An elderly, 70-year-old, female went to the emergency room for breathing difficulty, and upon examination you discover she has developed a viral infection of the lungs.
Alveoli fill up with excess fluid seeped out of the blood vessels in the lung instead of ai
Causes problems with the exchange of gas
Resulting in breathing difficulty and poor oxygenation of blood.
With age, immune systems don't work as well.
Harder to fight of infection
Pneumonia attacks alveoli causing them to become inflamed and sometimes filled with fluid.
Responsible for moving oxygen from the lungs to the blood
Lowers the level of oxygen in the blood.
With increasing altitude, air density, humidity and temperature also decrease
Airway reactivity, insensible water losses, ventilatory changes and alterations in pulmonary hemodynamics
Respiratory failure or death
Change in oxygen levels
Possible underlying cardiac or pulmonary disease
Respiratory & Immune System
Respiratory & Circulatory System
Respiratory & Cardiovascular System
Circulate blood and oxygen throughout the body
Lungs have thin epithelial cells that allow for gas exchange and secrete mucus into the alveoli
Keeps the airways moist and traps unwanted particles that have been inhaled.
Removal of debris is an important part of the immune system protecting the respiratory system from infections.
Oxygen from the respiratory system moves into blood vessels that then circulate oxygen-rich blood to tissues and cells.
Bring oxygen and nutrients to the cells
Moves gases into and out of the blood.
HOMEOSTATIS
Anatomy of the Respiratory System
Supply body with O2 for cellular respiration
Dispose of CO2
Pulmonary Ventilation
Breathing in and out of lungs
External Respiration
Exchange of O2 and CO2 between lungs and blood
Upper respiratory
Nose, nasal cavity, paranasal sinuses and pharynx
Lower respiratory
Larynx, trachea, bronchi and branches, lungs and alveoli
Nose and Paranasal Sinuses
Nasal Cavity
Inlet for air
Moistens and warms air
Filters and cleans inspired air
Serves as resonating chamber for speech
Houses olfactory receptors
Mucus-secreting cells and serous cells
Serous cells secrete watery fluid containing enzymes
Nasal conchae
Mucosa-covered projections that protrude medially from lateral wall of nasal cavity
Increase mucosal area
Enhance air turbulence
Filter, heat, and moisten air
The Pharynx
Connects nasal cavity and mouth to larynx and esophagus
Skeletal muscle
Conducting zone
Cleanses, warms, and humidifies air
Respiratory zone
site of gas exchange
larynx, trachea, bronchi
respiratory bronchioles, alveolar ducts, and alveoli
The Larynx
Provides patent airway
Routes air and food into proper channels
Voice production
Houses vocal folds
Nine hyaline cartilages (except for epiglottis), connected by membranes and ligaments
Epiglottis
Consists of elastic cartilage
Covers laryngeal inlet during swallowing
The Trachea
extends from larynx into mediastinum, where it divides into two main bronchi
Mucosa lined with ciliated pseudostratified epithelium with goblet cells
Submucosa is connective tissue supported by 16–20 C-shaped cartilage rings that prevent collapse of trachea
The Bronchi and Subdivisions
Air passages undergo 23 orders of branching (bronchial tree)
Conducting zone structures give rise to respiratory zone structures
Divides to form right and left main (primary) bronchi
Right main bronchus larger and straighter than left
Each main bronchus then divides into secondary (lobar) bronchi
branches into tertiary bronchi and these divide repeatedly, becoming very small
Elastic fibers
Smooth muscle increases
Respiratory zone structures
Feed into respiratory bronchioles, which lead into alveolar ducts and finally into alveolar sacs (saccules)
Alveolar sacs contain clusters of alveoli
Sites of actual gas exchange
Respiratory membrane
Blood air barrier that consists of alveolar and capillary walls along with their fused basement membranes
Single layer of squamous epithelium (type I alveolar cells)
