ES. Haemostasis, Haemorrhage and shock

Question 1

why is excessive blood loss a medical emergency?

Answer 1

decreased blood volume results in fall in blood pressure and impaired delivery of nutrients to cells which is called shock

Question 2

what is the immediate physiological response to blood less?

Answer 2

stop the bleeding

Question 3

what is short term physiological response to blood loss?

Answer 3

restore blood pressure

Question 4

what is the medium term physiological response to blood loss?

Answer 4

restore fluid volume

Question 5

what is the long term physiological response to blood loss?

Answer 5

replace blood constituents

Question 6

what components are involved in an immediate response to blood loss?

Answer 6

vascular response
platelet response
plasma response (coagulation)

Question 7

what is the vascular response of smooth muscle during blood loss?

Answer 7

spasm due to trauma
- myogenic response
- humoral factors (vasoconstrictors)

Question 8

what is the vascular response of endothelium during blood loss?

Answer 8

• platelet adhesion and aggregation
• anticlotting and fibrinolysis

Question 9

how do platelets respond to blood loss?

Answer 9

damage to blood vessels therefor turbulent blood flow
platelets come into contact with vessel wall (collagen)

Question 10

what is it called when platelets adhere and clump together in response to blood loss?

Answer 10

aggregate

Question 11

what do platelets do in positive feedback when there is blood loss?

Answer 11

release chemicals that cause further aggregation and form platelet plug

Question 12

how is a blood clot formed?

Answer 12

plasma proteins and tissue components combine to convert fibrinogen to fibrin to form the blood clot

Question 13

where are clotting factors formed for coagulation in blood loss?

Answer 13

liver

Question 14

how are clotting factors synthesised and activated?

Answer 14

synthesised upon presence of vitamin c
activated in an enzyme cascade

Question 15

what does a platelet plug do?

Answer 15

seals small blood vessels

Question 16

what factor converts soluble fibrin to insoluble fibrin?

Answer 16

factor XIIIa

Question 17

…….^

Question 18

how do the extrinsic and intrinsic pathway need to convert factor X to factor Xa?

Answer 18

phospholipid and calcium ion

Question 19

what is the intrinsic pathway in coagulation?

Answer 19

vascular damage
contact activation
factors = XII, XI, IX, VIII

Question 20

what is the extrinsic pathway in coagulation?

Answer 20

tissue damage
(tissue factors eg. tissue thromboplastin)
factors = VII

Question 21

is the intrinsic or extrinsic pathway more important in initiating blood clotting?

Answer 21

extrinsic

Question 22

what pathway (intrinsic or extrinsic) maintains the process in coagulation?

Answer 22

intrinsic

Question 23

what is thrombosis?

Answer 23

intrinsic system of coagulation where a blood clot forms inside an intact blood vessel

Question 24

what is fibrinolysis?

Answer 24

when blood clot has saved its purpose it is dissolved

Question 25

how is fibrinolysis undertaken?

Answer 25

by enzyme called plasmin

Question 26

what converts plasminogen to plasmin?

Answer 26

plasminogen activator

Question 27

what are the short term bodily reaction to loosing blood pressure?

Answer 27

- loss of blood volume/pressure

Question 28

what mechanisms help to restore the blood pressure in the short term? what triggers it?

Answer 28

compensatory mechanisms triggered by arterial baroreceptors

Question 29

what are the medium term responses to restore blood volume in blood loss?

Answer 29

- shifting interstitial fluid back into blood vessels - decreasing fluid loss in kidney - increasing fluid intake

Question 30

through baroreceptor reflexes, low arterial blood pressure has what effect on arterioles?

Answer 30

vasoconstriction - increases total peripheral resistance - decreased capillary blood pressure

Question 31

through baroreceptor reflexes, low arterial blood pressure has what effect on hydrostatic pressure?

Answer 31

decreases it pushing fluid out of the capillary

Question 32

haemorrhage causes a reduction in capillary pressure, what happens to our reabsorption/filtration when we are trying to recover?

Answer 32

more reabsorption than filtration

Question 33

how do we decrease fluid loss in the kidney?

Answer 33

decrease the glomerular filtration increase reabsorption of na and h2o

Question 34

how do we increase the reabsorption of na and h20 in the kidney?

Answer 34

stimulate the release of renin-angiotensin- aldosterone and antidiuretic hormone

Question 35

how do vasoconstrictors facilitate the process of decreasing fluid loss in the kidney?

Answer 35

they increase peripheral resistance

Question 36

what does the presence of resin do in the kidney?

Answer 36

converts angiotensinogen to angiotensin I

Question 37

what does angiotensin converting enzyme do in the kidney?

Answer 37

converts angiotensin I to angiotensin II

Question 38

what structure in the kidney facilitates the release of increased aldosterone?

Answer 38

adrenal cortex

Question 39

what does aldosterone do in the kidney?

Answer 39

increases sodium and water reabsorption by the distal convoluted tubes and cortical collecting ducts

Question 40

what does secretion of the antidiuretic hormone do to plasma ?

Answer 40

reduces volume increases osmolarity

Question 41

what does antidiuretic hormone secretion do to the baroreceptors and the osmoreceptors?

Answer 41

decreases their effect and increases effect of osmoreceptor activation

Question 42

what stimulates thirst?

Answer 42

increased plasma osmolarity and decreased extracellular volume angiotensin II promotes thirst dry mouth

Question 43

what receptors in the stomach suppress drinking?

Answer 43

stretch receptors

Question 44

in long term responses to blood loss how long does it take restore the plasma proteins?

Answer 44

released from the liver in 3 to 4 days

Question 45

in long term responses to blood loss how long does it take to replace the blood cells?

Answer 45

2-3 months

Question 46

how are blood cells returned to normal after blood loss?

Answer 46

erythropoiesis - regulated by erythropoietin - EPO released from kidney stimulates RBC production in bone marrow

Question 47

how is shock characterised in tissues?

Answer 47

inadequate blood flow to tissues

Question 48

how is shock characterised in tissues?

Answer 48

inadequate blood flow to tissues

Question 49

what is shock associated with in term of blood?

Answer 49

decreased cardiac output decreased blood or ECF volume

Question 50

give features of hypovolaemic shock?

Answer 50

decreased ECF volume due to: haemorrhage, sweating, diarrhoea or burns

Question 51

give examples of low resistance shock?

Answer 51

decreased peripheral resistance, due to widespread vasodilation

Question 52

give an example of when lo resistance shock would occur?

Answer 52

anaphylactic shock

Question 53

what is cardiogenic shock ?

Answer 53

heart fails as a pump

Question 54

when would cariogenic shock occur?

Answer 54

heart attack