Biology 9 Quarter 1: Respiratory System

Study Notes

Respiratory System

Responsible for breathing; oxygen intake and carbon dioxide expulsion are critical functions.
Nose: Filters, warms, humidifies air; primary entry point for inhalation.
Mouth: Alternative airway that allows for increased airflow during activities such as exercise.
Pharynx: Connects nasal and oral cavities to the larynx and esophagus, serving as a passageway for air and food.
Larynx: Contains vocal cords; directs air from the pharynx to the trachea, preventing food from entering the airway.
Trachea: Tube that transports air; lined with cilia to trap particles and transport inhaled air to bronchi.
Lungs: Spongy organs facilitating gas exchange between air and bloodstream.
Bronchi: Main branches from the trachea that carry air into each lung, dividing into smaller passages.
Bronchioles: Smaller air passages that lead to alveoli, branching from the bronchi.
Alveoli: Tiny air sacs where oxygen enters the blood and carbon dioxide is expelled; critical for gas exchange.
Diaphragm: Dome-shaped muscle that contracts and relaxes to change chest cavity pressure, enabling breathing.

Breathing Mechanism

Inhalation (Inspiration): Diaphragm and intercostal muscles contract, expanding chest cavity and reducing thoracic pressure, allowing air to flow into lungs.
Exhalation (Expiration): Diaphragm relaxes, chest cavity volume decreases, thoracic pressure increases, forcing air out of the lungs.

Circulatory System

Life support structure that nourishes cells with oxygen and nutrients; transports waste products away from the body.
Comprises the heart, blood, and blood vessels, distributing oxygen and nutrients while removing carbon dioxide and waste.

Components of the Circulatory System

Heart: Pumps blood throughout the body; has four chambers - two atria (upper chambers) and two ventricles (lower chambers).
- Atria: Receive blood from the body (Right Atrium) and lungs (Left Atrium).
- Ventricles: Pump blood to the lungs (Right Ventricle) and body (Left Ventricle).
- Four valves prevent backward blood flow, controlling circulation through heart and vessels.
Blood Vessels: Transport blood throughout the body.
- Arteries: Carry oxygenated blood away from the heart to tissues.
- Veins: Transport deoxygenated blood back to the heart.
- Capillaries: Smallest vessels, connecting arteries and veins; site for gas and nutrient exchange.
Blood: Delivers materials (oxygen and nutrients) throughout the body.

Blood Flow through the Heart

Blood from lungs enters the left atrium.
Contraction of the left atrium pushes blood to the left ventricle.
Left ventricle contraction sends blood to the body.
One-way valves ensure blood flows in the correct direction and prevents backflow.
Blood circulates through two pathways: pulmonary circulation and systemic circulation.

Description

Explore the essentials of the respiratory system in this quiz designed for Biology 9 students. Learn about the parts of the respiratory system and their functions. This quiz will help reinforce your understanding of how we breathe and the importance of the respiratory system.