Scattered cuboidal type II alveolar cells secrete surfactant and antimicrobial proteins
Surrounded by fine elastic fibers and pulmonary capillaries
Alveolar pores connect adjacent alveoli
Equalize air pressure throughout lung
Provide alternate routes in case of blockages
Alveolar macrophages keep alveolar surfaces sterile
2 million dead macrophages/hour carried by cilia to throat and swallowed
The Lungs
Hilum
The site for entry/exit of blood vessels, bronchi, lymphatic vessels, and nerves
Cardiac notch
concavity for heart to fit into (left lung)
The Pleurae
Fills slitlike pleural cavity between two parietal and visceral pleurae
Lubrication and surface tension that assists in expansion and recoil of lungs
Respiratory Physiology
Atmospheric pressure
Pressure exerted by air surrounding the body
760 mm Hg at sea level = 1 atmosphere
Intrapulmonary pressure
Pressure in alveoli
Fluctuates with breathing
Always eventually equalizes with Patm
Intrapleural pressure
Pressure in pleural cavity
Always a negative pressure
Kept free from excess fluid thanks to lymphatics
If fluid accumulates, positive Pip pressure develops
Lung collapses
Pulmonary Ventilation
inspiration and expiration
depends on volume changes in thoracic cavity
Volume changes lead to pressure changes
Pressure changes lead to flow of gases to equalize pressure
Boyle’s law
inverse relationship between pressure and volume of a gas
Gases always fill the container they are in
If amount of gas is the same and container size is reduced, pressure will increase
Volume increase = Pressure decrease
Inspiration
Active process- contraction of inspiratory muscles (diaphragm and external intercostals)
Chest volume increases, lungs are stretched as they are pulled out with thoracic cage
Causes intrapulmonary pressure to drop by 1 mm Hg
Expiration
Quiet expiration normally is passive process
Inspiratory muscles relax, thoracic cavity volume decreases, and lungs recoil
Volume decrease causes intrapulmonary pressure to increase by +1 mm Hg
Forced expiration is an active process that uses oblique, transverse abdominal muscles and internal intercostal muscles
Nonrespiratory air movements
Many processes can move air into or out of lungs besides breathing
May modify normal respiratory rhythm
Most result from reflex action, although some are voluntary
Examples: coughing, sneezing, crying, laughing, hiccups, and yawns
Gas Exchange
External respiration
diffusion of gases between blood and lungs
Internal respiration
diffusion of gases between blood and tissues
Both processes are subject to:
Basic properties of gases
Composition of alveolar gas
Basic Properties of Gases
Dalton’s law of partial pressures
Total pressure exerted by mixture of gases = sum of pressures exerted by each gas
Partial pressure = Pressure exerted by each gas in mixture
Carbon Dioxide Transport
Dissolved in plasma
Chemically bound to hemoglobin
As bicarbonate ions in plasma
CO2 + H2O <=> H2Co3 <=> H+ + CO3-
High Altitude, decrease in Atmospheric Pressure
High altitude conditions always result in lower-than-normal Hb saturation levels
less availability of O2
Decline in blood O2 stimulates kidneys to accelerate production of EPO
RBC numbers increase slowly
C6H12O6 + 6O2 -> 6CO2 + 6 H2O + 36 ATP
THE GOAL OF RESPIRATION IS TO GAIN ENERGY
Henry's Law
When a liquid is exposed to a mixed gas, the partial pressure of each gas at equilibrium is the same in the liquid as in the gas.
The partial pressure response of a gas in alveoli will diffuse into blood the same as it would to air
Inflammation on the Respiratory System
Continual bronchial
irritation and inflammation
Chronic bronchitis
Excess mucus production
Chronic productive cough
Airway obstruction or air trapping
Dyspnea
Frequent infections
Asthma
Characterized by coughing, dyspnea, wheezing, and chest tightness
Active inflammation of airways precedes bronchospasms
Airway inflammation is an immune response leading to inflammation
Airways thickened with inflammatory exudate magnify effect of bronchospasms – spasms of smooth muscle