blood Flashcards
blood functions (3) and what its made of
- Transports everything that must be carried form one place to another in the body - o2, nutrients, water and waste
- protection against infection and bleeding. this includes wbc and platelets.
- regulation plays role in temp, acid-base balance and fluid electrolyte balance.
Components of blood
– Formed elements (45%) • Erythrocytes 41% (red blood cells). • Leukocytes 4% (white blood cells) • Platelets 0.1 % – Plasma (55%)
characteristics of blood
pH: 7.35–7.45
• the respiratory system and kidneys help restore blood
pH to normal
- blood volume is about 4–6 litres in average sized adult
- 8% of body weight
• Acidosis:
Blood becomes too acidic (below 7.35) high levels of co2
• Alkalosis:
Blood becomes too basic (above 7.45)
Erythrocytes (red blood cells or RBCs)
• Main function is to carry oxygen • Biconcave discs - no nucleus • holder of haemoglobin (fe and protiens) (globular protein) • Anucleate - • very few organelles • 5 million RBCs/cm3 blood
Blood Plasma
• 90% water • carrier of: – Nutrients – Electrolytes – Respiratory gases – Hormones – Albumin (protein which helps maintain osmotic pressure) – Antibodies – Clotting proteins – Waste products – Gases
Haemoglobin
• A molecule found in red blood cells made from
protein and Iron (Fe)
• Binds strongly, but reversibly, to oxygen
• Each haemoglobin molecule has four oxygen binding sites
• Each erythrocyte has 250 million hemoglobin molecules
• each RBC can carry 1 billion molecules of O2
• Normal range:
Male: 130 – 180 g/l
Female: 120 – 160 g/l
Leukocytes (white blood cells or WBCs)
- Defend against viruses, bacteria, parasites and tumour cells
- Able to move into and out of blood vessels (diapedesis)
- Respond to chemicals released by damaged tissue (positive chemotaxis)
- Increase in WBC (Leukocytosis)
- Decrease in WBC (Leukopenia)
Platelets
• disc shaped fragments of cells
• involved in clot formation
• A reduction in the platelet count is called thrombocytopenia.
• If the platelet count falls below 300,000/mm3 there is risk of bleeding
• Platelet transfusions may be given to bring
platelet count to normal level
Haemostasis
- the process that stops the loss of blood when a blood vessel is damaged
1.Vasoconstrction
(reduces blood flow)
2.Platelet plug formation
(platelets become sticky and stick to each other)
3.Coagulation (platelet plug is stabilised by fibrin and blood cells and proteins)
4. Fibrinolysis (clot breaks down as blood vessel wall heals)
• first 3 steps takes 3-6 minutes
antigens and antibodies pairs with blood group
blood A = antib B, antig A
blood B = antib A, antig B
blood AB = none antib, antig AB
blood O = antib AB, none antig (no spikes)
blood transfusion rules
Blood AB = receive A, B, AB, and O blood - Universal RECIPIENT Blood B = B and O blood Blood A = A and O blood Blood O = O blood - Universal DONOR
RH blood factors
- If you have the Rh factor you are Rh positive
- If you don’t have the Rh factor you are Rh negative
- anti-Rh antibodies are not automatically formed but as soon as they receive Rh positive blood their system begin to produce antibodies. First transfusion is OK but any subsequent ones will result in hemolysis (rupture of RBCs)
- Blood from an Rh positive person cannot be given to a Rh negative person
neg can receive pos (short periods)
pos cant receive neg
Anaemia , s&s
• A decrease in the oxygen carrying capability of the blood due to decrease in RBC or Iron deficiency/ heamoglobin.
increased HR, RR - low o2 needs to work faster
Fatigue - atp needs o2, glu, h2o
Pale gums,
conjunctiva (the mucous membrane that covers the front of the eye and lines the inside of the eyelids)
Anaemia due to decrease in RBC
Vitamin B12 (folic acid) Deficiency
• necessary for maturation of RBCs in bone marrow
(pernicous anaemia)
Aplastic anemia
• depression of blood cell production due to destruction of the bone marrow
Haemorrhagic anaemia – Can be a sudden haemorrhage (1000ml or more is serious) – Causes a loss of red blood cells – surgery, trauma, burns
