Disorders of circulation (year 2) Flashcards
where is blood at the highest pressure?
left ventricle
where is blood at the lowest pressure?
right atrium
what are the types of redistribution of blood? (2)
local increased volume to a particular tissue
reduced blood supply to organ/tissue
what is an abnormal accumulation of arterial blood in arterioles/capillary beds known as?
active hyperaemia
what is an accumulation of blood in veins/venule capillary beds known as?
passive hyperaemia (congestion)
what is decreased blood supply to an organ/tissue known as?
ischeamia
what colour does tissue affected by active hyperaemia look?
bright red
what colour does tissue affected by passive hyperaemia look?
dark red/blue
what can cause local passive hyperaemia? (3)
organ misalignment
venous thrombosis or embolism (mass in vein)
compression
what can cause compression leading to local passive hyperaemia? (2)
fibrosis
tumour/abscess
why are veins more susceptible to compression? (2)
lower pressure
thinner walls
what are the consequences of local passive hyperaemia? (4)
necrosis
atrophy
fibrosis
loss of function
what are the types of organ misalignment? (5)
intussusception volvulus torsion twist herniation
what is intussusception?
one part of tubular organ telescopes inside itself
what is the intussusceptum?
part of the organ that goes inside the intussuscepiens
what is volvulus?
when an organ twists around its mesenteric root
what animals is gastric dilation and volvulus mainly seen in?
deep chested dogs
what is torsion?
rotation around an organs long axis
what is a twist?
two or more structures wrap around each other
what is the main consequence of organ misalignment known as?
haemorrhagic infarction
how does haemorrhagic infarction occur?
venous occlusion
persistent arterial blood supply
increased blood pressure
blood extravasation
what is the end result of haemorrhagic infarction?
necrosis
what is a venous thrombosis/embolism?
mass inside lumen of a vein
what is ischeamia?
inadequate blood supply to an organ/tissue
what can cause ischeamia? (3)
heart failure
artery obstruction
venous obstruction
what can cause generalised passive hyperaemia? (3)
heart failure
impeded venous return
increased pulmonary resistance
what can cause impeded venous return? (3)
caval thrombosis
hydropericardium
exudative pericarditis
what can cause increased pulmonary resistance? (3)
thoracic fluid
pulmonary fibrosis
pulmonary emphysema
what is haemorrhage?
loss of blood from the vascular system
what are the sizes of haemorrhage, in order of smallest to largest? (3)
petechia
purpura
ecchymoses
how large is petechia haemorrhage?
1-2mm
what is the size of purpura haemorrhage?
> 3mm
what is the size of ecchymoses haemorrhage?
> 1-2cm
what is diapedesis?
crossing of the vessel wall by cells
what is extravasation?
outside of a blood vessel
what is a haematoma?
focal accumulation of blood, usually within a tissue
what is another word for rhexis?
rupture
what are the possible outcomes of haemorrhage? (4)
haemorrhagic (hypovolaemic) shock
complete recovery
loss of function
iron deficient anaemia
what happens to erythrocytes when they are extravascular?
phagocytosed by macrophages
what is formed at the different stages of haemoglobin degradation? (4)
haem
biliverdin
bilirubin
haemosiderin
what is oedema?
accumulation of fluid in intercellular tissue space or body cavities