NEET MDS Synopsis
Hormones of the Pituitary -The Posterior Lobe
Physiology
The Posterior Lobe
The posterior lobe of the pituitary releases two hormones, both synthesized in the hypothalamus, into the circulation.
Antidiuretic Hormone (ADH).
ADH is a peptide of 9 amino acids. It is also known as arginine vasopressin. ADH acts on the collecting ducts of the kidney to facilitate the reabsorption of water into the blood.
A deficiency of ADH
leads to excessive loss of urine, a condition known as diabetes nsipidus.
Oxytocin
Oxytocin is a peptide of 9 amino acids. Its principal actions are:
stimulating contractions of the uterus at the time of birth
stimulating release of milk when the baby begins to suckle
Alveolar Osteitis
Oral and Maxillofacial SurgeryDry Socket (Alveolar Osteitis)
Dry socket, also known as alveolar osteitis,
is a common complication that can occur after tooth extraction, particularly
after the removal of mandibular molars. It is characterized by delayed
postoperative pain due to the loss of the blood clot that normally forms in the
extraction socket.
Key Features
Pathophysiology:
After a tooth extraction, a blood clot forms in the socket, which is
essential for healing. In dry socket, this clot is either dislodged or
dissolves prematurely, exposing the underlying bone and nerve endings.
The initial appearance of the clot may be dirty gray, and as it
disintegrates, the socket may appear gray or grayish-yellow, indicating
the presence of bare bone without granulation tissue.
Symptoms:
Symptoms of dry socket typically begin 3 to 5 days after
the extraction. Patients may experience:
Severe pain in the extraction site that can radiate to the ear,
eye, or neck.
A foul taste or odor in the mouth due to necrotic tissue.
Visible empty socket with exposed bone.
Local Therapy:
Management of dry socket involves local treatment to alleviate pain
and promote healing:
Irrigation: The socket is irrigated with a warm
sterile isotonic saline solution or a dilute solution of hydrogen
peroxide to remove necrotic material and debris.
Application of Medications: After irrigation,
an obtundent (pain-relieving) agent or a topical anesthetic may be
applied to the socket to provide symptomatic relief.
Prevention:
To reduce the risk of developing dry socket, patients are often
advised to:
Avoid smoking and using straws for a few days post-extraction,
as these can dislodge the clot.
Follow postoperative care instructions provided by the dentist
or oral surgeon.
Acute pericarditis
General Pathology
Acute pericarditis
1. Characterized by inflammation of the pericardium.
2. Causes include:
a. Viral infection.
b. Bacterial infection, including Staphylococcus, Pneumococcus.
c. Tuberculosis.
d. MI.
e. Systemic lupus erythematosus.
f. Rheumatic fever.
3. Signs and symptoms include:
a. Pericardial friction rub on cardiac auscultation.
b. Angina.
c. Fever.
4. Consequences include constrictive pericarditis,which results from fusion and scarring of the pericardium. This may lead to the restriction of ventricular expansion, preventing the heart chambers from filling normally.
Diagnostic techniques used in pathology
General Pathology
Diagnostic techniques used in pathology
The pathologist uses the following techniques to the diagnose diseases:
a. Histopathology
b. Cytopathology
c. Hematopathology
d. Immunohistochemistry
e. Microbiological examination
f. Biochemical examination
g. Cytogenetics
h. Molecular techniques
i. Autopsy
Condensers/pluggers
Conservative DentistryCondensers/pluggers are instruments used to deliver the forces of compaction
to the underlying restorative material. There are
several methods for the application of these forces:
1.
Hand pressure: use of this method alone is contraindicated
except in a few situations like adapting the first piece of gold to
the convenience or point angles and where the line of force will not permit
use of other methods. Powdered golds are also
known to be better condensed with hand pressure. Small condenser points of
0.5 mm in diameter are generally
recommended as they do not require very high forces for their manipulation.
2.
Hand malleting: Condensation by hand malleting is a team work
in which the operator directs the condenser and moves it
over the surface, while the assistant provides rhythmic blows from the
mallet. Long handled condensers and leather faced
mallets (50 gms in weight) are used for this purpose. The technique allows
greater control and the condensers can be
changed rapidly when required. However, with the introduction of mechanical
malleting, use of this method has decreased
considerably.
3.
Automatic hand malleting: This method utilizes a spring loaded
instrument that delivers the desired force once the spiral
spring is released. (Disadvantage is that the blow descends very rapidly even
before full pressure has been exerted on the
condenser point.
4.
Electric malleting (McShirley electromallet): This instrument
accommodates various shapes of con-denser points and has a
mallet in the handle itself which remains dormant until wished by the
operator to function. The intensity or amplitude
generated can vary from 0.2 ounces to 15 pounds and the frequency can range
from 360-3600 cycles/minute.
5.
Pneumatic malleting (Hollenback condenser): This is the most
recent and satisfactory method first developed by
Dr. George M. Hollenback. Pneumatic mallets consist of vibrating nit
condensers and detachable tips run by
compressed air. The air is carried through a thin rubber tubing attached to
the hand piece. Controlling the air
pressure by a rheostat nit allows adjusting the frequency and amplitude of
condensation strokes. The construction
of the handpiece is such that the blow does not fall until pressure is placed
on the condenser point. This continues
until released. Pneumatic mallets are available with both straight and angled
for handpieces.
Thalassaemia
General Pathology
Thalassaemia. Genetic based defect in synthesis of one of the normal chains.
Beta thalassaemia ---> reduced Hb A and increased HbF (α2, Y2) HBA2(α2)
Alpha thalassaemia ---> reduced Hb-A, Hb-A2 and Hb-F-with formation of Hb-H(β4) and Hb Barts (Y4).
Thalassaemia may manifest as trait or disease or with intermediate manifestation.
Features:
• Microcytic hypochromic RBC is in iron deficjency.
• Marked anisopoikilocytsis with prominent target cells.
• Reticulocytosis and nucleated RBC seen.
• Mongoloid facies and X-ray findings characteristic of marrow hyperplasia
• Decreased osmotic. fragility.
• Increased marrow iron (important difference from iron deficiency anaemia).
• Haemosiderosis, especially with repeated transfusions.
Diagnosis is by Hb electrophoresis and by Alkali denaturation test (for HbF).
Histology
Anatomy
Histology
Histology is the study of tissues.
A tissue is a group of cells with similar structure and function plus the extracellular substances located between the cells.
There are four basic types of tissues:
- Epitheliums
- Connective tissue
- Muscle tissue
- Nervous tissue
The Skull
AnatomyThe skull, the skeleton of the head, is the most complex bony structure in the body because it:
Encloses the brain, which is irregular in shape;
Houses the organs of special senses for seeing, hearing, tasting, and smelling; and
Surrounds the openings in to the digestive and respiratory tracts.
In the anatomical position, the skull is oriented so that the inferior margin of the orbit (eye socket) and the superior margin of the external acoustic meatus (auditory canal) are horizontal. This is called the orbitomenial plane (Frankfort plane).
The term cranium (L. skull) is sometimes used when referring to the skull without the mandible (lower jaw), but the cranium is often used when referring to the part of the skull containing the brain.
The superior part is the box-like structure called the calvaria (cranial vault, brain case); the remainder of the cranium, including the maxilla (upper jaw), orbits (eyeball sockets) and nasal cavities, forms the facial skeleton.
The term skullcap (calotte) refers to the superior part of the calvaria, which is removed during autopsies and dissections. The inferior aspect of the cranium is called the cranial base.