NEET MDS Synopsis
SELENIUM
Biochemistry
SELENIUM
normal serum level is 50-100 mg/day
Selenium dependent enzymes include glutathione Peroxidase and 5-de-iodinase. Selenium concentration in testis is the highest in adult. It is very necessary for normal development and maturation of sperm.
Muscles Around the Eyelids
AnatomyMuscles Around the Eyelids
The function of the eyelid (L. palpebrae) is to protect the eye from injury and excessive light. It also keeps the cornea moist.
The Orbicularis Oculi Muscle
This is the sphincter muscle of the eye.
Its fibres sweep in concentric circles around the orbital margin and eyelids.
It narrows the eye and helps the flow of tears from the lacrimal sac.
This muscle has 3 parts: (1) a thick orbital part for closing the eyes to protect then from light and dust; (2) a thin palpebral part for closing the eyelids lightly to keep the cornea from drying; and (3) a lacrimal part for drawing the eyelids and lacrimal punta medially.
When all three parts of the orbicularis oculi contract, the eyes are firmly closed and the adjacent skin becomes wrinkled.
The zygomatic branch of the facial nerve (CN VII) supplies it.
The Levator Palpebrae Superioris Muscle
This muscle raises the upper eyelid to open the palpebral fissure.
It is supplied by the oculomotor nerve (CN III).
Tanaka & Johnson Analysis
Orthodontics
Mixed Dentition Analysis: Tanaka & Johnson Analysis
This analysis is crucial for predicting the size of unerupted permanent
teeth based on the measurements of erupted teeth, which is particularly useful
in orthodontics.
Mixed Dentition Analysis
Mixed dentition refers to the period when both primary and permanent teeth
are present in the mouth. Accurate predictions of the size of unerupted teeth
during this phase are essential for effective orthodontic treatment planning.
Proportional Equation Prediction Method
When most canines and premolars have erupted, and one or two succedaneous
teeth are still unerupted, the proportional equation prediction method can be
employed. This method allows for estimating the mesiodistal width of unerupted
permanent teeth.
Procedure for Proportional Equation Prediction Method
Measurement of Teeth:
Measure the width of the unerupted tooth and an erupted tooth on the
same periapical radiograph.
Measure the width of the erupted tooth on a plaster cast.
Establishing Proportions:
These three measurements form a proportion that can be solved to
estimate the width of the unerupted tooth on the cast.
Formula Used
The following formula is utilized to calculate the width of the unerupted
tooth:
[ Y_1 = \frac{X_1 \times Y_2}{X_2} ]
Where:
Y1 = Width of the unerupted tooth whose measurement is
to be determined.
Y2 = Width of the unerupted tooth as seen on the
radiograph.
X1 = Width of the erupted tooth, measured on the
plaster cast.
X2 = Width of the erupted tooth, measured on the
radiograph.
Application of the Analysis
This method is particularly useful in orthodontic assessments, allowing
practitioners to predict the size of unerupted teeth accurately. By using the
measurements of erupted teeth, orthodontists can make informed decisions
regarding space management and treatment planning.
Root Formation and Obliteration
Dental Anatomy
Root Formation and Obliteration
1. In general, the root of a deciduous tooth is completely formed in just about one year after eruption of that tooth into the mouth.
2. The intact root of the deciduous tooth is short lived. The roots remain fully formed only for about three years.
3. The intact root then begins to resorb at the apex or to the side of the apex, depending on the position of the developing permanent tooth bud.
4. Anterior permanent teeth tend to form toward the lingual of the deciduous teeth, although the canines can be the exception. Premolar teeth form between the roots of the deciduous molar teeth
Introduction. The Jaws and Dental Arches
Dental Anatomy
Introduction. The Jaws and Dental Arches
The teeth are arranged in upper and lower arches. Those of the upper are called maxillary; those of the lower are mandibular.
The maxilla is actually two bones forming the upper jaw; they are rigidly attached to the skull..
The mandible is a horseshoe shaped bone which articulates with the skull by way of the temporomandibular joint the TMJ.
The dental arches, the individual row of teeth forming a tooth row attached to their respective jaw bones have a distinctive shape known as a catenary arch.
Characteristics of Facilitated Diffusion & Active Transport
PhysiologyCharacteristics of Facilitated Diffusion & Active Transport - both require the use of carriers that are specific to particular substances (that is, each type of carrier can 'carry' one type of substance) and both can exhibit saturation (movement across a membrane is limited by number of carriers & the speed with which they move materials
Superior Constrictor Muscle
AnatomySuperior Constrictor Muscle
Origin: Hamulus, pterygo-mandibular raphe, and
mylohyoid line of the mandible.
Insertion: Median raphe of the pharynx.
Nerve Supply: Vagus nerve via the pharyngeal plexus.
Arterial Supply: Ascending pharyngeal artery, ascending
palatine artery, tonsillar branch of the facial artery, and dorsal branch of
the lingual artery.
Action: Constricts the wall of the pharynx during
swallowing.
Infections caused by N. meningiditis
General Pathology
Infections caused by N. meningiditis
1. Bacteremia without sepsis. Organism spreads to blood but no major reaction.
2. Meningococcemia without meningitis. Fever, headache, petechia, hypotension, disseminated intravascular coagulation. The Waterhouse-Friderichsen Syndrome is a rapid, progressive meningococcemia with shock, organ failure, adrenal necrosis, and death.
3. Meningitis with meningococcemia. Sudden onset fever, chills, headache, confusion, nuchal rigidity. This occurs rapidly.
4. Meningoencephalitis. Patients are deeply comatose.
Diagnosis made by examining CSF.