NEET MDS Shorts
48001
Physiology
Oxytocin is synthesized in the paraventricular nucleus of the hypothalamus and acts on the uterus to increase the force and frequency of contractions during childbirth. It is released during labor and stimulated by the stretching of the cervix and vagina as the baby descends. Estrogens increase the sensitivity of the uterus to oxytocin, while progesterone decreases it. Prolactin is involved in milk production and let-down reflex. Cortisol is a stress hormone that prepares the body for parturition but does not directly increase uterine contractions.
54926
General Medicine
Although the question mentions that hypoprothrombinemia is associated with vitamin K deficiency, the most common congenital cause of hypoprothrombinemia is actually deficiency of factor II, which is vitamin K-dependent. Vitamin K deficiency can lead to impaired synthesis of factors II, VII, IX, and X in the liver.
94534
AnatomyStarling's law of the heart states that the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (end-diastolic volume) when all other variables remain constant. This intrinsic mechanism is a direct consequence of the length-tension relationship within the cardiac muscle fibers. As the muscle is stretched to an optimal length by the increased blood volume, the overlap between actin and myosin filaments improves, leading to a more forceful contraction and increased stroke volume.
69282
AnatomyThe external (lateral) pterygoid muscle has two primary functions: it assists in depressing the mandible (opening the mouth) and in moving the mandible forward (protrusion). This dual function distinguishes it from other muscles of mastication, which primarily elevate the mandible.
27552
Dental Materials
Potassium sulfate acts as an accelerator by increasing the solubility of the hemihydrate and promoting the formation of dihydrate, which speeds up the setting process.
28143
Orthodontics
The possibility that a distal step would become class II is very real, and this not self correcting problem. When the central incisors erupt, these teeth use up essentially all of the excess space in the normal primary dentition. With the eruption of the lateral incisors, space becomes tight in both arches. Continued development of the arches improves the spacing situation, and by the time the canine teeth erupt, space is once again adequate.
Normal child will go through a transitory stage of mandibular incisor crowding at age 8 to 9 even if there will eventually be enough room to accommodate all the permanent teeth in good alignment. In other words, a period when the mandibular incisors are slightly crowded is a normal developmental stage.
70984
Pathology
Nuclear cytoplasmic asynchrony refers to a condition where the nucleus and
cytoplasm of a cell do not develop at the same rate. This can occur in various
forms of anemia and other pathological conditions. Here's a detailed explanation
of the concept and its relevance to the options provided: correct answer is:
1. Megaloblastic Anemia: Megaloblastic anemia is a type of anemia characterized
by the presence of large, immature, nucleated red blood cells (megaloblasts) in
the bone marrow and peripheral blood. This condition is primarily caused by a
deficiency in vitamin B12 or folic acid, which are essential for DNA synthesis
during cell division. The nucleus of the cells divides more slowly than the
cytoplasm, leading to an asynchronous development and the formation of large,
abnormal cells. In megaloblastic anemia, the nucleus is often large and
hyperchromatic (darkly stained), while the cytoplasm is relatively less
developed and pale. Therefore, this option is the most appropriate answer.
2. Fe Deficiency Anemia: Iron deficiency anemia is the most common type of
anemia worldwide, resulting from a lack of iron in the body. Iron is a critical
component of hemoglobin, which is responsible for carrying oxygen in red blood
cells. In this condition, the body produces smaller than normal red blood cells
(microcytic) that lack hemoglobin, leading to decreased oxygen transport. The
nucleus and cytoplasm of the erythrocytes are typically smaller than normal, and
there is no significant asynchrony in their development. Hence, this option is
not a characteristic feature of nuclear cytoplasmic asynchrony.
3. Erythroblastosis Fetalis: This is a condition that occurs when an Rh-negative
mother has an Rh-positive fetus. The mother's immune system produces antibodies
against the fetal red blood cells, leading to their destruction. This causes
anemia in the newborn. However, erythroblastosis fetalis is not typically
associated with nuclear cytoplasmic asynchrony. The anemia is a result of
hemolysis (destruction of red blood cells) rather than an intrinsic defect in
the development of the cells themselves. Thus, this option is not the correct
answer for this characteristic feature.
1. Megaloblastic anemia
This is because megaloblastic anemia is the condition where nuclear cytoplasmic
asynchrony is a hallmark feature due to the disproportionate growth of the
nucleus and cytoplasm in red blood cell precursors, resulting from vitamin B12
or folic acid deficiencies affecting DNA synthesis.
58035
NEETMDS
The typical recall time for a patient after periodontal flap surgery to remove sutures and check for initial healing is approximately one week
92462
Oral Medicine
The initial event in a vasovagal syncope episode is an increase in catecholamine release, leading to a decrease in peripheral vascular resistance and tachycardia.
42470
Dental Materials
Resilience is the amount of energy absorbed by a structure when it is stressed to proportional Limit.
The elastic area of the stress-strain graph gives resilience; entire area up to breaking point is a measure of toughness.
The slope of straight Line gives Young’s modulus.