NEET MDS Synopsis
TRIGLYCEROL
Biochemistry
TRIGLYCEROL
Triacylglycerols (formerly triglycerides) are the esters of glycerol with fatty acids. The fats and oils that are widely distributed in both plants and animals are chemically triacylglycerols.
They are insoluble in water and non-polar in character and commonly known as neutral fats.
Triacylglycerols are the most abundant dietary lipids. They are the form in which we store reduced carbon for energy. Each triacylglycerol has a glycerol backbone to which are esterified 3 fatty acids. Most triacylglycerols are "mixed." The three fatty acids differ in chain length and number of double bonds
Structures of acylglycerols :
Monoacylglycerols, diacylglycerols and triacylglycerols, respectively consisting of one, two and three molecules of fatty acids esterified to
a molecule of glycerol
Lipases hydrolyze triacylglycerols, releasing one fatty acid at a time, producing diacylglycerols, and eventually glycerol
Glycerol arising from hydrolysis of triacylglycerols is converted to the Glycolysis intermediate dihydroxyacetone phosphate, by reactions catalyzed by:
(1) Glycerol Kinase
(2) Glycerol Phosphate Dehydrogenase
Free fatty acids, which in solution have detergent properties, are transported in the blood bound to albumin, a serum protein produced by the liver.
Several proteins have been identified that facilitate transport of long chain fatty acids into cells, including the plasma membrane protein CD36
Ligaments of the Joint
AnatomyLigaments of the Joint
The fibrous capsule is thickened laterally to form the lateral (temporomandibular) ligament. It reinforces the lateral part of this capsule.
The base of this triangular ligament is attached to the zygomatic process of the temporal bone and the articular tubercle.
Its apex is fixed to the lateral side of the neck of the mandible.
Two other ligaments connect the mandible to the cranium but neither provides much strength.
The stylomandibular ligament is a thickened band of deep cervical fascia.
It runs from the styloid process of the temporal bone to the angle of the mandible and separates the parotid and submandibular salivary glands.
The sphenomandibular ligament is a long membranous band that lies medial to the joint.
This ligament runs from the spine of the sphenoid bone to the lingula on the medial aspect of the mandible.
Cement Applications
Dental Materials
Root canal sealers
Applications
Cementation of silver cone gutta-percha point
Paste filling material
Types
Zinc oxide-eugenol cement types
Noneugenol cement types
Therapeutic cement types
properties
Physical-radiopacity
Chemical-insolubility
Mechanical-flow; tensile strength
Biologic-inertness
Gingival tissue packs
Application-provide temporary displacement of gingival tissues
Composition-slow setting zinc oxide-eugenol cement mixed with cotton twills for texture and strength
Surgical dressings
1.Application-gingival covering after periodontal surgery
2. Composition-modified zinc oxide-eugenol cement (containing tannic, acid. rosin, and various oils)
Orthodontic cements
Application-cementation of orthodontic bands
Composition-zinc phosphate cement
Manipulation
Zinc phosphate types are routinely mixed with cold or frozen mixing slab to extend the working time
Enamel bonding agent types use acid etching for improved bonding
Band, bracket, or cement removal requires special care
Hand Instruments
Conservative DentistryHand Instruments - Design and Balancing
Hand instruments are essential tools in dentistry, and their design
significantly impacts their effectiveness and usability. Proper balancing and
angulation of these instruments are crucial for achieving optimal control and
precision during dental procedures. Below is an overview of the key aspects of
hand instrument design, focusing on the shank, angulation, and balancing.
1. Importance of Balancing
A. Definition of Balance
Balanced Instruments: A hand instrument is
considered balanced when the concentration of force can be applied to the
blade without causing rotation in the grasp of the operator. This balance is
essential for effective cutting and manipulation of tissues.
B. Achieving Balance
Proper Angulation of Shank: The shank must be
angled appropriately so that the cutting edge of the blade lies within the
projected diameter of the handle. This design minimizes the tendency for the
instrument to rotate during use.
Off-Axis Blade Edge: For optimal anti-rotational
design, the blade edge should be positioned off-axis by 1 to 2 mm.
