BIOL 162 -> Histology

Tissues

Groups of similar cells that work together to perform a particular function

Histology

The study of tissues

Pathology

The study of how tissues are altered due to disease

Epithelial tissue

Covers body surfaces and lines cavities, playing roles in protection, absorption, secretion, and sensation. Characterized by a high number of cells packed tightly together

Avascular

lacking blood vessels, often seen in epithelial tissue.

Epithelium

Another name for epithelial tissue

Glandular tissue

A type of epithelial tissue that specializes in the secretion of substances such as hormones, enzymes, and mucus.

squamous

flat cells

cuboidal

square-shaped cells

columnar

rectangular cells

simple

single-layer

stratified

multiple layers

Simple Squamous Epithelium

Structure: a single layer of flat cells

Function: thin surface allows rapid diffusion; smooth surface

Locations: alveoli of the lungs, inner lining of blood vessels, lining Bowman’s capsule of the kidneys

Stratified Squamous Epithelium

Structure: multiple layers of cells, flattened on the exterior

Function: protection of exposed surfaces; limiting fluid loss

Locations: skin, esophagus, tongue, oral cavity, vagina

Simple Cuboidal Epithelium

Structure: single layer of square-shaped cells

Function: absorption and secretion

Locations: tubules of the kidney, ducts of exocrine glands

Simple Columnar Epithelium

Structure: Single layer of rectangular cells

Function: protection of GI tract; absorption, and secretion

Locations: stomach, small and large intestines, uterus

Pseudostratified Columnar Epithelium

Structure: Single layer of cells with nuclei at varying depths

Function: protection and secretion of mucus

Locations: respiratory tract

Connective tissue

connects structures of the body together, supports and protects organs

Matrix

extracellular space of connective tissue is often called the matrix

Adipose tissue

Structure: thin cell membrane with large, clear-appearing fat droplet in the center

Function: energy storage; insulation; protection

Locations: subcutaneous layer (hypodermis); surrounding organs like the kidneys and eyes

Hyaline Cartilage

Structure: Hazy matrix with cells in open spaces (lacunae)

Function: rigid, yet flexible and lightweight support

Locations: trachea, larynx, ends of ribs (costal cartilages)

Bone (Osseous) Tissue

Structure: osteocytes organized in concentric rings of matrix encircling a central canal

Function: rigid support and protection

Locations: skeleton

Blood

Structure: fluid matrix with suspended red cells, white cells, and platelets

Function: transport of blood gases & nutrients; immunity

Locations: lumen of blood vessels

Muscle tissue

tissue that is specialized for movement

Nervous tissue

transmits and processes information in the form of electrical signals

Skeletal Muscle

Structure: Parallel rows of muscle cells with striated myofibrils perpendicular to the cells

Function: contraction

Locations: skeletal (voluntary) muscles

Nervous (Neural) Tissue

Structure: large neuronal cell bodies with attached axons and dendrites; numerous much smaller neuroglial cells

Function: Generating and transmitting electrical signals (action potentials)

Locations: brain, spinal cord, peripheral ganglia

Integumentary System

skin, largest organ of the body

Two Primary Layers of Skin

Epidermis and dermis

Accessory Structures

hair follicles, sebaceous glands, sweat glands