Overview
This lecture covers the structure and functions of the respiratory and circulatory systems, focusing on how they transport nutrients, gases, and wastes throughout the body.
The Respiratory System
- The respiratory system (breathing system) takes in oxygen and expels carbon dioxide.
- Main parts: nose and mouth (air entry), nasal cavity (warms and cleans air), pharynx (throat), larynx (voice box), trachea (windpipe), lungs, bronchi (large tubes to lungs), bronchioles (hair-like tubes), and alveoli (site of gas exchange).
- Inhalation: oxygen enters, ribs move out, chest space increases, diaphragm contracts (moves down).
- Exhalation: carbon dioxide exits, ribs move in, chest space decreases, diaphragm relaxes (moves up).
The Circulatory System
- The circulatory system (cardiovascular system) delivers nutrients, oxygen, and removes wastes from cells.
- Main parts: heart (pumps blood), blood vessels (carry blood), and blood.
- Three types of blood vessels: arteries (away from heart), veins (towards heart), capillaries (site of gas and nutrient exchange).
- The heart is a hollow muscle about the size of your fist.
- Heart chambers: right and left atria (receive blood), right and left ventricles (pump blood); valves prevent backflow.
- Blood flow path: vena cava → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → lungs (oxygenation) → pulmonary vein → left atrium → bicuspid valve → left ventricle → aortic valve → aorta → body.
Interaction of Respiratory and Circulatory Systems
- Oxygen enters lungs, moves to left heart, and is pumped to body cells.
- Cells use oxygen to release energy, producing carbon dioxide as waste.
- Blood carries carbon dioxide back to the right heart, then to lungs for exhalation.
- Both systems work together to supply oxygen/nutrients and remove wastes.
Types of Circulation
- Pulmonary circulation: blood moves between heart and lungs.
- Coronary circulation: blood supplies heart tissues.
- Systemic circulation: blood moves from heart to rest of body (except lungs).
Key Terms & Definitions
- Respiratory System — organ system for breathing (oxygen in, carbon dioxide out).
- Circulatory System — system moving blood, nutrients, and wastes around the body.
- Diaphragm — muscle aiding in breathing.
- Atrium — heart chamber receiving blood.
- Ventricle — heart chamber pumping blood.
- Valve — structure preventing backward blood flow.
- Pulmonary Circulation — blood flow between heart and lungs.
- Systemic Circulation — blood flow between heart and body.
- Coronary Circulation — blood flow to heart tissue.
Action Items / Next Steps
- Review parts and functions of respiratory and circulatory systems.
- Draw and label diagrams of both systems for practice.