PBL 7

Question 1

what is the composition of blood?

Answer 1

55% plasma

 - proteins 7% —> albumins, globulins, fibrinogen, prothrombin
 - water 91%
 - other solutes 2% —> ions, nutrients, waste products, gases, regulatory substances 

45% formed elements

 - platelets < 1%
 - leukocytes < 1% —> neutrophils, lymphocytes, monocytes, eosinophils, basophils
 - erythrocytes > 99% —> biconcave discs, approx 6-7um

Question 2

plasma vs. serum

Answer 2

plasma = liquid portion of blood. transports proteins, nutrients, antibodies, hormones etc around the body

serum = plasma - clotting factors (esp. fibrinogen) and blood cells. it is the liquid part of the blood after coagulation

Question 3

if you want to obtain just plasma, what must be added?

Answer 3

anti-coagulants

Question 4

why does the spleen rupture easily?

Answer 4

filled will blood therefore like a balloon so ruptures easily

Question 5

what is yellow bone marrow mainly composed of?

Answer 5

• adipose tissue

- stem cells for cartilage and bone

Question 6

what is used to diagnose leukaemia?

Answer 6

bone marrow biopsy

Question 7

where is bone marrow taken from in bone marrow biopsy?

Answer 7

sternum, pelvis

Question 8

what is TIBC?

Answer 8

• total iron binding capacity

- amount of iron bound to carrier proteins

Question 9

ferrous vs. ferric iron

Answer 9

ferrous - Fe++

ferric - Fe+++ — cannot be absorbed

Question 10

serum levels of what can be measured to determine iron?

Answer 10

• ferritin
• transferrin
• iron

Question 11

what blood group is the universal donor?

Answer 11

O-

Question 12

what blood group is the universal recipient?

Answer 12

AB+

Question 13

what is the Rh antigen?

Answer 13

• the +ve or -ve part of the blood type refers to the presence or absence of the Rh antigens on the surface of the red cells
• most people are Rh positive
• the full Rh blood group system includes around 50 different red blood cell antigens, but the most important is RhD protein — if you have RhD, you are Rh positive, if you don’t, you are Rh negative
• a person with Rh-negative blood can donate to a person with or without Rh
• a person with Rh positive blood can only donate to someone with Rh positive blood
• the Rh antigens are transmembrane proteins that appear to be used for the transport of CO2 and/or ammonia across the plasma membrane

Question 14

how can problems occur in pregnancy to do with Rh antigen?

Answer 14

• problems can occur if the mother has Rh-negative blood and the child has Rh-positive blood
• some RBCs can cross the placenta into the mother’s bloodstream — anti-RhD antibody develops
• these antibodies then go back into a future foetus and attack the foetus’ RBCs
• mother can receive an anti-RhD injection to prevent this immune response

Question 15

how is blood tpye inherited?

Answer 15

codominance

Question 16

what blood antigens are dominant?

Answer 16

A and B

Question 17

what happens to Hb in sickle cell anaemia?

Answer 17

polymerises to form a large Hb chain

• dehydrates
• changes shape
• O2 can’t bind

Question 18

what is a common cause of microcytic anaemia?

Answer 18

thalassaemia

Question 19

how is thalassaemia inherited?

Answer 19

autosomal recessive

Question 20

what are some causes of low Hb levels?

Answer 20

• cancer
• Hodgkin’s lymphoma
• cirrhosis
• chronic kidney disease

Question 21

is folic acid deficiency anaemia macro/normo/micro cytic?

Answer 21

macrocytic

Question 22

in what form is iron stored in cells?

Answer 22

Fe+++

Question 23

what could cause too much iron in the body?

Answer 23

• excessive intake, liver disease, alcohol abuse

- could lead to cirrhosis, heart disease and diabetes

Question 24

how do you treat iron deficiency anaemia?

Answer 24

• iron supplements — ferrous sulphate tablets

- eat an iron-rich diet — red meat, green veg, fruit

Question 25

what is glandular fever and how is it diagnosed?

Answer 25

- common in teenagers, young adults and students - usually stems from an infection with the Epstein-Barr virus (EBV) = a highly contagious herpes virus - can cause mild inflammation of the liver known as hepatitis - symptoms: flu-like symptoms, sore throat, swelling of lymph nodes, fatigue, weakness, temperature, nausea - no cure — rest and sleep, drink lots of fluids, take painkillers, do not drink alcohol

Question 26

what are some weird symptoms of Fe deficient anaemia?

