HPD Flashcards
Name the components of the respiratory system.
External nose, nasal cavity, pharynx, larynx, trachea and bronchi.
What are lungs enclosed from?
Parietal fluid, Intrapleural fluid and visceral fluid.
What’s the difference between passive and active breathing?
Active breathing involves the use of many muscles while passive is quiter and involves mainly the diaphragm.
What is the movement of the diaphragm when it contracts?
It goes down pulling thee lungs.
Which muscles move the rib cage hence the lungs?
Scalenes, sternocleidomastoids and internal and external intercostals.
What is the ratio of N, O, CO2 in the air?
Nitrogen 79%, Oxygen 21% and carbon dioxide 0.04%.
What’s the ratio of oxygen and CO2 in the arterial blood?
100:40 oxygen to CO2
What is the ratio of oxygen to CO2 in venous blood?
40:45 oxygen to CO2
What’s the effect of pH on haemoglobin binding to oxygen?
The higher the pH the fastest the binding.
What is the effect of the temperature on the binding of haemoglobin with oxygen?
The higher the temperature the slower the binding.
What is the effect of CO2 concentration on the binding of oxygen on haemoglobin?
The higher the concentration of CO2 the slower the binding.
What’s the effect of BPG on the binding of haemoglobin to oxygen?
The more the DPG the slower the reaction gets.
How is oxygen transported in the bloody through circulatory system?
Oxygen is taken by red blood cells that contain haemoglobin and bind with it. When the red blood cell reaches the cells that require oxygen, it brakes it’s bonds with haemoglobin and is transported to the cell…
How is CO2 transported in the blood?
CO2 is taken from the cell to the red blood cell. 23% binds on haemoglobin. Then the other 70% of it reacts with water forming H2CO3. Some of this will bind to haemoglobin in the form of H+ and the HCO3- which is left will be excreted. Cl- will be inserted to replenish the negative charge. When the red blood cell reaches the lungs, Cl- will come out letting HCO3- come in. Then the reverse reaction will occurs with H+ letting CO2 leave the red blood cell. Also, some dissolved CO2 will get into the alveoli.
What is haemoglobin made of ?
4 Globin chains and a 4 heme groups which is a porphyrin ring with an Iron atom.
Describe the local control of gas exchange in alveoli.
If ventilation decreases pO2 decreases and pCO2 increases. Hence, the capillaries next to the alveoli that are under ventilated is constricted and the blood is redirected to better ventilated alveoli.
How are bronchioles, pulmonary arterioles and systemic arterioles modified by pO2 and pCO2?
Bronchioles are controlled mainly by pCO2. If pCO2 increases they dilate to suck it and excrete it to the environment. Pulmonary arteries don’t tend to be modified by the neural system much. However when pO2 drops the get restricted. Systemic arteries on the other hand dilate with low pO2 so that more O2 comes to them.
How does the nervous system react on the decrease of pO2?
Decreases pO2 stimulates the peripheral chemoreceptors which increase ventilation increasing the plasma pO2.
How does the increase of pCO2 in CSF affect the nervous system?
This kind of increase of pCO2 causes a reaction that generates h+ and HCO3-. This causes an increase in pH. However, the central chemoreceptors monitor only pCO2 hence when pCO2 increases ventilation is increased and pCO2 decreases.
How does the nervous system respond in an increase in pCO2 in arterial system?
CO2 again generates the production of H+ and HCO3- which increase the pH in the plasma. The peripheral chemoreceptors monitor the pH increase, the H+ increase and the CO2 increase hence, increase ventilation in order to decrease them.
How do the nerves help in passive breathing?
When inspiration has achieved the maximum volume of air for passive breathing, active neurons for inspiration shut off causing expiration to start.
Hat does Emphysema cause to ventilation?
Emphysema is a disorder that causes the destruction of alveoli. This reduces the transport of O2 in the blood.
What does asthma cause to ventilation?
Asthma is a disorder that causes the restriction of bronchioles. Hence, O2 can’t be transported to the alveoli easily.
What does fibrotic lung disease cause to ventilation?
This is when the membranes of alveoli gets so thick that the diffusion of O2 gets slowed down.
What does pulmonary enema cause to ventilation?
This is when a big gap appears between alveoli and capillaries because of fluid slowing down the reach of O2 to the capillaries.
What is hypoxic hypoxia?
This is caused by high altitude that causes less ventilation. Hence, less O2 reaches the blood.
What is anaemic hypoxia?
This is caused by loss of blood and it causes loss of haemoglobin hence worse transport of O2 in the body.
What’s ischemic hypoxia?
This is when thrombosis or heart failure occurs causing reduced blood flow hence O2 flow?
What’s histotoxic hypoxia?
It’s caused by toxins such as cyanide and cause failure of cells to use O2 because of being poisoned.
What is thlalasaemia?
Thlalasaemia is genetic disease that is caused by a mutation in the α ορ β globin gene. BGT is more severe and it’s hosts need blood transfusions. In general, thlalasaemia causes distraction of haemoglobin hence lack of transport of O2. It is observed that Mediterranean countries are more prone to get it.
How is lung collapse caused and what happens?
If air is introduced in the rib cage (knife) the intrapleural space increases causing the pressure of the rib cage to be equal with the atmospheric pressure. Hence, the lung is suppressed causing it not to function.
How does smoking affect ventilation?
Tobacco smoke has CO2 which does not let alveoli to be cleaned increasing mucus. Also, it binds to haemoglobin irreversibly causing its saturation. Hence, more blood should be pumped to get the required oxygen. Also, smokers tend to have emphysema or COPD.
How is food digested in the stomach?
Food is stored in the fundus which is located in the upper part of the stomach. Then, it is moves in the Antrum which is the lower part and is digested there with the use of enzymes by peristaltic movement.
