Oxygenation- resp and cardio. Volume 1
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- How does lung compliance, elastic recoil and airway resistance effect ventilation?
- lung compliance is the ability of the lungs to stretch. Elastic recoil is how they return to their normal position (people with emphysema have overstretched lungs that dont recoil, leaving stale air trapped in the alveoli)...and airway resistance is pretty obvious :p. ...anything that makes your airway smaller will impede ventilation.
- What is the upper airway comprised of?
- nasal passages, mouth, pharynx
- what is the lower airway comprised of?
- it is located below the larynx, and includes the trachea, bronchi, and bronchioles
- which is sterile--upper or lower airway?
- lower airway is sterile
- In what way is mouth breathing not as efficient as nasal breathing?
- the mouth does not warm and moisten inhaled air, and it has no filtering capability.
- where are the tonsils located? ..and what is another name for them?
- lymphoid tissue = tonsils. They are located in the pharynx (aka..throat).
- Where is the trachea located?
- just behind the espohagus. It lies just under the skin of the anterior neck.
- what is the narrowest part of the upper airway? What problems can exist here?
- the larynx is the narrowest part, so it is a common site for airway obstruction.
- what are the differences between the right and left mainstem bronchus?
- The right mainstem bronchus is shorter and fatter than the left and leaves the trachea at a more vertical angle. It is more susceptible to aspiration of foreign bodies, food and fluid. The left bronchus is narrower, longer, and leaves the trachea at a sharper, more horizontal angle (which is why food doesnt usually go there).
- What is the mediastinum?
- it is the space between the lungs that contains the heart and great vessels.
- How many lobes does the right and left lung have?
- The right lung contains 3 lobes, the left lung contains 2.
- Where is the cardiac notch located?
- it sits up against the left lung (which is why it only has 2 lobes.)
- Describe the location of the apex and the base of the lungs?
- It is opposite from the heart. The apex extends upward above the clavical. The base sits on the diaphragm.
- What are alveoli?
- tiny air sacs with thin walls surrounded by a fine network of capillaries. They are the site of gas exchange in external respirations.
- What are type I and type II alveolar cells?
- Type I are the gas exchange site cells. Type II are the cells that are not involved in gas exchange, but they produce surfactant.
- What is surfactant?
- a lipoprotein that lowers the surface tension within alveoli and prevents their walls from adhering together.
- What is the pleura and the pleural space?
- The pleura is a thin, double layered membrane. one layer lines the inside of the chest cavity, and the other covers the outside of the lungs. The space between is the plural space, and it contains a thin flim of fluid that allows the two layers to remain in contact but glide over eachother during breathing movements.
- What is the pressure within the pleural space?
- a negative pressure.
- What is ventilation ?
- the act of breathing. Movement of air into and out of the lungs.
- What is respiration?
- the exchange of gases (oxygen and carbon dioxide) in the lungs.
- What is oxygenation?
- how well the cells, tissues and organs are being supplied with oxygen.
- What are the two steps in oxygenation *IMPORTANT CONCEPT*
- The first step is getting oxygen to diffuse into the blood cells at the alveolar-capillary membrane. The second step is transporting the oxygen (via the blood) to the tissues so that it is available for their use. The first step is teh responsibility of the lungs, the second step is the responsiblity of the cardiovascular system.
- What is hypoxemia?
- low blood oxygen levels. It occurs when blood is not adequately oxygenated at the alveolar-capillary membrane.
- What is perfusion?
- the circulation of blood to all the body regions
- Hypoxia
- inadequate oxygen levels in the tissues and organs.
- What happens during inhalation?
- the chest expands (duh), there is a NEGATIVE pressure inside the lungs which causes air to be drawn inward. The diaphragm contracts and pulls the chest cavity downward.
- What happens during exhalation?
- it occurs when the diaphragm and intercostal muscles relax, allowing the chest and lungs to return to their normal size. The pressure inside the lungs rises ABOVE atmospheric pressure, so air flows out of the lungs. Exhalation requires no energy or effort.
- Hyperventilation
- rapid breathing. It can be in response to hypoxemia (low blood-oxygen levels at the alveolar capillary membrane). It also causes carbon dioxide levels to fall.
- Hypoventilation
- decreased breathing. It can CAUSE hypoxemia because less air is reaching the alveolar-capillary membrane. Hypoxemia can then lead to hypoxia (inadequate oxygen at the tissue level). *check to make sure, but from what I understand, Carbon Dioxide levels should be HIGH.
- Respiration
- refers to gas exchange. Its the oxygenation of blood and elimination of carbon dioxide in the lungs.
