Cellular Level of Organization and Histology

Vocabulary flashcards reviewing cellular structures, transport mechanisms, medical imaging types, cell division stages, and histology concepts based on the lecture notes.

Amphipathic Molecules

Molecules containing both a polar, hydrophilic region (such as a phosphate head) and a nonpolar, hydrophobic region (such as fatty acid tails).

Phospholipid Molecule

A major cell membrane component consisting of a polar hydrophilic phosphate head and nonpolar hydrophobic fatty acid tails.

Phospholipid Bilayer

A two-layered biological membrane structure where hydrophilic heads orient toward watery environments and hydrophobic tails cluster together in the interior.

Transmembrane Proteins

Integral proteins that span the entire width of the cell membrane to act as gateways for molecule transport.

Glycocalyx

A carbohydrate-rich surface layer formed by glycoproteins on certain cells that aids cell recognition, serves as hormone receptors, breaks down nutrients, and prevents pathogen entry.

Facilitated Diffusion

Passive movement of substances across a cell membrane from higher to lower concentration with the assistance of transmembrane proteins.

Tonicity Effects on Cells

The behavior of cells based on surrounding solute concentration: isotonic solutions maintain shape, hypotonic solutions cause swelling/bursting, and hypertonic solutions cause shrinking.

Sodium-Potassium Pump

A primary active transport mechanism using ATP to transport 3 sodium ions out of the cell and 2 potassium ions into the cell against their concentration gradients.

Phagocytosis

A form of endocytosis where the cell membrane extends outward to engulf large particles or cells.

Pinocytosis

A form of endocytosis involving membrane invagination to take in fluid containing dissolved substances.

Exocytosis

An active cellular transport process where a vesicle fuses with the plasma membrane to export materials out of the cell.

Computed Tomography (CT)

An imaging technique using computers and a series of X-rays to visualize internal structures in cross-sectional planes and 3D reconstructions.

Positron Emission Tomography (PET)

A nuclear medicine imaging modality using a weak radioactive tracer tag to evaluate metabolic activity in tissues.

Model Human Cell

A schematic representation showing major organelles and internal structures enclosed within a plasma membrane.

Mitochondrion

An organelle that extracts energy from food during oxidative metabolism and synthesizes ATP; known as the powerhouse of the cell.

Lysosome

A membrane-bound vesicle produced by the Golgi apparatus containing digestive enzymes to break down intracellular wastes.

Peroxisome

An organelle containing enzymes that produce and decompose hydrogen peroxide during lipid metabolism and toxic substance breakdown.

Cytoskeleton

An internal structural framework composed of protein filaments (microtubules, intermediate filaments, and actin filaments) that supports cell shape and organizes organelles.

Cell Surface Specializations

Apical membrane structures including microvilli (surface area absorption), cilia (moving surface substances), and flagella (cell propulsion).

Phases of Cell Division

The sequential cycle of cell multiplication consisting of Interphase (DNA duplication), Mitosis (Prophase, Metaphase, Anaphase, Telophase), and Cytokinesis.

Structural Organization of DNA

The progression of genetic material from double-stranded DNA wrapped around histone proteins to form nucleosomes, chromatin, and condensed chromosomes.

Histology

The scientific branch dedicated to the microscopic study of tissue structure, organization, and function.

Tight Junction

A specialized cell junction that tightly fuses adjacent plasma membranes together to prevent fluid leakage across cell layers.

Desmosomes

Anchoring junctions that structurally unite neighboring cells together to withstand mechanical stress.

Gap Junction

An intercellular channel allowing direct transport of ions and small molecules between the cytoplasm of adjacent cells.

Epithelial Tissue

A primary tissue class consisting of tightly packed, polarized cells covering body surfaces, lining cavities, and forming glands.

Basement Membrane

An extracellular supporting layer composed of the lamina lucida and lamina densa that anchors epithelial cells to underlying connective tissue.

Merocrine Secretion

An exocrine secretion mechanism where products are released via exocytosis without damaging the cell body.

Apocrine Secretion

An exocrine secretion method where secretory products gather at the cell apex, which then pinches off from the cell body.

Holocrine Secretion

An exocrine secretion method involving the complete breakdown and destruction of the cell to release its accumulated products.

Connective Tissue

The most structurally diverse primary tissue, composed of cells suspended within an extracellular matrix, functioning to connect, support, and protect body organs.

Collagen Fibers

Extracellular matrix fibers offering high tensile strength and flexibility, commonly found in tendons and ligaments.

Chondrocytes

Mature cartilage cells located in tiny matrix chambers called lacunae.

Hyaline Cartilage

The most abundant cartilage type in the human body, characterized by short dispersed collagen fibers and proteoglycans.

Areolar Tissue

A loose connective tissue type with a web-like weave of protein fibers that binds and cushions body structures.

Pseudostratified Columnar Epithelium

A single layer of column-like cells of varying heights whose nuclei appear at different levels, creating a stratified appearance.