NEET MDS Synopsis
Carbohydrates
PhysiologyCarbohydrates:
about 3% of the dry mass of a typical cell
composed of carbon, hydrogen, & oxygen atoms (e.g., glucose is C6H12O6)
an important source of energy for cells
types include:
monosaccharide (e.g., glucose) - most contain 5 or 6 carbon atoms
disaccharides
2 monosaccharides linked together
Examples include sucrose (a common plant disaccharide is composed of the monosaccharides glucose and fructose) & lactose (or milk sugar; a disaccharide composed of glucose and the monosaccharide galactose)
polysaccharides
several monosaccharides linked together
Examples include starch (a common plant polysaccharide made up of many glucose molecules) and glycogen (commonly stored in the liver)
Multiple myeloma
General Pathology
Multiple myeloma.
Blood picture:
- Marked rouleaux formation.
- Normpcytic normochromic anaemia.
- There may be leucopenia or leucoery!hrohlastic reaction.
- Atypical plasma cells may be seen in some patients
- Raised ESR
- Monoclonal hypergammaglobulinaemia
- If light chains are produced in excess, they are excreted in urine as bence jones protein
Bone marrow
- Hyper cellular
- Plasma cells from at least 15 – 30% atypical forms and myeloma cells are seen.
Dental Plaque
PeriodontologyDental Plaque
Dental plaque is a biofilm that forms on the surfaces of teeth and is
composed of a diverse community of microorganisms. The development of dental
plaque occurs in stages, beginning with primary colonizers and progressing to
secondary colonization and plaque maturation.
Primary Colonizers
Timeframe:
Acquired within a few hours after tooth cleaning or exposure.
Characteristics:
Predominantly gram-positive facultative microbes.
Key Species:
Actinomyces viscosus
Streptococcus sanguis
Adhesion Mechanism:
Primary colonizers adhere to the tooth surface through specific
adhesins.
For example, A. viscosus possesses fimbriae that bind to
proline-rich proteins in the dental pellicle, facilitating initial
attachment.
Secondary Colonization and Plaque Maturation
Microbial Composition:
As plaque matures, it becomes predominantly populated by
gram-negative anaerobic microorganisms.
Key Species:
Prevotella intermedia
Prevotella loescheii
Capnocytophaga spp.
Fusobacterium nucleatum
Porphyromonas gingivalis
Coaggregation:
Coaggregation refers to the ability of different species and genera
of plaque microorganisms to adhere to one another.
This process occurs primarily through highly specific stereochemical
interactions of protein and carbohydrate molecules on cell surfaces,
along with hydrophobic, electrostatic, and van der Waals forces.
Plaque Hypotheses
Specific Plaque Hypothesis:
This hypothesis posits that only certain types of plaque are
pathogenic.
The pathogenicity of plaque depends on the presence or increase of
specific microorganisms.
It predicts that plaque harboring specific bacterial pathogens leads
to periodontal disease due to the production of substances that mediate
the destruction of host tissues.
Nonspecific Plaque Hypothesis:
This hypothesis maintains that periodontal disease results from the
overall activity of the entire plaque microflora.
It suggests that the elaboration of noxious products by the entire
microbial community contributes to periodontal disease, rather than
specific pathogens alone.
Multiphase and Multistage random sampling
Public Health DentistryMultiphase and multistage random sampling are advanced
sampling techniques used in research, particularly in public health and social
sciences, to efficiently gather data from large and complex populations. Both
methods are designed to reduce costs and improve the feasibility of sampling
while maintaining the representativeness of the sample. Here’s a detailed
explanation of each method:
Multiphase Sampling
Description: Multiphase sampling involves conducting a
series of sampling phases, where each phase is used to refine the sample
further. This method is particularly useful when the population is large and
heterogeneous, and researchers want to focus on specific subgroups or
characteristics.
Process:
Initial Sampling: In the first phase, a large sample is
drawn from the entire population using a probability sampling method (e.g.,
simple random sampling or stratified sampling).
Subsequent Sampling: In the second phase, researchers
may apply additional criteria to select a smaller, more specific sample from
the initial sample. This could involve stratifying the sample based on
certain characteristics (e.g., age, health status) or conducting follow-up
surveys.
Data Collection: Data is collected from the final
sample, which is more targeted and relevant to the research question.
Applications:
Public Health Surveys: In a study assessing health
behaviors, researchers might first sample a broad population and then focus
on specific subgroups (e.g., smokers, individuals with chronic diseases) for
more detailed analysis.
Qualitative Research: Multiphase sampling can be used
to identify participants for in-depth interviews after an initial survey has
highlighted specific areas of interest.
Multistage Sampling
Description: Multistage sampling is a complex form of
sampling that involves selecting samples in multiple stages, often using a
combination of probability sampling methods. This technique is particularly
useful for large populations spread over wide geographic areas.
Process:
First Stage: The population is divided into clusters
(e.g., geographic areas, schools, or communities). A random sample of these
clusters is selected.
Second Stage: Within each selected cluster, a further
sampling method is applied to select individuals or smaller units. This
could involve simple random sampling, stratified sampling, or systematic
sampling.
Additional Stages: More stages can be added if
necessary, depending on the complexity of the population and the research
objectives.
Applications:
National Health Surveys: In a national health survey,
researchers might first randomly select states (clusters) and then randomly
select households within those states to gather health data.
