Haematology - Plasma

Question 1

Main fluid compartments

Answer 1

Intracellular (55% of body H2O); interstitial(36%); extracellular (45%); blood plasma (7%); transcellular fluid (cerebrospinal (CSF), ocular, synovial fluid 2%)

Question 2

Interstitial fluid

Answer 2

Between cells, carrying nutrients and oxygen to cells + vehicle for cellular waste removal; drained from tissues by lymphatic vessels (becomes lymph) & then to secondary lymphoid organs (ie lymph nodes) & is component of adaptive immune response

Question 3

Definition

Answer 3

Liquid component of blood; second largest component of extracellular fluids; similar composition to interstitial fluid but with much more protein; ~55% of given blood volume

Question 4

Separation from blood sample

Answer 4

Before centrifuge, treat whole sample with coagulant; red cells (~45%) separated from plasma by buffy coat (leukocytes and platelets, ~1%)

Question 5

Apherisis

Answer 5

Blood of a donor collected and passed through centrifuge to separate particular cellular component, with remained returned to donor; different cell fractions purified for further use; therapeutic uses: plasma exchange (multiple sclerosis and myeloma), red cell exchange (SCD), LDL removal (patients prone to atherosclerosis), platelet depletion (homeostasis disorders), white blood cell depletion (leukaemia)

Question 6

Harvesting peripheral blood stem cells (PBSC)

Answer 6

Commonly used in bone marrow transplantation to treat leukaemia and lymphoma; Optia machine with intravenous access circulates blood so stem cells can be collected, 1 needle/arm (exit & re-entrance), centrifuged and stem cells in collection bag, another plasma bag (protection for stem cells), citrate = anticoagulant to prevent clotting in machine, saline solution (fill empty machine before and after connected), 3.5 - 5hrs

Question 7

Serum

Answer 7

Generated by letting blood clot for several minutes depleting plasma of coagulation factors + trapping cells and platelets in clots

Question 8

Why for diagnostic blood tests?

Answer 8

Easy to obtain for tests like disease biomarkers; serum is a cleaner sample (few cells) but takes longer to generate

Question 9

Functions

Answer 9

Clotting (clotting and Von Willebrand factors), immune defence (antibodies and complement proteins), osmotic pressure maintenance (proteins like albumin help maintain colloidal osmotic pressure), metabolism (nutrients), endocrine, excretion

Question 10

Proteins

Answer 10

Most abundant = albumin (-), globulins (increasing + -> alpha1, alpha2, beta1, beta2, gamma)

Question 11

Albumin

Answer 11

55% of plasma, produced by liver, transport of lipids + hormones + ions, maintains osmotic pressure, fatty acids are released by lipolysis from breakdown of triglycerides in adipose tissue and transported by albumin for use by other tissues in beta oxidation

Question 12

Globulins

Answer 12

35% of plasma, alpha 1 -> alpha 1 antitrupsin (A1AT), produced by liver, inhibits proteases (protect tissues ie from neutrophil elastase released during inflammation) (defective/deficient A1AT can compromise lung tissues = loss of elasticity and respiratory problems), alpha 2 -> haptoglobin (binds to hemoglobin released from erythrocytes, complex removed by spleen, measuring levels for diagnosis of haemolytic anemia) & alpha2 macroglobulin (protease inhibitor that can stop fibrinolysis); beta -> complement proteins C3 and C4, transferrin (iron transport, generated by liver, transports both dietary age and that from ferrin stores); gamma -> immunoglobulins and C-reactive protein

Question 13

Electrolytes

Answer 13

1% weight/volume, major contributors to osmolarity; component/plasma concentration/blood cell concentration: Na+/150/5, K+/5/140, Ca2+/3/1x10^-4, Mg2+/2/0.5, Cl-/110/10; + charge from intracellular K+ balanced by extracellular Cl- in anions like proteins, nucleic acids and phosphorylated proteins; increase in intracellular Ca2+ associated with signalling can be due to Ca2+ channels opening or release of intracellular stores; intracellular Mg2+ -> cofactors for many enzymes

Question 14

Na+-K+ ATPase

Answer 14

Maintains electrolyte balance, active ion transport, 3Na+ out, 2K+ in, more than 1/3 of ATP consumed at rest, key to functioning of electrically excitable cells, depleted ATP levels -> cells more spherical because of inward Na+ and H2O movement

Question 15

COVID

Answer 15

Recovery = relatively high levels of polyclonal antibodies, harvested for passive immunity (“convalescent plasma” ie 1918 influenza)