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408 Exam II Things I found
Terms in this set (57)
Respiratory Control System
System that is comprised of RECEPTORS that gather information and feed it to the CENTRAL CONTROLLER in the brainstem which coordinates the information and, in turn, sends its impulses to the EFFECTORS (respiratory muscles) which cause ventilation
Part of the respiratory control system that is located in the MEDULLA, and contains within it the minimal number of neurons needed to generate a ventilatory sequence. Includes the central pattern generator (CPG) and numerous respiratory-related neurons (RRNs) that are divided into the ventral respiratory group (VRG) and dorsal respiratory group (DRG).
Central Pattern Generator (CPG)
The neural network within the medulla that is responsible for generating the central neural rhythm that is modulated to adjust breathing pattern. Comprised of three groups of neurons that determine the timing of each phase of breathing. Inspiration (preBotzinger complex), post-inspiration (retrotrapezoid nucleus), and expiration (retrotrapezoid nucleus).
Dorsal Respiratory Group (DRG)
Group of respiratory-related neurons that are primarily responsible for inspiration. Output goes to CN IX and X (larynx, pharynx), CN V (open mouth), CN VII (flare nostrils), CN XI (other muscles)
Ventral Respiratory Group (VRG)
Group of respiratory-related neurons that are primarily responsible for expiration. Output goes to the internal intercostal and abdominal muscles.
Receptors that are the most important, involved in minute-by-minute control of ventilation. Respond to changes in the [H+] of the cerebral spinal fluid (brain interstitial fluid) caused by changes in arterial PCO2. Several central sites have been identified with redundancies, so no single site appears to be responsible for central sensing
Receptors that respond rapidly to changes in arterial PO2 and pH, and increases in arterial PCO2. Located in glomus cells in the carotid bodies at the bifurcation of the common carotid arteries and in the aortic bodies above and below the aortic arch. These receptors respond to changes in PaO2, which is influenced by PaCO2 and pH.
Cells contained within the carotid and aortic bodies that have neuronal properties, including innervation by preganglionic sympathetic fibers, contain numerous voltage-gated ion channels, depolarizing these cells results in action potentials, and they contain vesicles that contain neurotransmitters.
Glomus Cell Activation
Activation of these cells that occurs in response to changes in PaO2, pH, and increases in PaCO2, each of which causes inhibition of K+ channels and opens Ca channels, which results in release of ACh, dopamine, Norepi, substance P and met-enkephalin that in turn activates afferent nerves that travel in the glossopharyngeal nerve or vagus nerve.
Receptors that are found throughout the tracheobronchial tree from the trachea to the terminal bronchioles and are associated with airway smooth muscles. Send impulses up the vagus nerve to the nucleus tractus solitarius, responding to changes in tension in the airway walls, and acting to inhibit inspiratory neurons in the medulla and pons. Slow breathing frequency due to an increase in expiratory time.
Other Respiratory Controls
Controls that include rapidly adapting pulmonary stretch receptors (RARs), lung C-fibers, type III and IV muscle afferents, arterial baroreceptors, and thermal receptors
Condition during which there is an increase in ventilation, tidal volume, and frequency that is determined by the respiratory centers in the medulla, rapidly responding receptors in the periphery, and the Type III and IV muscle afferents. PCO2 does NOT drive this
Functional Residual Capacity (FRC)
The volume of gas in the lungs after a resting expiration. Represents the volume of the respiratory system AT REST, and the volume to which the lung normally returns after a passive exhalation. At this volume, the outward elastic recoil of the chest wall is equal but opposite in direction to the inward elastic recoil of the lung
Total Lung Capacity (TLC)
The volume of gas in the lungs after a maximal inspiration. At this point, the lungs cannot expand any further because the elastic limits of collagen and connective tissue of the lung are reached. Inspiratory strength usually exceeds the effort needed to fill the lungs
The volume of gas in the lungs after a maximal expiration. The smallest volume possible in an intact respiratory system (lung + chest wall together), limited by the structure of the thorax.
The volume of gas trapped in the lung if the lung is removed from the thorax and deflated. Typically, this volume is less than RV, though sometimes this volume will set RV making them equal if the chest wall is very compliant (decreasing RV), or when the airway collapses at high volumes (increasing this volume).
The volume of gas expired during normal breathing
The maximum volume that can be expired after a maximal inspiration. TLC - RV
The change in volume for a given change in pressure. Change in Volume/Change in Pressure. A decrease in this measurement leads to an increase in pressure to inflate, making the lungs work harder to breathe.
Lung Compliance Curve
Graph that depicts the lung volume at various magnitudes of pressure across the lungs (inside relative to outside).
Condition in which proliferation of interstitial material reduces the lung's compliance, making it stiffer and harder to expand on inspiration (the tendency of the lung to collapse outstrips that of the chest wall to expand).
