NEET MDS Synopsis
Hormones of the Hypothalamus
Physiology
Gonadotropin-releasing hormone (GnRH)
GnRH is a peptide of 10 amino acids. Its secretion at the onset of puberty triggers sexual development.
Primary Effects
FSH and LH Relaese
Secondary Effects
Increases estrogen and progesterone (in females)
testosterone Relaese (in males)
Growth hormone-releasing hormone (GHRH)
GHRH is a mixture of two peptides, one containing 40 amino acids, the other 44. GHRH stimulates cells in the anterior lobe of the pituitary to secrete growth hormone (GH).
Corticotropin-releasing hormone (CRH)
CRH is a peptide of 41 amino acids. Its acts on cells in the anterior lobe of the pituitary to release adrenocorticotropic hormone (ACTH) CRH is also synthesized by the placenta and seems to determine the duration of pregnancy. It may also play a role in keeping the T cells of the mother from mounting an immune attack against the fetus
Somatostatin
Somatostatin is a mixture of two peptides, one of 14 amino acids, the other of 28. Somatostatin acts on the anterior lobe of the pituitary to
inhibit the release of growth hormone (GH)
inhibit the release of thyroid-stimulating hormone (TSH)
Somatostatin is also secreted by cells in the pancreas and in the intestine where it inhibits the secretion of a variety of other hormones.
Antidiuretic hormone (ADH) and Oxytocin
These peptides are released from the posterior lobe of the pituitary
Antral Puncture and Intranasal Antrostomy
Oral and Maxillofacial SurgeryAntral Puncture and Intranasal Antrostomy
Antral puncture, also known as intranasal antrostomy, is a
surgical procedure performed to access the maxillary sinus for diagnostic or
therapeutic purposes. This procedure is commonly indicated in cases of chronic
sinusitis, sinus infections, or to facilitate drainage of the maxillary sinus.
Understanding the anatomical considerations and techniques for antral puncture
is essential for successful outcomes.
Anatomical Considerations
Maxillary Sinus Location:
The maxillary sinus is one of the paranasal sinuses located within
the maxilla (upper jaw) and is situated laterally to the nasal cavity.
The floor of the maxillary sinus is approximately 1.25 cm below
the floor of the nasal cavity, making it accessible through the nasal
passages.
Meatuses of the Nasal Cavity:
The nasal cavity contains several meatuses, which are passageways
that allow for drainage of the sinuses:
Middle Meatus: Located between the middle and
inferior nasal conchae, it is the drainage pathway for the frontal,
maxillary, and anterior ethmoid sinuses.
Inferior Meatus: Located below the inferior
nasal concha, it primarily drains the nasolacrimal duct.
Technique for Antral Puncture
Indications:
Antral puncture is indicated for:
Chronic maxillary sinusitis.
Accumulation of pus or fluid in the maxillary sinus.
Diagnostic aspiration for culture and sensitivity testing.
Puncture Site:
In Children: The puncture should be made through
the middle meatus. This approach is preferred due to
the anatomical differences in children, where the maxillary sinus is
relatively smaller and more accessible through this route.
In Adults: The puncture is typically performed
through the inferior meatus. This site allows for
better drainage and is often used for therapeutic interventions.
Procedure:
The patient is positioned comfortably, usually in a sitting or
semi-reclined position.
Local anesthesia is administered to minimize discomfort.
A needle (often a 16-gauge or larger) is inserted through the chosen
meatus into the maxillary sinus.
Aspiration is performed to confirm entry into the sinus, and any
fluid or pus can be drained.
If necessary, saline may be irrigated into the sinus to help clear
debris or infection.
Post-Procedure Care:
Patients may be monitored for any complications, such as bleeding or
infection.
Antibiotics may be prescribed if an infection is present or
suspected.
Follow-up appointments may be necessary to assess healing and sinus
function.
The Skeleton of the Nose
AnatomyThe Skeleton of the Nose
The immovable bridge of the nose, the superior bony part of the nose, consists of the nasal bones, the frontal processes of the maxillae, and the nasal part of the frontal bones.
The movable cartilaginous part consists of five main cartilages and a few smaller ones.
The U-shaped alar nasal cartilages are free and movable.
They dilate and constrict the external nares when the muscles acting on the external nose contract.
The Nasal Cavities
The nasal cavities are entered through the anterior nares or nostrils.
They open into the nasopharynx through the choanae.
The Roof and Floor of the Nasal Cavity
The roof is curved and narrow, except at the posterior end.
The floor is wider than the roof.
It is formed from the palatine process of the maxilla and the horizontal plate of the palatine bone.
The Walls of the Nasal Cavity
The medial wall is formed by the nasal septum; it is usually smooth.
The lateral wall is uneven owing to the three longitudinal, scroll-shaped elevations, called the conchae (L. shells) or turbinates (L. shaped like a top).
These elevations are called the superior, middle and inferior conchae according to their position.
The superior and middle conchae are parts of the ethmoid bone, whereas the inferior conchae are separate bones.
The inferior and middle conchae project medially and inferiorly, producing air passageways called the inferior and middle meatus (L. passage). Note: the plural of "meatus" is the same as the singular.
The short superior conchae conceal the superior meatus.
The space posterosuperior to the superior concha is called the sphenoethmoidal recess.
Dental Terminology
Dental Anatomy
Dental Terminology.
Cusp: a point or peak on the occlusal surface of molar and premolar teeth and on the incisal edges of canines.
Contact: a point or area where one tooth is in contact (touching) another tooth
Cingulum: a bulge or elevation on the lingual surface of incisors or canines. It makes up the bulk of the cervical third of the lingual surface. Its convexity mesiodistally resembles a girdle encircling the lingual surface at the cervical.
