Cells and Tissues: An Overview

Viewing Cells and Tissues

• Tissues in the human body perform specific tasks and are categorized into four main types: epithelial, connective, muscular, and nervous.

• Microscopy techniques are used for the collection of valid and reliable data in scientific investigations.

• All living organisms are made up of cells that work together for structure and function.

• Cells make up tissues, tissues make up organs, and organs make up body systems.

Tissue Types

• Tissues are composed of multiple similar cells that work together to perform a specific task.

• Four main tissue types are epithelial, connective, muscular, and nervous.

Epithelial Tissue

• Epithelial tissue is made up of tightly packed epithelial cells.

• Its function is to cover the outside of the body and line the inside of organs.

• It protects underlying structures and carries out absorption and secretion.

• Simple squamous, stratified squamous, simple cuboidal, stratified cuboidal, simple columnar, and stratified columnar are different types of epithelial tissue, each with its specific structure and function.

Connective Tissue

• Connective tissue consists of widely spaced cells surrounded by a matrix.

• Its function is to connect and support various tissue types and organs while providing structure.

• Types include loose connective tissue (under the skin), adipose tissue (fat), blood, fibrous connective tissue (forming ligaments), cartilage, and bone.

Muscular Tissue

• Muscular tissue is made up of long, thin, closely associated muscle cells.

• The cells communicate with each other to coordinate movement.

• Types include skeletal muscle, cardiac muscle, and smooth muscle.

Nervous Tissue

• Nervous tissue is made up of star-shaped nerve cells called neurons.

• Nervous tissue sends nerve impulses to muscles, organs, and glands to regulate body functions.

• The brain and spinal cord are examples of nervous tissue.

Viewing Cells and Tissues with Microscopes

• Microscopes use a series of lenses to magnify objects and make them easier to view. Cells and tissues are too small to see with the naked eye.

• Microscopy is essential in studies of tissues and cells.

Microscope Parts

• Ocular lens (eyepiece)
• Objective lens
• Revolving nosepiece
• Body tube
• Stage clips
• Diaphragm
• Light source
• Stage
• Coarse adjustment knob
• Fine adjustment knob
• Arm
• Base

Magnification

• Ocular lens magnifies the image.
• Objective lens magnifies the image.
• Total magnification is the product of ocular and objective magnifications.

Drawing Techniques

• Use a pencil for diagrams.
• Neat and ruled lines should be used and lines should not overlap.
• Labels should be placed on the right side of diagram.
• No arrows on the diagram.
• Each diagram should occupy at least half a page.
• Magnification should be at the bottom of the diagram.
• Descriptive title under the drawing.

Explore the organization of cells into tissues, organs, and systems. Learn about the four main tissue types: epithelial, connective, muscular, and nervous. Discover the function of Epithelial tissue. Includes microscopy techniques to view the cells.