Chronic Obstructive Pulmonary Disease (COPD)
Condition which there is destruction of lung parenchyma (loss of elastic tissue) which increases lung compliance ,making it easier to fill the lungs on inhalation, but reduces elastic recoil of the lung so that expiration, which is normally passive, requires forced muscular effort.
The area that holds a small volume of lubricating fluid between the pleural layers (outside lung and inside chest wall) and contains no gas (normally). The SURFACE TENSION in this area keeps the lung and chest wall intimately associated so that the tendency of the lung to collapse is directly opposed by the tendency of the chest wall to spring out
Condition in which a hole is made in the chest wall, disrupting the pleural space and bringing it to atmospheric pressure (0) which results in disruption of the apposition of the chest wall and lung causing the chest to spring out and the lungs to collapse. Animal is no longer able to ventilate that lung.
Property of gas-liquid interface that exists within the alveoli of the lungs. The attractive forces between liquid molecules are much stronger than the attractive forces between liquid and gas molecules. In the alveoli, the liquid surfactant pulls together making its surface area as small as possible.
Law that states that Pressure = (2 x Tension)/Radius. If T is held constant in different sized alveoli, the pressure would be much greater in the smaller alveoli, causing them to empty their gases into larger alveoli and subsequently collapse
Substance produced by Type 2 alveolar cells composed of phospholipid-protein-carbohydrate complex. Functions to change the surface tension in each alveolus depending on its size, exerting a greater effect of reducing surface tension on smaller alveoli, keeping them open. May reduce surface tension in small alveoli so much that it allows them to pull gas from the larger alveoli. Its effect is inversely related to lung volume or alveolar size.
Surfactant Physiologic Effects
Physiologic effects that include increasing compliance and therefore reducing the work of breathing, promoting stability of alveoli and small airways by keeping them open and preventing the small alveoli from emptying into larger ones, and resists fluid transudation into alveoli.
Condition the results in poor compliance, increasing the work of breathing, alveolar collapse (atelectasis) reduces area for gas exchange, and pulmonary edema which reduces area for gas exchange and further reduces compliance
-air sacs allow for unidirectional flow of air through the respiratory system
-Breathing in which the lungs act as gas exchange and the air sacs accomplish ventilation, happening at almost atmospheric pressure
Avian Respiratory System
-Birds inhale in two separate inhalation and exhalation phases. A system of air sacs stores air between the two phases
-System that is comprised of SMALL lungs (do not change size while breathing) and 9 airsacs (NO gas exchange), capable of 2x the respiratory volume with small lungs than in mammals. The coelomic cavity is at environmental pressure and there is NO DIAPHRAGM
Avian Upper Airways
Portion of the respiratory tract that consists of the nares-mouth (choana), oro-nasal cavity which is separated from the trachea by the larynx. There is rhythmic opening of th eglottis when breathing. Complete cartilage rings in the trachea. Tracheal volume is 4-5x larger in brids than in sae size mammals. Deep/slow breathing pattern compensates for increased dead space. Loops caused by tracheal elongations are common in several bird spp, of unknown function
constant supply of oxygen
highest efficiency lung
two cycles to expel original air
-Small breathing structures that do not change size while the animal is breathing, located dorsal inside the coelomic cavity. Dorsal aspect has rib impressions. Primary and secondary bronchi are only conducting airways. Parabronchi are the functional unit of gas exchange
Avian air sacs
Membranous structures connected to the primary or secondary bronchi, possess most of the volume of the respiratory system. Poorly vascularized, NO GAS EXCHANGE, only function as a bellows to ventilate. Nine in most spp in cranial and caudal groups
Avian Relaxed Resting Volume
Volume in avian species that occurs midway between inspiratory and expiratory volumes
Process that occurs when active muscle force is applied to the relaxed respiratory system. Functions to increase the volume of the thoracic cavity, which causes the pressure to drop and gas to flow into the alveoli. At this point, intra-airway pressure is negative, intra-pleural pressure is more negative, and the intrathoracic airways are pulled open. Extrathoracic airways are kept open against the pressure gradient via structural reinforcement (tracheal rings) and muscle activity (larynx/pharynx).
*diaphragm and external intercostals
-Muscles that work to expand the size of the thoracic cavity, includes the diaphragm (forces the abdominal contents caudally and ventrally, increasing the size of the thoracic cavity), external intercostals (pull the ribs cranially and outward, increasing the lateral dimensions of the thoracic cavity), and upper airway muscles (flare the nostrils and oppose inward movement of the pharynx and larynx).
Process that is passive during quiet breathing, as the muscle effort that was applied to expand the thoracic cavity stops and the inherent elasticity of the respiratory system is allowed to come to rest at FRC
Muscles that don't normally need to work, as this process is passive. During increased respiratory effort, the abdominal muscles are the most important, pushing the diaphragm forward
Breathing Cycle Start Inspiration
Point in the breathing cycle at which muscular effort is applied to increase the thoracic space, bringing it closer to its unstressed volume. As the thoracic volume increases, pressure inside the pleural space decreases, pulling the lungs outward with the thorax. As lung volume increases, pressure inside the lungs decreases, and gas begins to move down the pressure gradient from the outside into the lungs until the pressure is equal.
