Blood & its components Flashcards
What is Haematopoiesis?
The process of blood cell formation from haematopoietic stem cells in the bone marrow.
What is pluripotential haematopoietic stem cell?
A type of stem cell found in the bone marrow and peripheral blood - that can differentiate into all blood cell lineages.
What is erythropoiesis?
The process of red blood cell formation in the bone marrow
What are the stages of erythropoiesis?
Haematopoietic stem cell → Myeloid progenitor → Proerythroblast → Early erythroblast → Late erythroblast → Normoblast → Reticulocyte → Erythrocyte
What is granulopoiesis?
The process of granulocyte formation in the bone marrow.
e.g. of granulocyte: neutrophil, eosinophil, basophil
What are the stages of granulopoiesis?
Haematopoietic stem cell → Myeloid progenitor → Myeloblast → Promyelocyte → Myelocyte → Meta-myelocyte → Band cell → Granulocyte
What regulates erythropoiesis?
Erythropoietin (EPO) from the kidneys in response to hypoxia
What regulates granulopoiesis?
Colony-stimulating factors, such as G-CSF, GM-CSF
What is the role of the mononuclear phagocyte system in health & disease?
mononuclear phagocytes = macrophages, dendritic cells
They engulf & digest pathogens, damaged cells and cellular debris by phagocytosis.
They secrete cytokines that regulate immune responses and inflammation.
Dendritic cells - antigen presentation
What is the composition of blood?
- plasma
- red blood cells
- white blood cells
- platelets
What is the function of blood plasma?
Transports nutrients, hormones, waste, and maintains osmotic balance
What is the function of red blood cells?
Oxygen transport via haemoglobin
What is the function of platelets?
Blood clotting and vascular repair
Name the 5 types of white blood cells.
- Neutrophils
- Eosinophils
- Basophils
- Monocytes
- Lymphocytes
Where does haematopoiesis occur throughout life?
In foetus: yolk sac → liver & spleen → bone marrow
In human being: bone marrow
Where is the spleen located?
In the left upper quadrant of the abdomen
What is the function of the spleen?
Blood filtration, immune response, and RBC breakdown
What is the arterial supply of the spleen?
Receives oxygenated blood from Splenic artery (branch of the celiac trunk)
Venous drainage of the spleen
Splenic vein, which drains into the hepatic portal vein
What is oncotic pressure?
The osmotic pressure exerted by plasma proteins to retain fluid in the vasculature
