Chapter 4 Robbin's

Question 1

OEDEMA

Answer 1

normally very little movement of water and electrolytes into tissues. In pathology oedema occurs (increased hydrostatic or decrease plasma protein)
OEDEMA = accumulation of fluid in tissues results from net movement of water into extravascular spaces

Question 2

HYPEREMIA vs CONGESTION

Answer 2

Both = increased blood volume in a tissue
hyperaemia = active process due to arteriolar dilatation and increased blood inflow (inflammation and exercising tissues)/ Red due to engorgment w oxygenated blood.
congestion = passive process from impaired outflow of venous blood from a tissue. Often blue-red “cyanoed” colour due to accumulation of deoxygenated haemoglobin in that are
long standing congestion = inadequate tissue perfusion and hypxeia - parenchymal cell death, secondary tissue fibrosis, elevated intravascular pressures - oedema and rupture - focal haemorrhage

Question 3

Morphology

Acute pulmonary congestion vs Chronic pulmonary oedema

Answer 3

ACUTE: blood engorged alveolar capillaries with variable alveolar septic oedema and intralveolar haemorrhage “pink frothy sputum”
CHRONIC= septa become thickened and fibrotic and the alveolar spaces contain macrophages laden with haemosiders

Question 4

Hepatic congestion

Answer 4

acute = central vein and sinusoids are distended with blood and may be necrosis of mental hepatocytes. Periportal hepatocytes fatty change (reversible) less severe hypoxia
chronic passive congestion- centriclobular necrosis, haemorrhaged haemosiderin laden macrophages

Question 5

Body water

Answer 5

60% of lean body weight is water
2/3 intracellular
5% in the blood plasma (the majority of 1/3 is in the interstitial fluid)

Question 6

Fluid homeostasis

Answer 6

Governed by hydrostatic pressure vs. oncotic pressure (colloid oncotic pressure)
normally the outflow by arteriolar end of microcirculation Is balances by inflow and the venular end, due to slightly elevated emote pressure.
NET ONLY small amount of fluid outflow into the interstitial space - drained by the lymphatic vessels
(returned to the circulation via the thoracic duct)

Question 7

Transudate vs. Exudate

Answer 7

Transudate protein poor - due to increases in hydrostatic pressures
inflammatory oedema/Exudate - protein rich w highgh specific gravity (increased vascular permeability)

Question 8

Haemorrhage

Answer 8

extravasation of blood from vessels.

1) blood vessel damage (i.e capillary bleeding in chronically congested tissues, trauma, ahteroclerosis or inflammatory/neoplastic haemorrhage of vessel wall)
2) defective clot formation
- bleeding/haemorrhagic diatheses

Haemorrhage into a tissue = haematoma

Extensive haemorrhage can even result in jaundice - huge bilirubin degradation products

Petichiae - 1-2mm haemorrhages into skin, MM, serosa surfaces
platelets fx or no, loss of vascular wall support (i.e vitamin nC def)

Purpura 3-5 mm - petichiael diorders _ traumatia, vasculaitis and increased vascular fragility

Ecchymoses 1-2cm subcutaneous haematomas (bruises)
- extravasated red cells a phagocytoses and degraded by macrophages - the colour change enzymatic conversion of haemoglobin –> bilirubin –> haemosiderin

Question 9

Interesting fact about iron deficiency

Answer 9

internal bleeding doesn’t cause it, phagocytoses RBCS recycle iron