Lecture E2, 6/4 & 6/5 notes

Cytology

The study of cells.

Innervation

The nerve that supplies (innervates) a muscle.

Polarity

Having two opposite poles; in epithelial cells, refers to distinct apical and basal surfaces.

A-/An-

A prefix meaning without or lack of, as in 'avascular' meaning lacking blood vessels.

BV’s (Vaso-)

A prefix referring to blood vessels (arteries, veins, capillaries).

Meso-

A prefix meaning middle.

Endo-

A prefix meaning inside.

Uni- / Multi-

A prefix meaning one / many.

AA’s

Acronym for amino acids; the building blocks of proteins.

–blast / –cyte

Suffixes where 'blasts' are immature, active cells (e.g., fibroblasts), and 'cytes' are mature, less active cells (e.g., fibrocytes).

Epithelial Tissue

Covers exposed surfaces, lines internal passageways, and forms glands; functions include physical protection, control of permeability, sensation, and specialized secretions.

Connective Tissue

Fills internal spaces, provides structural support, transports materials, stores energy, and defends against microorganisms.

Muscle Tissue

Specialized for contraction, includes skeletal, cardiac, and smooth muscle.

Nervous Tissue

Conducts electrical impulses; composed of neurons and neuroglia.

Simple Epithelia

Single cell layer; specialized for absorption, secretion, diffusion.

Stratified Epithelia

Multiple layers; specialized for protection against mechanical or chemical stresses.

Microvilli

Short, finger-like projections that increase surface area for absorption.

Cilia

Long, hair-like structures that move substances across the epithelium.

Basal Surface

The surface of epithelial cells attached to the basement membrane.

Apical Surface

The surface of epithelial cells facing the lumen or external environment.

Tight Junctions

Intercellular connections that prevent passage of water and solutes between cells.

Gap Junctions

Intercellular connections allowing rapid communication between cells via connexons.

Desmosomes

Intercellular connections that link adjacent cells, allowing bending/twisting.

Avascularity

The condition of having no blood vessels; nutrients are obtained via diffusion.

Regeneration in Epithelial Cells

Stem cells near the basement membrane that continually divide to replace lost cells.

Squamous Epithelium

Thin, flat epithelial cells.

Cuboidal Epithelium

Cube-shaped epithelial cells.

Columnar Epithelium

Tall, rectangular epithelial cells.

Simple Squamous Epithelium

Single layer of flat cells found in alveoli of lungs and lining of blood vessels.

Stratified Squamous Epithelium

Multiple layers of flat cells found in epidermis and lining of mouth and esophagus.

Simple Cuboidal Epithelium

Single layer of cube-shaped cells found in gland ducts and kidney tubules.

Transitional Epithelium

Multi-layered epithelium that can stretch; found in urinary bladder.

Exocrine Glands

Glands that have ducts and discharge secretions onto epithelial surfaces.

Endocrine Glands

Glands that release hormones directly into the bloodstream without ducts.

Merocrine Secretion

Secretions released by exocytosis, e.g., sweat glands.

Apocrine Secretion

Secretions released by shedding cytoplasm, e.g., mammary glands.

Holocrine Secretion

Entire cell bursts to release contents, e.g., sebaceous glands.

Dense Connective Tissue

Connective tissue with more fibers and less ground substance.

Loose Connective Tissue

Connective tissue with more ground substance and fewer fibers.

Fibroblasts

Most abundant cells in connective tissue that secrete proteins and hyaluronan.

Adipocytes

Fat cells that store lipid droplets.

Chondrocytes

Cells located in lacunae within cartilage tissue.

Osteocytes

Mature bone cells located in lacunae, arranged around central canals.

Plasma (Blood)

The fluid portion of blood that contains proteins, electrolytes, and hormones.

Erythrocytes (RBCs)

Red blood cells that transport oxygen and carbon dioxide.

Leukocytes (WBCs)

White blood cells that defend against infection and disease.

Platelets (Thrombocytes)

Cell fragments involved in blood clotting.

Lymphatic System

Monitors the immune system and returns interstitial fluid to the circulatory system.

Cartilage

A firm gel-like matrix with chondrocytes, avascular and covered by perichondrium.

Hyaline Cartilage

A type of cartilage providing support and reducing friction.

Elastic Cartilage

Cartilage that tolerates distortion without damage and returns to original shape.

Fibrocartilage

Cartilage that resists compression and limits movement, found in intervertebral discs.

Connective Tissue Proper

Connective tissues that connect and protect such as loose and dense types.

Fluid Connective Tissues

Connective tissues that transport, such as blood and lymph.

Supporting Connective Tissues

Connective tissues that provide structural strength, such as cartilage and bone.

Mucous Membranes

Line passageways with external connections; must be moist for absorption and secretion.

Serous Membranes

Line cavities not open to the outside; secrete serous fluid to reduce friction.

Cutaneous Membrane

The skin, providing a protective barrier; thick and waterproof.

Synovial Membranes

Line synovial joint cavities; produce synovial fluid for lubrication.

Inflammation

A response to injury characterized by redness, warmth, swelling, pain, and loss of function.

Regeneration

The process by which tissues repair themselves after injury; varies by tissue type.

Aging Effects on Tissue

A decline in regeneration speed and effectiveness, leading to thinner epithelia and brittle bones.