Module 16: The Respiratory System Flashcards
functions of respiratory system
continuous supply of oxygen for metabolic activities
Removal of CO2
Regulation of pH of blood
Processes of respiratory system
pulmonary ventilation
external respiration
transport of respiratory gases
internal respiration
Pulmonary ventilation
aka breathing in and out
External respiration
exchange of gases between blood and lungs
Transport of respiratory gases
gases are transported in RBC and blood plasma
Internal respiration
exchange of gases between blood and tissue cells
Structures of respiratory system (2 zones)
conducting zone (macroscopic) respiratory zone (microscopic)
Conducting zone consists of
passageways for the conduction of air nose pharynx (throat) Larynx (voice box) Trachea (windpipe) Bronchi Terminal bronchioles
Functions of conducting zone - nose
Provides airway for respiration moistens and warms air cleans and filters unwanted particles aids in speech provides a sight for the olfactory receptors
Parts of the nose:
External nares: Nostrils, anterior portion is vestibule
Nasal cavities: separated by nasal septum; 3 bony projections called conchae; sticky mucus traps foreign particles
Internal nares: opening between nose and throat
Paranasal sinuses: maxillary, frontal, ethmoidal and sphenoidal sinuses
Pharynx
aka throat
consists of nasopharynx (air), oropharynx and laryngopharynx(food and air)
Larynx
aka voice box
contains vocal cords
connects pharynx to trachea
epiglottis covers opening of larynx
Trachea
aka windpipe
provides passageway for air to move in and out of lungs
Cleans warms and moistens incoming air
Bronchi
Trachea branches into left bronchus and right bronchus which lead to each lung
Terminal bronchioles
provide the passageway into the respiratory zone
Respiratory zone (microscopic)
respiratory bronchioles and alveolar ducts
Respiratory bronchioles
formed from branchings of the terminal bronchioles
Alveolar ducts
respiratory bronchioles lead into ducts
Ducts lead into clusters of alveoli
Alveoli (air sacs)
provide surface area for exchange of gases
found in clusters called alveolar sacs
3 types of cells in alveoli
Type I alveolar (simple squamous epithelium) provide site for gas exchange
Type II alveolar (septal cells) produce surfactant (compound that prevents alveoli from collapsing)
Macrophages (dust cells) clean up foreign material
Structure of the lungs
weigh 1kg soft spongy and elastic Take up all of thoracic cavity Cone shaped Each lung encased in pleura sac base sits on diaphragm
Hilus
area in each lung where blood vessels, lymphatic vessels, nerves and the bronchus enter and leave the lung
lobes in lungs
right lung has 3 lobes (55% of gas exchange)
left lung has 2 lobes (45% of gas exchange)
Lobes of lungs are divided into
bronchopulmonary segments
Lobules
small macroscopic subdivisions of bronchopulmonary segments
2 layers of pleura
visceral layer hugs lung surface
Parietal layer lines thoracic wall and upper surface of diaphragm
During normal inhalation (inspiration)
thoracic volume increases
pressure in lungs decreases
During normal exhalation (expiration)
pressure in lungs increases and forces air out of the lungs
Thoracic volume decreases
Gas exchange in lungs
air inhaled
o2 from air diffuses from alveoli into capillaries
CO2 diffuses from capillaries into the alveoli
CO2 is exhaled
Gas exchange in body cells
oxygen leaves capillary blood and diffuses into the cells where it can be used during cellular metabolism
Co2 diffuses into the capillary blood as metabolism occurs in the cell
Transportation of oxygen
diffuses across alveoli into capillaries
O2 then dissolves in plasma
3% of O2 is transported as dissolved gas
97% of O2 is carried by Hb molecules
Transport of CO2
diffuses from tissue cells into capillaries
7% dissolved in plasma
23% with Hb in RBC
70% as bicarbonate ions in plasma
Medullary rhythmicity center
sets basic pattern of respiration inspiration lasts 2 seconds expiration lasts 3 seconds normally 12-20 breaths per min in adult 20-40 in children
Chemical control of respiration
chemoreceptors are stimulated and relay messages to the brain
Central and peripheral
Central chemoreceptors
found in CNS (in medulla)
sensitive to increases in CO2 and H+ levels
Peripheral chemoreceptors
found in PNS (walls of carotid arteries and in aorta)
Detect decreases in oxygen levels
Factors that influence breathing
yawning sneezing coughing hiccupping crying laughing
Bronchitis
inflammation of bronchial tubes
coughing up sputum
Laryngitis
inflammation of larynx
dry, sore throat with hoarse or no voice
Pneumonia
inflammation of lungs
inflamed lungs, high fever, cough, sputum with pus and blood
sinusitis
inflammation of sinuses
inflammation of paranasal cavities, headaches, pain, pressure in the bones of the face
Pharyngitis
Inflammation of the pharynx
sore throat and fever
Bacterial diseases
bronchitis laryngitis pneumonia sinusitis pharyngitis
Viral diseases
influenza
common cold
Respiratory distress syndrome (RDS)
aka Hyaline membrane disease (HMD)
most common cause of death in newborn
caused by deficient amount of surfactant
Difficulty breathing (exhausts the infant)
Lung cancer
accounts for 30% of all cancer deaths
most patients die within one year of diagnosis
85-90% of lung cancers are due to cigarette smoke
asthma
inflammatory disorder
narrowing of airways
coughing, difficulty breathing, wheezing
Aging and the respiratory system
lung capacity decreases
lungs becomes less elastic (oxygen delivery to tissue cells is impaired)
Elderly more susceptible to diseases due to decreases activity of macrophages
