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Respiratory System
Rapid review of the A&P Respiratory System
| Question | Answer |
|---|---|
| Respiration encompasses 3 related functions. What are they? | Ventilation, gas exchange and oxygen utilization (cellular respiration) |
| What is ventilation? | Moves air in and out of lungs for gas exchange with blood. |
| Gas exchange in lungs and tissues is active or passive? Via what? | Passive via diffusion. |
| Which is bigger: R Main Stem Bronchus or L Main Stem Bronchus? Describe structure and what this means. | Right is bigger, and runs more vertically. This means that things generally tend to go into the right main stem. |
| Where does gas exchange occur? | Respiratory Zone = Respiratory bronchioles and alveoli. |
| All other structures except for the respiratory zone constitute the what? | Conducting Zone. |
| Bronchioles have what in their walls? Why is this groovy? | Bronchioles have muscles in their walls... this is groovy because it permits regulation of flow. |
| How many alveoli are there? What is the total surface area? | 300 million alveoli (60-80 cubic meters of surface area) |
| What does the conducting zone do? | Warms and humidifies (100% saturation) inspired air. |
| What do the mucus linings do? | Filters and cleans inspired air. (Forms a blanket of mucus which I moved by cilia to be expectorated) |
| What do cilia in the nasal cavity do? What do cilia in the airways do? | Nasal cavity: move blanket of mucosa back toward the throat. Airways: move blanket of mucosa up and out, towards the throat. |
| A thin layer of fluid between visceral pleura covering lungs and parietal pleura lining thoracic cavity walls. | Intrapleural space. |
| Ventilation results from what? | Pressure differences induced by changes in lung volumes. |
| Air moves from a __________ pressure to a ___________ pressure. | Higher pressure to a lower pressure. |
| What influence the ease of ventilation? | Compliance, elasticity, and surface tension of lungs influence ease of ventilation. |
| Visceral and parietal pleura normally adhere to each other so that what? | Lungs remain in contact with the chest walls. And expand and contract the thoracic cavity. |
| Intrapleural space contains what? | A thin layer of lubricating fluid which, well, lubricates, but this fluid also is what makes the pleura stick together. |
| During inspiration, intrapulmonary pressure is about __________. | -3 mm Hg. |
| What is intrapulmonary pressure? | Pressure in the airways. |
| During expiration, intrapulmonary pressure is _____________. | +3 mmHg. |
| 3 aspects of transportation during ventilation: | 1) Exchange of gas between alveolar lumen and capillaries (blood). 2) Ensuring the proper amount of blood passes by the alveoli for the circumstances. 3) Chemistry of dissolved gases in the blood. |
| Pressure that a particular gas in a mixture exerts independently: | Partial pressure. |
| Law that states that total pressure of a gas mixture is the sum of partial pressures of each gas in the mixture: | Dalton's Law. |
| Atmospheric pressure at sea level is what? | 760 mm Hg. |
| Gas exchange is facilitated by what 3 things? | 1) Surface Area of Alveoli. 2) Short diffusion distance between alveolar air and capillaries. 3) Tremendous density of capillaries. |
| For someone standing at rest, the alveoli at apex of lungs are what? | Underperfused and overventilated. |
| For someone standing at rest, the alveoli at the base of the lungs are what? | Overperfused and underventilated. |
| How many membranes does gas have to pass through? | 6: Surfactant, Alveolar membrane, interstitial fluid, capillary membrane, plasma and RBC. |
| Under normal circumstances, the gas passes through the 6 membranes in _________ seconds and blood can spend about _____ seconds in transit through the pulmonary caps. | (1/4 second.) (3/4 second) |
| Gas exchange in the lungs is driven by ___________________. | Differences in partial pressures of gases between the alveoli and capillaries. |
| Gasses will travel down their [partial] pressure gradients and move to wherever their [partial] pressure is _____________. | Lower. |
| Gas partial pressures must be considered in both the _____________ and the _____________. | Alveoli and the blood. |
| What happens to 97% of oxygen in the blood? | Is bound to Hb inside RBCs - oxyhemoglobin. |
| Each RBC has how many molecules of Hb? | 280 million. |
| Hb increases what? | O2 carrying capacity of blood. |
| O2 carrying capacity of blood depends on what? | its hemoglobin levels. |
| Condition in which hemoglobin levels are below normal. | Anemia. |
