Phase 1 week 3 Flashcards
What are the three layers formed from using a centrifuge of the blood?
The haematocrit = 45%
the buffy coat
the plasma = 55%
what is contained within the plasma?
proteins enzymes nutrients waste hormones gases
What are the functions of proteins in the plasma?
reserve supply of amino acids for cell nutrition - can be broken down by macrophages
carriers for other molecules
act as weak acids to maintain slightly basic pH
involved in the coagulation cascade
distribution of fluid between blood and tissue fluid- colloid osmotic pressure
What is the most abundant electrolyte in the plasma?
sodium ions which amount for most of the blood’s osmolarity
What is another name for white blood cells?
leukocytes
What are platelets made from?
small fragments of bone marrow
What are the functions of platelets?
secrete vasoconstrictors
form temporary platelet plugs to stop bleeding
secrete procoagulants
dissolve blood clots when they are no longer needed
digest and destroy bacteria
secrete cytokines
What are the main functions of red blood cells?
to pick up oxygen from the lungs and deliver them to tissues elsewhere
to pick up CO2 from the tissues and unload it in the lungs
What is another name for red blood cells?
eryhtrocytes
What is the structure of red blood cells?
disk shaped cell with thick rim and sunken centre
plasma membrane has glycoproteins and glycolipids that determine blood type
spectin and actin proteins give membrane resilience and durability
What are the advantages of the structure of RBCs?
they can stretch, bend and fold as they squeeze through small blood vessels and spring back to shape
Why are RBCs incapable of aerobic respiration?
They don’t contain mitochodria
What is the advantage of RBCs not containing mitochondria?
They can’t consume the oxygen that they are transporting
What is the advantage of the biconcave disk shape?
Greater ratio of surface area to volume to allow gases to diffuse quickly
What proportion of an RBC is haemoglobin?
33%
why can RBCs not repair themselves?
they don’t contain ribosomes
How long do circulating RBCs live for/
120 days
what is haematopoiesis?
the production of the formed elements of the blood
What are haematopoietic tissues?
The tissues where blood is produced
What is the earliest haematopoietic tissue?
the yolk sac
What is another name for a multipotent haematopoietic stem cell?
haemocytoblast
What do common myeloid progenitor cells differentiate into?
megakarycytes
erythrocytes
mast cells
myoblasts
What do megakaryocytes differentiate into?
thrombocytes (platelets)
What do myoblasts differentiate into?
basophils
neutrophils
eosinophils
monocytes
what do monocytes differentiate into?
dendritic cells
macrophages
What do common lymphoid progenitor cells differentiate into?
natural killer cels
small lymphocytes
what do small lymphocytes differentiate into?
B lymphocytes and T lymphocytes
What can B lymphocytes differentiate into
plasma cells
In what order are RBCs formed? (in terms of stem cells)
haemocytoblast pro erythroblast erythroblast normoblast reticulocyte erythrocyte
which cells have receptors for erythropoietin?
proerythroblasts
how many RBCs are produced each day?
10 to the power of 12
how many RBCs are produced from a single proebrythroblst ?
16
where is EPO produced?
90% kidney
10% liver
What induces the production of EPO?
hypoxia
How is haemostasis achieved after wounding?
Immediate vasoconstriction to slow blood flow and reduce exsanguation
break in the epithelial barrier leads to recruitment of platelets to form an occlusive plug
platelets release serotonin which is a vasoconstrictor
platelets are activated by the sub endothelial matrix and each other
What is the receptor on platelets for collagen?
Glycoprotein Ia/IIa complex
What is the receptor on platelets for von Willebrand’s factor and thrombin?
Glycoproteun Ib/IX complex
What is the receptor for fibrinogen and vWF?
Glycoprotein IIb/IIIa complex
What happens when platelets are activated?
Convert from compact to disk to a sphere
surface receptors become activated
cytoplasmic granules secrete their contents
What is the result of the activation of platelets?
mediation and reinforcement of aggregation and adhesion, promotion of further activation
What activates the intrinsic pathway?
Activated platelets
What activates the extrinsic pathway?
Exposed subendotheial tissue
What happens in the intrinsic pathway?
XII, XI, IX, VIII, X
What happens in the extrinsic pathway?
Tissue factor is required to convert VII to VIIa, which then activates X
What happens in the final common pathway?
Xa and Va cause the activation of prothrombin (II) to thrombin (IIa). This causes fibrinogen (I) to become fibrin (Ia)
XIIIa in the presence of fibrin leads to a cross-linked clot being formed
At what stages are calcium ions needed in the coagulation cascade?
Conversion of IX to IXa
Conversion of VII to VIIa
At what stages is vitamin K important?
Prothrombin, VII, IX, and X
What substances are involved in the regulation of the coagulation cascade?
Anti-thrombin, proteins C and S, and tissue factor pathway inhibitor
What causes fibrinolysis?
When the clot is no longer needed tissue plasminogen factor is released from the endothelial cells and causes plasminogen to be converted into the active plasmin.
what is a stem cell?
a stem cell can renew itself and differentiate into many types of cell
What is differentiation?
The process by which relatively unspecialised cells acquire specialised structural and / or functional features that characterise the cells, tissues or organs of the organism
What is the definition of stem cell potency?
The number of possible biological fates open to the cell
What does totipotent mean?
all fates possible (zygote)
what does multi / pluripotent mean?
many fates possible (embryonic / adult tissue stem cell)
What does bi / unipotent mean?
one or two fates open to the cell (adult tissue)
describe embryonic stem cells
pluripotent
able to become more than 220 types of cell in the body
Describe adult stem cells
multipotent or single type
able to become specialised cells within the residing tissue or specific cell type of the tissue
Give examples of different types of wounds
abrasion degloving insides laceration bites
What is the first aid for a wound?
elevate the area direct pressure indirect pressure control bleeding replace lost blood history of bleeding problems
What is shock?
a clinical syndrome where tissue perfusion, and hence oxygenation, is inadequate to maintain normal metabolic function
What are the different types of shock?
hypovolaemic cardiogenic septic spinal / neuro anaphylactic
What causes hypovolaemic shock?
haemorrhage, burns, GI, sweat, dehydration
What causes cariogenic shock?
pump failure
What causes spinal / near shock?
altered / loss of vascular tone
What % of total blood volumes are involved in the classification of hypovolaemic shock?
40
What blood loss in ml relates to each classification of shock?
2000
What are the pulse rates of the different classifications of shock?
100, >120, >140
At what classification of shock does BP start to decrease?
class III
How does the mental status of a patient change through the classes of shock?
normal, mild anxiety, anxious, confused
What is the emergency treatment of hypovolaemic shock?
Airway with C-spine control Breathing with oxygenation Circulation with haemorrhage control Disability Exposure
Give examples of one standard safety protocols
Hand hygiene at the “5 moments” as described by WHO
care in the use and disposal of sharps
the correct use of PPE for contact with all blood, body fluids, secretions and excretions
providing care in a suitably clean environment with adequately decontaminated equipment
safe waste disposal
safe management of linen
