NEET MDS Synopsis
Stippling of the Gingiva
PeriodontologyStippling of the Gingiva
Stippling refers to the textured surface of
the gingiva that resembles the skin of an orange. This characteristic is
best observed when the gingiva is dried.
Characteristics:
Location:
The attached gingiva is typically stippled, while the marginal
gingiva is not.
The central portion of the interdental gingiva may exhibit
stippling, but its marginal borders are usually smooth.
Surface Variation:
Stippling is generally less prominent on the lingual surfaces
compared to the facial surfaces and may be absent in some
individuals.
Age-Related Changes:
Stippling is absent in infancy, begins to appear around 5 years
of age, increases until adulthood, and may start to disappear in old
age.
Attached Gingiva
Definition: The attached gingiva is the portion of the
gingiva that is firmly bound to the underlying alveolar bone and extends
from the free gingival groove to the mucogingival junction, where it meets
the alveolar mucosa.
Characteristics:
Structure:
The attached gingiva is classified as a mucoperiosteum, tightly
bound to the underlying alveolar bone.
Width:
The width of the attached gingiva is greatest in the incisor
region, measuring approximately:
3.5 – 4.5 mm in the maxilla
3.3 – 3.9 mm in the mandible
It is narrower in the posterior segments, measuring about:
1.9 mm in the maxillary first premolars
1.8 mm in the mandibular first premolars.
Histological Features:
The attached gingiva is thick and keratinized (or
parakeratinized) and is classified as masticatory mucosa.
Masticatory mucosa is characterized by a keratinized epithelium
and a thick lamina propria, providing resistance to mechanical
forces.
Masticatory vs. Lining Mucosa
Masticatory Mucosa:
Found in areas subject to high compression and friction, such as the
gingiva and hard palate.
Characterized by keratinized epithelium and a thick lamina propria,
making it resistant to masticatory forces.
Lining Mucosa:
Mobile, distensible, and non-keratinized.
Found in areas such as the lips, cheeks, alveolus, floor of the
mouth, ventral surface of the tongue, and soft palate.
Specialized Mucosa:
Found on the dorsum of the tongue, adapted for specific functions
such as taste.
Urine excretion
Physiology
Concentration versus diluting urine
Kidney is a major route for eliminating fluid from the body to accomplish water balance. Urine excretion is the last step in urine formation. Everyday both kidneys excrete about 1.5 liters of urine.
Depending on the hydrated status of the body, kidney either excretes concentrated urine ( if the plasma is hypertonic like in dehydrated status ) or diluted urine ( if the plasma is hypotonic) .
This occurs thankful to what is known as countercurrent multiplying system, which functions thankfully to establishing large vertical osmotic gradient .
To understand this system, lets review the following facts:
1. Descending limb of loop of Henle is avidly permeable to water.
2. Ascending limb of loop of Henly is permeable to electrolytes , but impermeable to water. So fluid will not folow electrolytes by osmosis.and thus Ascending limb creates hypertonic interstitium that will attract water from descending limb.
Pumping of electrolytes
3. So: There is a countercurrent flow produced by the close proximity of the two limbs.
Juxtamedullary nephrons have long loop of Henle that dips deep in the medulla , so the counter-current system is more obvious and the medullary interstitium is always hypertonic . In addition, peritubular capillaries in the medulla are straigh ( vasa recta) in which flow is rapid and rapidly reabsorb water maintaining hypertonic medullary interstitium.
In distal tubules water is diluted. If plasma is hypertonic, this will lead to release of ADH by hypothalamus, which will cause reabsorption of water in collecting tubules and thus excrete concentrated urine.
If plasma is hypotonic ADH will be inhibited and the diluted urine in distal tubules will be excreted as diluted urine.
Urea contributes to concentrating and diluting of urine as follows:
Urea is totally filtered and then 50% of filtrated urea will be reabsorbed to the interstitium, this will increase the osmolarity of medullary interstitium ( becomes hypertonic ). Those 50% will be secreted in ascending limb of loop of Henle back to tubular fluid to maintain osmolarity of tubular fluid. 55% of urea in distal nephron will be reabsorbed in collecting ducts back to the interstitium ( under the effect of ADH too) . This urea cycle additionally maintain hypertonic interstitium.
INFLUENZA
General Pathology
INFLUENZA
An acute viral respiratory infection with influenza, a virus causing fever, coryza, cough, headache, malaise, and inflamed respiratory mucous membranes.
