Exam 3 Pulmonary Physiology Flashcards
What are the inspiratory muscles?
Diaphragm, external intercostals, SCM,anterior serratus, scalenes and levator costarum
What are the expiratory muscles?
Abdominals, internal intercostals, post inferior. Serratus, transverse thoracis, Pyramidal
What is the only muscle during inspiration doesn’t lift the rib cage?
Diaphragm, which drops the floor of the thoracic cage
Which muscle of expiration is involved in low back pain?
Transverse abdominis
During what conditions is expiration passive and associated with recoil of the lungs?
Resting conditions
What is pleural pressure?
Negative pressure between parietal and visceral pleura which keeps lung inflated against chest wall
Various between -5 to -7.5 cmH20
What are the two different kinds of alveolar pressure?
Sub Atmospheric and supra-atmospheric
Which alveolar pressure is associated with inspiration
Subatmospheric
What alveolar pressure is associated with expiration
Supra-atmospheric
What is transpulmonary pressure?
The difference between alveolar P and pleural P
What measures the recoil tendency of the lung and peaks at the end of inspiration_____________.
Transpulmonary pressure
True or False
At the onset of inspiration the pleural pressure changes at a faster rate than lung volume?
True
Known as “hysteresis” phenomenon
Which lung is easier to inflate a saline or air filled one?
Saline because surface tension is gone
What overrides the natural recoil tendency of the lung?
Expansion of the thoracic cage resulting in an increase of lung volume
What is Eupnea
Normal breathing 12-17 B/min 500-600 ml
Arterial CO2= 40mmHg
What is Hyperpnea
Increase in pulmonary ventilating matching metabolic demand
Arterial CO2= 40mmHg
What is happening during hyperventilation
Increase in pulmonary ventilation greater than metabolic demand
Arterial CO2 decreases to less than 40mmHg
What occurs during hypoventilation
Pulmonary ventilation lower than metabolic demand
Increase in Arterial CO2 greater than 40 mmHg
What is Tachypnea
Increase in the frequency of respiratory rate
What is apnea?
Absence of breathing
Ex. Sleep apnea
What is Dyspnea
Difficult or labored breathing
What is Orthopnea
Dyspnea when recumbent, relieved when upright
Ex. Congestive heart failure, asthma, lung failure
True or False
Lungs have a natural tendency to collapse
True
Surface tension forces 2/3
Elastic Fibers 1/3
What keeps lungs against the chest wall
By negative pleural pressure “suction”
True or False
If the pleural P= atmospheric P the lung will collapse?
True
Examples
Puncture of parietal pleural
Erosion of visceral pleura
If a major airway is blocked the air trapped distal to the block will be absorbed by the blood and that segment of the lung will collapse
What is Pleural fluid?
Thin layer of mucous fluid
Provides lubrication
Transudate ( interstitial fluid + protein)
Total amount is only a few ml’s
What happens to excess of pleural fluid?
Is removed by lymphatics
- mediastinum
- superior surface of diaphragm
- lateral surfaces of parietal pleural
- helps create negative pleural pressure
What is a pleural effusion?
Collection of large amounts of free fluid in pleural space.
Edema of pleural cavity
What are the causes of pleural effusion?
Blockage of lymphatic drainage
Cardiac failure- increased capillary filtration P
Reduced plasma colloid osmotic pressure
Infection/inflammation of pleural surfaces which breaks down capillary membranes
What is surfactant?
Reduces surface tension forces by forming a mono molecular layer between aqueous fluid lining the alveoli and air, preventing a water-air interface
Surfactant is produced by ________________. It consists of _________________________.
Type II alveolar epithelial cells. Dipalmitoyl lecithin, surfactant apoproteins, Ca++ ions
What is the Law of Laplace?
P=2T/r
Without surfactant smaller alveolar have increased collapse P and tend to empty into larger alveoli
AKA big would get bigger and small would get smaller
Role of surfactant??
As alveolar size decreases the surfactant is concentrated which decreases surface tension forces, of setting the decrease in radius of a smaller cell
What is interdependence?
Size of one alveoli determined in part by surrounding alveoli
What is tidal volume
Amount of air moved in or out each breath
500ml
What is inspiratory reserve volume?
Maximum volume one can inspire above normal inspiration
3000ml
What is expiratory reserve volume
Maximum volume one can expire below normal expiration
1100ml
This is the volume of air left in the lungs after maximum expiratory effort
residual volume
1200ml
This is the volume of air left in the lungs after a normal expiration, balance point of lung recoil and chest wall forces
Functional residual capacity (RV+ERV)
Maximum volume one can inspire during an inspiration effort
Inspiratory capacity (TV+IRV)
max volume one can exchange in a respiratory cycle
Vital capacity (IRV+TV+ERV)
The air in the lungs at full inflation is called _________________
Total lung capacity (IRV+TV+ERV+RV)
What lung volumes cant be determined by basic Spirometry?
RV, FRC, TLC
Must use helium dilution method for these
How do you find RV?
RV=FRC-ERV
How do you find TLC?
TLC=RV+VC
How many generations of branching is there in the lungs?
20
How many generations of branching are there in the bronchi?
First 11 generations of branching
How many generations of branching are in the bronchioles
Next 5 generations after bronchi
How many generations of branching are in respiratory bronchioles
Last 4 generations of branching
Where can gas exchange cannot occur?
Dead space
SNS beta receptors cause __________
Dilation due mainly to indirect effect via circulating epinephrine
Parasympathetic muscarinic receptors cause______________
Constriction
NANC nerve (non adrenergic, non cholinergic) due what?
Inhibitory release VIP and NO= bronchodialtion
Stimulatory= bronchoconstriction, mucous secretion, vascular hyperpermeability, cough, vasodilation, “neurogenic inflammation”
What are the two types of adapting receptors of afferent nerves?
Slow adapting receptors and rapidly adapting receptors
What are slow adapting receptors?
Associated with smooth muscle of proximal airways
Stretch receptors- involved in reflex control of breathing and cough reflex
What are rapidly adapting receptors?
Sensitive to mechanical +, protons, low Cl solutions, histamine, cigarette smoke, ozone, serotonin, PGF2
what are C fibers
They are high density fibers that contain neuropeptides ex. Substance P, neurokinin A, calcitonin gene related peptide
Selectively + by capsaicin
What happens when histamine binds to H1 receptors?
Constriction
What happens when histamine binds to H2 receptors
Dilation
Slow reactive substance of anaphylaxisis causes?
Constriction- allergic response to pollen
What do prostaglandins E series do?
Dilation
Prostaglandins F series do?
Constriction
Environmental pollution results in _______________. Which is mediated by ___________ and ________________.
Constriction
Parasympathetic reflex and local constrictor response
What is the normal level of HCO3?
Metabolic acidosis levels?
Metabolic alkalosis levels?
24 mEq/L
Acidosis HCO324 will decrease ventilation