Bleeding and Shock

Question 1

What three factors can be classified as shock

Answer 1

Decreased blood perfusion of tissue
Increased oxygen demand from tissues
Inadequate blood oxygen

Question 2

How can shock be recognised

Answer 2

lactate
urine output
Biochemical markers

Question 3

Describe distributive shock

Answer 3

Failure of vasoregulation (vasodilation relaxes blood vessels and organs dont get enough blood). Can be caused by sepsis, anaphylaxis or be neurogenic

Question 4

Describe hypovolaemic shock

Answer 4

Loss of intravascular blood volume (due to bleeding? sickness?). Includes haemorrhage (trauma) or non haemorrhage (burns)

Question 5

Describe obstructive shock

Answer 5

Barrier to cardiac flow
eg PE or tension pneumothorax

Question 6

Treatment for distributive shock

Answer 6

Fluid
antibiotics

Question 7

Treatment for hypovolaemic shock

Answer 7

Fluid
blood
stop losses

Question 8

Treatment for Cardiogenic shock

Answer 8

inotropes
Vasopressors
fluids
a cardiologist

Question 9

Treatment for obstructive shock

Answer 9

Relieve obstruction (needle for unctured lung burst clots)

Question 10

How are HR and RR BP and OF affected by shock

Answer 10

HR and RR increase
BP and OF decrease

Question 11

4 types of wounds

Answer 11

laceration
incised
degloving
bites

Question 12

Describe laceration wounds

Answer 12

Blunt force trauma resulting in skin splitting or tearing

Question 13

describe incised wounds

Answer 13

Sharp or penetrating trauma stab/slash type
clean edges/uniform shape

Question 14

Describe degloving wound

Answer 14

Skin and its blood supply are torn off limbs/digits
major trauma

Question 15

Describe bite wounds

Answer 15

Small entry wound
possibly deep
foreign body contamnination

Question 16

Describe components of blood

Answer 16

RBCs
WBCs
platelets
Plasma (mainly water)
carries coagulation factors
electrolytes
nutrients
hormones and waste products.

Question 17

Describe red blood cells

Answer 17

Biconcave discoid shape
large surface area
no nuclei or organelles
packed with haemoglobin (gives blood its red colour)

Question 18

Describe white blood cells

Answer 18

“leucocytes”
lymphocytes: b, t and NK (shapes vary from spherical to pleomorphic)
nuclei are large
round, densely staining and eccentrical
granulocytes
basophils
monocytes

Question 19

structure of platelets

Answer 19

biconvex discoid shape maintained by circumferential bundle of microtubules

Question 20

fucntion of RBCs

Answer 20

gas exchange
transport oxygen from the lungs to peripheral tissues and carbon dioxide in reverse. they carry haemoglobin which has high affinity for oxygen in lungs and low in tissues allowing it to be displaced.

Question 21

fucntion of wbcs

Answer 21

defence against infection. Neutrophils,
monocytes, basophils and eosinophils are phagocytes that engulf and destroy pathogens. B-Ls produce antibodies against a specific antigen and T-Ls specifically recognise foreign/infected antigens and bind to the cell to release proteins that induce apoptosis

Question 22

describe role of platelets

Answer 22

involved in blood clot formation. they form an occlusive plug to stop blood flow by binding to the vessel (adhesion) and each other (aggregation)
They are also ‘antibody factories’

Question 23

function of tranexamic acid

Answer 23

can help control bleeding as it prevents clot lysis by inhibiting activation of plasminogen into plasmin

Question 24

what causes haemophilia A

Answer 24

deficiency of factor VIII (intrinsic pathway)

Question 25

what causes haemophilia B

Answer 25

deficiency of factor IX (intrinsic pathway)

Question 26

explain production of blood cells

Answer 26

haematopoiesis. haematopoietic stem cells can develop into myeloid or lymphoid progenitor. M: further differentiates into RBC, platelet and the phagocytes L: further differentiates into B-Ls, T-Ls and NKCs

Question 27

three steps in blood clot formation

Answer 27

vasoconstriction platelet plug formation coagulation cascade

Question 28

importance of von Willebrand Factor

Answer 28

vWF acts as an anchor for platelets to bind to the vessel wall in platelet plug formation

Question 29

describe the extrinsic pathway

Answer 29

Damaged tissue triggers tissue factor which activates factor VII. this stimulates the final common pathway

Question 30

describe the intrinsic pathway

Answer 30

Sub-endothelial contact activates platelets. This activates factors XII, XI and IX in a cascade. Then activated VIII stimulates the final common pathway.

Question 31

describe the final common pathway

Answer 31

Activated of factor X converts prothrombin into thrombin. This activates conversion of fibrinogen into fibrin forming a stable fibrin clot.

Question 32

what are the tests for haemophilia

Answer 32

APTT (intrinsic) PT (extrinsic)

Question 33

Describe the process of fibrinolysis

Answer 33

process by which a clot is removed. 1. plasmiogen is synthesised in the liver and circulates in the plasma. 2. plasminogen gets trapped in a clot as it forms 3: plasminogen is activated by a serine protease called tissue plasminogen activator (tPA) 4. tPA converts plasminogen into plasmin which breaks down the fibrin mesh.

Question 34

What is EPO and where is it primarily synthesised

Answer 34

Erythropoietin is a peptide growth hormone that stimulates the production of red blood cells mainly produced in the kidneys

Question 35

What does a fucntional haemoglobin molecule contain

Answer 35

four haem groups and four polypeptide chains

Question 36

Why is sodium citrate added to blood donation samples

Answer 36

It is a chelating agent chelates calcium and inhibits clot formation

Question 37

What surfaces does the Phospholipid/kaolin suspension mimick in vitro?

Answer 37

negatively charged surfaces of activated platelets when they change from spherical to finger-like projections

Question 38

What is the major protein missing from serum compared to plasma

Answer 38

Fibrinogen this means clots cannot form with just serum

Question 39

is calcium required for clotting?

Answer 39

Yes but it is not required for thrombin action

Question 40

what is TXA

Answer 40

Tranexamic Acid Antifibrinolytic - reversibly binds to 4 or 5 Lysin receptor sites on plasminogen Prevents conversion into plasmin thus preventing vlot lysis/breakdown of fibrin matrix

Question 41

What is vitamin K a cofactor for

Answer 41

the activation of factors II, VII, IX and X