Respiratory System

The main function of the respiratory system is to supply oxygen to, & eliminate carbon dioxide from the body In order to accomplish this task, the respiratory system must work in conjunction with the cardiovascular system

Functions of the Respiratory System A. Uptake of oxygen into the blood and the elimination of carbon dioxide out of the blood (Pulmonary Ventilation, External Respiration) B. Vocalization (Larynx) C. Olfaction (Smell)

Regions of the Respiratory System A. Nasal Cavities B. Pharynx – Throat C. Larynx – Voicebox D. Trachea – Windpipe E. Lungs

Anatomy Overview The respiratory tract includes: Nose (nasal cavity) Pharynx (nasopharynx, oropharynx, laryngopharynx) Larynx Trachea Bronchi (primary, secondary (lobar), tertiary (segmental) Bronchioles Terminal bronchioles Respiratory bronchioles Alveolar ducts Alveoli Nasal cavity Pharynx Larynx Trachea Bronchi Bronchioles Respiratory bronchioles Right Lung Left Lung Alveolar duct Alveoli

Histology Respiratory Epithelium = Pseudostratified Ciliated Columnar (PSCC)

III. The Nasal Cavities A. Nasal Cartilages B. Anterior Nares (Nostrils) Rhinitis – clinical term for cold Rhino means nose C. Olfactory Receptors D. Cribriform Plate of the Ethmoid Bone E. Nasolacrimal Aperture

Cribriform Plate

Ethmoid Bone

Nasolacrimal Aperture – tears come out of your nose

F. Nasal Septum G. Nasal Conchae (“Shelves”) H. Paranasal Air Sinuses – when you inhale air it goes into the paranasal air sinuses lined with ciliated epithelium * Frontal Sinus to the Sphenoid Sinus * If the sinuses become infected it is called sinusitis I. Choanae (Posterior Nares)

Sinuses are lined with ciliated epithelium that warms and humidifies the air

Choanae (Posterior Nares)

Pharyngeal Tonsil – if it is enlarged it is called an adenoid

The Pharynx A. Nasopharynx

Pharynx Air passes from nasal cavity, across internal nares into nasopharynx, past oropharynx & through laryngopharynx to larynx Nasopharynx lined with PSCC epithelium, but oro & laryngopharynx lined with stratified squamous epithelium because they are also part of digestive system

A. Nasopharynx 1. Eustachian Canal (Auditory Tubes) Earache (Otitis Media) 2. Pharyngeal Tonsil (Adenoids)

Eustachian (auditory) tube – connects nasopharynx & middle ear cavity Pharyngeal tonsil – lymphatic tissue embedded in wall of nasopharynx Palatine tonsils - lymphatic tissue embedded in wall of oropharynx Uvula – posterior tissue from soft palate; protects nasopharynx when swallowing

Eustachian Canal (Auditory Tubes)

Nasopharynx and Phryngeal Tonsil

Oropharynx and Laryngopharynx shared by the respiratory and digestive system but it is also in the laryngopharynx where the respiratory and digestive system separate

Larynx (Voicebox) – large, outer part is made up of cartilage A. projects outward as the “Adam’s apple” B. lined by non-keratinizing stratified squamous epithelium Laryngeal Aperture Ventricle – chamber where the vocal cords are

Larynx Air passageway made of 9 pieces of cartilage – (1) Thyroid cartilage, (1) Epiglottis, (1) Cricoid cartilage, (2) Arytenoid, (2) Corniculate, (2) Cuneiform A.K.A your “voicebox” because it contains the vocal cords

Larynx Thyroid cartilage – protects anterior & lateral walls of airway Epiglottis – leaf-shaped cartilage that protects opening (“glottis”) of airway when swallowing Cricoid cartilage – complete ring of cartilage; protects posterior wall of airway; attaches to trachea

Larynx Arytenoid, corniculate & cuneiform cartilages – attach to upper (vestibular) vocal folds & lower (true) vocal cords

