Lecture 5 Flashcards by Colm Corcoran

What is haemopoiesis?

Production of blood cells in bone marrow

How well did you know this?

Not at all

Perfectly

Where does haemopoiesis take place in the infant ad adult?

Infant throughout skeleton

Adult in pelvis, ribs, vertebrae, skull, sternum

How well did you know this?

Not at all

Perfectly

Where are bone marrow biopsies and blood samples commonly taken from?

Right side posterior iliac crest of pelvis

How well did you know this?

Not at all

Perfectly

Haemopoiesis?

Multipotent stem cell goes to common lymphoid progenitor and common myeloid progenitor.

Common lymphoid progenitor becomes T lymphocyte and B lymphocyte

Common myeloid progenitor goes to megakaryocyte, erythrocyte, and myeloblast.

Myeloblast forms the granulocytes which are neutrophils, monocytes, macrophages and eosinophils

How well did you know this?

Not at all

Perfectly

What determines what cells stem cells will differentiate into?

Exposure to given chemicals such as erythropoietin

How well did you know this?

Not at all

Perfectly

Haemopoietic stem cell?

Greatest power of self renewal compared to any other cell of body

Can differentiate into a variety of specialised cells

Can mobilise out of bone marrow and into blood

Can undergo apoptosis if required

How well did you know this?

Not at all

Perfectly

What is a HPSC transplantation?

Haemopoietic stem cell transplant more commonly known as a bone marrow transplant

How well did you know this?

Not at all

Perfectly

Where can we get haemopoietic stem cells from?

Bone marrow aspiration- done under anaesthetic and rarely performed

GCSF given to patient to mobilise stem cells into peripheral blood. Stem cells removed and blood returned to patient. Cells frozen to be transplanted back later.

Umbilical cord- provide stem cells at time of normal birth delivery

How well did you know this?

Not at all

Perfectly

What is leucopharesis?

When white blood cells are separated from a blood sample

How well did you know this?

Not at all

Perfectly

What is the reticuloendothelial system?

Part of the immune system that is made up of a network of tissues that contain phagocytise cells eg microglial in CNS and kupffer cells in the liver.

Main organs are the spleen and liver. Lymph nodes also important

How well did you know this?

Not at all

Perfectly

What does the spleen consist of?

White pulp- WBCs

Red pulp- red cells

How well did you know this?

Not at all

Perfectly

What main artery supplies the spleen?

Splenic artery and vein

How well did you know this?

Not at all

Perfectly

Functions of spleen in adults?

Sequestration and phagocytosis- abnormal or old red cells removed by macrophages

Blood pooling- stores RBCs and platelets if required

Immune function- T cells and B cells

Haemopoietic- if marrow fails or under haematological stress. Results in splenomegaly.

How well did you know this?

Not at all

Perfectly

How do you you determine splenomegaly?

Start to palpate in the right iliac fossa. It is never normal to feel the spleen below the costal margin.
With splenomegaly you would feel the spleen edge move towards your hand on inspiration

How well did you know this?

Not at all

Perfectly

What is the costal margin?

Lower edge of chest formed by bottom of the rib cage

How well did you know this?

Not at all

Perfectly

What causes splenomegaly?

Haemopoiesis

Immune response

Portal hypertension in liver disease

Expanding as cells entering eg cancers

How well did you know this?

Not at all

Perfectly

What is sarcoidosis?

Abnormal collections of inflammatory cells forming lumps called granulomas

How well did you know this?

Not at all

Perfectly

What is hypersplenism?

And overactive spleen which removes red blood cells too quickly. Blood can also pool in the spleen which enlarges it.

How well did you know this?

Not at all

Perfectly

What is the danger of an enlarged spleen?

No longer protected by the rib cage and so can rupture easily

How well did you know this?

Not at all

Perfectly

What are two complications associated with splenomegaly?

Haematoma- spleen ruptures and bleeds into its surrounding capsule so bleeding is not noticed. Patient becomes hypovolaemic and dies.

Infarction- enlarged spleen compresses blood vessels that supply it

How well did you know this?