Breathing Cycle End Inspiration
Point in the breathing cycle at which the lungs are at a larger volume, and thus have a higher inward recoil pressure, while the chest wall's larger volume results in a lower outward recoil pressure. Pleural pressure is very negative. At this point, pressure has equalized, and gas won't move anymore, because there is no pressure gradient. The elastic recoil of the system opposes the amount of muscular effort applied
Breathing Cycle Expiration
Point in the breathing cycle at which muscular effort is removed and the respiratory system recoils back to its resting volume (FRC). The recoil of the thorax to a smaller volume creates a positive alveolar pressure, and gas moves out of the lung towards the lower pressure in the mouth. Pleural pressure is still negative.
Type of expiration that requires effort, creating a positive intrapleural pressure, with positive alveolar pressure dissipating toward the mouth. A point somewhere in the airways will have an airway pressure that is equal to pleural pressure, and just mouth-ward of this point, the pressure inside the airway will be less than the surrounding pleural pressure and the airway will tend to want to collapse. This creates a flow limiting mechanism during expiration. This normally occurs in the central airways which are reinforced with cartilage.
Blood Oxygen Capacity
Capacity that is dependent on partial pressure of oxygen in water, partial pressure of carbon dioxide, pH, temperature, and the activity of the fish
Fish Response to Oxygen Availability
Fish adaptations to limited oxygen availability include their blood composition, morphology of the circulatory apparatus, behavioral responses to oxygen levels, and the structure and function of the gills and other respiratory surfaces
Fish respiratory pump that involves the buccopharyngeal cavity opening to allow water in, then closing to trap the water, and using the musculature of the head region to pump it through the parabranchial/opercular cavity, producing a continuous flow of water across the gills. Some pelagic fish species exhibit RAM ventilation, holding their mouth open as they swim. Some stream fish hold their mouth open to irrigate the gills passively while maintaining position in swift water
Volume of water pumped over the gills that is determined by the fish's morphology, size, the temperature, carbon dioxide content in the water, oxygen content, and the activity level of the fish.
Method of maximizing dissolved oxygen extractions by the gills. Accomplished by ensuring the flow of blood runs opposite to the flow of water across the gills, so that the gases may diffuse across the membrane. Movement of respiratory system in fish is always passive and dependent on concentration gradients
A right shift indicates________ affinity of haemoglobin allowing more oxygen to be available to the tissues.
A left shift indicates ______ affinity of haemoglobin allowing less oxygen to be available to the tissues.
A decrease in the pH shifts the curve to the________
increase in pH shifts the curve to the_____
This occurs because a higher hydrogen ion concentration causes an alteration in amino acid residues that stabilizes deoxyhaemoglobin in a state (the T state) that has a lower affinity for oxygen. This rightwards shift is referred to as the Bohr effect.
A decrease in CO2 shifts the curve to the_____, while an increase in CO2 shifts the curve to the_______.
How CO2 affects the curve
CO2 affects the curve in two ways. Firstly, accumulation of CO2 causes carbamino compounds to be generated, which bind to oxygen and form carbaminohaemoglobin. Carbaminohaemoglobin stabilizes deoxyhaemoglobin in the T state. Secondly, accumulation of CO2 causes an increase in H+ ion concentrations and a decrease in the pH, which will shift the curve to the right as explained above.
How temperature affects the curve
An increase in temperature shifts the curve to the right, whilst a decrease in temperature shifts the curve to the left. Increasing the temperature denatures the bond between oxygen and haemoglobin, which increases the amount of oxygen and haemoglobin and decreases the concentration of oxyhaemoglobin. Temperature does not have a dramatic effect but the effects are noticeable in cases of hypothermia and hyperthermia.
2,3-Diphosphoglycerate (2,3-DPG) is the main primary organic phosphate. An increase in 2,3-DPG shifts the curve to the right, whilst a decrease in 2,3-DPG shifts the curve to the left. 2,3-DPG binds to haemoglobin and rearranges it into the T state, which decreases its affinity for oxygen.
What are the things that cause right shift?
Desire to unload more into the tissues.. increasing all of these increase oxygen delivery to the tissue and all stabilize the taut form of Hb, which increases oxygen unloading into the tissues.
ACE BATs are for "right" handed people
Altitude (increased altitude)
Temperature (increase T of the tissue)
Note: this also makes sense if you just think about Exercise. Exercise will increase temperature of your tissues, increase CO2 content, and there's also increases acidity during exercise. So on top of that, just remember increase altitude, you want to deliver more oxygen to your tissues during that time so you also makes more 2,3-BPG.
What kind of poisoning can also shift the oxygen-hemoglobin dissociation curve to the left? but it also lowers the oxygen-carrying capacity?
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