Human Tissue Types and Cellular Components: Functions

Human Tissue Types: Location and Function

Epithelial Tissue: This tissue is found on the body's exterior surfaces, lining internal cavities (such as blood vessels), and in glands. Its cells are directly linked, without any intermolecular substance between them. The primary function is to coat and protect the body's exterior and internal cavities.

Connective Tissue: Located around organs, tendons, ligaments, in the dermis of the skin, and bone marrow. It consists of several cell types and connects other organs, muscles, and bones. It also fuels the dermal tissue and generates red blood cells.

Adipose Tissue: Found under the skin and around certain organs (like the kidney or heart). It is composed of round cells that store fat. Its functions include energy storage, thermal insulation, and shock protection.

Cartilaginous Tissue: Present in the ear, nose, tracheal rings, joints, and intervertebral discs. It provides consistency in these areas due to its tough, elastic nature and facilitates the movement of bone joints.

Bone Tissue: Located in bones, its function is to support the body, anchor muscles to facilitate movement, house bone marrow, and protect certain organs.

Muscle Tissue: Found in striated skeletal muscles (voluntary muscles like those in the legs), smooth muscles, and striated cardiac muscles (in the heart). It consists of highly elongated cells called muscle fibers. Its function is to contract and relax, enabling muscle movement.

Nervous Tissue: Located in the nervous system. It is composed of neurons and other cells. Its primary function is to transmit electrical impulses to muscles and glands.

Cellular Components and Their Functions

• Plasma Membrane: Limits the cell's content, selectively allowing the passage of substances.
• Nucleus: Surrounded by a porous membrane, it is the cell's control center, containing DNA. During cell division, DNA coils into rod-shaped structures called chromosomes.
• Mitochondria: The cell's powerhouses, where cellular respiration occurs. This process breaks down organic matter with oxygen to release energy.
• Golgi Apparatus: Produces and packages substances within vesicles. These substances can be discharged outside or remain inside the cell.
• Ribosomes: Responsible for protein synthesis.
• Rough Endoplasmic Reticulum: Transports and stores proteins synthesized in the ribosomes.
• Smooth Endoplasmic Reticulum: Responsible for the production of certain lipids.

Health and Common Pathogens

Health is the complete state of physical, mental, and social well-being and not merely the absence of disease. The main causative agents of infectious diseases are pathogens:

• Bacteria: Microscopic unicellular organisms that lack a nucleus, with their genetic material immersed in the cytoplasm. Bacteria can be cocci (spherical), bacilli (rod-shaped), vibrios (comma-shaped), or spirilla (spiral-shaped).
• Virus: Diminutive entities that bridge living and inert matter. They can crystallize and remain dormant for extended periods.
• Protozoa: Unicellular microorganisms that cause diseases like Malaria, often using an animal vector to transmit between people.
• Fungi: Simple organisms that often live in decaying organic matter in the soil.