| Condition in which Hb levels are above normal. | Polycythemia. |
| Hb production is controlled by what? | Erythropoietin (EPO) |
| Production/release of erythropoietin is stimulated by what? | Low PO2 in kidneys. |
| Loading of Hb with O2 occurs in the ______________. Unloading occurs in ________________. | Lungs. unloading occurs in all other tissues (this occurs because the reaction of oxygen with hemoglobin is reversible) |
| Is the reaction of oxygen with hemoglobin reversible or irreversible? | Reversible. |
| What can effect the amount of oxygen bound to Hb? | Amount of oxygen dissolved in the blood. |
| High PO2 of lungs favors ___________. Low PO2 in tissues favors ___________. | High PO2 favors loading. Low PO2 favors unloading. |
| About 75% of Hb which leaves vascular beds is _________________ under normal, resting type circumstances. | still combined with oxygen under normal, resting type circumstances. |
| What is the structure of each hemoglobin? | Each Hb has 4 globin polypeptide chains and 4 heme groups that bind O2. Each heme has a ferrous ion that can bind one O2. |
| Each Hb can carry _______ O2. | Four. |
| What is the oxyhemoglobin dissociation curve? What does it reflect? | Gives percent of hemoglobin sites that have bound O2 at different PO2s. It reflects the loading and unloading of oxygen. |
| What is the oxyhemoglobin dissociation curve affected by? | Changes in Hb-O2 affinity caused by pH and temperature. |
| Affinity decreases when _____________________. | pH decreases (Bohr Effect) or temperature increases. |
| What is carboxyhemoglobin? Is this good or bad? | Heme combined with carbon monoxide. This bond is 210 times stronger than bond with oxygen, so the heme can't bind with oxygen = bad. |
| 10% of CO2 goes where? 20% of CO2 goes where? 70% of CO2 goes where? | 10% is transported in blood as dissolved CO2. 20% is bound to hemoglobin (carbaminohemoglobin). 70% is bicarbonate ion, HCO3. |
| What catalyzes the formation of bicarbonate from carbon dioxide and water? | Carbonic anhydrase. |
| Consider the reaction of CO2 and water to bicarbonate to carbonic acid. High CO2 levels cause the reaction to shift ___________. This also occurs in _________________. What is the net result? | Right. Also occurs in hypoventilation. Net result is acidosis. |
| What does boyle's law tell us about the relationship between intrapulmonary pressure and lung volume? | Pressure is inversely proportional to volume. An increase in lung volume decreases intrapulmonary pressure (in with the good air). Decrease in lung volume raises intrapulmonary pressure (out with the bad air). |
| What is surface tension of water? | Result of H-Bonding occurring on water molecules. Water attracts other water molecules - causes a certain amount of tension on the surface of the water. |
| Relate surface tension to our lungs. What prevents our lungs from collapsing? | Air is saturated with water by the time it reaches the Upper Respiratory Tract. Lungs would collapse alveolar surface if water attracted too much water to itself (surface tension). Surfactant decreases surface tension and keeps lungs from collapsing. |
| Fluid secretion is driven by __________________ out of alveolar epithelial cells. | Active transport of chloride ions. |
| What is surfactant produced by? | Type II pneumocytes |
| What does smoking do to surfactant? | It kills cells and you lose surfactant. |
| Why do pre-mature babies not have surfactant? what can this cause? | You don't develop surfactant until later on in fetal life. Premies are often born with insufficient surfactant, which can lead to Respiratory Distress Syndrome. (RDS) |
| Why is lung collapse so bad and almost always irreversible? | Alveoli are very sticky. |
| What is the primary muscle used in breathing? | Diaphragm. |
| Pulmonary ventilation consists of what 2 things? | Inspiration (inhalation) and expiration (exhalation). |
| How is pulmonary ventilation accomplished, and by what muscle? | The diaphragm increases and decreases the volumes of the thorax and lungs. Diaphragm contracts for inhalation and relaxes for expiration. |
| What increases thoracic volume vertically for quiet inspiration? | Diaphragm contracts. |
| What increases the thoracic volume laterally for quiet inspiration? | Parasternal and external intercostal contraction. |
| Quiet expiration happens by default due to _________________. | Passive recoil. |
| Deep inspiration involves the contraction of extra muscles to elevate the ribs. Which muscles? | Scalenes, pectoralis minor, and sternocleidomastoid muscles. (In addition to the diaphragm) |
| Deep expiration involves the contraction of which muscles? | Intercostals and abdominal muscles. |
