Lecture 21: Blood composition and function

Question 1

Why is blood pressure important?

Answer 1

Ensures

1. even and efficient flow through the small capillaries
2. low enough to prevent capillary leakage but high enough to avoid coagulation

Question 2

What are the major components of blood?

Answer 2

Cells
Proteins
Lipids 
Electrolytes 
Vitamins, hormones
Complement
Glucose

Question 3

What are the 3 types of cells in the blood

Answer 3

Erythyroid
Myeloid
Lymphoid

Question 4

What are the 3 layers created when blood is centrifuged?

Answer 4

Red blood cells on the bottom

Buffy coat, comprised of white blood cells and platelets in the middle

Plasma on the top

Require anti-coagulant

Question 5

What are examples of proteins found in blood?

Answer 5

Albumin - homeostatic function
Haemoglobin - carry oxygen
Fibrinogen - causes blood to clot
Immunoglobulins - antibodies

Question 6

How are lipids found in the blood?

Answer 6

Lipids are found bound in lipoproteins - HDL, LDL, VLDL

Question 7

What are electrolytes?

Answer 7

Salts and minerals e.g. Na+ Cl- Ca2+ etc.

Question 8

What are erythyroids?

Answer 8

Red cells that carry haemoglobin

Question 9

What are myeloids?

Answer 9

Cells involved in internal innate immunity e.g. phagocytes

Question 10

What are lymphoids?

Answer 10

Cells involved in adaptive immunity

Question 11

What is plasma?

Answer 11

The viscous liquid fraction of blood without cells - contains fibrinogen that is removed with coagulation

Question 12

What is serum?

Answer 12

Less viscous yellow liquid remaining after removal of the clot

Question 13

What is serum electrophoresis?

Answer 13

Serum proteins exposed to an electric field separates into 5 distinct bands

Question 14

What is multiple myeloma?

Answer 14

Is a form of leukaemia where a malignant lymphocyte overproduces monoclonal Ig.

Serum electrophoresis is used to diagnose this condition.

Question 15

What is albumin?

Answer 15

Constitutes 50% of total blood protein

Maintains colloidal osmotic pressure. Binds and transports many small molecules, hormones.

Question 16

What is fibrinogen?

Answer 16

Constitutes 7% of total blood protein. Activated through the coagulation cascade to form cross-linked fibrin (blood clot)

Question 17

What is a complement?

Answer 17

Component of blood - 9 proteins that coat bacteria allowing them to be targeted for phagocytosis (process called opsonisation)

Question 18

What is opsonisation?

Answer 18

Binding to pathogen and coat the bacteria

Deposition of complements on microbes become convertases. Convertases are able to activate more complement that then deposits to coat the surface.

Question 19

What are coagulation factors?

Answer 19

13 proteins cleaved in an ordered cascade resulting fibrinogen -> fibrin. Failure for this process to occur due to factor VIII deficiency causes haemophilia

Question 20

What is the function of electrolytes?

Answer 20

Isotonicity and buffering - blood pH is very tightly maintained at 7.4.

Question 21

What is the name of the stem cell which gives rise to blood cells?

Answer 21

CD34+ Multipotential hematopoietic stem cell (hemocytoblast)

Question 22

What are the two progenitor cells formed from hemocytoblast?

Answer 22

Common myeloid progenitor and common lymphoid progenitor

Question 23

What is the application of CD34+ antigens?

Answer 23

The body contains anti-CD34 antibodies that can select and concentrate HSCs from blood prior to a bone marrow transplant in patients that have undergone chemotherapy (killed stem cells) - autologous human stem cell transplants

Question 24

What are the cells created from the common myeloid progenitor?

Answer 24

Megakaryocyte
Erythrocyte
Mast cell
Myeloblast

Question 25

What are megakaryoctes?

Answer 25

Cells that produce thrombocytes (platelets)

Question 26

What are the cells created from the myeloblasts?

Answer 26

myeloid cells - cells involved in the internal innate immune response Basophils (filled with granules) Neutrophil (multi-lobed nucleus) Eosinophil (stain red and divided nucleus) Monocyte (forms macrophage)

Question 27

What are the cells created from the common lymphoid progenitor?

