lymph node organs, iron cycle, hemostasis, evaluation of blood - Sheet1 Flashcards
What is the spleen, and what are its primary functions?
The spleen is the largest secondary lymphoid organ and functions as a site of fetal hematopoiesis, filters and cleanses the blood, mounts immune responses to bloodborne microorganisms, phagocytoses old, damaged, and dead blood cells, and serves as a blood reservoir (up to 300 mL).
What role does the spleen play in hematopoiesis?
The spleen serves as a site for fetal hematopoiesis, producing blood cells before birth.
How does the spleen filter and cleanse the blood?
The spleen filters the blood by removing old or damaged blood cells and pathogens through phagocytosis, ensuring the blood is clean and healthy.
What is the immune response function of the spleen?
The spleen mounts immune responses to bloodborne microorganisms, producing lymphocytes and antibodies to fight infections.
What is the lymphatic system, and how do lymph nodes function within it?
The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials. Lymph nodes are part of this system and serve as sites for the development and activity of lymphocytes, monocytes, and macrophages, filtering interstitial fluid (lymph) and transporting it back into circulation.
What structural features do lymph nodes possess?
Lymph nodes have fibrous capsules that provide structural support and protect the tissues within.
What role do lymph nodes play in the immune system?
Lymph nodes are the first encounter between antigens and lymphocytes, housing macrophages that filter lymph of debris, foreign substances, and microorganisms while providing antigen-processing functions.
How do macrophages function in lymph nodes?
Macrophages in lymph nodes filter lymph, removing debris and pathogens, and facilitate the activation of lymphocytes during immune responses.
What are Kupffer cells, and what is their function?
Kupffer cells are specialized macrophages located in the liver that play a critical role in filtering and phagocytosing pathogens and dead cells from the blood, contributing to immune response and maintaining liver health.
What are the implications of dysfunction or injury to the spleen?
Dysfunction or injury to the spleen can lead to an increased risk of infections, as the organ is crucial for filtering blood and mounting immune responses. Additionally, it can result in anemia due to the inability to effectively remove old or damaged RBCs.
What are the consequences of lymph node removal (e.g., during cancer treatment)?
Removal of lymph nodes can lead to lymphedema (swelling due to lymph accumulation), impaired immune responses, and increased susceptibility to infections due to the reduced ability to filter lymph and mount effective immune responses.
How does dysfunction of Kupffer cells affect the body?
Dysfunction of Kupffer cells can lead to impaired filtration of pathogens and dead cells, resulting in increased infections, liver disease progression, and a compromised immune response.
What is the iron cycle?
The iron cycle describes the processes of iron absorption, storage, and utilization in the body. Approximately 67% of iron is bound to erythrocytes and myoglobin, 30% is stored in phagocytes, and 3% is lost daily through urine, sweat, bile, sloughing cells, and bleeding.
How much iron is needed daily for erythropoiesis?
About 25 mg of iron is needed daily for erythropoiesis, with 23-24 mg coming from the recycling of erythrocytes and 1-2 mg from dietary sources.
What happens to iron during the breakdown of senescent cells?
During the breakdown of senescent cells, iron is released into the bloodstream. This free iron can either bind to transferrin for transport in circulation or be stored in macrophages’ cytoplasm as ferritin or hemosiderin.