Not at all

Perfectly

What is hyposplenism?

Lack of adequately functioning splenic tissue.

Hyposplenism causes?

SPLENECTOMY

Sickle cell disease which causes infarcts

Coeliac disease

How is hyosplenism diagnosed?

Blood sample will show abnormal blood cells that should have been removed. Eg Howell jolly bodies

What is extremely important clinically with the spleen?

Severely impaired immune function and much increased risk of sepsis especially from encapsulated organisms

Splenectomy= penicillin prophylaxis for remainder of life

Red blood cell values?

See lecture

RBC functions?

Carry oxygen Carry haemoglobin Maintain osmotic equilibrium

Haemoglobin structure?

Two pairs of globin chains each with its own ahem group. T state and R state

What is haemolytic anaemia?

Anaemia due to the abnormal breakdown of RBCs

How does the body react to haemolytic anaemia?

Less RBCs results in less oxygen. This is detected by the interstitial peritubular cells of the kidney. Cause increased erythropoietin synthesis. RBC count increases and through a feedback loop erythropoietin production falls

Haemoglobin catabolism complications?

Excess of RBC destruction results in increased bilirubin production which can lead to jaundice particularly if the liver is overwhelmed

What is cytopenia?

Low blood cell count

What is anaemia? leucopenia? Neutropenia? Thrombocytopenia?

Low red cell count Low white blood cell count Low neutrophil count Low platelet count

What is the term for having low RBCs, WBCs and platelets?

Pancytopenia

``` High RBSs? High WBCs High neutrophils High platelets High lymphocytes ```

Polycythaemia or erythrocytosis Leucocytosis Neutrophilia Thrombocytosis Lymphocytosis

How do neutrophils find pathogens?

Through chemotaxis

What is a neutrophil?

First responder of innate immune system. Lives for 1-4 days in blood and then tissue. Commonest white cell and a phagocyte

What hormone stimulates neutrophil production?

Granulocyte colony stimulating factor (G-CSF) Enhances chemotaxis and phagocytosis of neutrophils

What do we do in the case of neutropenia and sepsis after chemo?

Administer recombinant g-csf. Works better than antibiotics

What causes neutrophilia?

``` Tissue damage Smoking Cancer Haemorrhage Myeloproliferative disease Acute inflammation ```

What causes neutropenia?

Decreased production or increased removal or use eg sepsis or enlarged spleen with blood pooling. Neutrophil count is also race dependent

What causes reduced neutrophil production?

``` B12 or folate deficiency Congenital defect Defect in bone marrow Viral infection Drugs eg chemotherapy which poison marrow Radiation Aplastic anaemia- empty marrow Infiltration of marrow by malignancy or fibrosis ```

Consequences of neutropenia?

Bacterial and fungal infections which can be life threatening Neutropenia sepsis is a medical emergency. IV antibiotics to be given within an hour

Monocytes?

First responders Antigen presenting cells for activating adaptive immune system Become macrophages once migrated into tissue Phagocytosis and pinocytosis

Monocytosis cause?

Myeloproliferative disorders Leukaemia Carcinoma Chronic infection

Eosinophils?

3-8 hours in circulation and then last 8-12 days Deal with parasites and immune responses eg asthma Can cause hypersensitivity reactions in asthma, certain drugs etc

Basophils?

Least common but largest Granules contain histamine Active in allergic reactions and inflammatory conditions Increased in rheumatoid arthritis and hypersensitivity reactions and myeloproliferative disorders

What is a myeloproliferative disorder?

Increased production of white blood cell

Lymphocytes?

B cells- produce antibodies T cells- kill directly and stimulate other immune cells Natural killer cells which undertake cell mediated cytotoxicity

What is cell mediated cytotoxicity?

When a cell such as a natural killer cell loses a target cell whose membrane antigens have been bound by a particular antibody

What is lymphoma?

Cancer of lymphocytes

What can cause lymphocytosis?

Reactive Viral infections Bacterial infections Post splenectomy (no place for storage) Smoking Lymphoproliferative Leukaemia Lymphoma