(04) Composition and Features of Blood Flashcards
describe the arterial and venous systems of blood circulation
LEFT ventricle pumps oxygenated blood forcefully through aorta around body via arterial system - thicker walls
Venous system takes blood from tissue back to RIGHT atrium of heart via vena cava
(has valves which prevents blood from flowing back)
blood pressure ensures…
even / efficient flow through small capillaries
prevents capillary leakage, but high enough to avoid coagulation
name the six major components of blood
Cells
Proteins
Lipids
Electrolytes
Vitamins / hormones
Glucose
name and briefly describe the three major types of cells in blood
erythroid = RBC
myeloid = innate immunity, typically neutrophils
lymphocytes = B / T cells
name the three main types of proteins that constitute 80% of total protein in blood
albumin - keeps the state of blood in the right condition
haemoglobin - protein responsible for O2 transport
fibrinogen - involved in blood clotting
describe the process of blood clotting
fibrinogen protein exists as a stable protein in blood
cascade –> enzymatic cleavage of fibrinogen into FIBRIN
fibrin subunits coalesce together to form blood clot
what are immunoglobulins?
the proteins making up the adaptive humoral (fluid, soluble) response
provides you with immunity
how to lipids exist in blood and what are the main types?
usually bound in lipoproteins
High density, Low and Very Low (HDL, LDL, VLDL)
use ratios of these to measure risk of coronary thrombosis (heart disease)
pH of blood, how is it regulated?
7.4
carbonate ions (electrolytes) keep pH balanced
what is isotonicity
maintenance of salt balance inside and outside tissue to ensure there is no water leakage
role of Mg++ and K+ electrolytes in blood
regulates the heart
K+ is kept at almost exactly the right concentration - slight deviation causes arrhythmia
centrifugation of blood - components
RBC
Buffy coat - WBC + platelets
Plasma - opaque
what are erythrocytes
donut shaped blood cell that transports oxygen / CO2
makes up most of blood
NO nucleus
what are leukocytes?
found in the buffy layer
involved in immune defence
(note: neutrophils and lymphocytes are a type of leukocyte)
describe platelets
very small - a 10th/50th the size of a leukocyte, x3 size of erythrocytes
tissue repair - first responders in clotting
what is serum?
blood plasma without the clotting factors
less viscous yellow liquid
fibrinogen is ABSENT because it has formed the insoluble fibrin clot + removed
what is electrophoresis?
a laboratory technique used to separate DNA, RNA or protein molecules based on SIZE and ELECTRIC CHARGE using an electrical current
what are one of the uses of electrophoresis?
to determine whether somebody has multiple myeloma (a type of bone cancer)
what is the role of the blood protein Albumin?
maintains COLLOIDAL OSMOTIC PRESSURE of blood (basically same pressure as tissue so no water leak)
constitutes 50% of total blood protein
also maintains viscosity
binds small molecules
what does the bioavailability of drugs refer to?
albumin is the main binder of small molecules / hormones / drugs
the ability of those drugs to be RELEASED from albumin that determines bioavailability
what is fibrinogen responsible for?
blood coagulation
activated through coagulation cascade to form cross-linked fibrin
name some major blood proteins
albumin
fibrinogen
haemoglobin
immunoglobins
complement
coagulation factors
what are immunoglobins?
a very diverse repertoire of antibodies produced by B lymphocytes
what is the complement?
9 proteins - involved in opsonisation
part of the innate immune response
describe the process of opsonisation
the process by which foreign particles are labelled for phagocytosis
9 proteins (complement) usually inert, but when exposed to foreign surface, reacts immediately
cleaved –> cascade
produces active proteins that bind to surface of bacteria so the immune system can recognise and destroy them
what are the coagulation factors?
