Structure & Function of the Respiratory System

Nostrils & Nasal Passages Entry & Exit for air (containing gases) Filter air to remove harmful substances (by cilia) Warming & moistening of air – protection for the lungs Turbinate Bones Intricate passageway of bone in the nasal cavity Small particles hit the walls are trapped by mucus (filter) More SA for more warming, moistening and cleaning of air Pharynx Chamber in the neck Allows a person to breathe through their nose & mouth This tube branches into both the esophagus & trachea Larynx Voice box or Adam’s Apple: composed of cartilage Allows vocalization Rises up to meet the epiglottis to prevent the entry of food while eating

5. Epiglottis Small flap at the top of the trachea Closes off the trachea to prevent inhaling food 6. Trachea Short cartilaginous tube in front of the esophagus Cartilage prevents the trachea from collapsing under the pressure of surrounding tissues Connects pharynx to the lung 7. Bronchi Two branches off the trachea Lead to the right and left lungs Contain cartilage 8. Bronchioles Smaller branches of the bronchi (up to 22 divisions) Do not contain cartilage Take air to the alveoli

9. Alveoli At the end of each terminal bronchiole Grape like cluster of microscopic air sacs Surrounded by a web of blood vessel (capillaries) Actual exchange of oxygen & carbon dioxide occurs here 10. Lung All bronchioles and alveoli No muscle, just elastic material 11. Diaphragm Separates the thoracic cavity and abdominal cavity Dome-shaped, muscular partition Helps air enter the lungs 12. Ribs & Intercostal Muscle Rib bones and the muscles in between them Provide protection for the internal organs Help the lungs with air

13. Pleural Lining Two membranes  one on the inside of the thoracic cavity and the other around each lung Keep the lungs separated Fluid filled in the space between the two linings. The fluid cushions and reduce friction, as well as allows the lungs to stick to the ribcage, this allows for greater expansion. 14. Cilia Fine hair lining the trachea, bronchi, bronchioles and nasal cavity At the top of columnar cells Wave like motion move fine particles trapped in the mucus up the trachea  coughed out as phlegm or swallowed. 15. Goblet Cells Special cells that make up the epithelial lining of the trachea, produce mucus which keeps the membranes moist and trap incoming particles such as dust Imbedded in between the columnar cells

Pons Medulla Turbinate Bones Pharynx Nasal Cavity Esophagus Epiglottis Trachea Larynx Cricoid Cartilage Primary Bronchi Secondary Bronchi Lung Upper Middle Lower Lobes Right Lung Thoracic Cavity Heart Diaphragm

Mouth Pharynx Epiglottis Larynx Esophagus Cartilage Ring Trachea Nasal Cavity Mouth Pharynx Epiglottis Larynx Esophagus Cartilage Ring Trachea Intercostal Muscles Left Lung Bronchus Heart Rib Bronchioles Visceral Pleura Parietal Pleura Diaphragm Right Lung

Hyoid Bone Larynx Cricoid Cartilage Trachea Primary Bronchi Secondary Epiglottis Hyoid Bone Larynx Cricoid Cartilage Trachea Primary Bronchi Secondary Bronchi Bronchioles

THE LUNGS The lungs are 2 cone-shaped organs molded into the form provided by the thoracic cavity. Well protected  surrounded by ribs, sternum, and spine. The base of each are in contact with the diaphragm and the tops reach just above the clavicle RIGHT LUNG: 3 lobes & takes up the entirety of the right thoracic cavity LEFT LUNG: 2 lobes & shares the left thoracic cavity with the heart THE PLEURA Parietal Pleura: outer membrane that lines the inner surface of the chest wall and covers the upper surface of the diaphragm Visceral Pleura: inner membrane that adheres to the surface of the lungs * Only a very thin film of fluid separate the pleural layers Pleurisy: Inflammation of the pleura that leads to difficult & painful breathing.