This slight offset helps maintain balance while allowing effective force
application.
2. Shank Design
A. Definition
Shank: The shank connects the handle to the blade
of the instrument. It plays a critical role in the instrument's overall
design and functionality.
B. Characteristics
Tapering: The shank typically tapers from the
handle down to the blade, which can enhance control and maneuverability.
Surface Texture: The shank is usually smooth,
round, or tapered, depending on the specific instrument design.
Angulation: The shank may be straight or angled,
allowing for various access and visibility during procedures.
C. Classification Based on Angles
Instruments can be classified based on the number of angles in the
shank:
Straight: No angle in the shank.
Monoangle: One angle in the shank.
Binangle: Two angles in the shank.
Triple-Angle: Three angles in the shank.
3. Angulation and Control
A. Purpose of Angulation
Access and Stability: The angulation of the
instrument is designed to provide better access to the treatment area while
maintaining stability during use.
B. Proximity to Long Axis
Control: The closer the working point (the blade)
is to the long axis of the handle, the better the control over the
instrument. Ideally, the working point should be within 3 mm of
the center of the long axis of the handle for optimal control.
4. Balancing Examples
A. Balanced Instrument
Example A: When the working end of the instrument
lies within 2-3 mm of the long axis of the handle, it
provides effective balancing. This configuration allows the operator to
apply force efficiently without losing control.
B. Unbalanced Instrument
Example B: If the working end is positioned away
from the long axis of the handle, it results in an unbalanced instrument.
This design can lead to difficulty in controlling the instrument and may
compromise the effectiveness of the procedure.
Loperamide
Pharmacology
Loperamide
Similar chemically and pharmacologically to Diphenoxylate.
Slows gastrointestinal motility by effects on the circular and longitudinal muscles of the intestine.
Not well absorbed following oral administration.
Useful in the treatment of diarrhea.
Glycogen Storage Diseases
Biochemistry
Glycogen Storage Diseases are genetic enzyme deficiencies associated with excessive glycogen accumulation within cells.
When an enzyme defect affects mainly glycogen storage in liver, a common symptom is hypoglycemia (low blood glucose), relating to impaired mobilization of glucose for release to the blood during fasting.
When the defect is in muscle tissue, weakness and difficulty with exercise result from inability to increase glucose entry into Glycolysis during exercise.
Various type of Glycogen storage disease are
Type
Name
Enzyme Deficient
I
Von Geirke’s Disease
Glucose -6-phosphate
II
Pompe’s Disease
(1, 4)glucosidase
III
Cori’s Disease
Debranching Enzymes
IV
Andersen’s Disease
Branching Enzymes
V
McArdle’s Disease
Muscles Glycogen Phosphorylase
COPD and Cancer
PhysiologyCOPD and Cancer
A. Chronic Obstructive Pulmonary Disease (COPD)
1. Common features of COPD
a. almost all have smoking history
b. dyspnea - chronic "gasping" for air
c. frequent coughing and infections
d. often leads to respiratory failure
2. obstructive emphysema - usually results from smoking
a. enlargement & deterioration of alveoli
b. loss of elasticity of the lungs
c. "barrel chest" from bronchiole opening during inhalation & constriction during exhalation
3. chronic bronchitis - mucus/inflammation of mucosa
B. Lung Cancer
1. squamous cell carcinoma (20-40%) - epithelium of the bronchi and bronchioles
2. adenocarcinoma (25-35%) - cells of bronchiole glands and cells of the alveoli
3. small cell carcinoma (10-20%) - special lymphocyte-like cells of the bronchi
4. 90% of all lung cancers are in people who smoke or have smoked
Classification of Local anesthetics
Pharmacology
Classification
I) Esters
1. Formed from an aromatic acid and an amino alcohol.
2. Examples of ester type local anesthetics:
Procaine
Chloroprocaine
Tetracaine
Cocaine
Benzocaine- topical applications only
2) Amides
1. Formed from an aromatic amine and an amino acid.
2. Examples of amide type local anesthetics:
Articaine
Mepivacaine
Bupivacaine
Prilocaine
Etidocaine
Ropivacaine
Lidocaine