Chapter 4: Histology

Tissues

Histology

Study of Tissues

Biopsy

Removal of tissues for diagnostic purposes

Autopsy

Examination of organs of a dead body to determine cause of death

Tissues

Classification based on structure of cells, composition of extracellular matrix, and cell function

Epithelial Tissue

Covers body surfaces and forms glands

Nervous Tissue

Composed of neurons

Muscular Tissue

Includes smooth, skeletal, and cardiac types

Connective Tissue

Supports and connects other tissues

Gastrulation

Formation of primary germ layers (ectoderm, mesoderm, endoderm)

Ectoderm

Develops into epidermis, hair, nails, and nervous system

Mesoderm

Forms notochord, paraxial mesoderm, intermediate mesoderm, lateral plate mesoderm, and head mesenchyme

Endoderm

Develops into lining of digestive, respiratory, and urinary systems, liver, gallbladder, pancreas, thyroid, parathyroid, and thymus

Basement Membrane

Base barrier providing protection for epithelial tissue

Microvilli

Increase surface area for absorption/secretion

Cilia

Move materials across epithelial surfaces

Simple Epithelium

Single layer of cells allowing diffusion, filtration, secretion, and absorption

Stratified Epithelium

Multiple layers providing protection against abrasion

Pseudostratified Epithelium

Appears layered but is a single layer; involved in secretion

Simple Squamous Epithelium

Allows filtration and diffusion; found in lungs and blood vessels

Simple Cuboidal Epithelium

Involved in secretion and absorption; found in kidney tubules

Simple Columnar Epithelium

Absorption and secretion; found in digestive tract

Pseudostratified Columnar Epithelium

Modified simple epithelium; found in respiratory system

Stratified Squamous Epithelium

Protects against abrasion; keratinized and non-keratinized types

Transitional Epithelium

Stretches for storage; found in urinary system

Glands

Infoldings of epithelium; include endocrine and exocrine types

Loose Connective Tissue

Provides support and nourishment; contains collagen and elastic fibers

Dense Connective Tissue

Thick bundles of fibers; includes regular and irregular types

Cartilage

Supporting connective tissue; includes hyaline, fibrocartilage, and elastic types

Bone

Hard connective tissue composed of living cells and mineralized matrix

Blood

Fluid connective tissue with plasma matrix; consists of red and white blood cells

Hemopoietic Tissue

Produces new blood cells; includes red and yellow bone marrow

Muscle Tissue

Contracts with force; includes skeletal, cardiac, and smooth types

Nervous Tissue

Composed of neurons and neuroglia; involved in action potentials

Tissue Regeneration

Process of repairing or replacing damaged tissues

Inflammation Phase

First stage of tissue repair characterized by pain, swelling, redness, and heat

Proliferation Phase

Follows inflammation; involves tissue repair or regeneration

Fibrotic Scar Formation

Result of tissue repair when complete restoration does not occur