioles and pericentriolar material containing tubulins used for growth of the mitotic spindle and microtubule formation.

Rough Endoplasmic Reticulum

A membranous network covered with ribosomes attached to the nuclear envelope that synthesizes glycoproteins and phospholipids for organelles, membranes, or secretion.

Smooth Endoplasmic Reticulum

A membranous network lacking ribosomes that synthesizes fatty acids and steroids, detoxifies harmful substances, removes phosphate from glucose-6-phosphate, and stores/releases calcium ions in muscle cells.

Golgi Complex

An organelle consisting of $3\text{--}20$ flattened membranous sacs called cisternae that modifies, sorts, packages, and transports proteins received from the rough ER.

Autophagy

The process carried out by lysosomes in which worn-out organelles are digested and recycled.

Autolysis

The process in which a lysosome digests an entire cell.

Proteasome

A tiny barrel-shaped structure containing proteases that degrades unneeded, damaged, or faulty proteins by cutting them into small peptides.

Mitochondrion

An organelle bounded by a double membrane with inner folds called cristae, serving as the site of aerobic cellular respiration reactions that produce most of a cell's ATP.

Mitosis

Somatic cell division resulting in two daughter cells that each receive a chromosomal set identical to the parent cell (diploid).

Meiosis

Reproductive cell division occurring only in gametes that reduces the chromosome number by half, producing four haploid daughter cells.

Interphase

The period of the cell cycle between cell divisions comprising $G_1$, S, and $G_2$ phases, during which the cell is metabolically active and replicates its DNA and organelles.

Gross Anatomy

The branch of anatomy that examines macroscopic structures that can be seen without a microscope.

Histology

The microscopic study of the structure of tissues.

Pathophysiology

The study of functional changes associated with disease and aging.

Metabolism

The sum of all chemical processes that occur within the human body.

Homeostasis

The condition of equilibrium or dynamic balance in the body's internal environment due to constant regulatory processes.

Interstitial Fluid

The extracellular fluid that fills the narrow spaces between cells of tissues.

Negative Feedback System

A regulatory mechanism that reverses a change in a controlled condition to return a variable to its homeostatic level.

Positive Feedback System

A regulatory mechanism that strengthens or reinforces a change in a controlled condition until an outside event interrupts it.

Etiology

The scientific study of the causes of disease and/or injury.

Idiopathic

Denoting a disease or condition with no identifiable cause.

Iatrogenic

Denoting a disease, condition, or injury that occurs as a result of medical intervention or treatment.

Nosocomial

Denoting an infection or disorder acquired as a consequence of being in a hospital environment.

Symptom

A subjective indication of disease reported by the patient, such as pain or nausea.

Sign

An objective indication of disease that can be observed or measured by a healthcare clinician.

Sequelae

Any abnormal conditions that follow and are the direct result of a disease, treatment, or injury.

Exacerbation

A period during a disease course when clinical manifestations become worse or more severe.

Anatomical Position

A standardized body posture where the subject stands erect facing the observer with head level, eyes facing forward, feet flat and directed forward, and upper limbs at the sides with palms facing forward.

Prone

The position of the body when lying face down.

Supine

The position of the body when lying face up.

Superior

Directional term meaning toward the head, or the upper part of a structure.

Inferior

Directional term meaning away from the head, or toward the lower part of a structure.

Anterior

Directional term meaning nearer to or at the front of the body.

Posterior

Directional term meaning nearer to or at the back of the body.

Ipsilateral

Directional term meaning located on the same side of the body as another structure.

Contralateral

Directional term meaning located on the opposite side of the body from another structure.

Proximal

Directional term meaning nearer to the attachment of a limb to the trunk or nearer to the origination of a structure.

Distal

Directional term meaning farther from the attachment of a limb to the trunk or farther from the origination of a structure.

Midsagittal Plane

A vertical plane passing through the midline of the body or organ that divides it into equal right and left sides.

Frontal Plane

A plane that divides the body or an organ into anterior (front) and posterior (back) portions; also called a coronal plane.

Transverse Plane

A plane that divides the body or an organ into superior (upper) and inferior (lower) portions; also called a cross-sectional or horizontal plane.

Mediastinum

The central anatomical region of the thoracic cavity between the medial walls of the pleural cavities, extending from the sternum to the vertebral column and from the first rib to the diaphragm.

Parietal Layer

The outer layer of a serous membrane that lines the wall of a body cavity.

Visceral Layer

The inner layer of a serous membrane that covers and adheres directly to the organs (viscera) within body cavities.

Tight Junctions

Cell junctions consisting of web-like strands of transmembrane proteins that fuse plasma membranes together to seal passageways, acting as a diffusion barrier between cells.

Adherens Junctions

Cell junctions containing plaque and cadherins that attach to microfilaments of the cytoskeleton, forming adhesion belts to resist shearing and abrasive forces.

Desmosomes

Cell junctions with plaque attaching to intermediate keratin filaments and cadherin glycoproteins, providing high tensile strength to prevent separation under tension.

Hemidesmosomes

Cell junctions using integrin transmembrane glycoproteins to anchor the basal surface of epithelial cells to the underlying basement membrane.

Gap Junctions

Cell junctions formed by connexins creating fluid-filled tunnels called connexons that connect neighboring cells for direct cell-to-cell communication and impulse transmission.

Transitional Epithelium

A variable, stretchable stratified epithelium featuring dome-shaped surface cells (umbrella cells) lining the urinary bladder, ureters, and urethra.

Endocrine Glands

Ductless glands that secrete hormones directly into the interstitial fluid and bloodstream.

Exocrine Glands

Glands that secrete their products into ducts that empty onto covering or lining surfaces such as skin or hollow organ lumens.

Merocrine Glands

Exocrine glands that release their secretions via exocytosis in secretory vesicles without loss of cellular material.

Apocrine Glands

Exocrine glands that accumulate secretion at the apical surface of the cell, which then pinches off to release the product.

Holocrine Glands

Exocrine glands whose cells accumulate secretory products in their cytosol, maturing until the entire cell ruptures and dies to become the secretion.

Fibroblast

Large, flat connective tissue cells with branching processes that secrete fibers and ground substance components into the extracellular matrix.

Mast Cell

Connective tissue cells derived from basophils that reside alongside blood vessels and produce histamine during inflammatory responses.

Chondrocytes

Mature cartilage cells residing singly or in groups within spaces called lacunae in the extracellular matrix.

Mucous Membrane

An epithelial membrane lining body cavities that open directly to the exterior, consisting of an epithelial layer and an underlying lamina propria of areolar connective tissue.

Synovial Membrane

A membrane lining joint cavities composed of a discontinuous layer of synoviocytes that secrete lubricating synovial fluid, lacking a formal epithelium.

Intercalated Discs

Specialized transverse thickenings of the plasma membrane in cardiac muscle tissue that contain desmosomes and gap junctions to facilitate structural integrity and rapid impulse conduction.