Fissure: A linear fault that sometimes occurs in a developmental groove by incomplete or imperfect joining of the lobes. A pit is usually found at the end of a developmental groove or a place where two fissures intersect.
Lobe: one of the primary centers of formation in the development of the crown of the tooth.
Mamelon: A lobe seen on anterior teeth; any one of three rounded protuberances seen on the unworn surfaces of freshly erupted anterior teeth.
Ridge: Any linear elevation on the surface of a tooth. It is named according to its location or form. Examples are buccal ridges, incisal ridges, marginal ridges, and so on.
Marginal ridges are those rounded borders of enamel which form the margins of the surfaces of premolars and molars, mesially and distally, and the mesial and distal margins of the incisors and canines lingually.
Triangular ridges are those ridges which descend from the tips of the cusps of molars and premolars toward the central part of the occlusal surface. Transverse ridges are created when a buccal and lingual triangular ridge join.
Oblique ridges are seen on maxillary molars and are a companion to the distal oblique groove.
Cervical ridges are the height of contour at the gingival, on certain deciduous and permanent teeth.
Fossa: An irregular, rounded depression or concavity found on the surface of a tooth. A lingual fossa is found on the lingual surface of incisors. A central fossa is found on the occlusal surface of a molar. They are formed by the converging of ridges terminating at a central point in the bottom of a depression where there is a junction of grooves
Pit: A small pinpoint depression located at the junction of developmental grooves or at the terminals of these groops. A central pit is found in the central fossa on the occlusal surfaces of molars where developmental grooves join. A pit is often the site of the onset of Dental caries
Developmental groove: A sharply defined, narrow and linear depression formed during tooth development and usually separating lobes or major portions of a tooth.
A supplemental groove is also a shallow linear depression but it is usually less distinct and is more variable than a developmental groove and does not mark the junction of primary parts of a tooth.
Buccal and lingual grooves are developmental grooves found on the buccal and lingual surfaces of posterior teeth.
Tubercle: A small elevation produced by an extra formation of enamel. These occur on the marginal ridges of posterior teeth or on the cingulum of anterior teeth. These are deviations from the typical form.
Interproximal space: The triangular space between the adjacent teeth cervical to the contact point. The base of the triangle is the alveolar bone; the sides are the proximal surfaces of the adjacent teeth.
Sulcus:-An elongated valley or depression in the surface of a tooth formed by the inclines of adjacent cusp or ridges.
Embrasures: When two teeth in the same arch are in contact, their curvatures adjacent to the contact areas form spillway spaces called embrasures. There are three embrasures:
(1) Facial (buccal or labial)
(2) Occlusal or incisal
(3) Lingual
(NOTE: there are three embrasures; the fourth potential space is the interproximal space ).
PLASMA FRACTIONS
Pharmacology
PLASMA FRACTIONS:
a) Fresh frozen plasma.
b) Platelets.
c) Plasma concentrates.
d) Non-plasma recombinant factor concentrates.
Theories of Tooth Movement
OrthodonticsTheories of Tooth Movement
Pressure-Tension Theory:
Concept: This theory posits that tooth movement
occurs in response to the application of forces that create areas of
pressure and tension in the periodontal ligament (PDL).
Mechanism: When a force is applied to a tooth, the
side of the tooth experiencing pressure (compression) leads to bone
resorption, while the opposite side experiences tension, promoting bone
deposition. This differential response allows the tooth to move in the
direction of the applied force.
Clinical Relevance: This theory underlies the
rationale for using light, continuous forces in orthodontic treatment to
facilitate tooth movement without causing damage to the periodontal
tissues.
Biological Response Theory:
Concept: This theory emphasizes the biological
response of the periodontal ligament and surrounding tissues to
mechanical forces.
Mechanism: The application of force leads to a
cascade of biological events, including the release of signaling
molecules that stimulate osteoclasts (bone resorption) and osteoblasts
(bone formation). This process is influenced by the magnitude, duration,
and direction of the applied forces.
Clinical Relevance: Understanding the biological
response helps orthodontists optimize force application to achieve
desired tooth movement while minimizing adverse effects.
Cortical Bone Theory:
Concept: This theory focuses on the role of
cortical bone in tooth movement.
Mechanism: It suggests that the movement of teeth
is influenced by the remodeling of cortical bone, which is denser and
less responsive than the trabecular bone. The movement of teeth through
the cortical bone requires greater forces and longer durations of
application.
Clinical Relevance: This theory highlights the
importance of considering the surrounding bone structure when planning
orthodontic treatment, especially in cases requiring significant tooth
movement.
Endodontics -Pulp, Innervation and Microbiology -MDS Lecture
Endodontics
The liver
PhysiologyFunctions
Manufacture - blood proteins - albumen, clotting proteins , urea - nitrogenous waste from amino acid metabolism , bile - excretory for the bile pigments, emulsification of fats by bile salts
Storage - glycogen , iron - as hemosiderin and ferritin , fat soluble vitamins A, D, E, K
Detoxification -alcohol , drugs and medicines , environmental toxins
Protein metabolism -
transamination - removing the amine from one amino acid and using it to produce a different amino acid. The body can produce all but the essential amino acids; these must be included in the diet.
deamination - removal of the amine group in order to catabolize the remaining keto acid. The amine group enters the blood as urea which is excreted through the kidneys.
Glycemic Regulation - the management of blood glucose.
glycogenesis - the conversion of glucose into glycogen.
glycogenolysis - the breakdown of glycogen into glucose.
gluconeogenesis - the manufacture of glucose from non carbohydrate sources, mostly protein