Haemopoiesis Flashcards Preview

Phase 1 - S2 Metabolism, Endocrinology, Haematology > Haemopoiesis > Flashcards

Flashcards in Haemopoiesis Deck (44)
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1

what are produced in the bone marrow

RBC, platelets and WBC

2

where is bone marrow found

throughout the skeleton in infancy but limited to the pelvis, skull, ribs, sternum and vertebrae in adults

3

what are the 2 types of bone marrow test

bone marrow trephine biopsy (taking a 1-2cm core of bone marrow to look at structure) or bone marrow aspiration (taking bone marrow cells to look at finer details)

4

what type of cells do blood cells come from

multipotent hematopoietic cells

5

what are hematopoietic cells differeniate into

myeloid progenitor cells or common lymphoid progenitor cells

6

what controls haematopoiesis

the reduced oxygen is detected by the peritubular kidney cells which then increase their production of erythropoietin which stimulates release and maturation of RBC

7

what cells are involved in the reticuloendotheial system

monocytes, macrophages, kupffer cells, microglial cells

8

what do cells in the RES system do

identify old, abnormal blood cells and phagocytose them mainly in the spleen or liver.

9

how long do erythrocytes live for

120 days

10

what are the functions of erythrocytes

- carry haemoglobin
- maintain the ferrous/reduced state of haemoglobin
- generate ATP
- maintain osmotic pressure

11

describe the structure of RBCs

- have proteins in their membranes making them flexible so can bend through capillaries
- large SA to vol ratio
-biconcave shape

12

which gene codes for the production of haemoglobin and where is it found

globin gene found on chromosomes 11 and 16

13

at what age do you switch from foetal to adult haemoglobin

3-6 months

14

what do the globin chains do

- prevent the haem molecule from oxidation, preventing the ferric form being produced from the ferrous
- allows variation in oxygen affinity by changing shape
- allow solubility

15

describe the break down of haemoglobin

macrophage or kupffer cells break it down into globin (a protein which is then broken down into amino acids) and heme. The irons is taken from the heme to be used. the rest of the molecule is converted to bilirubin in the liver and conjugated to be excreted

16

what does an excess in bilirubin result in

jaundice

17

why do you get anaemia with damaged kidneys

cant produce erythropoietin hormone so there is a decrease in haemoglobin production

18

what are the 2 main metabolic pathways in RBC

- glycolysis
- pentose phosphate pathway

19

what happens if metabolism is altered in RBC

their membrane changes and so they break down quicker so you become anaemic

20

what are the types of available iron

- in haemoglobin
- in myoglobin
- tissue iron e.g. iron used in enzymes
- serum/transported iron

21

what are the types of stored iron

- ferritin
- haemosiderin

22

what happens to iron requirement in pregnancy

increases

23

where does most of the active iron in our body come from

breakdown of RBC (not absorption in the gut from food)

24

what is 95% of iron in the liver stored as and in what cells?
what about the remaining 5%

- ferritin in hepatocytes
- the other 5% is as haemosiderin in kupffer cells

25

how is iron excreted from the body

its not excreted - only small amounts are lost each day by the loss of skin, hair and gut cells

26

how much iron enters and leaves the body in a day

1-2mg

27

what are the differences between haem and non-haem iron

- haem is a better source of iron found in meat which enters enterocytes (cells lining intestines) as Fe 2+ (ferrous)
- non-haem is found in pulses and grains and exists as Fe3+ (ferric)

28

what happens to non-haem iron in order to be taken up by enterocytes

stomach acid converts it into ferrous which then binds to transferrin which allows it to be taken up by the enterocytes in the duodenum and upper jejunum. can then be stored in the liver as ferritin or transported in the blood for use

29

what exports iron out of the cells

ferroportin

30

what is lactoferrin

primary iron source in infants