13 proteins cleaned in cascade resulting in
fibrinogen –> fibrin
name the ion that is essential to coagulation
Ca++
regulates coagulation pathway
can stop coagulation by adding something that removes Ca++
what is the stem cell that all blood originates from
multipotential hematopoietic stem cell (HSC)
or Hemocytoblast
what does the hematopoetic stem cell divide into
the common myeloid and lymphoid progenitors
which progenitor gives rise to the cells involved in the innate immune system?
the myeloid progenitor
(Myeloblasts give rise to basophils, neutrophils, eosinophils, monocytes etc)
which progenitor gives rise to the cells involved in the adaptive response system?
the lymphoid progenitor, produces lymphocytes –> B and T cells
what is CD34+?
CD34 is a surface antigen marker on Hematopoietic stem cells
what is haematopoiesis?
the formation of blood cellular components
name three factors that drive haematopoiesis
GM-CSF: granulocyte macrophage colony-stimulating factor
EPO: Erythropoietin
G-CSF: Granulocyte colony-stimulating factor
what is GM-CSF?
granulocyte-macrophage colony-stimulating factor
produced by macrophages, T cells, endothelial cells and fibroblasts
stimulates the production of neutro/eosino/basophils and monocytes
what is EPO and what does it do?
erythropoietin
drives the production of erythrocytes
a way to drive RBC to increase O2 capacity (athletes use it to cheat)
produced mainly by the kidney (adulthood, liver in perinatal)
what is G-CSF and what does it do?
granulocyte colony-stimulating factor
produced by many different types of cells
stimulates production of granulocytes
acts to mature neutrophils
how does a lung alveolus facilitate the transport of gases?
capillary network covers surface of alveolus
pulmonary arteriole brings flow of oxygen-depleted blood to the surface for exchange, pulmonary venule brings oxygenated blood back to heart
what are the main parts of haemoglobin
four heme group lobes with a porphyrin ring with a ferrous ion in the middle which binds O2
exchanges due to concentration difference
name the three pathways by which the complement system can be activated
the classical pathway
the alternative pathway
the lectin pathway
describe classical activation of the complement cascade
initiated by antibodies binding to antigens on pathogen surface
C1 binds to the antigen-antibody complex
C2 and C4 break, C2a and C4b form C3 Convertase
breaks to C3a (attracts other phagocytes) and C3b (cleaves C5) fragments
C5b joins with C6, 7, 8, 9 to form membrane attack complex, makes hole in membrane and pathogen is destroyed by flooding with water
how is the alternative pathway of the complement cascade activated?
C3 gets activated by directly binding to the pathogen
interacts with proteins: factor P, B, D
causes C3 to split and cascade continues same as classical
what are lectins?
carbohydrate-binding proteins in blood that bind to unusual carbohydrates found only on microbes
how is the lectin pathway of the complement cascade activated?
lectin binds to microbial surface
form complexes which cleave C2 and C4 and cascade continues as usual
what type of bond do convertases make?
covalent bonds to the microbe - they are irreversibly bound
what are anaphylotoxins?
the smaller fragments produced in the cleavage of complements that attract and activate other phagocytes (neutrophils)
eg. C3a and C5a
what are the two ways the coagulation pathway is activated?
tissue damage - EXTRINSIC
contact with the right surface - INTRINSIC
what is the common component in the coagulation pathway?
Factor X (ten)
how does factor X activate the coagulation pathway?
Factor X cleaves to form the enzyme Factor Xa, which cleaves prothrombin to thrombin
thrombin is the enzyme that cleaves the fibrinogen to the fibrin to form a clot
what enzyme do anticoagulants target to stop coagulation from happening?
thrombin
medicinal anticoagulants include heparin and wafarin
what is one enzyme that digests fibrin and where is it usually found?
plasminogen
exists in an inactive form in blood
what is plasminogen, what is it activated by?
a protease activated by tissue plasminogen activator (TPA) or streptokinase
what happens when plasminogen is activated?
when activated, plasma very rapidly digests the fibrin (THROMBOLYSIS)
