Objectives
List and identify the structures of the respiratory system and describe the function of each.
Objectives
Describe the process of respiration. Describe the mechanism by which the
respiratory system helps to maintain homeostasis.
Objectives
Describe common diseases, disorders, and conditions of the respiratory system including signs and symptoms, diagnosis, and available treatment options.
Demonstrate knowledge of medical terminology related to the respiratory system verbally and in the written form.
Respiration
More than breathing in and out. Process by which oxygen is obtained
from the environment, delivered to the cells, and waste products such as carbon dioxide are removed from the body.
Terms Respiration- Inhaling and exhaling facilitate
the process of taking in oxygen and getting rid of waste CO2. Internal respiration- exchange of O2 and CO2
between the blood and body cells.External respiration- exchange of O2 and CO2
between the lungs and the circulatory system.Cellular respiration- the use of O2 by the cells of
the body & production of CO2. Ventilation- movement of air in & out of the
lungs (breathing)
Functions of the Respiratory System
Pulmonary ventilationInhalationExhalation
Diffusion of gasesInto and out of the blood
Transport to and from the cells (cellular respiration)OxygenCarbon dioxide
Upper Respiratory Tract Nose-
Covered by skin and supported by bone and cartilage. Air enters through the external nares and coarse hairs line the internal part of the nares to act as filters.
Nasal CavitiesSeparated by nasal septum. Lining is made of
ciliated epithelium (nasal mucosa). Highly vascularized, which warms inhaled air.
Nasal conchaeCurved scroll-like bones Superior, middle, and inferior turbinates
Sinuses
Maxillary, frontal, sphenoid, and ethmoid○ Named for associated bones
Move mucus into nasal cavities Make skull lighter in weight
Upper Respiratory Tract Pharynx
Tubular structure Posterior to oral & nasal cavitiesConducts air and foodThree sections:
○ Nasopharynx○ Oropharynx○ Laryngopharynx
Composed of muscle, lined with mucous membrane
Lower Respiratory Tract Larynx
“voice box” contains vocal cords (2 short fibrous bands that stretch across the interior of the larynx)
The space between the vocal cords is called the glottis
Connects pharynx to tracheaServes as part of the air passagewayLined with mucous membraneComposed of cartilaginous rings:
○ ThyroidAdam’s apple = thyroid cartilage
○ CricoidSellick’s maneuver
Lower Respiratory Tract
LarynxDuring swallowing, larynx elevates &
epiglottis closes over opening to prevent food from entering
Vocal cords-located on either side of glottis○ Breathing- cords close over glottis. ○ Speaking- cords are stretched & exhaled air
vibrates cords causing speech.
Lower Respiratory Tract Trachea
“wind pipe”Extends from layrnx to carinaComposed of 20 C-shaped rings of hyaline cartilage.
○ Flexible, keep trachea continuously open.
Primary bronchi = right and left bronchusMediastinal spaceLined w/ resp. epitheliumEnter lung & continue to divide
○ AKA “bronchial tree”
Respiratory System
Bronchi
Trachea divides (bifurcates) into two primary bronchi
Secondary bronchi Tertiary bronchi Bronchioles
Lower Respiratory Tract
Bronchial TreeTrachea2 primary bronchiSecondary branchesSegemental/tertiary bronchiBronchiolesTerminal bronchiolesAlveolar ductsalveoli
Lower Respiratory Tract
BronchiolesSimple epitheliumLack cilia, goblet cells, & cartilageContain smooth muscle bundles-regulate
diameter of lumenExchange of gasesDivide into alveolar ducts w/ alveoli
surrounding each duct = alveolar ducts
Pleural Cavity Pleura = covers the outer surface of
lungs and the lining of the inner surface of the rib cage
Parietal pleura lines the walls of the thoracic cavity
Visceral pleura covers the lungs Contains:
LungsPleural membranes
○ divided into parietal pleura and visceral pleura○ Pleural space- space between parietal &
visceral pleura, contains serous fluid,