| What is a pulmonary function test? | Easy test to figure out how blood moves in and out of the lungs. Measures volumes of air moved during inspiration and expiration. |
| What is anatomical dead space? | Air in conducting zone where no gas exchange occurs. |
| The amount of air expired/breath in quiet breathing. | Tidal volume. |
| The amount of air that can be forcefully exhaled after a maximum inhalation. | Vital capacity. |
| What is vital capacity the sum of?? | Inspiratory reserve, tidal volume and expiratory reserve. |
| Automatic breathing is controlled by what? | A rhythmicity center in the medulla oblongata. |
| The rhythmicity center in medulla oblongata consists of _______________ that drive inspiration and _________________ that inhibit inspiratory neurons. | Inspiratory neurons, expiratory neurons. |
| Can our heart beat without our brain? Can we breathe without our brain? | The heart can beat without the brain, but we need the brain to breathe. |
| Inspiratory neurons stimulate _________________ that _____________________________. | Stimulate spinal motor neurons that innervate respiratory muscles. |
| Expiration is _______________ and occurs when ________________. | Passive and occurs when inspiratory neurons are inhibited. |
| How do we know how fast to breathe? | Our body monitors our CO2 levels. Body is also on the lookout for acids (obviously). |
| Automatic breathing is influenced by activity of _______________ that monitor ______________________. | chemoreceptors that monitor blood PCO2, PO2, and pH. |
| Where are central chemoreceptors located? | In the medulla. |
| Where are peripheral chemoreceptors located? | in the large arteries near the heart (aortic bodies) and in the carotids (carotid bodies). |
| what is the primary "thing" that is monitored to gauge how well blood is being oxygenated? This is monitored by what? Why is this (according to Bradley)? | CO2 by the central chemoreceptors in the brain. Bradley suspects this is because CO2 dissolves in plasma better than oxygen, and CO2 can move through membranes faster than oxygen. |
| What receptors can sense oxygen levels? | Peripheral chemoreceptors. Detecting oxygen levels is a backup plan if CO2 concentration changes don't trigger ventilation responses. |
| What is the relationship between the rate of blood flow through pulmonary circuit and the flow through the systemic circulation? | Rate of blood flow through pulmonary circuit EQUALS the flow through systemic circulation. |
| *Rate of blood flow through pulmonary circuit is pumped at a significantly (lower or higher) pressure than flow through the systemic circulation? Why is this? | Lower pressure. Lower pressure produces less net filtration than in systemic capillaries (and this is cool, as the purpose of pumping blood through the lungs is not to push into interstitium, but to exchange gases). |
| Pulmonary vascular resistance is (low or high)? | Low. |
| Resistance in the pulmonary pathway is approximately _______ the resistance of the systemic pathway? | (1/7) |
| What is the normal pulmonary capillary pressure? | 26 mmHg. |
| what is a consequence of having low pressure environment of the pulmonary circulation? | Small changes in pressure can have big consequences on lung function. |
| What results when hydrostatic pressure in the pulmonary vasculature exceeds the colloid osmotic (oncotic) pressure? | Pulmonary Edema. |
| What is the pulmonary capillary blood pressure in pulmonary hypertension? | 35 mmHg. |
| Airways all the way down to the terminal bronchioles have smooth muscles in their walls - this muscle is controlled by ___________________. | the autonomic nervous system (ANS). |
| Tone (tension) in the vessels of the walls of the airway is the result of a balance between what? | contractile and relaxing influences of ANS. |
| Parasympathetic (PNS) stimulation is via what? What does this cause? | acetylcholine. Causes contraction. |
| Sympathetic (SNS) stimulation is via what? What does this cause? | norepinephrine (from nerves) and epinephrine via the adrenal medulla. Causes relaxation. |
| Non-adrenergic, non-cholinergic (NANC) stimulation is via what? What does this cause? | nitric oxide. causes relaxation. |
| What is consolidation when the pulmonary capillary pressure is too great? | Filling up the alveoli with liquids. This happens because you've pressurized the pulmonary pathway. |
| People with liver disease don't make ____________ like they should. | Plasma. |
| Lungs filling with fluid is a result of _____________________. | Pulmonary hypertension. |
Created by:
sam_melillo
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