D2.1 - Structures of the Respiratory System

Respiratory System Structures

• The respiratory system is responsible for supplying oxygen to body cells and removing carbon dioxide.
• Main structures include nasal passages, pharynx, larynx, epiglottis, trachea, bronchi, bronchioles, alveoli, diaphragm, rib muscles, and pleural membranes.

Respiration Definition

• Respiration encompasses all processes bringing oxygen to cells for glucose breakdown and carbon dioxide removal.
• Respiration involves gas exchange between an organism and its environment.
• Cellular respiration is the process where cells break down fuel molecules to produce energy and release carbon dioxide.

Cells and Oxygen

• Cells require oxygen to perform essential survival processes, notably producing ATP (energy).
• Carbon dioxide is a waste product of these processes and must be expelled.

Respiratory Tract Structures

• The respiratory tract includes the nasal passages, pharynx, larynx, epiglottis, trachea, bronchi, bronchioles, and alveoli.
• The pharynx serves as a pathway for both air and food.
• The epiglottis covers the trachea opening during swallowing, preventing food from entering the lungs.
• The larynx contains the vocal cords.
• The trachea, reinforced with cartilage rings, carries air to the bronchi.
• The bronchi branch into bronchioles, smaller airways leading to alveoli.
• Alveoli are tiny air sacs where gas exchange occurs.

Structures and Functions of Nasal Passages

• Nasal passages are lined with cells that filter, moisten, and warm incoming air.
• Turbinate bones increase the surface area for these processes.
• The heating of air is done by blood vessels.

Structures and Functions of Turbinates and Cilia

• Turbinate bones are thin, curved, bony plates inside the nasal cavity increasing surface area for air filtering.
• Cilia are tiny, hair-like structures that line the respiratory tract and move mucus and trapped particles away from the lungs.

Structures and Functions of Pharynx

• The pharynx, or throat, is a pathway for both air and food.
• Two openings branch from the pharynx: the esophagus (to the stomach) and the trachea (to the lungs).

Structures and Functions of Epiglottis

• The epiglottis is a flap of cartilage that closes the trachea opening during swallowing to prevent food from entering the lungs.
• This prevents unwanted substances from entering the lungs.

Structures and Functions of Larynx

• The larynx is the voice box, containing the vocal cords that vibrate to produce sound.
• The Adam's apple is cartilage protecting the larynx.
• The vocal cords vibrate due to airflow.

Differences Between Male and Female Larynges

• Males' larynges typically enlarge more at puberty, resulting in a larger Adam's apple and often a deeper voice.

Trachea and Bronchi

• The trachea, or windpipe, is supported by C-shaped rings of cartilage and lined with cilia.
• It transports air to the bronchi.
• Bronchi, similar to the trachea, carry air to the lungs.

Bronchioles

• Bronchioles are smaller airways inside the lungs, without cartilage support.

Alveoli

• Alveoli are tiny air sacs at the end of bronchioles where gas exchange occurs.
• They are the site of gas exchange, facilitating oxygen uptake and carbon dioxide release.

Lungs

• Lungs are primary organs of respiration, divided into lobes (3 lobes in right lung, 2 lobes in left lung–to accommodate the heart).

Pleural Membrane

• The pleural membrane is a thin, fluid-filled membrane that surrounds the lungs and reduces friction during breathing.
• It facilitates smooth lung expansion.

Diaphragm

• The diaphragm is a dome-shaped muscle below the lungs.
• It aids in breathing by contracting and relaxing during inhalation and exhalation.

Intercostal Muscles

• Intercostal muscles are located between the ribs.
• They help with rib movement, aiding the diaphragm in inhalation and exhalation.

Oxygen's Role in Survival

• Oxygen is crucial for cellular respiration, a process that provides energy for life functions.

Cilia Function

• Cilia in the respiratory tract sweep mucus and trapped particles upward toward the pharynx for removal.

Related Functions of Trachea, Esophagus, and Epiglottis

• These structures are related by their coordinated actions in preventing food from entering the lungs and ensuring smooth airflow.
• The epiglottis covers the trachea during swallowing, and the esophagus allows food passage.

Difference Between Breathing and Cellular Respiration

• Breathing is the physical process of taking in air (inhalation) and releasing air (exhalation).
• Cellular respiration is a metabolic process where cells utilize oxygen to create energy.

Test your knowledge on the structures and functions of the human respiratory system. This quiz covers the main components like the nasal passages, trachea, and alveoli, along with the processes involved in respiration. Prepare to explore how oxygen is utilized by cells and the importance of gas exchange.