RESPIRATORY SYSTEM

Standard: HS-EHS-5   5.1 Analyze the basic structures and functions of the respiratory system.

RESPIRATORY SYSTEM Consists of lungs and air passages Responsible for taking in oxygen and removing carbon dioxide Body has only 4-6 minute supply of O2 Respiratory system must work continuously or death will occur

RESPIRATORY SYSTEM PARTS Nose Pharynx Larynx Trachea Bronchi Alveoli Lungs

NOSE Nostrils (nares) Nasal septum Openings through which air enters Partition or wall of cartilage Divides nose into two hollow spaces called nasal cavities

NASAL CAVITIES Lined with mucous membrane Have a rich blood supply As air enters cavities, it is warmed, filtered, and moistened Mucus, produced by the mucous membranes, also helps trap pathogens (germs) and dirt

NASAL CAVITIES (CON’T) Cilia Tiny hair like structures in nasal cavity Filter inhaled air Traps dust & pathogens as they enter nose so the particles can be pushed toward the esophagus and swallowed Olfactory receptors are located in the nose

SINUSES Cavities in skull around nasal area Connected to nasal cavity by short ducts Provide resonance for voice

PHARYNX (THROAT) Lies directly behind nasal cavities As air leaves nose it enters the pharynx Three sections Nasopharynx Upper portion behind nasal cavities Pharyngeal tonsils, eustachian tube openings Oropharynx Middle section Behind oral cavity Receives air from nasopharyx and food and air from mouth

PHARYNX (CON’T) Laryngopharynx Bottom section of pharynx Branches into trachea, which carries air to and from the lungs and esophagus, tube that carries food to stomach

LARYNX Voice box Between pharynx & trachea Has “Adam’s apple” (framework of cartilage) Contains two folds Vocal cords As air leaves lungs, vocal cords vibrate to produce sound Tongue and lips act on sound to produce speech

LARYNX (CON’T) Epiglottis Leaf like structure that closes the opening into the larynx during swallowing Prevents food & liquids from entering the respiratory tract

TRACHEA “Windpipe” Extends from larynx to center of chest Carries air b/t pharynx and bronchi

BRONCHI Two divisions of trachea near center of the chest Right bronchi shorter, wider, and extends more vertically Continue to divide into smaller and smaller bronchi Smaller branches = bronchioles End in “air sacs,” or alveoli

ALVEOLI Resemble a bunch of grapes Approx. 500 million in adult lung Contain a rich network of capillaries Capillaries allow oxygen and carbon dioxide to be exchanged between blood and lungs Inner surface covered with surfactant Fatty substance that keeps alveoli from collapsing

Alveoli

LUNGS Organs that contain divisions of bronchi and alveoli Right lung has 3 lobes superior, middle, inferior (upper, middle, lower) Left lung has 2 lobes superior & inferior (upper & lower) Smaller because the heart lies more to the left

LUNGS (CON’T) Pleura Membrane or sac enclosing each lung Pleural space Visceral pleura is attached to surface of lung Parietal pleura attached to chest wall Pleural space Located b/t the two layers Filled with thin layer of pleural fluid that lubricates membranes and prevents friction as lungs expand during breathing

VENTILATION , A.K.A. “BREATHING” Inspiration & expiration (see vocabulary terms) Diaphragm and intercostal muscles (between ribs) contract to expand thoracic cavity during inspiration Diaphragm and intercostal muscles relax to collapse the thoracic cavity during expiration.

VENTILATION (CON’T) Respiration controlled by medulla oblongata Decreased oxygen or increased carbon dioxide increased respirations

Write Q&A to the following questions. What is Epistaxis? List all of the different causes for epistaxis. Which populations are most at risk? How is it treated? How do you avoid it? What is the prognosis?