DAANCE Anatomy and Physiology 5 — Questions and Answers
Question 1: Which physiological reflex is most responsible for laryngospasm when a foreign substance contacts the laryngeal inlet?
- Hering-Breuer reflex
- Laryngeal adductor reflex (Correct answer)
- Cough reflex via tracheal irritation
- Swallowing reflex
Correct answer: Laryngeal adductor reflex
The laryngeal adductor reflex causes rapid, forceful closure of the vocal cords in response to laryngeal stimulation, protecting the lower airway.
Question 2: Which foramen in the mandible is the primary landmark for mandibular nerve block administration?
- Mental foramen
- Mandibular foramen (Correct answer)
- Incisive foramen
- Infraorbital foramen
Correct answer: Mandibular foramen
The mandibular foramen on the medial surface of the ramus is where the inferior alveolar nerve enters the mandibular canal, making it the target for IANB.
Question 3: Which cardiac valve prevents backflow of blood from the aorta into the left ventricle?
- Mitral valve
- Tricuspid valve
- Pulmonary valve
- Aortic semilunar valve (Correct answer)
Correct answer: Aortic semilunar valve
The aortic semilunar valve closes during ventricular diastole to prevent regurgitation of blood from the aorta back into the left ventricle.
Question 4: The phrenic nerve, which innervates the diaphragm, originates primarily from which cervical nerve roots?
- C1-C2
- C3-C5 (Correct answer)
- C6-C8
- C2-C4
Correct answer: C3-C5
The phrenic nerve arises from cervical roots C3, C4, and C5, remembered by the mnemonic 'C3, 4, 5 keeps the diaphragm alive.'
Question 5: In the context of dental anesthesia, what is the clinical significance of the pterygomandibular space?
- It is the site where the parotid duct empties into the oral cavity
- It houses the inferior alveolar and lingual nerves targeted in IANB (Correct answer)
- It contains the facial artery and vein
- It is the attachment site of the buccinator muscle
Correct answer: It houses the inferior alveolar and lingual nerves targeted in IANB
The pterygomandibular space contains the inferior alveolar and lingual nerves, making it the target region for inferior alveolar nerve block injections.
Question 6: Which baroreceptors are primarily responsible for the rapid reflex response to acute changes in arterial blood pressure?
- Aortic arch and carotid sinus baroreceptors (Correct answer)
- Pulmonary capillary wedge receptors
- Ventricular wall stretch receptors
- Renal juxtaglomerular receptors
Correct answer: Aortic arch and carotid sinus baroreceptors
Baroreceptors in the carotid sinus and aortic arch detect acute changes in arterial pressure and mediate rapid autonomic reflex responses.
Question 7: The lingual nerve, a branch of the mandibular division (V3), provides sensory innervation to which structure?
- Posterior one-third of the tongue for taste
- Anterior two-thirds of the tongue for general sensation (Correct answer)
- Hard palate mucosa
- Buccal mucosa of the maxilla
Correct answer: Anterior two-thirds of the tongue for general sensation
The lingual nerve (V3 branch) carries general somatic sensation from the anterior two-thirds of the tongue, while taste in that region is carried by the chorda tympani (VII).
DAANCE Anatomy and Physiology 5
Which physiological reflex is most responsible for laryngospasm when a foreign substance contacts the laryngeal inlet?