NEET MDS Shorts
19090
Physiology
The primary mechanism of H+ secretion by parietal cells is through the action of the H+-K+ ATPase pump, also known as the proton pump. This enzyme is responsible for actively transporting H+ ions into the gastric lumen while moving K+ ions into the cells, thereby acidifying the gastric content.
71889
General PathologyThe symptoms described are indicative of primary hypoparathyroidism, which can occur after surgical removal of the parathyroid glands.
47516
Anatomy
The largest resting membrane potential is observed in skeletal muscle.
Resting membrane potential (RMP) is the electrical potential difference across
the membrane of a cell when it is not undergoing an action potential or a
similar excitation. It is crucial for the functioning of excitable cells, such
as neurons and muscle cells, as it is the basis for the transmission of
electrical signals. The RMP is primarily determined by the concentration
gradients of ions across the cell membrane and the permeability of the membrane
to those ions.
In skeletal muscle cells, the resting membrane potential is typically around -90
millivolts (mV). This relatively high negative value is due to the higher
concentration of potassium ions (K+) inside the cell compared to the outside,
and the lower concentration of sodium ions (Na+) inside the cell compared to the
outside. The cell membrane is more permeable to K+ than to Na+ at rest, which
allows K+ to leak out through potassium channels and sets up the resting
membrane potential.
Smooth muscle cells, on the other hand, have a resting membrane potential that
is generally less negative than that of skeletal muscle cells. The typical RMP
in smooth muscle cells ranges from -40 to -70 mV, which is closer to the
threshold for depolarization and makes these cells more responsive to stimuli
that could cause contraction. The difference in RMP between smooth and skeletal
muscle is due to variations in ion channel expression and the activity of ion
pumps, which control the ionic composition of the intracellular and
extracellular environments.
To summarize:
1. Skeletal muscle cells have a resting membrane potential of approximately -90
mV.
2. Smooth muscle cells have a resting membrane potential that is generally more
positive than skeletal muscle cells, typically ranging from -40 to -70 mV.
71703
Oral SurgeryThe advantage of chisel and mallet over bur in removing bone is that no coolant is necessary.
43433
PedodonticsA chisel can effectively remove gross subgingival calculus in deep narrow pockets with fibrotic tissue.
59433
PeriodonticsAn enamel pearl located on the distal furcation of a maxillary molar with furcation involvement can be best treated by flap surgery and odontoplasty.
13867
Periodontics
Tetracycline is often prescribed for juvenile periodontitis (also known as aggressive periodontitis) due to its effectiveness against the specific bacteria involved in the condition, such as Aggregatibacter actinomycetemcomitans.
46171
Public Health Dentistry
After the administration of a local anesthetic (L.A.), the sensations are typically lost in a specific order based on the diameter and myelination of the nerve fibers. The order of loss is generally:
Pain and temperature (carried by small, unmyelinated or lightly myelinated fibers) are lost first.
Touch and pressure (carried by larger, myelinated fibers) are lost later.
51668
PhysiologyThe primary stimulus for the secretion of Secretin is low pH in the duodenal lumen, which indicates the presence of acidic chyme.
88187
General Medicine
While wheezing can occur in patients with COPD, it is not a common physical examination finding.