Tissues

by Whitney Gandy

What is a Tissue?

A tissue is a group or mass of similar cells working together to perform common functions.

What are the Four Major Types of Tissues?

  • Epithelial
  • Connective
  • Muscle
  • Nervous

What are the Functions of Tissues?

Epithelial: protection, secretion, absorption, excretion, sensory perception

Connective: support, protection, framework, produces blood cells, fights infections, helps repair

Muscle: movement, posture maintenance, joint stabilization, heat generation

Nervous: sensing stimuli, transmitting signals to and from parts of an organism

Classification

Epithelial: simple squamous, simple cuboidal, simple columnar, stratified squamous, pseudostratified columnar, transitional epithelium

Connective: areolar tissue, adipose tissue (fat), fibrous tissue, cartilage, bone tissue, blood tissue

Muscle: skeletal, smooth, cardiac

Nervous: neurons, neuroglia

Specializations of Epithelial

  • lateral cell surfaces
  • maintain close cell-to-cell contact and form covering sheets
  • epithelium structurally and functionally polarized to increase efficiency of absorption and transport

Example

  • Epithelial: air sacs of lungs, kidney tubules, digestive tract, uterus, mouth, outer layers of skin, lining air passages, lining urinary bladder
  • Connective: tendons, ligaments, blood, external ear, larynx, ends of bones and joints
  • Muscle: wall of the heart, stomach, in hollow organs
  • Nervous: brain, spinal cord, nerves

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