Haemotology Flashcards
what is the role of the spleen in the life cycle of a RBC?
- produces RBCs during foetal life (haemopoiesis)
- macrophages remove damaged and worn-out blood cells
describe the location of the spleen
- left upper quadrant of the abdomen
- posterior to the stomach
- under cover to the lower ribs and diaphragm
what are the borders of the spleen?
- superior
- inferior
what vessels leave/enter the hilum of the spleen?
splenic artery and splenic vein
what impression does the spleen have?
gastric impression
where are the splenic notches?
anterior aspect of the superior border
identify A-F
A - superior border B - inferior border C - splenic notches D - splenic artery E - splenic vein F - gastric impression
what is the role of the liver in the life cycle of a RBC?
- produces RBCs during foetal life (haemopoiesis)
- Kupffer cells break down damaged and worn out blood cells
- uses broken down heme to form bile
where is the liver?
- right upper quadrant of the abdomen
- under cover of ribs and diaphragm
identify A, B and C
A - liver (cut)
B - stomach
C - gall bladder
what is the ligament between the right and left lobes of the liver?
falciform ligament
what does the falciform ligament do?
attaches the liver to the anterior abdominal wall
what is located under the liver?
gall bladder
what does the gall bladder do?
stores and concentrates bile
name the 4 lobes of the liver A-D
A - right
B - left
C - quadrate
D - caudate
where does the IVC run in relation to the liver?
runs up the posterior aspect of the liver
what is the porta hepatis?
= door the the liver
- hepatic arteries
- portal vein
- hepatic ducts
describe an erythrocyte
= RBC
- biconcave discs
- average size 6.7um
- no nucleus
what are the functions of platelets?
- form platelet plugs to occlude sites of vascular damage
- provide a surface for the accumulation of coagulation protein complexes
- secrete factors involved in vascular repair
what are the granulocytes?
- neutrophils
- eosinophils
- basophils
what are the agranulocytes?
- lymphocytes
- monocytes
what is this?
basophil
what is this?
monocyte
what is this?
eosinophil
what is this?
lymphocyte
what is this?
neutrophil
describe a neutrophil
- granulocyte
- a type of leucocyte
- approx 12-14um
- multilobed nucleus
- accounts for 40-75% of the differential count
- function: phagocytic, involved in the acute inflammatory response
describe a basophil
- type of leucocyte
- granulocyte
- approx 14-16um
- bilobed nucleus — usually obscured by granules
- accounts for less than 1% of the differential count
- function: releases histamine and heparin, involved in immune response
describe an eosinophil
- type of leucocyte
- granulocyte
- approx 12-17um
- bilobed nucleus
- accounts for 1-6%
- function: defence against parasites, involved in allergic reactions
describe a lymphocyte
- type of leucocyte
- agranulocyte
- approx 6-9um
- nucleus is large and round, almost fills cell
- accounts for 25%
- function: phagocytic
describe a monocyte
- type of leucocyte
- agranulocyte
- up to 20um
- indented nucleus
- accounts for 2-10%
- differentiate into macrophages in tissue
- function: phagocytic
how do you remember the % make up of leucocytes?
most-fewest
Never Let Monkeys Eat Bananas
- neutrophils
- lymphocytes
- monocytes
- eosinophils
- basophils
what is a leucocyte?
WBC
where is haemopoiesis in a foetus?
- first 3 months: yolk sac — blood islands
- 3rd-5th month: spleen, liver and lymph nodes
- 5th month — : bone marrow in all bones
where is haemopoiesis in a child?
bone marrow of long bones eg. femur, tibia etc.
where is haemopoiesis in an adult?
bone marrow of pelvis, cranium, vertebrae and sternum
where is bone marrow located?
between trabeculae of cancellous bones (spongy bones)
what is erythropoiesis directly stimulated by?
erythropoietin = a peptide hormone that is secreted by the kidneys and liver
what does erythropoietin stimulate?
- increased cell division rates of erythroblasts and stem cells
- speeds up maturation of RBCs by accelerating the rate of Hb
when do increased erythropoietin levels occur?
host:
- is anaemic
- has declining blood perfusion to the kidneys
- has low O2 saturation
- has damaged respiratory surfaces of the lungs
how long can erythrocytes last in the blood before being recycled by macrophages?
100-120 days
when RBCs fully mature, what % of RBCs are recycled, haemolyse or rupture?
recycled = 90%
haemolyse or rupture = 10%
what happens to the a and b chains when Hb breaks down?
alpha and beta chains are filtered in the kidneys and eliminated in urine
what do macrophages do to RBCs?
phagocytose the remaining fragments of the RBCs
what happens to the amino acids from RBCs?
either metabolised by macrophage or released in the bloodstream for use by other cells
what happens to the haem groups?
stripped of its iron and converted to biliverdin, a green organic compound
what happens to biliverdin?
converts to bilirubin in the macrophage and is then released into the blood where it binds to albumin and gets transported to the liver to be excreted in bile
haem removed of iron — biliverdin — bilirubin in macrophage — binds to albumin in blood — liver to be excreted in bile
what is the blood composition of plasma vs. formed elements?
plasma = 55%
formed elements = 45%
where does phagocytosis of Hb occur?
- by macrophages in spleen and bone marrow
- by Kupffer cells in liver
red vs yellow bone marrow
red:
- haematopoiesis
- present in most bones in newborns
- in adults, found in axial skeleton, scapula and pelvis
- rich vascular supply
yellow:
- mainly composed of adipose tissue
- replaces red marrow with age
- chronic hypoxia can result in yellow —> red conversion
- poor vascular supply
red vs white pulp in the spleen
red:
- makes up the majority of the spleens parenchyma
- involved in removal of old RBCs
- site of haematopoiesis in utero
- consists of manly venous sinuses and splenic cords
white:
- compromise of lymph-related nodules containing lymphocytes and macrophages
- plays a role in opsonisation of encapsulated bacteria
when does membrane rupture of RBCs occur?
occurs as cells squeeze through red pulp of spleen
