Blood 1 Flashcards
How does blood contribute to homeostasis?
Serves as:
- The vehicle for transporting materials to & from cells
- Buffering changes in pH
- Carrying excess heat to the body surface for elimination
- Plays major role in body’s defence system
- Minmising blood loss when a blood vessel is damaged
Why is blood crucial for the survival of cells?
- Cells need constant supply of O2 & removal of CO2
- Cells can only survive & function only in a narrow pH & temp range
- Cells must be protected against disease causing microorganisms
Why is O2 important for cells?
It supports their energy generating chemical reactions - which produce CO2
What is the total amount of fluid in the body?
42 litres
How is the 42 litres of body fluid divided around the body?
- Intracellular volume = 28L
- Extracellular vol = 14L
- Plasma vol = 3L
- Red cell vol = 2.5L
How much of your body fluid does blood make up?
5.5L
(Plasma 3L and Red cell 2.5L)
How does circulation support the need of tissues?
- Transports nutrients to tissues
- Transports waste products away from tissues
- Carries hormones from one part of the body to another
- Maintains appropriate environement in all tissue fluids for optimal survival & func of cells
What is the composition of blood?
Plasma (3L - 55%)
Formed elements (2.5L - 45%)
- Red cells (erythrocytes)
- White cells (leukocytes)
- Platelets (thrombocytes)
What is another name for red cells?
Erythrocytes
What is another name for white cells?
Leukocytes
What is another name for platelets?
Thrombocytes
What is the haematocrit?
The proportion of red cells in the blood volume - is approx 45%
When blood is spun the RBCs pool at the bottom so can count them
Males = 42% - 52%
Females = 37% - 47%
How will Anaemia, Polycythaemia and Dehydration change the haematocrit?
Anameia = 35%
Polycythaemia = 70%
Dehydration = 70%
Why does the Haematocrit look the same in Polycythaemia and Dehydration?
Polycythaemia - total blood volume stays the same however the amount of RBCs increases from 45% to 70%
Dehydration - total blood volume dec (to lets say 65% of normal), so the RBC vol stays the same but the total vol of blood dec, therefore is 70%
What can your blood proportions help to determine?
Whether you are healthy or not
What is an external factor that can affect the proportion of RBCs in your blood?
Altitude
What can cause anaemia?
Blood loss, e.g. haemorrhage
Haemolytic disease, e.g. sickle cell
(Causes haematocrit to dec)
What causes Polycythaemia?
Secondary factor/physiologic i.e. hihg altitude
Polycythaemia vera = bone marrow tumours (a type of blood cancer that causes production of too many RBCs)
What % of world pop suffer from anaemia?
40%
What are 3 major causes of anaemia?
- Dietary iron deficiency
- Micronutrient deficiencies
- Iron absorption
How does dietary iron deficiency cause anaemia?
Diagnosed by low haemoglobin - low serum ferritin response to iron supplements
How does micronutrient deficiencies cause anaemia?
Haemoglobin synthesis dec due to lack of vitamin B12 or folic acid
How does low iron absorption cause anaemia?
A lack or riboflavin alters level of iron absorption
Riboflavin is involved in RBC production and transportation of oxygen to the cells
What is polycythaemia also known as?
Erythrocytosis
What is Polycythaemia?
Having a high concetration of RBCs in you blood
What are the symptoms of of Polycythaemia?
- A ruddy complexion
- Headache
- Blurred/patchy vision
- Confusion
- Stroke or coma (extreme)
What are the subtypes of Polycythaemia?
Absolute erythrocytosis
Apparent erythrocytosis
What is absolute erythrocytosis?
Rasied red cell mass - normal plasma volume
What is apparent erythrocytosis?
Normal red cell mass - reduced plasma volume
What is the treatment for Polycythaemia (erythrocytosis)?
Venesection (blood letting)
What is the Congenital primary cause of Polycythaemia (erythrocytosis)?
(Caused by an abnormality in the red cells)
Congenital –> Abnormal erythropoietin cell receptor, von Hippel Linda protein or proline dehydroxgenase enzyme
What is the Acquired primary cause of Polycythaemia (erythrocytosis)?
