Take in oxygen Get rid of carbon dioxide Helps with smelling Filters air that is inhaled Produces sounds Rids the body of some water and heat in exhaled air

The organs of the respiratory system include the nose, pharynx, larynx, trachea, bronchi, bronchioles, alveoli and lungs. Nose: The 2 external openings are called external nares. The internal portion of the nose has 2 openings that connect to the throat called internal nares The nose is divided into right and left internal parts by the septum.

Coarse hairs in the nose filter out large dust particles Nasal conchae- 3 shelves that extend out of the wall of the nasal cavity to increase surface area for warming, moistening and filtering. Mucous membranes line the nasal cavity and secrete mucus that moistens the air and traps dust particles. Above the conchae is the olfactory epithelium which detects smells.

Pharynx is also called the throat- A tube that starts at the internal nares and extends part way down the neck. A passageway for air and food and provides a resonating chamber for speech sounds. Larynx is the voice box. It is a short passageway that connects the pharynx with the trachea. Thyroid cartilage (Adam’s apple) forms the anterior wall of the larynx Epiglottis is elastic cartilage that is the top part of the larynx. It prevents food and drink from entering the larynx.

The mucous membrane of the larynx forms 2 pairs of folds: false vocal cords and true vocal cords. True vocal cords produce sound. They are elastic ligaments that are stretched between pieces of cartilage. They are also attached to muscles that pull the ligaments tightly when contracted. This moves the true vocal cords out into the air passageway. Air pushed against the cords causes them to vibrate and produce sound waves. Males have thicker vocal cords due to male sex hormones. These vibrate more slowly and produce a deeper pitch.

Windpipe- Air passageway anterior to the esophagus Extends from the larynx to the 5 th thoracic vertebra Wall is lined with a mucous membrane Cilia also line the wall and help move mucus up the trachea Supported by cartilage- 16 to 20 C-shaped rings that are stacked on top of another.

Heimlich maneuver may be used to expel an aspirated object. If not successful, a tracheostomy may be performed- incision in the trachea below the cartilage and a tube is inserted. Intubation is another method when a tube is inserted into the mouth or nose and passed down through the larynx and trachea.

Bronchi are branches of the trachea that each feed a lung. The right bronchus is more vertical, shorter and wider than the left. As a result, foreign objects are more likely to enter and lodge in the right bronchus than in the left. Bronchi contain C-rings of cartilage and are lined with cilia. Bronchi branch into smaller bronchioles, which do not contain cartilage rings but are lined with more smooth muscle for support.

Asthma is chronic airway inflammation due to hypersensitivity to a variety of stimuli. These triggers include allergens, emotional upset, exercise, breathing cold air and cigarette smoke. Triggers cause the walls of the bronchi and bronchioles to spasm, the mucous membranes to swell, increased mucus secretion or damage to the lining of an airway. Asthma symptoms include difficulty breathing, coughing, wheezing, chest tightness, fatigue and anxiety.

Lungs are covered directly with visceral pleura and the lung cavity is lined with parietal pleura. Pleurisy- inflammation of the pleural membranes which causes friction during breathing which is quite painful. The narrow top of each lung is the apex. The broad bottom is the base. The area on the medial side through which bronchi enter is called the hilus. The right lung has 3 lobes and the left lung has 2 lobes. The left lung has a concavity where the heart lies- called the cardiac notch.

The airways dead-end with thin air sacs called alveoli. Capillaries surround the alveoli and allow for gases to be exchanged.

Diffusion- movement of molecules from where there is more of them to where there is less of them. What do you think will happen to a drop of food coloring placed in a beaker of water?

 This occurs due to differences in air pressure between the thoracic (chest) cavity and the atmosphere.  Air always moves from where it is under greater pressure to where it is under less pressure.

 Draw 8 air molecules in each of the containers below: Which one has greater air pressure inside?

Inhalation (Inspiration) Diaphragm contracts and moves down Ribcage moves out Air pressure in the thoracic cavity goes down Air rushes in Exhalation (Expiration) Diaphragm relaxes and moves up Ribcage moves in Air pressure in the thoracic cavity goes up Air rushes out

Why do we need to breathe in oxygen? What produces carbon dioxide? Why do we need to get rid of carbon dioxide?

 CO is an odorless and colorless gas produced when there is incomplete burning of natural gas or any carbon containing fuel.  Why is it dangerous when inhaled?

As we age, the following changes occur to the respiratory system: Tissues become less elastic which results in a decrease of lung capacity. There is a decrease in oxygen levels in the blood. There is a decrease in the activity of alveolar macrophages There is diminished ciliary action of the respiratory tract Because of these, elderly people are more susceptible to pneumonia, bronchitis, and emphysema.

1. Apneustic center Septum Thyroid cartilage Olfactory epithelium Larynx