Respiratory System Overview

Respiratory System Overview

• The respiratory system's function is to exchange gases, primarily oxygen and carbon dioxide, between the body and the environment.
• It involves a series of tubes that filter, warm, and moisten incoming air.
• Gas exchange happens in microscopic air sacs called alveoli within the lungs.

Respiration Types

• External respiration: Gas exchange between blood capillaries and the air sacs (alveoli) of the lungs.
• Internal respiration: Gas exchange between blood capillaries and body cells.
• Cellular respiration: The breakdown of organic molecules (usually glucose) in cells to release energy.

Respiratory System Organs and Functions

• Nose and Mouth: These structures provide an entry point for air, filtering, warming, and moistening it.
• Nasal Cavity: Warms, filters, and humidifies incoming air and contains fine hairs.
• Pharynx (Throat): A common passageway for air and food.
• Larynx (Voice Box): Cartilaginous structure preventing food from entering the trachea. Contains the vocal cords.
• Trachea (Windpipe): C-shaped cartilage maintains its structure and allows the esophagus to expand. Lined with cilia and mucus to trap particles.
• Bronchi: The trachea divides into two primary bronchi, each leading to a lung.
• Bronchioles: Smaller branches of the bronchi leading to the alveoli.
• Alveoli: Microscopic air sacs where gas exchange occurs.
• Lungs: Cone-shaped organs filled with alveoli, enclosed by the diaphragm and rib cage.
• Diaphragm: A large muscle separating the chest cavity from the abdominal cavity. Moves during breathing, contracting for inhalation and relaxing for exhalation.
• Ribs and Intercostal Muscles: Protect the respiratory organs and aid in the process of ventilation by moving the ribs to change the size of the chest cavity..

Activity 1 - Atmospheric Gases

• The most prevalent gases in the atmosphere are nitrogen, oxygen, and noble gases. Carbon dioxide is present in much smaller quantities.

Cigarette Smoking and Respiratory Health

• Smoking leads to tar buildup in the airways, harming the lungs and impeding gas exchange.
• This increases risks for bronchitis and lung cancer.

Breathing Mechanics

• The movement of air into and out of the lungs is called ventilation (breathing).
• Breathing involves inspiration (inhalation) and expiration (exhalation).
• Inspiration: Diaphragm contracts, intercostal muscles contract, increasing chest cavity size, and lowering air pressure in alveoli.
• Expiration: Diaphragm relaxes, intercostal muscles relax, decreasing chest cavity size, raising air pressure in alveoli.

Control Mechanisms

• Breathing is often controlled involuntarily by the brain.
• Chemical signals in the blood (e.g., carbon dioxide levels) and receptors in the lungs provide feedback to the brain for adjusting breathing rate.

Gas Transport and Diffusion:

• Oxygen is primarily carried in the blood by hemoglobin.
• Carbon dioxide is transported in the blood in several forms.
• Gas exchange in the alveoli relies on diffusion across the thin alveolar-capillary membrane, driven by differences in partial pressure.
• The respiratory system depends on the properties of the gases and how the membrane is structured, factors like membrane thickness, surface area and pressure differences play a critical role in gas diffusion efficiency.