Answer 27

Natural killer cell | Small lymphocytes

Question 28

What are the types of small lymphocytes?

Answer 28

T lymphocyte and B lymphocyte

Question 29

What do B cells do?

Answer 29

Produce plasma cells that secrete antibodies

Question 30

What are the three factors that drive haematopoiesis?

Answer 30

GM-CSF, EPO, G-CSF drive production of blood components

Question 31

What is the GM-CSF?

Answer 31

Granulocyte macrophage colony-stimulating factor Produced by macrophages, T cells, endothelial cells and fibroblasts Stimulates production of neutrophils, eosinophils, basophils and monocytes

Question 32

What is the G-CSF?

Answer 32

Granulocyte colony-stimulating factor Produced by many different cells Stimulates production of granulocytes but also acts to mature neutrophils

Question 33

What is EPO?

Answer 33

Erythropoietin - drives production of RBCs It is produced mainly by the kidney during adulthood and liver in perinatal Can be taken as a drug for improved oxygen uptake

Question 34

How are GM-CSF and G-CSF used following radio-ablation?

Answer 34

These factors are administered to re-populate white cells in leukaemia patients - only small group of white blood cells following transplant

Question 35

Where does oxygen transport occur?

Answer 35

At the alveoli in the lung - little air sacks that increase surface area for O2 and CO2 to be exchanged between the capillaries and air space.

Question 36

What is haemoglobin?

Answer 36

Protein found in the blood containing 4 heme groups which contain iron atoms that bind oxygen

Question 37

What is the binding of O2 to haemoglobin regulated by?

Answer 37

The partial pressure of O2

Question 38

How does cyanide cause death?

Answer 38

Cyanide binds to cytochrome C in the ETC interrupting oxidative phosphorylation and preventing the heart from beating

Question 39

What are neutrophils?

Answer 39

Phagocyte which engulfs invading bacteria Functions as the complements in the blood coat the bacteria by opsonisation

Question 40

What are the 3 ways of activating complements?

Answer 40

Classical antibody activation Lectin activation Alternative activation

Question 41

How does classical antibody activation work?

Answer 41

An antibody binds to the pathogen causing a cascade to occur and complement to be activated

Question 42

Which is the most abundant complement component that causes the proteolytic activation cascade?

Answer 42

C3 activated to form C3b which bind to the pathogen

Question 43

What are convertases?

Answer 43

Deposited complements on pathogens that bind irreversibly via covalent bonds and allow the pathogen to be engulfed by phagocytes

Question 44

How does oponisation allow neutrophils to seek and engulf bacteria?

Answer 44

Cleavage of C3, C4, and C5 convertases (deposited complements) produce small fragments when cleaved - C3a, C4a, C5a These fragments act as powerful chemoattractants called anaphylotoxins that attract and activate neutrophils

Question 45

What are the two pathways for activation of the proteolytic activation cascade which causes coagulation?

Answer 45

Intrinsic - caused by contact with surfaces | Extrinsic - caused by tissue damage

Question 46

What is the enzyme that is involved in both the intrinsic and extrinsic pathways to coagulation activation?

Answer 46

Factor X forms factor Xa which causes the formation of thrombin from prothrombin Thrombin then causes fibrinogen to cleave forming fibrin that forms the blood clot

Question 47

What is thrombin?

Answer 47

Thrombin is the enzyme that cleaves fibrinogen to fibrin which forms cross-links

Question 48

What do anticoagulants produced by parasites do?

Answer 48

As they rely on blood flow, they produce anti-coagulants that target the thrombin step preventing fibrinogen to form fibrin

Question 49

What is plasminogen?

Answer 49

An enzyme converted to active plasmin which dissolves the clot - thrombolysis

Question 50

What is TPA and Streptokinase?

Answer 50

These are plasminogen activators that are used to treat thrombosis - formation of unwanted blood clots. Plasminogen will form active plasmin which breaks down blood clots.