The Respiratory System Part I Functional Anatomy

5 Amazing Fun Facts about Respiratory System The left lung is smaller than the right lung. (Why?) We take around 22,000 breaths a day. We inhale over 2,000 gallons of air every single day The nose traps particles in the air. (What does this?) If flattened completely, one lung would reach almost the size of a tennis court.   The lungs are not responsible for inhaling and exhaling. (What is responsible?

Respiratory Stems The organs of the respiratory system include the nose, pharynx, trachea, bronchi and their smaller branches, and the lungs, which contain the alveoli Consists of an upper respiratory tract (nose to larynx) and a lower respiratory tract (trachea onwards).

Conducting Zone Respiratory passages that carry air to the site of gas exchange Filters, humidifies and warms air includes the nose, nasal cavity, pharynx, larynx, trachea, & progressively smaller airways (bronchi to bronchioles)

Respiratory Zone Site of gas exchange Composed of Respiratory bronchioles Alveolar ducts Alveolar sacs

The Nose It is the only externally visible part of the respiratory system Breathing  air enters the nose by passing through the nostrils The interior of the nose consists of the nasal cavity, divided in middle by nasal septum

The Nose The olfactory receptors for sense of smell are located in the mucosa in the slit like superior part of the nasal cavity Rest of the mucosa lining of nasal cavity is called respiratory mucosa, rests on network of thin-walled veins which warms the air as it flows past

Mucosa lining function Moistens the air and traps incoming bacteria and other foreign debris The ciliated cells of the nasal mucosa (Cilia) create a gentle current that moves contaminated mucus posteriorly towards the throat, where it is swallowed & digested by stomach juices

Conchae The lateral walls of the nasal cavity are uneven because of 3 mucosa covered projections/lobes called conchae Increases the surface area of the mucosa exposed to air It also increases the air turbulence in the nasal cavity, prevent particles from reaching the lungs

Palate The nasal cavity is separated from the oral cavity by the palate Anteriorly, where the palate is supported by bone, is the hard palate The unsupported posterior part is the soft palate

Paranasal sinuses Located in the frontal, sphenoid, ethmoid and maxillary bones They produce mucus, which drains into the nasal cavities

Pharynx It is a muscular passageway ~13 cm long Commonly called the throat, the pharynx serves as a common passageway for food and air

Pharynx Air enters the superior portion, the nasopharynx, from the nasal cavity anteriorly and then descends through the oropharynx and laryngopharynx to enter the larynx below

Tonsils lymph tissue called tonsils are also found in the pharynx: The pharyngeal tonsils (adenoids) are located high in the nasopharynx The palatine tonsils are in the oropharynx at the end of the soft palate The lingual tonsils are at the base of the tongue

Larynx The larynx, or voice box, routes air and food into the proper channels and plays a role in speech Located inferior to the pharynx, it is formed by 8 rigid cartilages & a spoon shaped flap of cartilage, the epiglottis

Epiglottis The epiglottis protects the superior opening of the larynx When we aren’t swallowing, the epiglottis does not restrict the passage of air into the lower respiratory passaged When we swallow the epiglottis falls over, forming a lid over the opening of the larynx

Vocal Cords Part of the mucous membrane of the larynx forms a pair of folds, called the vocal folds (cords) which vibrate with expelled air

Trachea Air entering the trachea (windpipe) from the larynx travels down its length to approximately mid-chest The trachea is lined with ciliated mucosa: they propel mucus away from the lungs to the throat where it can be swallowed or spat out

Primary Bronchi The right and left primary bronchi are formed by the division of the trachea The right primary bronchus is wider, shorter, and straighter than the left is the more common site for an inhaled foreign object to become lodged

Lungs The lungs are fairly large organs The narrow superior portion of each lung, the apex, is located around clavicle The broad lung area resting on the diaphragm is the base Each lung is divided into lobes, the left lung has two lobes and the right lung has three

Lungs The surface of each lung is covered with a visceral membrane called the pulmonary pleura, and the wall of the thoracic cavity are lined by the parietal pleura The parietal pleura produces a slippery secretion, plural fluid, which allows the lungs to glide easily over the thorax wall during breathing

Bronchioles After the primary bronchi enter the lungs, they subdivide into smaller branches, finally ending in the smallest of the conducting passageways, the bronchioles

Alveoli It is the only site of gas exchange There are millions of the clustered alveoli (look like bunches of grapes) and they make the bulk of the lungs

Respiratory Membrane The walls of the alveoli are composed largely of a single, thin layer of squamous epithelial cells The external surfaces of the alveoli are covered with a web of pulmonary capillaries The gas exchanges occur by simple diffusion through the respiratory membrane