Influenza B viruses typically cause mild respiratory disease
Symptoms and Signs
mild cases:
Chills and fever up to 39 to 39.5° C
Prostration and generalized aches and pains, Headache, photophobia and retrobulbar aching
Respiratory tract symptoms may be mild at first, with scratchy sore throat, substernal burning, nonproductive cough, and sometimes coryza. Later, the lower respiratory illness becomes dominant; cough can be persistent and productive.
severe cases
sputum may be bloody. Skin is warm and flushed. Soft palate, posterior hard palate, tonsillar pillars, and posterior pharyngeal wall may be reddened, but no exudate appears. Eyes water easily, and the conjunctiva may be mildly inflamed
Encephalitis, myocarditis, and myoglobinuria are infrequent complications of influenza and, if present, usually occur during convalescence
DIAGNOSIS
Pharmacology
DIAGNOSIS
Affective disorders:
I. unipolar depression – depression alone
bipolar affective disorder – alternating II. bipolar affective disorder – alternating depression and mania
Diagnosis is based on
At least five of the following for 2 weeks
I. Depressed mood most of the day
II. Markedly diminished interest or pleasureII. Markedly diminished interest or pleasure
III. Significant weight loss or weight
IV. Insomnia or hypersomnia
V. Psychomotor agitation or retardation
VI. Fatigue or loss of energy
VII. Feelings of worthlessness or excessive guilt
VIII. Diminished ability to think or concentrate,
IX. Recurrent thoughts of death
Underlying biological basis for depression is a deficiency of the monoamine neurotransmitters norepinephrine and/or serotonin in the brain.
Prognosis After Traumatic Brain Injury
Oral and Maxillofacial SurgeryPrognosis After Traumatic Brain Injury (TBI)
Determining the prognosis for patients after a traumatic brain injury
(TBI) is a complex and multifaceted process. Several factors can
influence the outcome, and understanding these variables is crucial for
clinicians in managing TBI patients effectively. Below is an overview of the key
prognostic indicators, with a focus on the Glasgow Coma Scale (GCS) and other
factors that correlate with severity and outcomes.
Key Prognostic Indicators
Glasgow Coma Scale (GCS):
The GCS is a widely used tool for assessing the level of
consciousness in TBI patients. It evaluates three components: eye
opening (E), best motor response (M), and verbal response (V).
Coma Score Calculation:
The total GCS score is calculated as follows: [ \text{Coma
Score} = E + M + V ]
Prognostic Implications:
Scores of 3-4: Patients scoring in this range
have an 85% chance of dying or remaining in a vegetative
state.
Scores of 11 or above: Patients with scores in
this range have only a 5-10% chance of dying or remaining
vegetative.
Intermediate Scores: Scores between these
ranges correlate with proportional chances of recovery, indicating
that higher scores generally predict better outcomes.
Other Poor Prognosis Indicators:
Older Age: Age is a significant factor, with older
patients generally having worse outcomes following TBI.
Increased Intracranial Pressure (ICP): Elevated ICP
is associated with poorer outcomes, as it can lead to brain herniation
and further injury.
Hypoxia and Hypotension: Both conditions can
exacerbate brain injury and are associated with worse prognoses.
CT Evidence of Compression: Imaging findings such
as compression of the cisterns or midline shift indicate significant
mass effect and are associated with poor outcomes.
Delayed Evacuation of Large Intracerebral Hemorrhage:
Timely surgical intervention is critical; delays can worsen the
prognosis.
Carrier Status for Apolipoprotein E-4 Allele: The
presence of this allele has been linked to poorer outcomes in TBI
patients, suggesting a genetic predisposition to worse recovery.
EPITHELIUMS
Anatomy
EPITHELIUMS
Epithelial Tissue Epithelial tissue covers surfaces, usually has a basement membrane, has little extracellular material, and has no blood vessels. A basement membrane attaches the epithelial cells to underlying tissues. Most epithelia have a free surface, which is not in contact with other cells. Epithelia are classified according to the number of cell layers and the shape of the cells.
Epitheliums contain no blood vessels. There is normally an underlying layer of connective tissue
Almost all epitheliums lie on a basement membrane.The basement membrane consists of a basal lamina and reticular lamina. The reticular lamina is connected to the basal lamina by anchoring fibrils. The reticular lamina may be absent in which case the basement membrane consist only of a basal lamina. The basal lamina consists of a - lamina densa in the middle (physical barrier) with a lamina lucida on both sides (+charge barrier),The basement membrane is absent in ependymal cells.The basement membrane is not continuous in sinusoidal capillaries.
