Biology Review Notes: Levels of Biological Organization, Respiratory & Circulatory Systems

Vocabulary flashcards covering key terms from the notes on biology, respiratory, and circulatory systems.

Biology

The study of life and living organisms.

Aristotle

Considered the father of biology.

Cell

The smallest unit of life.

Tissue

A group of similar cells that work together to perform a function.

Organ

A structure formed by tissues that performs a specific function.

Organ System

A group of organs working together to sustain life.

Organism

Any living thing.

Population

A group of the same species living in the same area.

Community

Different species living together in a particular area.

Ecosystem

A community interacting with its physical environment (habitat).

Biome

A large region defined by its ecosystem type (e.g., tundra, rainforest).

Biosphere

The global sum of all ecosystems—the largest life zone on Earth.

Respiratory System

System responsible for gas exchange and respiration, enabling breathing and sound production.

Diffusion

The movement of molecules from an area of higher concentration to lower concentration; key mechanism of gas exchange.

Gas exchange

The uptake of oxygen and release of carbon dioxide in the lungs.

Nose

Filters, humidifies, and regulates the temperature of inhaled air, improving lung function.

Mouth

Alternative airway; air enters here if the nose is congested; air may be less filtered and humidified.

Frontal sinus

Sinus located in the forehead; part of the sinus group.

Ethmoid sinus

Sinus located behind the eye.

Maxillary sinus

Largest sinus, located in the cheeks.

Sphenoid sinus

Sinus near the eyes.

Pharynx

Throat; connects the mouth and nose to the trachea and is part of both the respiratory and digestive systems.

Epiglottis

Flap that separates the airway from the digestive tract to prevent food from entering the trachea.

Larynx

Contains the voice box.

Trachea

Windpipe; tube connecting the pharynx to the lungs.

Bronchi

Main airways that lead from the trachea into the lungs.

Bronchioles

Smaller branches of the bronchi.

Alveoli

Grape-like air sacs where gas exchange occurs; wrapped in capillaries.

Lung

Organ that facilitates gas exchange; has lobes and a cardiac notch on the left side.

Cardiac Notch

Indention in the left lung to accommodate the heart.

Diaphragm

Primary muscle of respiration; contracts to enable inhalation and relaxes for exhalation.

Inhalation

Breathing in; lungs expand as the diaphragm contracts.

Exhalation

Breathing out; lungs contract as the diaphragm relaxes.

Allergy

Immune reaction causing inflammation of the airways.

Asthma

Chronic inflammatory disease of the airways.

Lung cancer

Common cancer linked to smoking; affects the lung’s ability to deliver air.

Aging (lung capacity)

A decrease in lung capacity as people grow older.

Normal lung capacity

About 6 liters of air.

Respiratory system in animals

Gas exchange methods: through the skin (some amphibians and worms), via the tracheal system (insects), or through gills (fishes).

Tracheal system

Network of air tubes used by insects for respiration.

Gills

Respiratory organs in many aquatic animals for extracting oxygen from water.

Circulatory System

System to transport nutrients, gases, and waste; protect against infection; regulate temperature; maintain fluid balance.

Cardiovascular System

Heart and blood vessels; ‘cardio’ means heart, ‘vascular’ means vessels.

Blood

Circulating fluid that delivers oxygen and nutrients and removes wastes; sometimes called the golden liquid.

Blood vessels

Tubes that carry blood throughout the body.

Arteries

Carry oxygen-rich blood away from the heart.

Veins

Carry deoxygenated blood back to the heart.

Capillaries

Small vessels where exchanges occur between blood and tissues.

Aorta

Largest artery; distributes oxygen-rich blood from the heart to the body.

Vena Cava

Largest vein; returns deoxygenated blood to the heart; has superior and inferior portions.

Right Atrium

Chamber receiving deoxygenated blood from the body.

Right Ventricle

Chamber pumping blood to the lungs via the pulmonary artery.

Left Atrium

Chamber receiving oxygenated blood from the lungs.

Left Ventricle

Chamber pumping oxygenated blood to the body via the aorta.

Tricuspid valve

Valve between the right atrium and right ventricle.

Pulmonary valve

Valve from the right ventricle to the pulmonary arteries.

Mitral valve

Valve between the left atrium and left ventricle.

Aortic valve

Valve from the left ventricle to the aorta.

Stenosis

Thickening or stiffening of a valve leaflet, hindering opening.

Regurgitation

Backward flow of blood due to a valve not closing properly.

Platelets

Small blood cells that help with blood clotting.

Phagocytosis

Process by which white blood cells engulf and destroy pathogens.

White blood cells

Cells of the immune system that fight infections.

Red blood cells

Cells that carry oxygen; oxygenated blood is bright red.

Oxygenated blood

Blood rich in oxygen; bright red in color.

Deoxygenated blood

Blood with little oxygen; darker red.

Pericardium

Protective sac surrounding the heart.

Pericardial effusion

Excess fluid around the heart that can threaten its function.

Epicardium/Myocardium/Endocardium

Three layers of the heart wall: outer, muscular, and inner.