Vocal Cords

Laryngeal Cartilages 3 large single cartilages a. epiglottis b. thyroid cartilage c. cricoid cartilage The epiglottis and thyroid cartilage are part of the larynx

Laryngeal Cartilages 3 pairs of small elastic cartilages A. arytenoids B. corniculates C. cuneiforms

Muscles of the Larynx 1. Extrinsic Muscles - circular constrictor muscles

Guys have large larynx than women thus they have deeper voices

Intrinsic Muscles - open and close the glottis by changing the tension on the vocal cords - innervated by the Laryngeal Nerve

Laryngospasm – spasmodic contractions of the laryngeal muscles Laryngospasm – spasmodic contractions of the laryngeal muscles. Use Heinlich Maneuver; form a bear-hug around the victim, and then press fist against the victim’s abdomen just below his xiphoid process = this will cause reflex exhalation Abdominal Thrust or Heimlich Maneuver

Laryngitis – hoarse throat

Carcinoma of the Larynx Associated with heavy smoking and heavy drinking After a laryngectomy, train patient to use: a. esophageal speech b. electric voicebox c. artificial voicebox

Trachea Lined with respiratory epithelium “C”-shaped pieces of hyaline cartilage protecting airway while allowing for swallowing Trachealis muscle (smooth muscle) runs across posterior wall of trachea connecting ends of tracheal cartilage

Trachea or windpipe have cartilage to prevent it from collapsing

Trachea Low power High power Medium power

Bronchi Trachea splits into a left & right primary bronchus which enters into the hilus of each lung Within the lung, the primary bronchi branch into secondary (lobar) bronchi (3 in right lung/2 in left lung) Secondary bronchi then branch into 10 tertiary (segmental) bronchi Tertiary bronchi then continue to branch into smaller & smaller bronchi & then into very narrow bronchioles Carina This branching patterns creates the “bronchial tree”

Changes In Airway As you go further down into the bronchial tree of each lung, changes in the airway occur: increased number of airways (1 primary; 2 or 3 secondary; 10 tertiary bronchi; 6000 terminal bronchioles; millions of alveolar ducts) decreased diameter of each airway decreased amount of cartilage in the airways (no cartilage at all by terminal bronchioles) increased amount of smooth muscle (relative to diameter) lining epithelium changes from PSCC  simple squamous epithelium (in alveoli)

Lungs Located within the thoracic cavity, surrounded by the double-layered pleural membrane – parietal pleura – lines cavity wall visceral pleura – covers the lungs

Lungs- Anatomical Features Apex – extends 1” above clavicle Base – rests on diaphragm Hilum – at medial surface; where primary bronchus, pulmonary artery & veins enter/exit lung Superior lobe Inferior lobe Oblique fissure Superior lobe Middle lobe Inferior lobe Right lung Horizontal fissure Oblique fissure Left lung Cardiac notch

Lung – medial surface getaprofessor.wordpress.com Groove for aorta Hilum Cardiac notch of Lt. lung

Airways within Lungs Each lung has a primary bronchus entering at the hilus Each lobe of a lung has a secondary (a.k.a. lobar) bronchus Lobes are functionally divided into bronchopulmonary segments & each segment has a tertiary (segmental) bronchus Segments are functionally divided into many lobules & each lobule receives a terminal bronchiole

Alveoli There are about 150 million alveoli in each lung Alveoli are expanded chambers of epithelial tissue that are the exchange surfaces of the lungs There are about 150 million alveoli in each lung Multiple alveoli usually share a common alveolar duct, creating “alveolar sacs”

Alveoli There are three types of cells found within alveoli: Alveolar Squamous epithelial (aka “type I”) cells – primary cells making up the wall of the alveoli Septal (aka “type II”) cells – secrete “surfactant” to reduce surface tension which prevents alveoli from sticking together & allows for easier gas exchange Alveolar macrophages (aka “dust cells”) – phagocytic cells that remove dust, debris & pathogens