UNIT 11: Respiratory Flashcards
What is respiration?
The process by which animals take in oxygen necessary for cellular metabolism and release carbon dioxide that accumulates in their bodies as a result of the expenditure of energy
How does gas transfer occur?
through passive diffusion
What does the respiratory system consist of?
nasal cavity, pharynx, trachea, bronchi and lungs
Where the pharynx and larynx lead to?
they lead to the lungs. The larynx is connected to thee trachea which will branch into the right and left bronchi
What do the bronchi divide into?
the bronchioles
Where do the terminal bronchioles lead air to?
they lead air to the respiratory bronchioles
Where do the respiratory bronchioles lead to?
they connect to a fan of alveolar ducts and sacs
What is the function of the alveolar ducts and sacs?
to moisten and cleanse the air that is taken in and transfer it to the gas-exchangeing portion of the lung.
What is found inside these ducts and sacs?
capillaries (contain connective tissue fibers)
What are some important factors of gas exchange?
the relationship between oxygen pressure in the alveoli, the thickness of the alveolar and endothelial cells
What are the two types of alveolar cells?
Type I and Type II
What is Type I
responsible for gas exchange
What is Type II
responsible for the secretion of pulmonary surfactant and the re-absorption of sodium around water
What are the two zones that air passages are divided into?
the respiratory and conducting zone
What is the respiratory zone?
where gas exchange occurs and it includes bronchioles and alveoli
What is the conducting zone?
all the structures through which air passes before reaching the respiratory zone
Where are the lungs suspended?
within the pleural cavity
What can be known as the thoracic cage?
the ribs and diaphragm
What does the thoracic cage consist of?
mainly the lungs, but between the lungs and the thoracic wall there is a low volume of pleural space that is sealed and fluid filled
What controls the contractions of muscles while breathing?
the respiratory center within the medulla oblongata
What happens during inhalation?
volume of thorax increases due to the lowering of the diaphragm. the ribs are also raised and moved outward by the contraction of the external intercostal muscles
What does the increase in thoracic volume do?
it reduces alveolar pressure and air is drawn into the lungs
What happens during exhalation
the diaphragm and external intercostal muscles relax and reduce the thoracic volume
What does reducing the thoracic volume do?
raises alveolar pressure and forces air out of the lungs
What is a surfactant?
found in alveoli and they reduce surface tension
Where are pulmonary surfactants produced?
in type II alveolar cells
What is the purpose of pulmonary surfactants?
helps reduce the effort of breathing and help prevents the collapse of alveoli
How do surfactants reduce the chances of alveolar collapse?
by stabilizing surface tension when the alveolar sac is expanded
When does collapse occur?
when the pressure inside a small alveolar sac is greater than the pressure of the larger alveolar sac which will then force the air from the small sac to the large sac.
How is oxygen transported in blood?
hemoglobin
What is hemoglobin?
principle part of a red blood cell, a large protein with 4 polypeptide chains and 4 iron-containing heme groups
Where does oxygen attach itself to in the hemoglobin?
to the iron atoms on the heme groups
What conditions effect oxygens ability to bind to the iron group?
pressure of oxygen in surrounding area, pH, and carbon dioxide levels
When does hemoglobins affinity for oxygen decrease?
if temperature increases, pH decreases, or carbon dioxide levels increase
What happens in a decrease in pH?
it will reduce Hb/O2 affinity since the shape of the oxygen binding sites of the hemoglobin molecule change
What happens when there is a ride in body temperature?
Hb/O2 affinity will be reduces (increased energy will prevent bonds from forming or break any bonds that are currently in place)
How does an increased CO2 content affect the affinity?
because the CO2 will be binding where O2 should be binding
What are the three main ways that CO2 is transported in the blood?
dissolved into molecular CO2 (small %), reacting with NH2 groups of hemoglobin and other proteins to form carbamino compounds (larger amounts), and transported as bicarbonate (Main method)
What is one way pH is regulated?
through breathing (pH decreases- respiration rate and depth increases)
What is breathing?
automatic and rhythmic behaviour regulated by several nerve centers in the brain (pons and medulla oblongata)
What helps ventilate the lungs?
the muscles and diaphragm
What drives inspiration?
the activity of the inspiratory neuron’s in the dorsal inspiratory group drive (this gets interrupted by inhibition from the pneumotaxic centre)
What is the pneumotaxic centre?
this allows exhalation and then allows the cycle of inspiration too occur again
What network of neurons allow breathing to be regulated?
higher brain center’s, chemoreceptors, and mechanoreceptors
What happens when PCO2 levels are increased?
level of pH in CSF decreases (body. has the ability to adjust breathing patterns to the environment)
What is PCO2?
the main drive for increased breathing rates since the chemoreceptors are more sensitive to high PCO2 than low O2
What is the Hering-Breuer reflex?
when the body is maintaining normal ventilation and refers to prevent over-inflation of the lungs. This reflex is stimulated by pulmonary stretch receptors (prevents over-extension of the lungs)
What is hypoxia?
when animals use anaerobic pathways, or adjust respiratory and cardiovascular systems in order to deliver oxygen throughout there body while there is reduced O2 availability
