Haemorrhage

Question 1

What are the clinical signs of haemorrhage?

Answer 1

• Rapid, feeble pulse
• Mucosal pallor
• Rapid resp. rate

Question 2

What are the ways in which the body attempts to recover from haemorrhage?

Answer 2

1. Baroreceptor reflex - decrease BP, decrease BR stim., this increases symp. stim. and contractility and heart rate increase (tachycardia, vasoconstriction)
2. Vasoconstriction - increases CVP, this stretches myocardium and Frank-Starlin mechanism kicks in. Most severe in skeletal muscle, skin and gut. Severe haemorrhage, renal constriction
3. Chemoreceptor reflex - if BP v low then BR not sensitive, CR aid BR reflex
4. Cerebral ischaemia - if BP drops too low, sets off symp. discharges as a reflex response
5. Atrial vol. receptor reflex - adds to symp. activity
6. Reabsorption of tissue fluid - decreases in venous and arterial P leads to decreased capillary HP, therefore get fluid reabsorption
7. Renal effects - renin secretion increases symp activity, increase ADH

Question 3

What is another action of the BRR?

Answer 3

Acts via the hypothalamus to induce sensation of thirst to increase water intake

Question 4

What are the decompensatory mechanisms for haemmorrhage?

Answer 4

1. Cardiac failure - hypotension reduces coronary blood flow and depresses ventricular function (decreased oxy, of HM)
2. Acidosis - decreased Q causes anoxia. This causes a build up of lactic acid which decreases kidney secretion of H+ and decreases symp. stimulation
3. CNS depression - if Q drops too low then cardiac and vasomotor centres become depressed, loss of symp. stim. and CO
4. Changes in clotting - intially high levels of clotting but decreases if clotting time is prolonged. Run out of clotting factors which aggravates the haemorrhage
5. Inhibition of immune system - envasion of endotoxins into systemic circulation, vasodilation (increases blood flow and loss)

Question 5

What decides whether an animal will recover or decompensate from haemorrhage?

Answer 5

• degree of haemorrhage
• individual variation

Question 6

Draw a diagram to represent the compensatory mechanisms for haemorrhage

Answer 6

Question 7

Draw a diagram to represent the compensatory mechanisms for heart failure

Answer 7