Bronchiole Alveolus Respiratory Bronchiole Air Sac Pulmonary Artery Pulmonary Vein Capillaries

Function of the Respiratory System

Larynx Pleura

PRIMARY FUNCTIONS Inhalation and Exhalation Are Pulmonary Ventilation—That’s Breathing External Respiration Exchanges Gases Between the Lungs and the Bloodstream Internal Respiration Exchanges Gases Between the Bloodstream and Body Tissues  Air Vibrating the Vocal Cords Creates Sound  Olfaction or Smelling, Is a Chemical Sensation 

1. Pulmonary Ventilation The respiratory system aids in breathing, also called pulmonary ventilation. In pulmonary ventilation, air is inhaled through the nasal and oral cavities (the nose and mouth). It moves through the pharynx, larynx, and trachea into the lungs. Then air is exhaled, flowing back through the same pathway. **Changes to the volume and air pressure in the lungs trigger pulmonary ventilation**

1. Pulmonary Ventilation During normal inhalation, the diaphragm and external intercostal muscles contract and the ribcage elevates. As the volume of the lungs increases, air pressure drops and air rushes in. During normal exhalation, the muscles relax. The lungs become smaller, the air pressure rises, and air is expelled.

1. Pulmonary Ventilation

2. External Respiration Inside the lungs, oxygen is exchanged for carbon dioxide waste through the process called external respiration. This respiratory process takes place through hundreds of millions of microscopic sacs called alveoli. Oxygen from inhaled air diffuses from the alveoli into pulmonary capillaries surrounding them. It binds to hemoglobin molecules in red blood cells, and is pumped through the bloodstream. Meanwhile, carbon dioxide from deoxygenated blood diffuses from the capillaries into the alveoli, and is expelled through exhalation.

2. External Respiration

3. Internal Respiration The bloodstream delivers oxygen to cells and removes waste carbon dioxide through internal respiration. Red blood cells carry oxygen absorbed from the lungs around the body, through the vasculature. When oxygenated blood reaches the narrow capillaries, the red blood cells release the oxygen. It diffuses through the capillary walls into body tissues. Meanwhile, carbon dioxide diffuses from the tissues into red blood cells and plasma. The deoxygenated blood carries the carbon dioxide back to the lungs for release.

3. Internal Respiration

**Lesser tension causes slower vibration and a lower pitch. 4. Vocal Sounds Phonation is the creation of sound by structures in the upper respiratory tract of the respiratory system.  During exhalation, air passes from the lungs through the larynx, or “voice box.” When we speak, muscles in the larynx move the vocal cords, or vocal folds, together. When the cords are pushed together, air passing between them makes them vibrate, creating sound. **Greater tension in the vocal cords creates more rapid vibrations and higher-pitched sounds. **Lesser tension causes slower vibration and a lower pitch.

4. Vocal Sounds False Vocal Folds (do not produce sound) help close airway during swallowing True Vocal Folds (produce sound) changing shape of the pharynx, and oral cavity changes sounds into words contracting and relaxing muscles changes pitch . Glottis Epiglottis  Closes like a Trash Can Lid Glottis  Closes like a set of Elevator Doors

4. Vocal Sounds

5. Sense of Smell The process of olfaction begins with olfactory fibers that line the nasal cavities inside the nose. As air enters the cavities, some chemicals in the air bind to and activate nervous system receptors on the cilia. This stimulus sends a signal to the brain: neurons take the signal from the nasal cavities and to the olfactory bulbs which processes the “scent”

5. Sense of Smell

THE RESPIRATORY TRACT

Upper Respiratory Tract nose, nasal cavity, paranasal sinuses, pharynx *Nasal cavity is divided in the nose by the nasal septum. Lower Respiratory Tract larynx, trachea, bronchial tree, lungs Anatomy Prt 1

The Trachea Trachea is commonly referred to as a persons windpipe Is a flexible cylinder of cricoid cartilage rings that give it stiffness and keep it from collapsing in on itself. Lies against the Esophagus The trachea leads to the Bronchial Tree  

Left Lung = 2 lobes & cardiac notch Right Lung = 3 lobes Left Lung  = 2 lobes & cardiac notch Serous fluid lubricates lungs during breathing 3D Model Anatomy Prt 2

Primary Bronchi Bronchioles Alveolar Ducts Alveolar Sacs                                                                         Alveoli *gas exchange occurs

Quick Quiz 1. What do you call the bones found within the nasal cavity? 2.  What specific bone divides the nasal cavity into two sides? 3.   The space at the back of the mouth is the________. 4.  The spaces within the bones of the skull are called the ______________________ 5. What structure is known as the windpipe? ______ 6.  What is the triangular slit that opens during breathing and talking? 7. In what structures does gas exchange occur? 8. During swallowing, this flap closes to prevent food from entering the airway: ______________________