Lecture 3

Question 1

What is too much blood flow called and what are the two types of it?

Answer 1

Too much blood is called hyperaemia. It can be separated into active where too much blood is being delivered or passive where not enough blood is being taken away

Question 2

Is hyperaemia localised or generalised and is it pathological or physiological?

Answer 2

Hyperaemia can be both localised or generalised and can be physiological or pathological (part of the acute phase of inflammation to deliver cytokines and cells)

Question 3

What is the name for too little blood delivery?

Answer 3

ischemia

Question 4

The two different types of ischemia that occurs are hypovolaemia and anemia, explain the difference between them.

Answer 4

Hypovolaemia- all of them Anaemia- just the red blood cells (note that neither of these are never likely to just be localised)

Question 5

How would passive hyperaemia appear histologically?

Answer 5

Lower venous drainage causing capillary beds to become engorged with blood

Question 6

What is the cause of the histological slide seen below?

Answer 6

This is likely caused by active hyperaemia. Notice in the image that there is increased arterial blood supply and that the capillary beds are engorged with blood. However, this is not fool proof as you can get a backing of venous that backs up into the artery

Question 7

Explain the physiological conditions at play with blood volume expansion:

Answer 7

Question 8

What are the effects of natriuretic peptides?

Answer 8

Question 9

How does reduced tissue perfusion (hypoxia) result?

Answer 9

1. Local obstruction of vessels
2. Local obstruction (stagnation)
3. Decrease cardiac output

Question 10

What is the occurs in the first stage of hypovolaemia (residistribution)?

Answer 10

1. venous return decreases
2. cardiac output is reduced
3. arterial blood pressure decreases
4. carotid and arotic bodies leads to stimulation of the vasomotor centres that then leads to strong sympathetic stimulation
5. Blood supply to vital organs maitained (brain and respiratory centres
6. Tachycardia continues
7. Adrenalin and nor-adrenaline are released causing general vasocontriction and coronary artery dilation
8. Decreasing blood volume leads to renin release leads to angiotensin 2 production and aldosterone production

Question 12

What is involved in stage two (restoration of blood volume) physiological response to hypovolaemia?

Answer 12

• Blood volume continues to drop despite phase one
• Fluid moves from extravascular space into circulation to replace lost fluid

Question 13

What is involved in stage three - replacement of blood cellular components in response to hypovolemia?

Answer 13

1. This phase is one of erythropoiesis – number of erythrocytes & haemoglobin content is restored to normal – enhanced manufacture of plasma proteins within the liver (hyperplasia of the bone marrow)
2. Reticulocytes and metarubricytes (immature blood cells) will be pushed out into the circulation) – takes approximately 4 days

Question 14

What is involved in shock?

Answer 14

• failure of one and two leads to shock
• shock = inadequete perfusion of organ microcirculation
• shock leads to multi organ failure exacerbating inadequete organ perfusion