MDS PREP
The primary canine is usually exfoliated between the ages of
1. 5 and 6 years
2. 10 and 11 years
3. l3 and l4years
4. 8 and 9years
Dental Anatomy
Answer: 2
The primary canine is usually exfoliated between the ages of 10 and 11 years
Foramen ovale is placed _____ to foramen rotundum:
1. Anteromedian.
2. Anterolateral.
3. Posteromedian.
4. Posterolateral
Anatomy Answer: 4
the foramen ovale and foramen rotundum are both openings in the sphenoid bone. The foramen ovale is located posterior and lateral to the foramen rotundum. The foramen rotundum transmits the maxillary nerve (V2), while the foramen ovale transmits the mandibular nerve (V3) and the accessory meningeal artery.
The largest resting membrane potential is observed in
1. skeletal muscle
2. smooth muscle
3. equal in both
4. -120 mv in resting smooth muscle
Anatomy
Answer: 1
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.
A wound to the posterior left axillary line, between the ninth and tenth rib, and extending approximately 5 cm deep, will most likely damage which organ?
1) Ascending colon
2) Duodenum
3) Left kidney
4) Spleen
Anatomy
Answer: 4
The spleen follows the long axes of ribs 9 to 11 and lies mostly posterior to the stomach, above the colon, and partly anterior to the kidney. It is attached to the stomach by a broad mesenterial band, the gastrosplemic ligament. Therefore, it is the most likely organ of the group to be pierced by a sharp object penetrating just above rib 10 at the posterior axillary line. Note that the pleural cavity, and possibly the lower part of the inferior lobe of the lung, would be pierced before the spleen. The ascending colon (choice 1) is on the wrong side (the right) to be penetrated by a sharp instrument piercing the left side.
Most of the duodenum (choice 2) is positioned too far to the right to be affected by this injury.
Even the third part of the duodenum, which runs from right to left, would still be out of harm's way. In addition, the duodenum lies at about levels L1 to L3, placing it too low to be injured in this case.
The superior pole of the left kidney (choice 3) is bordered by the lower part of the spleen. However, it is crossed by rib 12 and usually does not extend above rib 11. It would probably be too low and medial to be injured in this case because this penetration is at the posterior axillary line.
The average overall length of the permanent maxillary central incisor is
1. 14.5mm
2. 18.0 mm
3. 22.5 mm
4. 30 mm
Dental Anatomy
Answer: 3
The average overall length of the permanent maxillary central incisor is 22.5 mm
The first teeth to erupt in the dental arches of the human being are the, primary
1. mandibular cuspids
2. maxillary central incisors.
3. mandibular central incisors
4. maxillary first molars
Dental Anatomy
Answer: 3
The first teeth to erupt in the dental arches of the human being are the, primary mandibular central incisors
The mandibular 1st molar is supplied by:
1. Inferior alveolar nerve only
2. Long buccal nerve only
3. A and B
4. Mental and inferior alveolar nerve
Anatomy
Answer: 3
The mandibular 1st molar is supplied by Inferior alveolar nerve and long Buccal Nerve
The beginning of active eruption of a human tooth occurs
1. before the root has begun to develop
2. coincidental with the beginning of root formation
3. before the root has begun to develop
4. after one half of the root is formed
Dental Anatomy
Answer: 4
The beginning of active eruption of a human tooth occurs after one half of the root is formed