Skip to main content

How does the circulatory system work with the respiratory system?

The respiratory and circulatory systems work together to deliver oxygen to the tissues and to remove the carbon dioxide byproduct of metabolism from the body. Respiration that occurs within cells and breaks down energy sources such as glucose to make ATP use oxygen and produce carbon dioxide. Oxygen must continuously be delivered to these cells in our tissues in order to keep respiration going and carbon dioxide must be removed to avoid issues like acidosis.  

At the systemic tissues carbon dioxide is at a relatively high partial pressure because it is being produced and oxygen is at a relatively low partial pressure because it is being used by the cells. When freshly oxygenated blood arrives from the left side of the heart to the capillaries surrounding the tissues, it has a relatively high partial pressure of oxygen and low partial pressure of carbon dioxide. Because of this and because gases diffuse from high partial pressure to low partial pressure, oxygen will diffuse from the capillaries to the tissues and carbon dioxide will diffuse from the tissues into the capillaries.  


This blood is then taken back toward the heart through the veins of the body and eventually enters the right atrium through the superior and inferior vena cava. At the same time blood is entering the left atrium from the pulmonary veins coming from the lungs. Both atria then contract, sending the blood they contain through the atrioventricular valves and into the ventricle on the same side of the heart. When the ventricles contract the pressure closes the atrioventricular valves and the blood enters the pulmonary trunk from the right ventricle and the aorta from the left. When the blood entering the aorta will then deliver more oxygen to the tissues, the blood from the right side will enter the pulmonary circulation.


From the pulmonary trunk, the blood will go into either the right or left pulmonary artery and then will enter the capillary beds around the alveoli (air sacs) of the lungs. Diffusion will happen here as well. Within the alveoli there is air that has recently been inhaled. It has a relatively high partial pressure of oxygen and relatively low partial pressure of carbon dioxide due to their concentration in the atmosphere. The blood that has traveled to the area from the right side of the heart was depleted of oxygen at the tissues of the body and has a relatively high partial pressure of carbon dioxide as it was picked up at the tissues by the blood. Because of these differences in partial pressure, oxygen gas will diffuse from the alveoli to the blood in the capillaries and carbon dioxide will diffuse from the blood into the alveoli so that it can be exhaled. Then, finally, this blood goes back to the left side of the heart through the pulmonary veins before it is again sent out to the tissues once again. 


Note that diffusion only occurs at the capillaries when we are talking about the circulatory system. This is because they are lined with thin, flat cells (simple squamous epithelium) so diffusion occurs readily. The walls of other vessels are too think for gasses to diffuse effectively.  

Comments

Post a Comment

Popular posts from this blog

What are some external and internal conflicts that Montag has in Fahrenheit 451?

 Montag, the protagonist of Fahrenheit 451, faces both external and internal conflicts throughout the novel. Some examples of these conflicts are: External Conflicts: Conflict with the society: Montag lives in a society that prohibits books and critical thinking. He faces opposition from the government and the people who enforce this law. Montag struggles to come to terms with the fact that his society is based on censorship and control. Conflict with his wife: Montag's wife, Mildred, is completely absorbed in the shallow and meaningless entertainment provided by the government. Montag's growing dissatisfaction with his marriage adds to his external conflict. Conflict with the fire captain: Montag's superior, Captain Beatty, is the personification of the oppressive regime that Montag is fighting against. Montag's struggle against Beatty represents his external conflict with the government. Internal Conflicts: Conflict with his own beliefs: Montag, at the beginning of th...
Post a Comment
Read more

In A People's History of the United States, why does Howard Zinn feel that Wilson made a flimsy argument for entering World War I?

"War is the health of the state," the radical writer Randolph Bourne said, in the midst of the First World War. Indeed, as the nations of Europe went to war in 1914, the governments flourished, patriotism bloomed, class struggle was stilled, and young men died in frightful numbers on the battlefields-often for a hundred yards of land, a line of trenches. -- Chapter 14, Page 350, A People's History of the United States Howard Zinn outlines his arguments for why World War I was fought in the opening paragraph of Chapter 14 (referenced above). The nationalism that was created by the Great War benefited the elite political and financial leadership of the various countries involved. Socialism, which was gaining momentum in Europe, as was class struggle, took a backseat to mobilizing for war. Zinn believes that World War I was fought for the gain of the industrial capitalists of Europe in a competition for capital and resources. He states that humanity itself was punished by t...
Post a Comment
Read more

Where did Atticus take the light and extension cord in To Kill a Mockingbird?

Atticus brings the light to the courthouse jail so that he can protect Tom Robinson.  Atticus learns that Tom Robinson, his client, is in danger.  A group of white men want to prevent the trial and lynch Robinson. He is warned by a small group of men that appear at his house.  He refuses to back down.  Atticus knows that the Cunninghams will target his client, so he plans to sit up all night with... Atticus brings the light to the courthouse jail so that he can protect Tom Robinson.  Atticus learns that Tom Robinson, his client, is in danger.  A group of white men want to prevent the trial and lynch Robinson. He is warned by a small group of men that appear at his house.  He refuses to back down.  Atticus knows that the Cunninghams will target his client, so he plans to sit up all night with Jim if that’s what it takes to protect him.  Atticus tells the men that he will make sure his client gets his fair shake at the law.  “Link, that boy might go to the chair, but he’s not going till ...
Post a Comment
Read more