Question

I have a few general questions

Pulmonary circulation: What is it? What is the specific purpose? What structures are involved? What's the function?

Lymph Nodes: What is it? What specifically does it do? Where is it found specifically?

Explain why there are different blood groups ALSO why is it that a person with Blood type O is incapable of receiving blood from blood type B?

Lastly

Describe the circulatory system between avian and non avian reptiles what are the main differences and why do those differences exist?

Answer 1

Pulmonary circulation:

What is it? What is its purpose?

Pulmonary ciculation is the ciculation of blood between lungs and heart. Basically, each cell in your body needs oxygen for metabolic production of energy and various other functions. So cells use up this oxygen and covert it into carbon dioxide. This carbon dioxide is carried by small venules from various parts of you body to meet at larger veins and empty deoxygenated blood into veins. The deoxygenated blood from veins is drained into the larger veins known as superior and inferior vena cava, which circulate this deoxygentaed blood into the right atrium of heart, it empties blood into right ventricle and this right ventricle sends this deoxygenated blood through pulmonary artery to lungs. Lungs oxygenate the deoxygenated blood through respiration and ciculate it through pulmonary veins into the left atrium and thus to left ventricle. So in the end oxygenated blood is ciculated by arteries to every organ and each cell for vital functioning of body.

What structures are involved?

1 Lungs: Lungs are needed for oxygenating the blood as described above. They take up environmental oxygen and put that into our blood ciculation and take up carbon dioxide from blood and give it back to the environment.

2. Heart: Heart pumps the deoxygenated blood into lungs and pumps oxygenated blood into the arteries for circulation.

3. Veins: Veins carry deoxygenated blood and they transfer blood from tissues to heart (exception, Pulmonary veins carry oxygenated blood and give it to heart; because basic definition of vein is that any vessel bringing blood to heart is called a vein.)

4. Arteries: Arteries carry oxygenated blood and they transfer blood from heart to other tissues. (Exception: Pulmonary arteries carry deoxygenated blood and give it to lungs; because basic definition of artery is any blood vessel taking blood away from heart)

What is the function?

The basic function of pulmonary system through respiration is to take away the carbon dioxide from deoxygenated blood and to oxygenate the blood. Because through this process, oxygen reaches each cell in your body which is of prime importance because it allows the cells to harness energyand perform vital functions of body.

Lymph nodes:

What is it?

Lymph nodes (also known as lymph glands) are part of lymphatic system (netwrok of lymphatic organs, lymphatic vessels and tissues) and adaptive immune system ( Immune system that is concerned with B and T cells for fighting against specific pathogen and cancer cells). They are important organs for lymphatic cells (B and T cells). They act as a storage organ for these cells.

What specifically does it do?

It lodges lymphatic cells and it is important for clearing of infection. Now, infection is caused by a bacteria or a virus. These pathogenic microbes are cleared by innate (non-specific) response and/or by adaptive (specific) immune response. The pathogenic foreign microbes contain on their cell wall a lot of antigens. (Assume as different color clothes wore by a criminal) So, when there is a microbe invasion these lymphatic cells, specifically B cells bind to the antigen through their receptors (Assume the criminal being recognized by the color it wears). If the receptor binds to the antigen, it would generate a response to fight against it by the B cell generating antibodies specific to that antigen (Imagine the cops recognizing the criminal by the black mask and attacking him with guns). T cells with the help of B cells are activated and enhance the immune response (Imagine the colleagues of the cop assisting him to kill the criminal). B cells which generate the antibodies against the pathogen are called plasma cell and the other type of B cells are called memory cells which make a memory against the invaded microbe. So lymphativ organs or glands are storage for the lymphatic cells and thus are important to clear a infection.

Where is it found?

Lymph nodes/glands are present throughout your body and there are approximately 450 lymph nodes in an adult. They are distributes in the head and neck, chest, arms and axilla, abdomen and legs.

Listing some of them :

• Ossipital lymph nodes
• cervical lymph nodes
• Sub-clavicular lymph nodes
• Gastric lymph nodes
• Splenic lymph nodes, etc

Why there are different blood groups?

There are different forms of blood group because each person have specific antigen/antigens on their red blood cells (RBC's) and presence or absence of antibodies against antigens inside their blood. These antigens on the RBC's are inherited to you from your parents. So a person with blood group A has a antigen A on the RBC and antibodies against B antigen, i.e., if blood from a person with blood group B is transfused into a person with blood group A, it would generate a response because antibodies against B antigen would bind to it, and evoke a immmune response.

Why a person with blood group O cannot receive blood from a person with blood group B?

A person with blood group O does not have any antigen on its RBC, but this person has antibodies against antigen A (present on RBC of a person with blood group A and AB) and antigen B (present on RBC of a person with blood group B and AB). So is blood from a person from blood group B is transfused into a person of blood group O, the antibodies against antigen B will bind to the donor RBC's and generate a immune response by attracting all the immune cells which can lead to hemolysis (destruction of RBC's), shock (ineffiecient circulation of blood to tissues and thus dying of tissues), etc. These responses are life threatening.

Circulatory system of avians vs. reptiles:

The major difference between circulatory system of birds and reptiles is that the reptiles have 3 chambered heart (or pseudo 4 chambered) and birds have 4 chambered heart just like mammals with completely clodes ciculatory system. And this difference is just on the basis of evolution of both the phylums. The ventricles of the reptilian heart are superficially divided and so the oxygenated and deoxygenated blood mixes while in avians, the circulatory system is similar to mammals.