CVS - blood p2 Flashcards
What is erythropoiesis + stages of it?
*process by which red blood cells are produced (15 days long)
*proerythroblast → erythroblast → reticulocyte → erythrocyte
What are the steps of the regulation of erythropoiesis?
1:Detection of hypoxia
2:EPO release
3:stimulation of erythropoiesis
4:restoration of oxygen levels
5:negative feedback inhibition
What occurs in detection of hypoxia?
*Kidney Becomes Hypoxic: When the oxygen level in the blood decreases (hypoxia), the renal arterial oxygen level drops
*Trigger for EPO Release: The kidneys detect the low oxygen levels through specialised cells in the renal cortex
What occurs in EPO release?
*Production: In response to hypoxia, the kidneys release erythropoietin (EPO) into the bloodstream.
*Function: EPO travels through the blood to the red bone marrow
What occurs in the stimulation of Erythropoiesis?
*EPO Action: EPO stimulates the red bone marrow to increase the production of erythrocytes (red blood cells) from haematopoietic stem cells
*Erythrocyte Production: The bone marrow responds by producing and releasing more red blood cells into the circulation
What occurs in oxygen restoration?
*Increased Oxygen Transport: The newly produced erythrocytes increase the oxygen-carrying capacity of the blood.
*improved oxygen delivery: as oxygen levels in the blood rise, more oxygen is delivered to the tissues, including the kidneys
What happens in the negative feedback inhibition?
*Reduced Hypoxia: As the kidneys receive more oxygen, the hypoxic stimulus decreases
*Inhibition of EPO Release: The increased oxygen levels in the renal arteries signal the kidneys to reduce the production and release of EPO
*Balanced Erythropoiesis: This feedback mechanism ensures that erythrocyte production is balanced, preventing excessive or insufficient red blood cell counts
What causes hypoxia?
-Haemorrhage or Injury
-Iron deficiency-
-High Altitude or Lung Disease (Pneumonia)
What nutrients are needed in erythropoiesis?
*Iron: Dietary
*65% in Hb
*Bound with protein and stored as ferritin and haemosiderin
*Transported by binding with transferrin
*Substrates, like amino acids, lipids and carbohydrates
Folic acid & Vitamin B12 – DNA synthesis/Development of RBC
What effects does testosterone have on EPO?
*testosterone enhances EPO production in kidneys = more RBC
*higher RBC = higher haemltocrit levels in males compared to females
What are the impacts of high EPO levels?
*Faster Maturation of Erythrocytes: Elevated EPO levels cause erythrocytes to mature more rapidly in the bone marrow
*Increased Haematocrit: Higher RBC production increases the proportion of red blood cells in the blood (haematocrit)
What are the potential risks to higher EPO?
*dehydration
*increased blood viscosity
What are the health risks associated with increased EPO and haemocrit?
*blood clotting
*stroke
*heart failure
What are the key stages in the life cycle of RBC?
100-120 days
-Cannot grow, divide and replicate (no nucleus)
-Get older and fragile and degenerate
-trapped/macrophage in spleen- RBC breakdown
What is recycled of RBC components?
Iron- recycled & stored
Heme- Degraded to bilirubin, yellow pigment-Liver secretes bilirubin in bile (in the intestine)-urobilinogen-stercoblin, brown pigment excreted in faeces
Globin- metabolised into aminoacids & recycled
What are the signs and risks of anaemia?
*low oxygen (Hypoxia) insufficient oxygen supply to tissues
*impact on growth and development
*metabolic dysfunction
What are the causes and types of anaemia?
1: blood loss =haemorrhagic anaemia
- acute blood loss
- chronic blood loss
2: RBC deficiency:
- iron deficiency anaemia
3: renal anaemia
4:pernicious anaemia
5:aplastic anaemia
What is iron deficiency caused + effect by?
Cause: Insufficient iron, leading to the production of small, pale RBCs (microcytes) that lack adequate haemoglobin
What is renal anaemia caused by + effect?
Cause: Kidney disease results in a lack of erythropoietin (EPO), which is necessary for RBC production
What is pernicious anaemia caused by + effect?
Cause: An autoimmune condition that impairs the absorption of vitamin B12, essential for RBC division.
Effect: Without B12, RBCs become large and abnormal (macrocytes).
What is aplastic anaemia caused by + effect?
Cause: Damage to the red bone marrow, often due to chemotherapy, radiation, or exposure to toxic chemicals.
Effect: The bone marrow fails to produce sufficient RBCs
What is thalassemia caused by? + effect (alpha and beta)
Alpha
Cause: Deficiency or absence of alpha-globin chains.
Effect: RBCs become thin, fragile, and deficient in haemoglobin
Beta:
Cause: Deficiency or absence of beta-globin chains.
Effect: Similar to alpha thalassemia, RBCs are thin, fragile, and lack adequate haemoglobin