Respiratory Flashcards
What is the central pattern generator?
A network of communicating pathways producing respiratory patterns depending on the animals need.
What input systems act to regulate respiration patterns?
Muscle stretch receptorsIrritant receptorsIntercostal Golgi tendon organsChemoreceptors
Name the peripheral chemoreceptors and the location of the main adult one.
AorticCarotid - at the carotid bifurcation, adjacent to the carotid sinus
Describe the Hering-Breuer reflex
Stretch receptors in the lung react to inflation of the lung, they send OFF signals to the pons of the brain stem which inhibit the dorsal respiratory group. Therefore preventing further inspiration.
What effects does activation of irritant receptors of respiratory epithelium have? Which nervous system is activated?
CoughingMucous productionShallow breathing BronchoconstrictionParasympathetic nervous system
Which respiratory group does the pre-botzinger complex work upon?
Dorsal respiratory group.
The ventral respiratory group works on which phase of respiration?
Expiration
Which cranial nerve controls the carotid body?
Glossopharyngeal
What parameters are monitored by the peripheral chemoreceptors?
PO2 PCO2(H+)
Which parameter doe central chemoreceptors measure?
PCO2
Which nerve is stimulated in activation of the carotid body in response to low PO2?
Carotid sinus nerve
Why is PCO2 the main governor of respiration?
Hb saturation doesn’t differ much until PO2 dips below 70mmHg
What is a respiratory acidosis caused by?
Increased h+ due to increased PaCO2
What is the normal pH of blood?
7.4
Why can’t h+ ions stimulate central chemoreceptors?
They can’t cross the BBB
What is the first line of defense against respiratory acidosis/alkalosis?
Buffers
What is a buffer?
A molecule that can pick up or donate h+ ions
What is a strong acid?
One which fully dissociates in solution
What is the equation of pH?
Negative log of h+ concentration.
How do we distinguish a bronchiole from a bronchii?
Bronchiolar walls have no cartilage
What is meant by monopodial division?
Divisions which make the further tubes smaller
What is the function of a type one alveolacyte?
Gas exchange
What is the function of a type 2 alveolacyte?
Secretion of surfactant
What is the function of the elastic fibres surrounding the alveolar sacs?
Elastic recoil
What artery supplies the lung mesenchyme with oxygen?
Bronchial artery which branches off the aorta
What vessels allows venous drainage of the lung tissue?
Caudal vena cava or the vessels drain directly into the left atrium
Name the types of fetal gas exchange occurring between the foetus and the placenta.
Counter currentConcurrentCross currentPool
How does the foetus adapt to its state of relative hypoxia within the uterus?
Insensitive carotid bodiesHigh cardiac outputHigh affinity of Hb for oxygen
Name a stimulus of the first breath of the neonate after birth.
HypoxiaDecreased body temperatureSensory stimuli from the mother
Which stage of respiratory development development involves the differentiation of type one and two epithelial cells?
Terminal sac phase
In which phase of respiratory development is there the most secretion of surfactant?
Alveolar phase
What does the endoderm of the fetal lung develop into?
Respiratory epithelium and glands
What happens in the pseudoglandular phase of development?
The bronchiole tree extends into the mesenchyme of the lung, vascularisation occurs
In which phase of respiratory development do the respiratory bronchioles form?
Canalicular
Describe the splitting of the principle bronchi.
The right has three splits whereas the left has only two. Also the left deviates more laterally than the right which remains within the midline.
Describe the process of inhalation.
Muscle relaxation, increased space in the lungs, drop in alveolar pressure relative to atmospheric pressure causing air to move into the lungs.
Which muscles contract during inspiration?
Diaphragm contracts and flattens.External intercostals pull the chest cavity cranially and outwards
What is meant by the transpulmonary pressure?
The difference between alveolar and interpleural pressure.
What is the difference between passive and active respiration?
Active utilizes muscle contraction whereas passive utilizes elastic recoil.
What causes surface tension in the alveolus?
Hydrogen bonding between air and water on the alveolar epithelium
What is the function of surfactant? How does it work?
It prevents surface tension by embedding its hydrophilic head into the solute present on the epithelial wall, thereby reducing hydrogen bonding between water and air.
What is the structure of surfactant like?
Phospholipid, protein and calcium, a bit like a cell membrane molecule
How does the volume of surfactant differ between alveolus?
It doesn’t, they all contain the same volume
How does the concentration of surfactant differ between small and large alveoli?
Smaller have a greater concentration
What is the equation for pressure in the alveoli?
P=2T/R
What effect does increased turbulence have on resistance?
Resistance increases
What is laminar flow of air?
All going in the same direction
What is the equation for airway resistance?
R = 8 x length x viscosity / pi x radius^4