Histology in Medical Technology

Integral proteins

Proteins incorporated within the cell membrane.

Transmembrane proteins

Proteins spanning the entire membrane thickness.

Peripheral proteins

Proteins attached to membrane surfaces by electrostatic forces.

Histology

Study of normal structures in tissues.

Glycocalyx

Outer coating of glycoproteins and glycolipids.

Eukaryote

Organism with a defined nucleus.

Prokaryote

Organism lacking membrane-bound organelles.

Plasmalemma

Outer limiting membrane of a cell.

Davson and Danielli model

Classical model of membrane structure.

Fluid Mosaic Model

Model describing membrane structure as fluid and dynamic.

Phospholipid bilayer

Two layers of phospholipids forming cell membranes.

Hydrophilic head

Water-attracting part of a phospholipid.

Hydrophobic tail

Water-repelling part of a phospholipid.

Endoplasm

Inner part of the cytoplasm with active streaming.

Exoplasm

Outer part of the cytoplasm, gel-like.

Nucleus

Largest organelle, control center of the cell.

Pyknotic nucleus

Small, condensed nucleus appearance.

Chromatic nucleus

Blotchy appearance of the nucleus.

Vesicular nucleus

Cleared out appearance of the nucleus.

Nucleolus

Site of RNA synthesis and ribosome assembly.

Chromatin

Complex of DNA and proteins in the nucleus.

Heterochromatin

Inactive, tightly coiled chromatin.

Euchromatin

Active, loosely packed chromatin involved in transcription.

Transcription

Process of copying DNA to mRNA.

Translation

Process of synthesizing proteins from mRNA.

Ribosomes

Sites of protein synthesis composed of RNA and proteins.

Polyribosomes

Multiple ribosomes attached to a single mRNA.

Nuclear envelope

Double membrane surrounding the nucleus.

Golgi apparatus

Stacked membranes for processing and packaging proteins.

Endoplasmic reticulum

Organelle involved in protein and lipid synthesis.

Active transport

Movement against concentration gradient requiring energy.

Exocytosis

Process of exporting materials from the cell.

Phagocytosis

Ingestion of pathogens by immune cells.

Mitochondria

Organelles responsible for energy production.

Aerobic respiration

Energy production process using oxygen.

Lysosomes

Organelles containing enzymes for degradation.

Peroxisomes

Organelles containing oxidases for metabolic processes.

Cytoplasmic inclusions

Stored materials within the cytoplasm.

Secretory granules

Vesicles containing substances for secretion.

Hydrogen Peroxide

A reactive oxygen species formed in cells.

Catalase

Enzyme that decomposes hydrogen peroxide.

Lipofuscin Granules

Brown pigments indicating cellular aging.

Nucleoid

Central structure containing urate oxidase.

Melanin

Pigment responsible for skin color.

Lipid Droplets

Storage organelles without limiting membranes.

Cell Membrane Turnover

Constant renewal of cellular membranes.

Glycogen

Polysaccharide stored in liver cells.

Cisternae

Parallel arrays of membrane-bound structures.

Beta Particles

Irregular single granules of glycogen.

Alpha Particles

Glycogen arranged in rosettes.

Tonofilaments

Intermediate filaments providing structural support.

Microfilaments

Actin filaments involved in cell shape.

Microtubules

Cylindrical structures aiding in cell division.

Centrosome

Microtubule-organizing center with centrioles.

Aster

Star-like arrangement of microtubules.

Delta Tubulin Ring Complexes

Nucleus for microtubule polymerization.

Facultative Dividers

Cells that can undergo mitosis when needed.

Cell Cycle

Interval between mitotic divisions.

G1 Phase

Cell growth and differentiation phase.

S Phase

DNA synthesis phase before mitosis.

G2 Phase

Preparation phase for mitosis.

G0 Phase

State of terminally differentiated cells.

Chromosomes

46 paired structures containing genetic information.

Karyotyping

Examination of chromosomes in dividing cells.

Mitotic Apparatus

Structure facilitating chromosome separation during mitosis.

Apoptosis

Controlled cell death minimizing tissue disruption.

Apoptotic Body

Fragment containing nuclear material post-apoptosis.

Simple Squamous Epithelium

Flattened cells facilitating diffusion and absorption.

Simple Cuboidal Epithelium

Square-shaped cells found in ducts.

Hypertrophy

Increase in cell size without division.

Atrophy

Decrease in cell size or tissue.

Metaplasia

Transformation of one cell type to another.

Hyperplasia

Abnormal increase in cell number.

Metabolites

Substances produced by metabolic processes.

Basement Membrane

Thin layer separating epithelium from underlying tissue.

Epithelial Tissue

Tissue covering body surfaces and organs.

Simple Columnar Epithelium

Single layer of tall, column-like cells.

Polarity

Orientation of cell nuclei in epithelial cells.

Absorptive Surfaces

Areas specialized for nutrient absorption.

Ciliated Epithelium

Epithelium with hair-like structures for movement.

Pseudostratified Epithelium

Single layer appearing stratified due to nuclei positioning.

Stratified Epithelium

Multiple layers of cells for protection.

Transitional Epithelium

Specialized epithelium in the urinary tract.

Umbrella Cells

Surface cells in transitional epithelium, may have 2 nuclei.

Endocrine Glands

Glands releasing hormones directly into blood.

Intercellular Junctions

Structures connecting adjacent epithelial cells.

Junctional Complex

Includes tight junctions, zonula adherens, and desmosomes.

Surface Specializations

Features enhancing epithelial function, like cilia.

Renal Tubules

Structures in kidneys involved in urine formation.

Cuboidal Cells

Cube-shaped cells found in basal layers.

Polygonal Cells

Multi-sided cells in intermediate layers.

Flattened Cells

Thin cells in surface layers of epithelium.

Chief Cells

Cells in glands that produce secretions.

Supporting Cells

Cells that provide structural support in tissues.

Zonula Occludens

Tight junctions forming continuous circumferential bonds.

Glandular Epithelia

Tissue specialized for secretion and absorption.

Fascia Occludens

Discontinuous tight junctions in blood vessels.

Zonula Adherens

Connects cells, controlling growth and differentiation.

Connexons

Transmembrane channels made of connexin proteins.

Macula Adherens

Desmosomes providing strong cell adhesion.