(04) Composition and Features of Blood Flashcards by Joanna Li

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)

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blood pressure ensures…

even / efficient flow through small capillaries
prevents capillary leakage, but high enough to avoid coagulation

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name the six major components of blood

Cells
Proteins
Lipids
Electrolytes
Vitamins / hormones
Glucose

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name and briefly describe the three major types of cells in blood

erythroid = RBC
myeloid = innate immunity, typically neutrophils
lymphocytes = B / T cells

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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

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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

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what are immunoglobulins?

the proteins making up the adaptive humoral (fluid, soluble) response
provides you with immunity

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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)

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pH of blood, how is it regulated?

7.4
carbonate ions (electrolytes) keep pH balanced

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what is isotonicity

maintenance of salt balance inside and outside tissue to ensure there is no water leakage

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role of Mg++ and K+ electrolytes in blood

regulates the heart
K+ is kept at almost exactly the right concentration - slight deviation causes arrhythmia

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centrifugation of blood - components

RBC
Buffy coat - WBC + platelets
Plasma - opaque

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what are erythrocytes

donut shaped blood cell that transports oxygen / CO2
makes up most of blood
NO nucleus

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what are leukocytes?

found in the buffy layer
involved in immune defence

(note: neutrophils and lymphocytes are a type of leukocyte)

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describe platelets

very small - a 10th/50th the size of a leukocyte, x3 size of erythrocytes
tissue repair - first responders in clotting

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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

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what is electrophoresis?

a laboratory technique used to separate DNA, RNA or protein molecules based on SIZE and ELECTRIC CHARGE using an electrical current

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what are one of the uses of electrophoresis?

to determine whether somebody has multiple myeloma (a type of bone cancer)

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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

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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

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what is fibrinogen responsible for?

blood coagulation
activated through coagulation cascade to form cross-linked fibrin

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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)