What roles does the respiratory system play in the body?
1. Intake oxygen, release of CO2 2. Controlling blood pH 3. Creating vocal responses
What is external respiration?
The point of gas exchange between alveoli and pulmonary capillaries
What is internal respiration?
The gas exchange between capillaries and other tissues
Describe the path of oxygen through the respiratory system
- External nares
- Nasal meatuses and conchae
- Carina (bifurcation)
- Primary bronchi
- Secondary bronchi
- Tertiary bronchi
- Terminal bronchioles
- Terminal bronchioles
Describe the flow of oxygen through the respiratory zone
- Respiratory bronchioles
- Alveolar duct
- Alveolar sac
- Alveolar capillaries
What is the name of the zone prior to the respiratory zone?
From where in the body does asthma originate?
What is pleurisy?
A condition in which the pleural cavity becomes inflamed, causing less sliding to occur
If a patient is suffering from pleurisy, what sound will you hear?
A sound like strands of silk sliding across each other, called "pleural friction rub"
What is COPD?
A chronic obstructive pulmonary disease; long-term airflow obstruction , reduced pulmonary ventilation
What is asthma and what are its symptoms?
Airway inflammation, bronchioles constrict; causes wheezing, coughing, suffocation
What is chronic bronchitis?
Sever, persistent inflammation of lower respiratory tract, goblet cells secrete excess mucus which gathers in lungs
What is emphysema and what are its symptoms?
Alveolar walls break down and alveoli converge into fewer and larger spaces, flabby lungs with grape to ping pong ball sized cavitated spaces
What receptors trigger inhalation?
Chemoreceptors (talk to brain respiratory centers)
Where are the central chemoreceptors located and what do they do?
Location: medulla oblongata
Function: monitor O2/CO2/pH, #1 driver of inhalation, triggered by low CSF pH
Where are the peripheral chemoreceptors located and what in their function?
Location: aortic and carotid bodies
Function: Monitor PO2/PCO2 in blood
What is PO2?
Partial pressure of oxygen
What are the four brain structures that control respiration?
- Cerebral cortex
What is the role of the DRG and where is it located?
Dorsal Respiratory Group
F: modifies depth of inspiration
What is the location and function of the VRG?
Ventral Respiratory Group
F: Drive inspiration, stimulate diaphragm and external intercostals
What is the location and function of the PRG?
Pontine Respiratory Group
F: Smooth transitions between inspiration and expiration
What is the role of the cerebral cortex in respiration?
Conscious override of breathing
What nerve innervates the diaphragm?
What does Boyle's Law state and what is its equation?
When volume goes up, pressure goes down;
What is the basic mechanism of inspiration?
The diaphragm flattens and the intercostals pull the rib cage up and out, expanding the volume of the lungs, thus decreasing the pressure, causing air to rush in as it follows the pressure gradient from high to low
What is the layer of the lung's pleura that attaches to the chest wall?
What is the visceral pleura?
The layer of the pleura that attaches to the lungs
What is the name of the space between the parietal and visceral pleura?
What are the functions of the liquid in the pleural cavity?
To hold the two layers together; reduces friction as lungs expand and contract; holds a pressure gradient that maintains residual volume; keeps lungs separate
Where does the intrapleural (intrathoracic) pressure have to remain?
Subatmospheric; keeps you from breathing out ALL the air in your lungs
What is pneumothorax?
Presence of air in pleural cavity, causes atelectasis
What is atelectasis?
What is the wall of the alveolar sac composed of?
Simple squamous epithelium and Type I Alveolar cells
How does oxygen get from the blood into the alveolar sacs?
It crosses the respiratory membrane
What does Dalton's Law state?
That the total pressure of air is the sum total of each of the partial pressures of the different gasses in the air
P(atmosphere) = PO2 + PN2 + PCO2 + Pother
How do the muscles and pressures change in exhalation?
Diaphragm and muscles of inspiration relax; volume decreases, pressure increases, air moves from high to low out of the lungs
What are the 4 muscles of inspiration?
- External intercostals
- Pectoralis minor
What two factors cause tension in the alveoli?
Elastic fibers in the alveolar walls and surface tension in the alveolar fluid
How do alveoli interact with constriction?
