Haemotology - RBCs

Question 1

avg abult blood volume

Answer 1

5L
~7% of your weight

Question 2

components of blood

Answer 2

45% cells (formed elements):
RBCs
WBCs
platelets

(46-63%) plasma

Question 3

plasma composition

Answer 3

92% water
plasma proteins 7%
other solutes 1% - electrolytes, org nutrients, waste

Question 4

examples of plasma proteins

Answer 4

albumin
globulin
fibrinogen (coagulation protein)
regulatory proteins e.g. hormones

Question 5

in a centrifuged sample of blood, what does the WBC/platelets layer look like?

Answer 5

very thin layer between plasma and RBCs
in healthy person can see less
increased visibility in unhealthy person

Question 6

what does blood transport and hoe does it defend

Answer 6

transports:
gases o2 and co2
nutrients
excretory products
temperature control (alongside blood vessels via vasodil and vasoconst)

defense:
antibodies, wbc
clotting factors (aka haemostatic process)

Question 7

what is the stem cell that can differentiate into any blood cell

Answer 7

multipotential haematopoietic stem cell (haemocytoblast)

Question 8

which type of cell produces RBCs, platelets and 4 types of WBCs?

Answer 8

common myeloid progenitor

Question 9

which type of cell produces lymphocytes?

Answer 9

common lymphoid progenitor

Question 10

whats the name of the immature cell found in bone marrow that forms 4 key WBCs

Answer 10

myeloblast

Question 11

what is the process of blood cell formation called

Answer 11

haematopoiesis

see onenot for detailed diagram and learn it pls xoxo

Question 12

what is the name of the commited cell in erythropoises

Answer 12

proerythroblast

Question 13

name the order of cell types in erythropoieses

Answer 13

haemocytoblast -> proerythroblast -> early erythroblast -> late erythroblast -> normoblast -> reticulocyte -> erythrocyte

see diagram in onenote i made it all pretty

Question 14

requirements for erythropoiesis

Answer 14

erythropoietin
iron
vit B12
folic acid (B9)
intrinsic factor (helps in absorption of B12)
amino acids (for globin production)

Question 15

RBC structure

Answer 15

~7.5micrometres (caps are a lot smaller so they must be flexible)

deform readily, highly flex
no organelles or nucleus
life span = 121 days

Question 16

breakdown process of a RBC

Answer 16

macrophages break down the aged RBCs

spilts Hb into heme and globin

heme turns into Bilirubin + iron
Bilirubin which is combined with serum albumin
transported to liver
secreted into bile

Iron combined with transferrin(transport protein)
stored as ferritin(storage protein) in the liver and spleen

the globin transormed back in into amino acids

see one note for diagram

Question 17

what are some causes of hypoxia

Answer 17

• inc in excercise
• high altitude
• smoking
• bleeding

Question 18

describe erythrocyte homeostasis

Answer 18

1. low o2 blood levels (stimulus)
2. picked up by blood vessels in kidneys (receptor)
   3 kidneys inc production of erythropoietin
3. stem cells increase RBC production
4. o2 blood levels return to normal

Question 19

what stage does Hb synthesis start

Answer 19

in the proerythroblast
65% is made at erythroblast
35% is made at reticulocyte stage (after nucleus is gone)

Question 20

how many on avg Hb molecules per RBC?

Answer 20

280million~

Question 21

how much (in g/dL) Hb is in blood, females and males

Answer 21

F= 12-16 g/dL
M= 13.5-12.5g/dL

Question 22

structure of Hb protein

Answer 22

4 subunits (2 alpha 2 beta)

each subunit has a haem
which is bound to globin (long polypeptide chain)

in middle of Haem group is ferrous iron atom (Fe2+)

this atom can bind (reversibly) with one molecule of O2

Question 23

def of anaemia

Answer 23

Hb conc in whole blood below the accepted normal range

men - less than 13.5g/dL
women - less than 12g/dL

Question 24

causes of anaemia

Answer 24

decreased RBC production - can happen if required units not there (e.g. less B12, folic acid etc)

increased RBC destruction - haemolytic anaemia (RBCs break down faster than made, can be casued by autoimmune disease, bone marrow disease etc.)

blood loss - acute (ie in an accident) or chronic (ie stomach ulcers, endometriosis, cancer etc)

Question 25

iron deficiency anaemia key points

Answer 25

most common anaemia

hypochromic (paler coloured cells)
microcytic RBCs (smaller diameter)

decreased mean volume (MCV)

causes -
pregnancy,
bleeding from GI tract (ulcer, malignancy etc), malabsorption,
menorrhagia (period),
malnutrition

diagnosis of iron deficiency not adequate - always seek cause

Question 26

megaloblastic anaemia

Answer 26

vit B12 deficiency or folate deficiency (affects the way in which cells mature - hence MEGAloBLASTic cuz theyre large and immature)

macrocytic cells (larger in diameter)

reduced Hb conc.

increased mean cell volume (MCV)

hypersegmented neutrophils (can see in blood smear under microscope)

Question 27

megaloblastic anaemia: as folate deficiency

Answer 27

causes macrocytic anaemia

the reason theyre big is cuz they dont mature properly
and cells are unable to divide without folate

causes - pregnancxy, elderly, diet

Question 28

megaloblastic anaemia: as B12 deficiency

Answer 28

to absorb B12, we need intrinsic factor (IF)
usually secreted by stomach

cuases:
lack of IF - PERNICIOUS ANAEMIA cuz lack of B12
Crohn’s, coeliac disease - affect absorption too

treatment: Intramuscular B12 inejctions

used to be fatal cuz people didnt know that giving B12 orally wasn’t helping

Question 29

sickle cell anaemia

Answer 29

hereditary (african, west indian communities have more)
abrnormal Hb structure
causes sickle shaped cells

RBCs get stuck in blood vessels or
RBCs die prematurely

Question 30

thalassaemias

Answer 30

hereditary (mediterranean, middle/far eastern)

Abnormal Hb production - alpha and beta thalassaemias