(Caused by an abnormality in the red cells)
Acquired:
- Polycythaemia vera
- Myeloproliferative Disease
What are the Congenital secondary causes of Polycythaemia (erythrocytosis)?
(Caused by an abnormality outsdie of the RBCs)
Congenital:
- Inherited High Erythropoietin
- Abnormal haemolgobin with increased O2 affinity
- Decreased levels of metabolites
What are the Acquired secondary causes of Polycythaemia (erythrocytosis)?
(Caused by an abnormality outsdie of the RBCs)
Acquired:
- Conditions causing low O2 levels: chronic lung disease, congenital heart disease, sleep apnoea
- Kidney disease: tumours, cysts, block to urine flow, kidney transplants
- Liver diease
What are the Idiopathic secondary causes of Polycythaemia (erythrocytosis)?
(Unknown cause)
Idiopathic erythrocytosis
What are the 3 main components of the blood?
- Plasma –> 55%
- Buffy coat –> leukocytes & platelets less than 1% of blood vol
- Erythrocytes –> 45% of whole blood vol
What is the role of plasma?
Transport of substances
What is the role of the Buffy coat?
Leukocytes –> Defence
Platelets –> Clotting
What is the role of erythrocytes?
Transport of gasses
What are the plasma components?
- Water (90%)
Solutes:
- Proteins (8%)
- Albumin
- Globulins
- Fibrinogen
- Others
What role does water play in plasma?
- Makes up 90% of plasma vol
- Prrovides dissolving & suspending medium for solutes & formed elements
What role do proteins play in plasma?
Account for 8% of plasma (by weight);
Most are synthesised by liver
What role does albumin play in plasma?
60% of plasma proteins;
Largely responsible for plasma osmotic pressure
What role do globulins play in plasma?
36% of plasma proteins;
Include:
- Clotting proteins
- Antibodies secreted by certain leukocytes during the immune response
- Proteins that bind to lipids
- Fat-soluble hormones & metal ions to transport these substances in the blood
What role does fibrinogen play in plasma?
Important in the formation of blood clots
What role do the other molecules play in plasma?
Enzymes, hormones & antibacterial proteins
Albumins:
Where is it made and what is its function?
Source: Liver
Function: Major contributors to colloid osmotic pressure of plasma; carriers for various substances
Globulins:
Where is it made and what is its function?
Source: Liver & lymphoid tissue
Function: Clotting factors, enzymes, antibodies, carriers for various substances
Fibrinogen:
Where is it made and what is its function?
Source: Liver
Function: Forms fibrin threads essential to blood clotting
Transferrin:
Where is it made and what is its function?
Source: Liver & other tissues
Function: Iron transport
Others in the plasma:
Where is it made and what is its function?
Source: various
Function: Enzymes, hormones & antibacterial proteins
What is hypotonic?
Cell swells & loses shape
What is hypertonic?
Cells collapse but rigid cytoskeleton remains intact
What are the components in plasma that are transported?
- Nitrogenous waste products
- Organic nutrients
- Electrolytes
- Cations
- Anions
- Respiratory gases
What are nitrogenous waste products?
By-products of metabolism, such as ureas, uric acid and creatine
What are organic nutrients?
Materials absorbed from the intestines & used by cells throughout the body;
Includes glucose and other simple sugars, amino acids, fatty acids, glycerol, triglycerides, cholesterol and vitamins
What are cations?
Sodium, potassium, calcium, magnesium (important in neuromuscular signaling), and trace metals (important in normal enzyme activity)
What are anions?
Chloride (important in neuromuscular signalling), bicarbonate and phosphate (important in maintenance of normal plasma pH)
What are respiratory gases?
O2 and CO2; most O2 and some CO2 is bound to Hb in erythrocytes
A sig fraction of CO2 is found in the plasma in the form of bicarbonate
What are the 5 blood cell types that can derive from a Myeloid stem cell?
- Platelets
- Eosinophil
- Basophil
- Neutrophil
- Macrophage
What are the 2 types of stem cells that derive fro, a haematopoietic stem cell?
- Myeloid stem cell
- Lymphoid stem cell
What is the type of blood cell that derives from a lyphoid stem cell?
A lymphocyte
