Overview
This lecture explains how the respiratory and circulatory systems transport nutrients, gases, and wastes in the human body, including the main parts, processes, and how the two systems work together.
Respiratory System Overview
- The respiratory system, or human breathing system, is responsible for taking in oxygen and removing carbon dioxide.
- Oxygen enters through the nose and mouth, passing by the nasal cavity which warms, moistens, and cleans the air.
- Air travels through the pharynx (throat), larynx (voice box), and trachea (windpipe).
- The trachea branches into bronchi, which further split into bronchioles and finally reach the alveoli, where gas exchange occurs.
- Inhalation brings oxygen in; exhalation removes carbon dioxide.
- During inhalation, ribs move out and diaphragm contracts, increasing chest space.
- During exhalation, ribs move in and diaphragm relaxes, decreasing chest space.
Circulatory System Overview
- The circulatory (cardiovascular) system delivers nutrients, oxygen, and removes wastes using blood.
- Main parts: heart (pumps blood), blood vessels (carry blood), and blood (transports materials).
- Blood vessels: arteries carry blood away from the heart; veins carry blood to the heart; capillaries are small vessels for material exchange.
- The heart has four chambers: two atria (receive blood) and two ventricles (pump blood).
- Valves prevent blood from flowing backward.
- Oxygen-poor blood enters the right atrium via superior/inferior vena cava, moves to right ventricle, and is pumped to the lungs to get oxygen.
- Oxygen-rich blood returns to the left atrium, goes to the left ventricle, and is pumped out through the aorta to the body.
Interaction of Respiratory and Circulatory Systems
- Oxygen from inhaled air enters lungs, moves into the bloodstream, and is delivered by the heart to body cells.
- Cells use oxygen to process nutrients and release energy; carbon dioxide is produced as waste.
- Carbon dioxide is carried by blood back to the heart and expelled from the lungs during exhalation.
Types of Circulation
- Pulmonary circulation: blood moves between heart and lungs.
- Coronary circulation: blood moves through the heart's tissues.
- Systemic circulation: blood moves between the heart and the rest of the body (excluding lungs).
Key Terms & Definitions
- Respiratory system — organ system for breathing and gas exchange.
- Diaphragm — muscle that helps in breathing.
- Circulatory system — system that transports blood, nutrients, and wastes.
- Atrium (atria) — upper heart chambers that receive blood.
- Ventricle — lower heart chambers that pump blood.
- Valves — structures ensuring one-way blood flow.
- Arteries — vessels carrying blood away from the heart.
- Veins — vessels carrying blood to the heart.
- Capillaries — smallest blood vessels where exchange occurs.
- Pulmonary circulation — heart-lung-heart blood route.
- Coronary circulation — heart tissue blood flow.
- Systemic circulation — heart-to-body blood flow.
Action Items / Next Steps
- Review the parts and functions of both respiratory and circulatory systems.
- Study the flow of blood through the heart and the types of circulation.
- Be ready to explain how the two systems work together to deliver oxygen and remove carbon dioxide.