Community Health Assessments: Multistage sampling can
be used to assess oral health in a large city by first selecting
neighborhoods and then sampling residents within those neighborhoods.
Key Differences
Structure:
Multiphase Sampling involves multiple phases of
sampling that refine the sample based on specific criteria, often
leading to a more focused subgroup.
Multistage Sampling involves multiple stages of
sampling, often starting with clusters and then selecting individuals
within those clusters.
Purpose:
Multiphase Sampling is typically used to narrow
down a broad sample to a more specific group for detailed study.
Multistage Sampling is used to manage large
populations and geographic diversity, making it easier to collect data
from a representative sample.
Titration of a weak acid with a strong base
Biochemistry
Titration of a weak acid with a strong base
• A weak acid is mostly in its conjugate acid form
• When strong base is added, it removes protons from the solution, more and more acid is in the conjugate base form, and the pH increases
• When the moles of base added equals half the total moles of acid, the weak acid and its conjugate base are in equal amounts. The ratio of CB / WA = 1 and according to the HH equation, pH = pKa + log(1) or pH = pKa.
• If more base is added, the conjugate base form becomes greater till the equivalance point when all of the acid is in the conjugate base form.
Space Maintainer
PedodonticsSoldered Lingual Holding Arch as a Space Maintainer
Introduction
The soldered lingual holding arch is a classic bilateral mixed-dentition
space maintainer used in the mandibular arch. It is designed to preserve the
space for the permanent canines and premolars during the mixed dentition phase,
particularly when primary molars are lost prematurely.
Design and Construction
Components:
Bands: Fitted to the first permanent molars.
Wire: A 0.036- or 0.040-inch stainless steel wire
is contoured to the arch.
Extension: The wire extends forward to make contact
with the cingulum area of the incisors.
Arch Form: The wire is contoured to provide an anterior
arch form, allowing for the alignment of the incisors while ensuring it does
not interfere with the normal eruption paths of the teeth.
Functionality
Stabilization: The design stabilizes the positions of
the lower molars, preventing them from moving mesially and maintaining the
incisor relationship to avoid retroclination.
Leeway Space: The arch helps sustain the
canine-premolar segment space, utilizing the leeway space available during
the mixed dentition phase.
Clinical Considerations
Eruption Path: The lingual wire must be contoured to
avoid interference with the normal eruption paths of the permanent canines
and premolars.
Breakage and Hygiene: The soldered lingual holding arch
is designed to present minimal problems with breakage and minimal oral
hygiene concerns.
Eruptive Movements: It should not interfere with the
eruptive movements of the permanent teeth, allowing for natural development.
Timing of Placement
Transitional Dentition Period: The bilateral design and
use of permanent teeth as abutments allow for application during the full
transitional dentition period of the buccal segments.
Timing of Insertion: Lower lingual arches should not be
placed before the eruption of the permanent incisors due to their frequent
lingual eruption path. If placed too early, the lingual wire may interfere
with normal incisor positioning, particularly before the lateral incisor
erupts.
Anchorage: Using primary incisors as anterior stops
does not provide sufficient anchorage to prevent significant loss of arch
length.
Vital Capacity
PhysiologyVital Capacity: The vital capacity (VC) is the maximum volume which can be ventilated in a single breath. VC= IRV+TV+ERV. VC varies with gender, age, and body build. Measuring VC gives a device for diagnosis of respiratory disorder, and a benchmark for judging the effectiveness of treatment. (4600 ml)
Vital Capacity is reduced in restrictive disorders, but not in disorders which are purely obstructive.
The FEV1 is the % of the vital capacity which is expelled in the first second. It should be at least 75%. The FEV1 is reduced in obstructive disorders.
Both VC and the FEV1 are reduced in disorders which are both restrictive and obstructive
Oxygen is present at nearly 21% of ambient air. Multiplying .21 times 760 mmHg (standard pressure at sea level) yields a pO2 of about 160. Carbon dioxide is .04% of air and its partial pressure, pCO2, is .3.
With alveolar air having a pO2 of 104 and a pCO2 of 40. So oxygen diffuses into the alveoli from inspired air and carbon dioxide diffuses from the alveoli into air which will be expired. This causes the levels of oxygen and carbon dioxide to be intermediate in expired air when compared to inspired air and alveolar air. Some oxygen has been lost to the alveolus, lowering its level to 120, carbon dioxide has been gained from the alveolus raising its level to 27.
Likewise a concentration gradient causes oxygen to diffuse into the blood from the alveoli and carbon dioxide to leave the blood. This produces the levels seen in oxygenated blood in the body. When this blood reaches the systemic tissues the reverse process occurs restoring levels seen in deoxygenated blood.
THE PITUITARY GLAND
General Pathology
THE PITUITARY GLAND
This is a small, bean-shaped structure that lies at the base of the brain within the confines of the sella turcica. It is connected to the hypothalamus by a "stalk," composed of axons extending from the hypothalamus. The pituitary is composed of two morphologically and functionally distinct components: the anterior lobe (adenohypophysis) and the posterior lobe (neurohypophysis). The adenohypophysis, in H&E stained sections, shows a colorful collection of cells with basophilic, eosinophilic or poorly staining ("chromophobic") cytoplasm.