They are always moving towards constriction
What is the role of Type II Alveolar cells in respiration?
Secrete a surfactant to decrease the surface tension of the alveolar fluid, thus keeping the alveoli from collapsing
What would be the result if the alveoli lost their elasticity?
They would remain expanded = emphysema = barrel chest
What happens if you inhale particle from the air and they move into the alveoli?
Alveolar macrophages in the alveolar sac devour and destroy any particles
How do the WBC alveolar macrophages work?
They engulf foreign particles and break it down with digestive enzymes in the macrophage
How does asbestos cause lung damage?
Sharp asbestos fibers are not destroyed, they poke a hole in the macrophage, releasing the digestive enzymes into the alveolus, which causes scarring (asbestosis) and sometimes cancer (mesothelioma)
What is respiratory distress syndrome?
An immaturity of Type II alveolar cells (like in premature babies), very constricted alveoli
How much O2 is dissolved in the blood plasma?
Where is 98.5% of O2 stored?
What is the name of a hemoglobin with 4 oxygen molecules?
At what level do we want O2 to bind to the Hb?
External respiration at the lungs
At what level do we want oxygen to dissociate from the Hb?
At the level of the tissues (internal respiration)
What 3 conditions can cause the oxygen to unbind from the Hb?
- Decrease in pH (more acidic)
- 2,3-biphosphoglycerate BPG increase
- Temperature increase
What causes increased acidity in the blood in the oxygen drop-off?
Conversion of CO2 waste into carbonic acid
What does the oxyhemoglobin dissociation curve represent?
Easier for the first oxygen to bind to Hb than for the last oxygen which needs a much greater pO2
How is fetal Hb different than adult Hb?
Fetal: HbF, binds oxygen more strongly, more efficient
Adult: HbA, less efficient
What is the name of the diffusion of oxygen across the extracellular matrix called?
What role does oxygen play in the cell?
It is the final electron acceptor at the end of the ETC, creates superoxide dismutase
What are the 4 kinds of hypoxia?
What is hypoxemic hypoxia?
Caused by low arterial pO2, inadequate pulmonary gas exchange; can happen at high elevation, drowing , aspiration, or CO poisoning
What causes ischemic hypoxia?
Inadequate circulation of blood, congestive heart failure
What causes anemic hypoxia?
Anemia, inability of blood to carry enough O2
What causes histotoxic hypoxia?
Metabolic poison like cyanide prevents tissues from using O2
What is hyperoxia?
What is the term for high pCO2?
What is hypocapnia?
How is carbon dioxide carried in the bloodstream?
- 7% dissolved in blood
- 23% bound in amino acids in Hb (carbaminohemoglobin)
- 70% forms bicarbonate ions
- Travels toward the lungs where it moves into alveoli and awaits low pressure in the alveoli so it can be exhaled
What is the role of bicarbonate in the blood?
How does the Bohr effect help dissociate oxygen from hemoglobin?
Increases blood acidity at the tissues which allows H+ to load onto the Hb, displacing oxygen and making available to the tissues
What is epistaxis?
What is aspiration?
Taking of foreign matter into the lungs
What is asphyxia?
The state of not being able to breath
What is dyspnea?
Difficult or labored respiration
What is apnea?
Transient cessation of respiration
What is sputum?
Expectorated matter from the air passages in disease of the lungs, bronchi, or URT
What is snot?
Mucus that has captured dust or other particles
Why do people snore?
Pharynx muscles are weak or tonsils are enlarged
How do drowning victims die?
H2O touches larynx which closes epiglottis and triggers laryngospasm; they suffocate
What is smokers hack?
Cigarattes paralyze the cilia for 20 minutes, after that time they bring up a crap load of lung debris = cough
How does the sympathetic nervous system change respiration?
Norepinephrine binds to walls of airways, diameter increase, more air is inhaled
What is phlegm?
Mucus, lung debris, and macrophages
What is a pink puffer?
Someone with emphysema
What is the term for someone with chronic bronchitis?
What muscles are used in inspiration?
diaphragm and external intercostals
In a forced expiration, what muscles are used?
Rectus abdominus, internal intercostals, external obliques
What are the 4 layers that make up the respiratory membrane?