NEET MDS Shorts
388981
Pathology
The principal chemical mediator of the immediate phase of acute inflammation
is Histamine. Here's a detailed explanation of the options given:
1. Serotonin: While serotonin is a vasoactive substance that can cause blood
vessels to constrict or dilate, it is not the primary mediator of the immediate
phase of acute inflammation. It is mainly associated with the regulation of
mood, appetite, and sleep. In the context of inflammation, it plays a minor role
compared to histamine.
2. Histamine: Histamine is indeed the correct answer. It is a potent chemical
mediator released from mast cells and basophils in response to injury or
antigenic stimulation. Upon release, histamine acts on blood vessels to cause
vasodilation, increased permeability, and increased blood flow to the injured
area, which are hallmark features of the immediate phase of acute inflammation.
This results in the cardinal signs of inflammation: redness (rubor), heat
(calor), swelling (tumor), and pain (dolor).
3. Kinin-Kallikrein system: The kinin-kallikrein system is another important
mediator of inflammation, but it is more involved in the later phases. When
activated, it results in the formation of kinins, such as bradykinin, which
contribute to increased vascular permeability and pain. However, it is not the
first line mediator in the immediate phase.
4. Complement system: The complement system is a group of proteins in the blood
that work with antibodies to destroy pathogens and trigger inflammation. It is a
key component of the innate immune response, but its activation and role are
more pronounced in the later stages of inflammation rather than the immediate
phase. The complement system is involved in the opsonization of pathogens,
recruitment of phagocytes, and the formation of the membrane attack complex,
which can lyse certain bacteria and cells.
The immediate phase of acute inflammation is characterized by the rapid response
to tissue injury, which includes vasoactive changes and increased vascular
permeability to allow fluid, cells, and proteins to move into the interstitial
space. Histamine is quickly released from mast cells and basophils and acts on
H1 receptors of blood vessels to induce vasodilation and increased permeability.
This leads to the early symptoms of inflammation, such as swelling, redness,
heat, and pain, and is crucial for the initiation of the inflammatory response
to protect the body from harm.
428104
General PathologyConjunctivitis is often associated with Sjögren's syndrome, which can cause oral mucosal swelling and xerostomia.
925493
PeriodonticsSite-specific characteristics are not seen in herpetic gingivostomatitis.
365506
Dental MaterialsWhen acrylic resin absorbs water, it expands linearly by approximately 0.23%, which can affect the fit and function of the denture.
409391
BiochemistryThe enzyme phosphatidate phosphatase converts phosphatidic acid to diacylglycerol during synthesis of triacylglycerides.
The function of adipose tissue is the storage of fatty acids as triacylglycerols in times of plenty and the release of fatty acids during times of fasting or starvation.
Fatty acids taken in by adipocytes are stored by esterification to glycerol-3-phosphate. Glycerol-3-phosphate is derived almost entirely from the glycolytic intermediate dihydroxyacetone phosphate through the action of glycerol-3-phosphate dehydrogenase. Glycolytic enzymes are active in adipocytes during triglyceride synthesis, but those of glycogen degradation (low levels in adipocytes) and gluconeogenesis (ie, glucose-6-phosphatase) are not.
Glycerol kinase is not present to any great extent in adipocytes, so that glycerol freed during lipolysis is not used to reesterify the fatty acids being released.
The enzyme triacylglyceride lipase is turned on by phosphorylation by a cyclic AMP-dependent protein kinase following epinephrine stimulation.
857869
Dental MaterialsClass I (dental stone) has a longer setting time than impression plaster but is stronger and more dimensionally stable, making it suitable for fabricating models.
848996
PharmacologyCisapride can cause QT prolongation when administered along with drugs like ketoconazole which inhibit hepatic cytochrome p-450 CYP 3A4 enzyme.
228352
General MedicineBronchiectasis is most common in the left lower lobe