Biology Levels of Organization

Chemical Level: Involves atoms and molecules, the basic components of all matter participating in chemical reactions.
Cellular Level: Represents the fundamental structural and functional units of an organism.
Tissue Level: Consists of groups of specialized cells and their surrounding substances, performing unique functions.
Organ Level: Comprised of two or more different tissues working together for specific functions.
System Level: An assembly of related organs with a shared function.
Organismal Level: An integrated collection of systems, embodying any living individual.

Integumentary System: Includes skin, hair, nails, and glands; vital for body protection and temperature regulation.
Skeletal System: Formed by bones and joints; provides structural support, protection, and movement assistance.
Muscular System: Involves skeletal muscles; responsible for body movement and heat generation.
Nervous System: Comprises brain, spinal cord, and nerves; regulates body activities through electrical impulses.
Cardiovascular System: Features blood, heart, and blood vessels; essential for nutrient and oxygen transportation and waste removal.
Lymphatic System: Consists of lymph fluid, vessels, and nodes; plays a key role in immune response and fluid balance.
Respiratory System: Contains lungs and pathways; facilitates gas exchange and voice production.
Digestive System: Encompasses gastrointestinal and accessory organs; responsible for food breakdown and nutrient absorption.
Urinary System: Includes kidneys and the urinary tract; regulates body fluid homeostasis.
Endocrine System: Made up of glands like pituitary and adrenal; controls body functions through hormone release.
Reproductive System: Comprises gonads and reproductive organs; involved in gamete production and transport.

Metabolism: Encompasses all chemical processes, including catabolism (breaking down substances) and anabolism (building up substances).
Homeostasis: The state of equilibrium in the body's internal environment, maintained by regulatory systems.
Feedback System: Involves monitoring processes through sensors, control centers, and effectors to maintain homeostasis.
- Negative Feedback: A mechanism that reverses changes in a controlled condition.
- Positive Feedback: Enhances or reinforces changes in a controlled condition.

Body Fluids: Equally dilute solutions harboring dissolved chemicals, categorized as:
- Intracellular Fluid (ICF): Fluid contained within cells.
- Extracellular Fluid (ECF): Fluid outside cells, including interstitial fluid and blood plasma.

Anatomical Position: Standardized observational stance with an upright body, forward facing, and limbs beside the body.
Prone Position: Body oriented face down.
Supine Position: Body oriented face up.
Directional Terms:
- Superior: Above or towards the head.
- Inferior: Below or towards the feet.
- Anterior: Toward the front of the body.
- Posterior: Toward the back of the body.
- Lateral: Farther from the body's midline.
- Distal: Further from the point of attachment.

Sagittal Plane: Divides the body into left and right sections.
Frontal Plane: Divides the body into anterior and posterior sections.
Transverse Plane: Divides the body into superior and inferior sections.
Cranial Cavity: Contains and protects the brain.
Vertebral Canal: Encloses the spinal cord.
Thoracic Cavity: Shielded by ribs and diaphragm, housing lungs and heart.
Abdominopelvic Cavity: Extends from the diaphragm to the groin, containing abdominal and pelvic organs.
Serous Membrane: Thin membranes lining and covering cavities and organs.
- Pleura: Serous membrane around the lungs.
- Pericardium: Serous membrane around the heart.
- Peritoneum: Serous membrane lining the abdominal cavity.
Abdominopelvic Regions: Designate specific locations of abdominal and pelvic organs.