Answer 26

- strange food cravings eg. ice, hair, paper, chalk - restless legs - flat tongue

Question 27

how long does foetal Hb stay in baby for?

Answer 27

around 6 months

Question 28

what is rhesus disease?

Answer 28

= a condition where antibodies in a pregnant woman’s blood destroy her baby’s blood cells - doesn’t harm the mother but can cause the baby to become anaemic and develop jaundice - occurs when baby is Rh positive and mother is Rh negative - the antibodies to Rh cannot cross to the placenta in the first pregnancy but can in subsequent pregnancies

Question 29

what is the anti-D immunoglobulin injection and why is it given?

Answer 29

- given to a mother to prevent causing rhesus disease in the baby - given at 28 weeks gestation and after childbirth - injection works by destroying any RhD positives blood cells that may have crossed over from the placenta into the mother’s bloodstream

Question 30

what is the Kleihauer test?

Answer 30

= a blood test to screen for foetal haemoglobin that may have transferred from a foetus to a mother’s bloodstream - mainly used to assess the severity of a fetomaternal haemorrhage (FMH) — a condition in which a disruption in the placental barrier allows foetal blood to enter the maternal circulation - shows if mother needs the anti-D immunoglobulin injection - the test is based in the fact that foetal Hb is more resistant to acid elation than adult Hb - 5ml threshold

Question 31

what is haemolysis?

Answer 31

= the destruction of red blood cells prior to the end of their normal 120 day lifespan - 2 types: extravascular (more common) and intravascular haemolysis - extravascular haemolysis occurs primarily in the spleen whereas intravascular is the breakdown of RBCs within the circulation, leading to the release of free Hb into the blood - the fall in RBC count leads to a reduced oxygen-carrying capacity of the blood and relative hypoxia, which stimulates EPO secretion, up regulating erythropoiesis

Question 32

what is iron overload and what can it cause?

Answer 32

= too much iron in body - can be a problem for people who get lots of RBC transfusions - as red cells break down over time, the iron in the Hb is released - the body has no natural way to rid itself of excess iron, so extra iron is stored in body tissues - transferrin carries iron through the blood to organs where it is stored (usually liver, spleen, bone marrow) — excess iron can lead to injury of the organs in which it is deposited

Question 33

what is Hb electrophoresis?

Answer 33

used to measure different types of Hb in the blood

Question 34

what is a sign of haemolytic anaemia?

Answer 34

yellow skin | increased destruction of RBC

Question 35

what are causes of megaloblastic anaemia?

Answer 35

- B12/folate def - drugs - impairment of DNA synthesis — grow but can’t divide

Question 36

is megaloblastic anaemia macro/normo/micro cytic?

Answer 36

macrocytic

Question 37

what is pernicious anaemia?

Answer 37

autoimmune condition where there is atrophy of the gastric mucosa, with failure of intrinsic factor — decreased Vit B12 absorption

Question 38

is pernicious anaemia macro/normo/micro cytic?

Answer 38

macrocytic

Question 39

name a chronic disorder that can cause anaemia

Answer 39

rheumatoid arthritis

Question 40

how to remember macrocytic anaemias. which are megaloblastic

Answer 40

``` F - folate def A - alcohol T - thryoid R - reticulocytosis B - B12 def C - cytotoxic drugs ``` F, B and C are megaloblastic

Question 41

what is the universal plasma donor?

Answer 41

AB+

Question 42

what is not included in the mandatory microbiological testing of donated blood?

Answer 42

gonorrhea - HIV - HEP B - HEP C - SYPHILLIS

Question 43

what is the primary production site of erythropoietin?

Answer 43

kidneys

Question 44

why are RBCs broken down in the spleen?

Answer 44

because they are much wider than the trabeculae of the spleen’s red pulp

Question 45

how wide are normal RBCs?

Answer 45

8um

Question 46

what conditions are Howell-Jolly bodies seen in? what are they not seen in?

Answer 46

``` seen in: - following splenectomy - coeliac disease - severe haemolytic anaemia - megaloblastic anaemia (these all affect the spleen_ ``` not seen in: - Hodgkin lymphoma

Question 47

what type of anaemia can be caused by excess alcohol?

Answer 47

non-megaloblastic anaemia (macrocytic)

Question 48

how many mls of blood does an average blood donor donate?

Answer 48

470mls

Question 49

what are haemolytic anaemias classed as?

Answer 49

anaemia caused by excessive erythrocyte destruction

Question 50

at 6 months pregnancy, where does the majority of haematopoiesis occur?

Answer 50

bone marrow