Histology

What are the four primary tissue types and their basic functions?

Epithelial (protection, absorption, secretion), Connective (support, binding, transport, energy storage), Muscle (movement, stabilization, heat), Nervous (electrical/chemical signaling).

What are the key characteristics of epithelial tissue?

Cellularity, polarity (apical vs basal surfaces), attachment to basal lamina, avascularity, arranged in sheets/layers, high regeneration rate.

What does the apical surface do?

Faces the open space (lumen or outside) and performs absorption, secretion, and sensory functions.

What does the basal surface do?

Anchors cells to the basement membrane and connects to underlying connective tissue.

What do lateral surfaces do?

Connect adjacent cells with junctions like tight junctions and desmosomes.

How are epithelia classified?

By number of layers (simple = 1, stratified = 2+) and cell shape (squamous = flat, cuboidal = cube, columnar = tall).

What is the function and location of simple squamous epithelium?

Absorption, diffusion, secretion; found in alveoli, endothelium, mesothelium.

What is the function and location of stratified squamous epithelium?

Protection from mechanical/chemical stress; epidermis (keratinized), esophagus, oral cavity.

What is the function and location of simple cuboidal epithelium?

Secretion and absorption; kidney tubules, small glands.

What is the function and location of simple columnar epithelium?

Absorption and secretion; digestive tract lining.

What is the function and location of pseudostratified ciliated columnar epithelium?

Secretes mucus and moves particles; trachea, upper respiratory tract.

What is the function and location of transitional epithelium?

Stretches and returns to shape; urinary bladder, ureters.

What are the modes of glandular secretion?

Eccrine (merocrine) = exocytosis; Apocrine = part of cell pinches off; Holocrine = whole cell bursts.

Give an example of an eccrine gland.

Salivary glands or sweat glands.

Give an example of an apocrine gland.

Mammary glands.

Give an example of a holocrine gland.

Sebaceous (oil) glands.

What are the three basic components of connective tissue?

Cells, protein fibers (collagen, elastic, reticular), ground substance.

What are the fiber types in connective tissue?

Collagen (strong), elastic (stretchy), reticular (fine support network).

What are the subtypes of loose connective tissue?

Areolar (cushions, inflammation; under epithelia), Adipose (stores fat; hypodermis, around kidneys/eyes), Reticular (supports soft organs; spleen, lymph nodes).

What are the subtypes of dense connective tissue?

Dense regular (parallel collagen; tendons, ligaments), Dense irregular (random collagen; dermis, joint capsules), Elastic (elastic fibers; large arteries, vertebral ligaments).

What are the types of supporting connective tissue?

Cartilage (hyaline = flexible; nose, costal cartilage. elastic = flexible; ear. fibrocartilage = strong; discs, pubic symphysis) and Bone (rigid, mineralized; skeleton).

What are the types of fluid connective tissue?

Blood and lymph (transport gases, nutrients, wastes, immune cells).

What are the types of muscle tissue?

Skeletal (striated, voluntary; attached to bones), Cardiac (striated, involuntary; heart), Smooth (non-striated, involuntary; walls of hollow organs).

What are the main cell types in nervous tissue?

Neurons (send electrical signals) and Neuroglia (support, protect, and nourish neurons).