Haemorrhage

Question 1

What is shock

Answer 1

Excessive blood loss leading to a decrease in blood volume and blood pressure, resulting in cells not having enough nutrients and oxygen

Question 2

What is the immediate, short, medium and long term response to blood loss

Answer 2

Immediate - stop bleeding
Short- increase blood pressure
Medium- increase fluid volume
Long - replace blood constituents

Question 3

What are the two steps in haemostasis

Answer 3

First is the vascular response. Second is the platelet response.

Vascular responses- the smooth muscle in the blood vessel will contract to reduce blood flow to that area. The endothelial cells also release substances that promote platelet aggregation

Platelet response is the platelets coming together to adhere and aggregate, for axing a platelet plug. Thromboxane released by the platelets via positive feedback causes further aggregation, sealing the damaged blood vessel

Question 4

What produces thromboxane a2

Answer 4

It is a vasoconstrictor that is released by activated platelets.

Question 5

Functions of thromboxane a2

Answer 5

Vasoconstriction
Promotes platelet aggregation
Bronchoconstriciton (constriction of smooth muscles in airways)
Inflammation

Question 6

What is the plasma response of haemostasis

Answer 6

Coagulation cascade - intrinsic, extrinsic, common pathway involving clotting factors, vitamin K

Question 7

Where are clotting factors made

Answer 7

Liver

Question 8

Important clotting factors

Answer 8

Hageman factor 12

Question 9

Which coagulation pathway is more important in clotting

Answer 9

Extrinsic pathway,

Intrinsic serves more to maintain the process once it has started

Question 10

Which clotting factor is associated with extrinsic pathway

Answer 10

7

Question 11

Which clotting factor is activated when blood comes into contact with sub-endothelial connective tissue outside the blood vessel

Answer 11

Hageman factor (12) in the intrinsic pathway

Question 12

Is it the extrinsic or intrinsic pathway that has a role in thrombosis

Answer 12

Intrinsic pathway

Question 13

Intrinsic pathway - vascular damage
Extrinsic pathway - connective tissue damage
Common pathway - fibrinogen to fibrin with the help of thrombin

Question 14

Due to heavy blood loss, blood pressure falls. What happens to baroreceptors?

Answer 14

Baroreceptors decrease firing in response to Low blood pressure causing an increase in sympathetic nervous system activity

Question 15

Does veins and arteries constrict or dilate when we haemorrhage

Answer 15

Constriction (response by baroreceptors)

Question 16

Which hormones (non local )causes vasoconstriction and increases total peripheral resistance?

Answer 16

Angiotensin II
Vasopressin = ADH
Adrenaline

Question 17

How do we restore blood volume (3 points)

Answer 17

Increase Reabsorption at kidneys
Increase thirst via hypothalamus
Shifting interstitial fluid back into blood vessels

Question 18

What stimulates the hypothalamus

Answer 18

An increase in plasma osmolarity and a decrease is ECF volume

Question 19

What is erythropoietin

Answer 19

It is a protein that is needed for the production of red blood cells

Question 20

Where is EPO made

Answer 20

Erythropoietin is made in the KIDNEYS

Question 21

What is hypovolaemic shock caused by

Answer 21

A huge decrease in blood volume
Eg severe bleeding or dehydration

Question 22

What is anaphylactic/septic shock caused by

Answer 22

A huge decrease in total peripheral resistance due to widespread vasodilation

Question 23

Hypovolaemic shock causes a decrease in cardiac output

Anaphylactic shock or septic shock causes a decrease in tpr

Map= co x tpr

Question 24

How does capillary hydrostatic fall during haemorrhage to favour shifting interstitial fluid back into blood vessels?

Answer 24

Vasoconstriction by baroreceptors and symoahtthic nervous system caused the resistance to rise, increase in resistance means slower blood flow and lower hydrostatic pressure pushing fluid out of the capillary

Question 25

Is there an increase or decrease in plasma osmolarity when we haemorrhage

Answer 25

Increase in plasma osmolarity