Pleural Cavity Lungs
Spongy, elastic tissueRight-3 lobesLeft-2 lobesConical shapeLayers-
○ External visceral pleura○ Sub serous layer of areolar tissue○ Parenchyma
Blood supply○ Arterial: bronchial arteries, branch from thoracic
aorta
Respiratory System
Alveoli
Located at the end of the terminal bronchioles
Tiny sacs surrounded by vascular capillaries
Gas (O2 and CO2) occurs in the alveoli
Pleural Cavity Alveoli
Primary functioning unitResponsible for gas exchange
Alveolar wallsSquamous epithelial cells-type 1 pneumocytesEach alveolus is surrounded by pulmonary
capillaries○ Consist of a single layer of endothelial cells○ A thin, filmy layer of fluid that covers the alveoli to
reduce surface tension forces and aid in the expansion of alveoli is called Pulmonary Surfactant
Pleural Cavity Alveolar-capillary barrier
3 layers ○ Between air in alveoli & blood in pulmonary
capillaries Pneumocytes
Type 2○ round in shape○ Contain
large nucleusLamellar bodies-contain phospholipids that release
surfactantOne alveolar sac is made up of numerous alveoli pg. 293
A&P
Pleural Cavity Diaphragm
Separates thoracic & abdominal cavityDivided into:
○ Crura○ Central tendon
Subdivided into 3 divisions-leafletsMajor openings
○ Aortic○ Esophageal○ Inferior vena cava
The diaphragm muscle flattens out when it contracts during inspiration
The diaphragm muscle returns to upward position during expiration
Pleural Cavity
DiaphragmBlood supply
○ Branches of internal thoracic arteriesThoracic aortaInferior phrenic arteries
Lymph nodes○ Located on superior surface○ Receive drainage from liver &
esophagogastric junction
Pleural Cavity
Intercostal musclesLocated between ribsDivided:
○ External intercostal muscles covered by intercostal fascia
Intercostal nerves innervate muscles○ Primary structures responsible for movement
during respiration.
Physiology of Respiration Inhalation
Diaphragm contractIntercostal muscles
relax
ExhalationDiaphragm relaxesIntercostal muscles
contract
Pulmonary and Systemic Circuits
Pulmonary circuitFrom the heart to
the lungs and back to the heart
Systemic circuitFrom the heart to
the tissues and back to the heart
External Respiration
O2 diffuses from alveoli into blood CO2 diffuses from blood to alveoli Blood high in O2 returns to heart,
pumped out by left ventricle through the aorta to the body
Exchange of gasses between the blood and the lungs by diffusion
Internal Respiration
O2 diffuses from blood to body cells CO2 diffuses from body cells to blood Venous blood is low in O2 returns to
right ventricle to lungs for reoxygenation.
Regulation of Respiratory System Nervous system
Medulla○ Responsible for inspiration & expiration
Pons○ Regulates normal rhythm of breathing
Centers- apneustic center- Pneumotaxic center
Regulation of Respiratory System Nervous System
Chemoreceptors○ Located in medulla, aortic bodies & carotid
bodies○ Detect changes in pH & blood gas levels
Phrenic nerve stimulates the diaphragm
Respiratory Monitors Pulmonary volumes
Tidal volumeMinute ventilationInspiratory reserve volumeExpiratory reserve volume – amount of air that
can be forcibly exhaled after expiring the total volume
Vital capacity – largest amount of air we can breathe out in one expiration
Residual volumeTotal lung capacityForced expiratory volume
Conditions Pulmonary edema-abnormal accumulation of fluid in
extravascular spaces or alveoli
Pneumothorax-abnormal accumulation of air between the parietal & visceral pleura
Pneumonia- acute infection of lungs
Chronic Obstructive Pulmonary Disease (COPD)-chronic airway obstruction
Emphysema-abnormal, irreversible enlargement of the alveoli due to destruction of alveolar walls
Pleurisy-Inflammation of the pleura that causes pain when the membranes rub together
Why is a tracheotomy done?- Gain access to airway before blockage- Create an open airway for breathing
Pulmonary Lobectomy Excision of one or
more lobes Performed to
excise benign lesions, malignant and metastatic malignant lesions