GEN-BIO-REVIEWER (1)

Cell Theory

Cell Theory

A scientific theory that states all organisms are made of one or more cells, the cell is the basic unit of structure and organization of all organisms, and all cells come from pre-existing cells.

Robert Hooke

An English scientist who used a compound microscope to observe cork and coined the term "cells" to describe the small compartments he observed.

Anton van Leeuwenhoek

A Dutch tradesman who developed a powerful microscope and was one of the first scientists to observe living cells, which he called animalcules.

Matthias Schleiden

A German botanist who studied plant cells and proposed that plant parts are made of cells.

Theodore Schwann

A German physiologist and histologist who determined that all animals are made of cells and published the first statement of the cell theory.

Rudolf Virchow

A scientist who stated that all cells come from preexisting cells, completing the cell theory in 1858.

Tissues

Groups of closely associated cells with similar structure and function that make up organs.

Epithelial Tissue

Tissue found in body coverings, linings, and glandular tissue, responsible for protection, absorption, filtration, and secretion.

Muscle Tissue

Specialized for contraction and responsible for body movement, classified into skeletal, cardiac, and smooth muscle types.

Striations

Banded appearance in muscle cells, characteristic of skeletal and cardiac muscle tissue.

Intercalated Disc

Structures present in cardiac muscle tissue that connect cardiocytes and help regulate muscle contractions.

Cellularity

Epithelial tissue characteristic of being composed almost entirely of cells with specialized contacts like tight junctions and adhesion junctions.

Polarity

Epithelial tissue characteristic of having one free surface (apical) and exhibiting modifications like microvilli and cilia.

Avascularity

Epithelial tissue characteristic of lacking blood vessels and receiving nutrients by diffusion from underlying connective tissue.

Regeneration

Epithelial tissue characteristic of having a high capacity to regenerate lost cells rapidly by cell division.

Cell arrangement

The organization of cells in tissues, categorized into two major types - simple (one layer) and stratified (more than one layer stacked on top of each other), with each type serving different functions based on the location in the body.

Simple squamous epithelium

A type of simple epithelial tissue that consists of a single layer of flat cells, primarily involved in absorption and diffusion processes.

Simple cuboidal epithelium

A type of simple epithelial tissue characterized by a single layer of cube-shaped cells, responsible for secretion and absorption functions.

Simple columnar epithelium

A type of simple epithelial tissue with a single layer of elongated cells, involved in absorption and secretion activities, and may or may not contain cilia.

Pseudostratified columnar epithelium

A type of simple epithelial tissue that appears stratified but is actually a single layer of cells, often containing cilia and participating in processes like movement.

Stratified squamous epithelium

A type of stratified epithelial tissue that protects against external attacks, with the outer layers containing keratin for strength and water resistance.

Transitional epithelium

A type of stratified epithelial tissue that can stretch and recoil without damage, changing appearance as it stretches, commonly found in regions of the urinary system.

Gland

One or more cells that produce and secrete fluid, typically water-based and containing proteins, with glandular cells obtaining necessary substances from the blood for transformation into the secretory product.

Exocrine glands

Glands that secrete their products onto epithelial surfaces through ducts, including sweat glands, salivary glands, and mammary glands.

Endocrine glands

Glands that release hormones into the interstitial fluid without ducts, playing a crucial role in the endocrine system.