Definition: A tissue is a collection of cells similar in structure and function, coming together to perform a common function.
Study: The science studying tissues is called histology.
Video Focus: This video provides a brief overview of four primary tissue types; detailed discussions on each will follow in separate videos.
Epithelial Tissue
Primary Function: Forms coverings or linings, e.g., skin, linings of digestive and urinary systems.
Glandular Epithelium:
Forms glands, part of the endocrine system.
Endocrine glands produce hormones that regulate body functions.
Works alongside the nervous system to control body activities.
Characteristics:
Highly cellular with densely packed cells and little matrix.
Functions include absorption and secretion.
Contains tight junctions essential for forming barriers.
Connective Tissue
Primary Function: Support and protection.
Characteristics:
Contains lots of matrix and fewer cells compared to other tissue types.
Highly varied in form and function.
Examples:
Bones are primarily composed of connective tissue.
Blood is also considered connective tissue.
Widely distributed, making related diseases challenging.
Muscular Tissue
Primary Function: Movement.
Types: Three types of muscle tissue:
Skeletal Muscle: Enables movement of body parts.
Cardiac Muscle: Facilitates movement of blood through the heart.
Smooth Muscle: Moves contents through organs, e.g., food through the digestive system.
Characteristics:
Unique in its ability to contract and exert force.
Highly cellular with little matrix, similar to epithelial tissue.
Capable of electrical events that trigger contraction.
Can stretch and return to original length.
Nervous Tissue
Primary Function: Control and regulation.
Components: Brain and spinal cord form the central nervous system.
Characteristics:
Highly delicate and requires abundant oxygen.
Protected by bony structures like the cranial cavity and vertebral canal.
Highly cellular with little matrix.
Summary
Tissue Types: Four primary types - epithelial, connective, muscular, and nervous.
Cellularity: Epithelial, muscular, and nervous tissues are highly cellular with little matrix; connective tissue is the exception with more matrix and less cell density.
Future videos will delve into subtypes, locations, and specific functions of each tissue type.