The Respiratory system Starts in the nose Starts with a big diameter tube trachea then divides into the left right lungs After trachea it divides in the primary bronchus Secondary Bronchi Tertiary Bronchi Bronchioles Terminal Bronchioles Bronchioles tube with smallest diameter o They have two divisions Terminal bronchiole Sacs alveolus Last respiratory sac end of respiratory system nothing else after the alveoli Capillaries surround the alveolus cause they are waiting for oxygen Single layer of epithelial cells surround the alveolus Whatever happens in one alveolus is happening in all of them Oxygen has to move from alveolus to blood via simple diffusion CO2 will move from blood to the alveolus Air has to move from the outside to the alveoli The only place in the respiratory tube where there is an exchange in gases is the alveolus Trachea Bronchioles without the alveolus o Conducting zone o Only function is to allow the movement of air o Conducting zone cuts off at the terminal bronchiole Diaphragm o Somatic system we can control breathing o Inserts in the skeletal muscle Respiratory Zone o Terminal bronchiole with the alveolus Respiratory membrane o Wall of the alveolus with the epithelial cells o Wall of capillaries have endothelial cells o In between we have fluid interstitial fluid o Main function is the exchange of gases The blood in the lung capillary is coming from the right ventricle it has a high concentration of CO2 In the lung blood vessel o Angiotensin converting enzyme ACE o Converts from 1 to 2 Breathing o Inspiration air flows into the lungs o Expiration gases exit lungs o We move air by changing the pressure o Diaphragm volume increases breathe out So low pressure in lungs moves from high to low so inspiration Our ribs function to protect internal vital organs muscle between the ribs intercostal allow rib cage to expand during inhalation Diaphragm most important respiratory muscle o Need this muscle when we move a big amount of air The abdominal muscles o If you get hit in abdominal region pressure inside increases cavity size decreases pushes diaphragm up so thoracic size increases pressure increases so expiration occurs o Ribs are expiratory o The diaphragm is the opposite inspiratory When the diaphragm relaxes it goes up the pressure increases expiration happens When you contract the diaphragm it goes down when diaphragm comes down contraction pressure DECREASES when it comes up relaxation pressure INCREASES at rest the diaphragm is doing all of the work The muscles of the abdomen are the main expiratory muscles needed when we are not at rest ex Imagine blowing up a balloon with your mouth Contraction of the abdomen increases pressure and pushes the diaphragm up causing expiration o relaxing theses muscles causes a decreases in pressure EXHILATION DIAPHRAGM COMING UP INCREASES PRESSURE INSPIRATION DIAPHRAGM COMING DOWN DECREASED PRESSURE 1 at rest the diaphragm is relaxed 2 during inspiration the diaphragm is contraction 3 during expiration the diaphragm is relaxing If we have a pressure in the alveolus 1 3ml less we will introduce a nor mal volume of air in each inspiration around 500ml of air ATM 760mmHg it takes GREATER than the atmospheric pressure 760mmHg to move air from inside of the lungs to the outside air expiration Contracting abdomen will increase pressure in thoracic cavity which will increase volume of air in expiration F air flow P change in pressure R resistance to airflow o Increase p by having a bigger difference between the environmental air the alveoli o Increased resistance decreased airflow o Example mucus in the air tube is causing resistance airflow decreases and as air tries to flow through the resistance causes us to cough up the mucus Movement of air chart graph o Tidal volume 500ml 600ml of air Volume of air moving in and out of the lungs during normal inspiration expiration Ventilation is what s occurring inside of the lungs Introduce and exhale from our lungs looks like a wave a constant wave o Depending on size of person it will be bigger or smaller big person bigger volume Anatomical dead space o The 500ml are divided into the two parts 350 alveolar air will reach the respiratory zone Conducting zone 150ml of air will not participate in the exchange Breathing rate is 12 15 breaths per minute If we multiply 350 times the breathing rate 15 we will have the air that reaches alveolar in one minute Volume is directly related to pressure meaning that that when volume increases pressure also increases Properties of gas o Pressure of the air depends on where you are at sea level it is 760mmHg o Most abundant gas is nitrogen the most important is oxygen o 160mmHg is the partial pressure of oxygen 760x 209 160mmHg Partial pressure of CO2 is 3mmHg o The pressure in the alveolus will not change unless we stop breathing the only one that changes is the partial pressure of gases in the blood o Oxygen to capillaries is a big change in pressure it keeps happening then eventually there will be an equal amount and no more gas exchange 104 104 The pulmonary vein Artery coming from the right ventricle same blood that s in the vena cava is what brings blood to the left atrium 7 24 12 Respiratory contin Partial pressure of oxygen and CO2 comes from the veins Partial pressure Gradients o Partial pressure of oxygen is close to 100 and 40 for CO2 o The blood arriving from pulmonary artery its 40 for O2 and 45 for CO2 o When the blood enters to the capillaries and encounters the high pressure of oxygen and low pressure of CO2 it will be an exchange from high pressure to low pressure o More oxygen pressure increase to 180 o Blood flows and gains more oxygen o Same type of blood that will arrive to the systemic capillaries o Partial pressure of CO2 in the environmental air is 0 clean air o We need only 5 mm of CO2 and 60 for O2 because C02 is more diffusible o More oxygen in arterial blood because at the level of the systemic capillaries it is receiving more oxygen Partial pressure will diffuse from 160 100 40 o Cells have to wait in systemic capillaries to get oxygen and dump the CO2 thus going to 40mm o Difference between the blood and the oxygen in the cells is 60mmhg o Partial pressure of oxygen and CO2 in the cell is the same in the venous blood as it is in the cells systemic capillaries Understand this chart about how the blood flows 4 molecules of oxygen from alveolus to the blood travels on a hemoglobin o One RBC has more than one molecule of
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