Describe coronary spasm, Biology

Assignment Help:

Q. Describe Coronary Spasm?

Usually spasm develops at the site of subcritical or critical stenoses, but it may also occur in angiographically normal coronary arteries, the so called variant form of angina. Occlusive spasm causes transmural ischaemia with ST-segment elevation, but when spasm is subocclusive, it may cause subendocardial ischaemia and ST-segment depression.

Coronary Collateral Circulation

1) The drop in poststenotic pressure caused by flow-limiting stenoses stimulates the development of collateral circulation from other coronary artery beds. The supply of collateral blood flow increases poststenotic pressure, thus improving coronary flow reserve and raising the ischaemic threshold.

2) Collateral vessels develop from the progressive enlargement of preexisting intercoronary arterial anastomoses.

3) Blood flow through these anastomeses begins as a consequence of the flow-limiting stenosis when a pressure gradient develops between their origin and termination.

4) In unanesthetized dogs, a pressure gradient of about 10mm Hg, caused by a lumen reduction of 70 to 80 per cent has been shown to elicit the development of collateral flow.

5) Preexisiting anastomoses progressively transform to vessels with a final diameter of 20 to 200 um.

6) Blood flow through collaterals is determined by the driving pressure and by their resistance, which is influenced by neural and humoral stimuli and by local vasoactive autacoids.

7) In patients, heparin and fibroblastic growth factor 1 (FGF-1) have been suggested to promote collateral growth.


Related Discussions:- Describe coronary spasm

Technique-ross operation--surgical techniques, Technique : The suitability...

Technique : The suitability of the pulmonary autograft for aortic valve replacement has to be studied by accurate measurement by echocardiogram of the aortic and pulmonary annuli.

Illustrate enzyme-substrate interaction, On what structural level of the en...

On what structural level of the enzyme (primary, secondary, tertiary or quaternary) does the enzyme-substrate interaction depend? The substrate binds to the enzyme in the activ

What are the two divisions of the autonomic nervous system, What are the tw...

What are the two divisions of the autonomic nervous system? The autonomic nervous system is separated into the sympathetic nervous system and the parasympathetic nervous system

How is the cooling of tissues and organs, Q. How is the cooling of tissues ...

Q. How is the cooling of tissues and organs for medical transplants associated with the effect of temperature upon enzymatic reactions? The molecular degradation during the dec

#biology tutor title.., When nd how i can srt my online work in this site q...

When nd how i can srt my online work in this site question #Minimum 100 words accepted#

Common respiratory disorders, COMMON RESPIRATORY DISORDERS: Respiratio...

COMMON RESPIRATORY DISORDERS: Respiration is one of the most vital functions of the body. The purpose of respiration is to provide oxygen ta  the body  cells and to remove exc

Which are the organs of the excretory system, Q. Which are the organs of th...

Q. Which are the organs of the excretory system? The excretory system is formed of ureters (two), kidneys (two), bladder and urethra.

C dna amplification, Steps of C dna amplification 1.  Smart-pcr amplif...

Steps of C dna amplification 1.  Smart-pcr amplification of cdna is the technique which initiates with the change of mrna to cdna utilizing mmlv-rt, mutated in the rnase h dom

Define the water bath with shaker, Define the Water Bath with Shaker? A...

Define the Water Bath with Shaker? An electric water bath with a shaker that can hold test tubes as well as conical flasks. When on a non-shake mode, it acts as a simple water

Steroids, STEROIDS They are a group of tetracyclic lipid derivative...

STEROIDS They are a group of tetracyclic lipid derivatives which have a nucleus of cyclopentano-perhydrophenanthrene  with phenanthrene part made of 3 hexane rings whil

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd