NEET MDS Synopsis
Lipids
PhysiologyLipids:
about 40% of the dry mass of a typical cell
composed largely of carbon & hydrogen
generally insoluble in water
involved mainly with long-term energy storage; other functions are as structural components (as in the case of phospholipids that are the major building block in cell membranes) and as "messengers" (hormones) that play roles in communications within and between cells
Subclasses include:
Triglycerides - consist of one glycerol molecule + 3 fatty acids (e.g., stearic acid in the diagram below). Fatty acids typically consist of chains of 16 or 18 carbons (plus lots of hydrogens).
phospholipids - Composed of 2 fatty acids, glycerol, phosphate and polar groups , phosphate group (-PO4) substitutes for one fatty acid & these lipids are an important component of cell membranes
steroids - have 4 rings- cholesterol, some hormones, found in membranes include testosterone, estrogen, & cholesterol
THROMBOPHLEBITIS AND PHLEBOTHROMBOSIS
General Pathology
THROMBOPHLEBITIS AND PHLEBOTHROMBOSIS
- The deep leg veins account for more than 90% of cases (DVT)
- the most important clinical predispositions are: congestive heart failure, neoplasia, pregnancy, obesity, the postoperative state, and prolonged bed rest or immobilization
- local manifestations: distal edema, cyanosis, superficial vein dilation, heat, tenderness, redness, swelling, and pain
- migratory thrombophlebitis (Trousseau sign): hypercoagulability occurs as a paraneoplastic syndrome related to tumor elaboration of procoagulant factors
The Masseter Muscle
AnatomyThe Masseter Muscle
This is a quadrangular muscle that covers the lateral aspect of the ramus and the coronoid process of the mandible.
Origin: inferior border and medial surface of zygomatic arch.
Insertion: lateral surface of ramus of mandible and its coronoid process.
Innervation: mandibular nerve via masseteric nerve that enters its deep surface.
It elevates and protrudes the mandible, closes the jaws and the deep fibres retrude it.
PULP
Dental Anatomy
PULP
Coronal
Occupies and resembles the crown,
Contains the pulp horns
It decreases in size with age
Radicular
Occupies roots
Contains the apical foramen
It decreases in size with age
Accessory apical canals
PULP FUNCTIONS
Inductive: The pulp anlage initiates tooth formation and probably induces the dental organ to become a particular type of tooth.
Formative: Pulp odontoblasts develop the organic matrix and function in its calcification.
Nutritive: Nourishment of dentin through the odontoblasts.
Protective: Sensory nerves in the tooth respond almost always with PAIN to all stimuli (heat, cold, pressure, operative procedures, chamical agents).
Defensive or reparative: It responds to irritation by producing reparative dentin. The response to stimuli is inflammation.
Histologically the pulp consists of delicate collagen fibers, blood vessels, lymphatics, nerves and cells. A histologic section of the pulp reveals four cellular zones:
Odontoblastic
Cell-free (Weil)
Cell-rich
Pulp core
Water Acid Bases & Buffers
Biochemistry
Keq, Kw and pH
As H2O is the medium of biological systems one must consider the role of this molecule in the dissociation of ions from biological molecules. Water is essentially a neutral molecule but will ionize to a small degree. This can be described by a simple equilibrium equation:
H2O <-------> H+ + OH-
This equilibrium can be calculated as for any reaction:
Keq = [H+][OH-]/[H2O]
Since the concentration of H2O is very high (55.5M) relative to that of the [H+] and [OH-], consideration of it is generally removed from the equation by multiplying both sides by 55.5 yielding a new term, Kw:
Kw = [H+][OH-]
This term is referred to as the ion product. In pure water, to which no acids or bases have been added:
Kw = 1 x 10-14 M2
As Kw is constant, if one considers the case of pure water to which no acids or bases have been added:
[H+] = [OH-] = 1 x 10-7 M
This term can be reduced to reflect the hydrogen ion concentration of any solution. This is termed the pH, where:
pH = -log[H+]
Amphotericin B
Pharmacology
Amphotericin B
Main use is in systemic fungal infections (e.g. in immunocompromised patients), and in visceral leishmaniasis. Aspergillosis, cryptococcus infections (e.g. meningitis) and candidiasis are treated with amphotericin B. It is also used empirically in febrile immunocompromised patients who do not respond to broad-spectrum antibiotics.
MOA:
As with other polyene antifungals, amphotericin B associates with ergosterol, a membrane chemical of fungi, forming a pore that leads to K+ leakage and fungal cell death
Side effects: nephrotoxicity (kidney damage) , headache, vomiting, convulsions and fever
The side-effects are much milder when amphotericin B is delivered in liposomes
Characteristics of Opioid Receptors
Pharmacology
Characteristics of Opioid Receptors
mu1
Agonists : morphine phenylpiperidines
Actions: analgesia bradycardia sedation
mu2
Agonists : morphine phenylpiperidines
Actions: respiratory depression euphoria physical dependence
delta
Actions: analgesia-weak, respiratory depression
kappa
Agonists: ketocyclazocine dynorphin nalbuphine butorphanol
Actions: analgesia-weak respiratory depression sedation
Sigma
Agonists: pentazocine
Action: dysphoria -delerium hallucinations tachycardia hypertension
epsilon:
Agonists: endorphin
Actions: stress response acupuncture
Periodontal Diseases Associated with Neutrophil Disorders
PeriodontologyPeriodontal Diseases Associated with Neutrophil Disorders
Acute Necrotizing Ulcerative Gingivitis (ANUG)
Description: A severe form of gingivitis
characterized by necrosis of the interdental papillae, pain, and foul
odor.
Association: Neutrophil dysfunction can exacerbate
the severity of ANUG, leading to rapid tissue destruction.
Localized Juvenile Periodontitis
Description: A form of periodontitis that typically
affects adolescents and is characterized by localized bone loss around
the permanent teeth.
Association: Impaired neutrophil function
contributes to the pathogenesis of this condition.
Prepubertal Periodontitis
Description: A rare form of periodontitis that
occurs in children before puberty, leading to rapid attachment loss and
bone destruction.
Association: Neutrophil disorders can play a
significant role in the development and progression of this disease.
Rapidly Progressive Periodontitis
Description: A form of periodontitis characterized
by rapid attachment loss and bone destruction, often occurring in young
adults.
Association: Neutrophil dysfunction may contribute
to the aggressive nature of this disease.
Refractory Periodontitis
Description: A form of periodontitis that does not
respond to conventional treatment and continues to progress despite
therapy.
Association: Neutrophil disorders may be implicated
in the persistent nature of this condition.