The Naked Scientists
Toggle navigation
Login
Register
Podcasts
The Naked Scientists
eLife
Naked Genetics
Naked Astronomy
In short
Naked Neuroscience
Ask! The Naked Scientists
Question of the Week
Archive
Video
SUBSCRIBE to our Podcasts
Articles
Science News
Features
Interviews
Answers to Science Questions
Get Naked
Donate
Do an Experiment
Science Forum
Ask a Question
About
Meet the team
Our Sponsors
Site Map
Contact us
User menu
Login
Register
Search
Home
Help
Search
Tags
Member Map
Recent Topics
Login
Register
Naked Science Forum
Life Sciences
Physiology & Medicine
How do emboli cause haemorrhages?
« previous
next »
Print
Pages: [
1
]
Go Down
How do emboli cause haemorrhages?
3 Replies
7802 Views
0 Tags
0 Members and 1 Guest are viewing this topic.
Igor
(OP)
Full Member
59
Activity:
0%
How do emboli cause haemorrhages?
«
on:
13/11/2006 17:34:32 »
How do emboli cause haemorrhages ?, e.g. splinter haemorrhages caused by endocarditis.
Does the blockage create a build up of pressure which causes the vessel to fail ?,
Or does the infarction cause surrounding tissue, including blood vessels, to die,
i.e. is necrosis responsible for the haemorrhage?
Logged
iko
Naked Science Forum King!
1624
Activity:
0%
Thanked: 1 times
Re: How do emboli cause haemorrhages?
«
Reply #1 on:
13/11/2006 22:05:00 »
Hi Igor,
...the second hypothesis is more correct:
quote:
Or does the infarction cause surrounding tissue, including blood vessels, to die,
i.e. is necrosis responsible for the haemorrhage?
Igor
...but before cells death (necrosis) you should simply consider hypoxia as initial damage to the tissue that normally receive oxigen from blood flow.
Septic (bacteria) or thrombotic (clots) microembolism (or both) stop regular blood circulation.
Hypoxia makes cells shift to
anaerobic glycolysis
for energy production and excessive and toxic accumulation of
lactate and pyruvate
leading to
'capillary leakage'
, i.e. extravasation of plasma proteins and white and red cells into the surrounding tissue (petechiae, splinter haemorrhages).
Necrosis of part of the hypoxic tissue comes later, after prolonged hypoxia, leading to
permanent damage
.
Skin petechial haemarrhages and splinter haemorrhages
http://www.medibyte.com/cme/tutorial08/fig1.jpg
Here you can find more details from:
INFECTIVE ENDOCARDITIS
by Sam Firoozi, Dept. of Cardiological Sciences, St. Georges Hospital, edited by Sanjay Sharma copyright 2001 Medibyte.com
http://www.medibyte.com/cme/tutorial08/tutiend.htm
ikod
«
Last Edit: 13/11/2006 22:28:51 by iko
»
Logged
ikod icon:
http://d2993411.u58.surftown.nu/images/Aalesund2.jpg
http://img234.echo.cx/img234/659/25917wa.gif
chris
Naked Science Forum King!
8007
Activity:
1%
Thanked: 296 times
The Naked Scientist
Re: How do emboli cause haemorrhages?
«
Reply #2 on:
13/11/2006 23:05:27 »
Hello Igor.
Infective emboli, such as those seen in endocarditis (infection of the heart and valves) or septicaemia (blood infection), trigger skin haemorrhages (known as petechiae) because the infectious material lodges in small capillaries and then triggers a localised immune response which damages the blood vessel and causes bleeding.
Usually this reponse results from activation of the components of the complement cascade, the products of which can cause bystander damage to adjacent healthy tissues, such as capillary walls. This damage causes capillary leak and some blood to spill out into the interstitial (extravascular) space. Complement can be activated by immune complexes (antibody stuck onto antigen), or directly by some bacterial cell wall components.
Another reason why emboli cause haemorrhage is due to distal infarction of the tissue supplied by an embolised blood vessel. This is most often seen in the lung after a pulmonary embolism, and in the brain following an embolic (occlusive) stroke.
Under these circumstances an embolic body lodges in a blood vessel (pulmonary or cerebral artery), occluding blood flow. The distal tissue is infarcted (fatally starved of oxygen) and dies. This includes the cells forming the blood vessel wall. As a result, when blood flow is restored, or when blood flows into the affected area via collateral vessels, haemorrhage occurs because the damaged blood vessels are highly leaky.
This is why patients who have had a pulmonary embolus cough up blood, and why patients who have had an embolic stroke can subsequently show signs of intracerebral bleeding.
Chris
Logged
I never forget a face, but in your case I'll make an exception - Groucho Marx -
https://www.thenakedscientists.com/
Igor
(OP)
Full Member
59
Activity:
0%
Re: How do emboli cause haemorrhages?
«
Reply #3 on:
16/11/2006 15:45:51 »
Thank you Iko,
Thank you Chris,
I had not considered an immune response (inflammation) as an explanation for this type of haemorrhage.
Logged
Print
Pages: [
1
]
Go Up
« previous
next »
Tags:
There was an error while thanking
Thanking...