Epitheliums always line or cover something
Epithelial cells lie close together with little intercellular space
Epithelial cells are strongly connected to one another especially those epitheliums that are subjected to mechanical forces.
Functions of Epithelium:
→ Simple epithelium involved with diffusion, filtration, secretion, or absorption
→ Stratified epithelium protects from abrasion
→ Squamous cells function in diffusion or filtration
Enophthalmos
Oral and Maxillofacial SurgeryEnophthalmos
Enophthalmos is a condition characterized by the inward
sinking of the eye into the orbit (the bony socket that holds the eye). It is
often a troublesome consequence of fractures involving the zygomatic complex
(the cheekbone area).
Causes of Enophthalmos
Enophthalmos can occur due to several factors following an injury:
Loss of Orbital Volume:
There may be a decrease in the volume of the contents within the
orbit, which can happen if soft tissues herniate into the maxillary
sinus or through the medial wall of the orbit.
Fractures of the Orbital Walls:
Fractures in the walls of the orbit can increase the volume of the
bony orbit. This can occur with lateral and inferior displacement of the
zygoma or disruption of the inferior and lateral orbital walls. A
quantitative CT scan can help visualize these changes.
Loss of Ligament Support:
The ligaments that support the eye may be damaged, contributing to
the sinking of the eye.
Post-Traumatic Changes:
After an injury, fibrosis (the formation of excess fibrous
connective tissue), scar contraction, and fat atrophy (loss of fat in
the orbit) can occur, leading to enophthalmos.
Combination of Factors:
Often, enophthalmos results from a combination of the above factors.
Diagnosis
Acute Cases: In the early stages after an injury,
diagnosing enophthalmos can be challenging. This is because swelling (edema)
of the surrounding soft tissues can create a false appearance of
enophthalmos, making it seem like the eye is more sunken than it actually
is.
CLEANING AND PICKLING ALLOYS
Dental Materials
CLEANING AND PICKLING ALLOYS
The surface oxidation or other contamination of dental alloys is a troublesome occurrence. The oxidation of base metals in most alloys can be kept to a minimum or avoided by using a properly adjusted method of heating the alloy and a suitable amount of flux when melting the alloy . Despite these precautions, as the hot metal enters the mold, certain alloys tend to become contaminated on the surface by combining with the hot mold gases, reacting with investment ingredients, or physically including mold particles in the metal surface. The surface of most cast, soldered, or otherwise heated metal dental appliances is cleaned by warming the structure in suitable solutions, mechanical polishing, or other treatment of the alloy to restore the normal surface condition.
Surface tarnish or oxidation can be removed by the process of pickling. Castings of noble or high-noble metal may be cleaned in this manner by warming them in a 50% sulfuric acid and water solution . . After casting, the alloy (with sprue attached) is placed into the warmed pickling solution for a few seconds. The pickling solution will reduce oxides that have formed during casting. However, pickling will not eliminate a dark color caused by carbon deposition
The effect of the solution can be seen by comparing the submerged surfaces to those that have still not contacted the solution. the ordinary inorganic acid solutions and do not release poisonous gases on boiling (as sulfuric acid does). In either case, the casting to be cleaned is placed in a suitable porcelain beaker with the pickling solution and warmed gently, but short of the boiling point. After a few moments of heating, the alloy surface normally becomes bright as the oxides are reduced. When the heating is completed, the acid may be poured from the beaker into the original storage container and the casting is thoroughly rinsed with water. Periodically, the pickling solution should be replaced with fresh solution to avoid excessive contamination.
Precautions to be taken while pickling
With the diversity of compositions of casting alloys available today, it is prudent to follow the manufacturer's instructions for pickling precisely, as all pickling solutions may not be compatible with all alloys. Furthermore, the practice of dropping a red-hot casting into the pickling solution should beavoided. This practice may alter the phase structure of the alloy or warp thin castings, and splashing acid may be dangerous to the operator. Finally, steel or stainless steel tweezers should not be used to remove castings from the pickling solutions. The pickling solution may dissolve the tweezers and plate the component metals onto the casting. Rubber-coated or Teflon tweezers are recommended for this purpose.