Respiratory System PDF

# Respiratory System ## Hello, my name is Melanie, and today I will discuss the respiratory system. ## Primary Function: The primary function of the respiratory system is **gas exchange**, allowing oxygen into the body and removing carbon dioxide. This process is essential for cellular respirati...

# Respiratory System ## Hello, my name is Melanie, and today I will discuss the respiratory system. ## Primary Function: The primary function of the respiratory system is **gas exchange**, allowing oxygen into the body and removing carbon dioxide. This process is essential for cellular respiration, ATP production, and maintaining blood pH balance through carbonic acid buffering. ## Key Components: The respiratory system consists of: 1. **Nose & Nasal Cavity:** Filters, warms, and moistens incoming air using cilia and mucus. The nasal conchae increase surface area, enhancing air filtration and humidification. 2. **Pharynx (Throat):** A shared passageway for air and food, divided into the nasopharynx, oropharynx, and laryngopharynx. Contains lymphatic tissue (tonsils) for immune defense. 3. **Larynx (Voice Box):** Contains the epiglottis, which prevents food aspiration, and the vocal cords, which produce sound through vibration. 4. **Trachea (Windpipe):** Lined with pseudostratified ciliated epithelium to trap debris and prevent infection. Supported by C-shaped cartilage rings to maintain an open airway. 5. **Bronchi & Bronchioles:** The primary bronchi split into secondary and tertiary bronchi, leading to smaller bronchioles that regulate airflow via smooth muscle control. 6. **Lungs:** Composed of lobes (three on the right, two on the left) and contain alveoli where gas exchange occurs. 7. **Diaphragm & Intercostal Muscles:** The diaphragm is the primary muscle for respiration, while intercostal muscles aid in thoracic expansion and contraction. ## Breathing Process: 1. **Inspiration (Inhalation):** The diaphragm contracts and moves downward, intercostal muscles lift the ribs, increasing lung volume and reducing intrapulmonary pressure, drawing air in. 2. **Expiration (Exhalation):** The diaphragm and intercostal muscles relax, reducing lung volume, increasing pressure, and pushing air out. 3. **Forced Breathing:** Involves additional muscles such as the sternocleidomastoid and abdominal muscles for deep or rapid breathing. ## Gas Exchange: - **External Respiration:** Oxygen diffuses from alveoli into pulmonary capillaries, while carbon dioxide diffuses into the alveoli for exhalation. - **Internal Respiration:** Oxygen moves from blood to tissues, while carbon dioxide enters the bloodstream for transport to the lungs - **Surfactant**, secreted by type II alveolar cells, reduces surface tension, preventing alveolar collapse and ensuring efficient gas exchange. ## Respiratory Regulation: - **Chemoreceptors** in the medulla oblongata and carotid bodies detect oxygen, carbon dioxide, and pH levels, adjusting breathing rate accordingly. - **Pulmonary stretch receptors** in the lungs prevent over-inflation by triggering the Hering-Breuer reflex. - The **autonomic nervous system** controls involuntary breathing, while the cerebral cortex allows voluntary control. ## Additional Functions: 1. **pH Regulation:** Prevents acidosis by expelling CO2, maintaining acid-base balance through the bicarbonate buffer system. 2. **Immune Defense:** Mucociliary clearance and alveolar macrophages help remove pathogens and debris. 3. **Speech Production:** The larynx and vocal cords generate sound, modulated by the tongue, lips, and resonance chambers. 4. **Olfaction (Smell):** The olfactory epithelium in the nasal cavity detects airborne molecules, contributing to the sense of smell. ## Effects of Aging & Development: - **Infants:** Have underdeveloped alveoli, higher respiratory rates, and weaker immunity, making them more prone to infections and respiratory distress syndrome (RDS). - **Elderly:** Experience decreased lung elasticity, weaker respiratory muscles, and reduced vital capacity, increasing susceptibility to conditions like pneumonia and chronic obstructive pulmonary disease (COPD). ## Conclusion: In summary, the respiratory system is vital for gas exchange, pH balance, immune defense, speech, and olfaction. It undergoes developmental and age-related changes that impact breathing efficiency. A thorough understanding of its anatomy and physiology is crucial in healthcare and medical practice. Thank you for your time!