Histology and Tissues Lecture Notes

Flashcards of key vocabulary from lecture notes on tissues and histology.

Tissues

Collections of specialized cells and cell products that perform specific functions.

Histology

The study of tissues.

Epithelial tissue

Lines surfaces of organs and cavities both external and internal.

Connective tissue

Proper, loose, dense, blood, lymph, bone.

Muscle tissue

Smooth, cardiac, and skeletal muscle.

Nervous tissue

Neurons and neuroglia.

Epithelium

Layers of cells covering internal or external surfaces.

Glands

Structures that produce fluid secretions.

Simple epithelial tissue

One layer of cells.

Stratified epithelial tissue

Two or more layers of cells.

Squamous

Flat shaped cells.

Cuboidal

Cube shaped cells.

Columnar

Column shaped cells.

Cell Junctions

Form bonds with other cells or extracellular materials.

Gap Junctions

Allow direct communication between cells; usually small molecules pass by.

Tight Junctions

Create a seal between cells.

Desmosomes

Provide mechanical strength, allowing epithelial cells to resist stretching and tearing.

Hemidesmosomes

Anchor epithelial cells to the basement membrane.

Squamous Epithelia

Thin and flat cells.

Cuboidal Epithelia

Square shaped cells.

Columnar Epithelia

Tall, slender rectangle cells.

Simple Epithelium

Single layer of cells.

Stratified Epithelium

Several layers of cells.

Endocrine Glands

Release hormones that enter the bloodstream.

Exocrine Glands

Discharge secretions through ducts onto epithelial surfaces, outside bloodstream.

Merocrine

Secretion happens via exocytosis.

Apocrine

Part of the cell is pinched off during secretion.

Holocrine

The cell bursts to release its contents.

Serous Glands

Involved in digestion, lubrication, and enzymatic processes; watery secretions.

Mucous Glands

Trap allergens, pathogens, protection and lubrication secreting mucins.

Mixed Exocrine Glands

Glands that contain both serous and mucous cells.

Connective Tissue

Specialized cells, extracellular protein fibers, and ground substance.

Specialized Cells (Connective Tissue)

Fibroblasts, adipocytes, chondrocytes, osteocytes, macrophages, and mast cells.

Extracellular Protein Fibers

Collagen, elastic, and reticular fibers.

Ground Substance

Gel-like fluid that is part of the extracellular matrix.

Matrix

Extracellular components of connective tissue (fibers and ground substance).

Functions of Connective Tissue

Establishing a structural framework, transporting fluids, protecting organs, supporting other tissues, storing energy, and defending the body.

Connective Tissue Proper

Connect and protect; areolar, adipose, reticular(loose), tendons, ligaments (dense).

Fluid Connective Tissues

Transport ex: blood and lymph.

Supporting Connective Tissues

Structural strength ex: cartilage and bone.

Fibroblasts

Most abundant; can become collagen and ground substances.

Fibrocytes

Maintain connective tissue matrix.

Adipocytes

Store energy.

Mesenchymal Cells

Stem cells of connective tissue.

Melanocytes

Produce melanin (pigment).

Macrophages

Immunity (white blood cells).

Mast Cells

Activate inflammation.

Lymphocytes and Microphages

Immunity.

Collagen Fibers

Find it in tendons, ligaments, and dermis (layer of skin).

Reticular Fibers

Found in liver, spleen, lymph nodes, and bone marrow.

Elastic Fibers

Found in skin, lungs, blood vessels, and elastic ligaments.

Loose Connective Tissue

Packing materials; fills spaces between organs, cushions, and supports epithelia.

Mesenchyme

Embryonic connective tissue; found only in embryos.

Mucous Connective Tissue

Loose embryonic connective tissue; found in the umbilical cord (Wharton's jelly).

Areolar Tissue

Cushion/support; around skin, blood vessels, nerves, lungs, and between muscles.

Adipose Tissue

Made of adipocytes (fat cells); long-term energy.

Reticular Tissue

Framework; liver, spleen, lymph nodes, and bone marrow.

Dense Regular Connective Tissue

Tendons and ligaments.

Dense Irregular Connective Tissue

Skin and periosteum (outer layer of bones).

Elastic Connective Tissue

Arteries and ligaments (elastic) lungs.

Blood

Whole blood made of plasma and formed elements.

Erythrocytes

Red blood cells (transport Oxygen/Carbon Dioxide).

Leukocytes

White blood cells (fight infections).

Platelets

Clotting (thrombocytes).

Lymph

Carries waste/dead pathogens; part of the lymphatic system.

Cartilage

Provides shock absorption and protection.

Chondroitin Sulfates

Resist compression.

Lacunae

Storage sites for chondrocytes (cartilage) and osteocytes (mature bone cells).

Skeletal Muscle

Striated (stripes), tubular or cylindrical shape, voluntary movement (somatic nervous system).

Cardiac Muscle

Striated, branched shape, involuntary movement.

Smooth Muscle

Not striated, spindle shaped, and involuntary movement.

Hyaline Cartilage

Found at the ends of long bones, nose, trachea, and larynx.

Elastic Cartilage

Found in external ear (pinna), epiglottis (flap), and eustachian tube (ear).

Fibrocartilage

Found in intervertebral discs (spine), pubic symphysis (pelvis), and meniscus (knee).

Serous Membrane

Line internal cavities and also cover organs.

Muscle Tissue

Muscle tissues specialized for contraction.

Cardiac Muscle Tissue

Cells form branching networks connected at intercalated discs.

Nervous Tissue

Specialized for conducting electrical impulses.

Neurons

Basic functional unit of nervous tissue.

Neuroglia

Supporting cells.