- External respiration
- occurs in the lungs at the alveolar-capillary membrane. The gas exchange occurs via diffusion.
- How does a high oxygen pressure in the alveoli effect diffusion?
- the higher the pressure the faster it will diffuse into the blood stream(remember from higher to lower concentration)
- How would a condition that thickens the alveolar-capillary membrane effect diffusion of oxygen and carbon dioxide?
- O2 and CO2 diffuse more rapidly through a thin membrane, so a condition that would thicken the membrane would slow the rate of diffusion because there is a greater distance for the gases to travel.
- Which gas -oxygen or carbon dioxide diffuses more rapidly?
- Carbon Dioxide diffuses 20 times more rapidly than oxygen, and will continue to diffuse accross and ABNORMAL capillary membrane long after oxygen diffusion has slowed dramatically.
- Internal respiration
- occurs in the tissue-capillary membrane. Oxygen diffuses from the blood into the cells where it is used for metabolism. CO2 (a waste product from cellular metabolism) is then produces and diffuses into the blood where it is transported to the lungs and exhaled.
- For tissue oxygenation to occur, what two things must adequately take place?
- Tissue oxygenation requires both adequate external respiration, and also adequate peripheral circulation. Limitations in either one can lead to tissue hypoxia.
- How would something like a fever effect the bodys need for oxygen. What problems could result?
- In a fever, the body cells have an increased need for oxygen due to a higher metabolism. Unless more oxygen is made available to the tissues (through increased breathing and adequate circulation) hypoxia will occur.
- What do chemoreceptors and lung receptors do?
- They send messages back to the respiratory centers in the brain stem to control the rate of breathing. Chemoreceptors detect the gas levels in the blood as well as the pH level of the blood, and send messages to adjust things accordingly. Lung receptors detect lung conditions, breathing patters, and external stimuli (irritants, etc) and send messages to adjust accordingly.
- Which gas is the primary stimulus for breathing?
- carbon dioxide. High CO2 levels stimulate breathing to eliminate the excess CO2. ..low oxygen levels also stimulate breathing, but the primary stimulus is carbon dioxide.
- Voluntary control of breathing controlled by what?
- the motor cortex.
- What is the pericardium?
- a sac of connective tissue that encases the heart.
- describe the base and apex of the heart
- opposite of lungs. The base is at the TOP of the body and the apex is at the bottom.
- Describe blood flow through the heart:
- Deoxygenated blood from organs and tissues travels via the venous system into the superior and inferior vena cava and into right atrium. It then travels through the tricuspid valve into the right ventricle, which then pumps it through the pulmonary semilunar valve to the pulmonary arteries and into the pulmonary circulation(to the lungs) where gas exchange occurs at the alveolar capillary membrane. The newly oxygenated blood then flows from the lungs into the pulmonary VEINS and into the left atrium. From the left atrium the oxygen rich blood passes through the mitral valve into the left ventricle, which then pumps it into the aortic semilunar valve and into the aortic arch (which contains ARTERIES). The oxygen rich blood then gets transported through arterial circulation to the body tissues. And the cycle repeats itself.
- When are veins and arteries 02 rich and O2 poor?
- Veins are usually O2 poor except when they are entering the heart from the lungs (in which case they have just picked up oxygen and are 02 rich). Arteries are usuall O2 rich, except when they are LEAVING the heart to go to the lungs to pick up oxygen. Just remember, arteries always go away and veins always come in. So if blood is leaving the hear to go to the lungs, it has to go via an artery, but it is going to be O2 poor because it hasnt yet gotten to the lungs. ..and vice versa for the Veins entering the heart.
- What is the cardiac cycle?
- it is the sequence of events that happens during a single heart beat. It is the simultaneous contraction of the two atrium follow a fraction of a second later by the simultaneous contraction of the two ventricles.
- What regulates the cardiac cycle?
- the electrical activity of the myocardium (thickest layer of heart--the middle layer).
- Describe the electrical conduction system of the heart:
- The SA node creates an impulse that triggers each heart beat. The impulse from the SA node travels down the atrial conduction system (which innervates both atrium) causing them to contract simultaneously. It then travels to the AV node where there is a slight delay before the impulses pass into the left and right bundles of HIS and into the Purkinji fibers which stimulate the ventricles to contract as one.
- Where is the SA node located?
- in the right atrium ...which is part of why its called sinoatrial node.
- What happens if the SA node fails?
- The AV node can take over as the pacemaker, but it generally triggers a slower heart rate.
- What happens if both the SA node and the AV node fail?
- the conduction fibers can generate impulses but this creates a very slow heart rate of less than 40 beats per minute.