NEET MDS Synopsis
Fourth Generation:
Pharmacology
Fourth Generation:
These are extended spectrum antibiotics. They are resistant to beta lactamases.
Cefipime
Control of processes in the stomach
PhysiologyControl of processes in the stomach:
The stomach, like the rest of the GI tract, receives input from the autonomic nervous system. Positive stimuli come from the parasympathetic division through the vagus nerve. This stimulates normal secretion and motility of the stomach. Control occurs in several phases:
Cephalic phase stimulates secretion in anticipation of eating to prepare the stomach for reception of food. The secretions from cephalic stimulation are watery and contain little enzyme or acid.
Gastric phase of control begins with a direct response to the contact of food in the stomach and is due to stimulation of pressoreceptors in the stomach lining which result in ACh and histamine release triggered by the vagus nerve. The secretion and motility which result begin to churn and liquefy the chyme and build up pressure in the stomach. Chyme surges forward as a result of muscle contraction but is blocked from entering the duodenum by the pyloric sphincter. A phenomenon call retropulsion occurs in which the chyme surges backward only to be pushed forward once again into the pylorus. The presence of this acid chyme in the pylorus causes the release of a hormone called gastrin into the bloodstream. Gastrin has a positive feedback effect on the motility and acid secretion of the stomach. This causes more churning, more pressure, and eventually some chyme enters the duodenum.
Intestinal phase of stomach control occurs. At first this involves more gastrin secretion from duodenal cells which acts as a "go" signal to enhance the stomach action already occurring. But as more acid chyme enters the duodenum the decreasing pH inhibits gastrin secretion and causes the release of negative or "stop" signals from the duodenum.
These take the form of chemicals called enterogastrones which include GIP (gastric inhibitory peptide). GIP inhibits stomach secretion and motility and allows time for the digestive process to proceed in the duodenum before it receives more chyme. The enterogastric reflex also reduces motility and forcefully closes the pyloric sphincter. Eventually as the chyme is removed, the pH increases and gastrin and the "go" signal resumes and the process occurs all over again. This series of "go" and "stop" signals continues until stomach emptying is complete.
Most Common Site of Primary Bone Tumors
Orthopaedics
Most Common Site of Primary Bone Tumors
Epiphyseal
- Chondroblastoma (before physeal closure)
- Osteoclastom/Giant cell tumor (after physeal closure in adults)
- Articular osteochondroma
Metaphyseal
- Chondrosarcoma
- Enchondroma
- Osteochondroma
- Osteoblastoma
- Bone cyst
- Osteosarcorna
- Osteoclastoma (in children)
- Osteomyelitis mostly starts in metaphysis
?Diaphyseal
- Round cell lesions: Ewing’s sarcoma/Multiple myeloma /Reticulum cell sarcoma
- Admantinoma
- Osteoid osteoma
WAR Lines - Impacted Mandibular Third Molars
Oral and Maxillofacial SurgeryWAR Lines in the Assessment of Impacted Mandibular Third Molars
The WAR lines, as described by George Winter, are a set of three imaginary
lines used in radiographic analysis to determine the position and depth of
impacted mandibular third molars (wisdom teeth). These lines help clinicians
assess the orientation and surgical approach needed for extraction. The three
lines are color-coded: white, amber, and red, each serving a specific purpose in
evaluating the impacted tooth.
1. White Line
Description: The white line is drawn along the occlusal
surfaces of the erupted mandibular molars and extended posteriorly over the
third molar region.
Purpose: This line helps visualize the axial
inclination of the impacted third molar.
Clinical Significance:
If the occlusal surface of the vertically impacted third molar is
parallel to the white line, it indicates that the tooth is positioned in
a vertical orientation.
Deviations from this line can suggest different angulations of
impaction (e.g., mesioangular, distoangular).
2. Amber Line
Description: The amber line is drawn from the surface
of the bone on the distal aspect of the third molar to the crest of the
interdental septum between the first and second mandibular molars.
Purpose: This line represents the margin of the
alveolar bone covering the third molar.
Clinical Significance:
The amber line indicates the amount of bone that will need to be
removed to access the impacted tooth.
After removing the soft tissue, only the portion of the impacted
tooth structure that lies above the amber line will be visible, guiding
the surgeon in determining the extent of bone removal required for
extraction.
3. Red Line
Description: The red line is an imaginary line drawn
perpendicular to the amber line, extending to an imaginary point of
application of the elevator, typically at the cementoenamel junction (CEJ)
on the mesial surface of the impacted tooth.
Exceptions: In cases of distoangular impaction, the
point of application may be at the CEJ on the distal aspect of the tooth.
Purpose: The length of the red line indicates the depth
of the impacted tooth.
Clinical Significance:
This measurement helps the surgeon understand how deep the impacted
tooth is positioned relative to the surrounding bone and soft tissue.
It assists in planning the surgical approach and determining the
necessary instruments for extraction.
Role of Coenzymes
Biochemistry
Role of Coenzymes
The functional role of coenzymes is to act as transporters of chemical groups from one reactant to another.
Ex. The hydride ion (H+ + 2e-) carried by NAD or the mole of hydrogen carried by FAD;
The amine (-NH2) carried by pyridoxal phosphate
Molecular techniques
General Pathology
Molecular techniques
Different molecular techniques such as fluorescent in situ hybridization, Southern blot, etc... can be used to detect genetic diseases.
Methods of general anesthesia
Pharmacology
Methods of general anesthesia
CIRCLE SYSTEM
*HIGH-FLOW
FRESH GAS FLOW > 3 l/min.
*LOW-FLOW
FGF ok. 1l/min.
*MINIMAL-FLOW
FGF ok. 0,5 l/min.
Zygomatic Bone Reduction
General SurgeryZygomatic Bone Reduction
When performing a reduction of the zygomatic bone, particularly in the
context of maxillary arch fractures, several key checkpoints are used to assess
the success of the procedure. Here’s a detailed overview of the important
checkpoints for both zygomatic bone and zygomatic arch reduction.
Zygomatic Bone Reduction
Alignment at the Sphenozygomatic Suture:
While this is considered the best checkpoint for assessing the
reduction of the zygomatic bone, it may not always be the most practical
or available option in certain clinical scenarios.
Symmetry of the Zygomatic Arch:
Importance: This is the second-best checkpoint and
serves multiple purposes:
Maintains Interzygomatic Distance: Ensures that
the distance between the zygomatic bones is preserved, which is
crucial for facial symmetry.
Maintains Facial Symmetry and Aesthetic Balance:
A symmetrical zygomatic arch contributes to the overall aesthetic
appearance of the face.
Preserves the Dome Effect: The prominence of
the zygomatic arch creates a natural contour that is important for
facial aesthetics.
Continuity of the Infraorbital Rim:
A critical checkpoint indicating that the reduction is complete. The
infraorbital rim should show no step-off, indicating proper alignment
and continuity.
Continuity at the Frontozygomatic Suture:
Ensures that the junction between the frontal bone and the zygomatic
bone is intact and properly aligned.
Continuity at the Zygomatic Buttress Region:
The zygomatic buttress is an important structural component that
provides support and stability to the zygomatic bone.
Zygomatic Arch Reduction
Click Sound:
The presence of a click sound during manipulation can indicate
proper alignment and reduction of the zygomatic arch.
Symmetry of the Arches:
Assessing the symmetry of the zygomatic arches on both sides of the
face is crucial for ensuring that the reduction has been successful and
that the facial aesthetics are preserved.