parotid gland: secretomotor supply

The secretomotor supply of the parotid gland is controlled by the parasympathetic nervous system. Specifically, the secretomotor innervation is provided by the glossopharyngeal nerve (cranial nerve IX) through its parasympathetic fibers.

Here's how the secretomotor supply of the parotid gland works:

1. **Glossopharyngeal Nerve (CN IX):**

   - The glossopharyngeal nerve is one of the cranial nerves that originates from the brainstem.

   - It contains parasympathetic fibers that are responsible for stimulating the secretion of the parotid gland.

2. **Otic Ganglion:**

   - The secretomotor fibers of the glossopharyngeal nerve synapse in a ganglion called the otic ganglion.

   - The otic ganglion is located near the foramen ovale, which is an opening in the skull through which the mandibular nerve (a branch of the trigeminal nerve, CN V) exits the cranial cavity.

3. **Postganglionic Fibers:**

   - From the otic ganglion, postganglionic parasympathetic fibers travel along the auriculotemporal nerve, which is a branch of the mandibular nerve (CN V3).

   - These postganglionic fibers reach the parotid gland and stimulate its secretory cells to release saliva.

4. **Salivation Response:**

   - Activation of the glossopharyngeal nerve's secretomotor fibers leads to the release of watery saliva from the parotid gland.

   - This response is part of the salivary reflex, which can be triggered by various stimuli, such as the sight, smell, or taste of food.

In summary, the glossopharyngeal nerve (CN IX) plays a crucial role in the secretomotor supply of the parotid gland. Its parasympathetic fibers stimulate salivary secretion by synapsing in the otic ganglion and then traveling to the parotid gland through the auriculotemporal nerve. This mechanism helps maintain proper salivary function and assists in the process of digestion.

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Certainly! Here are ten multiple-choice questions (MCQs) along with their answers about the secretomotor supply of the parotid gland:

**Question 1:**

Which cranial nerve is responsible for the secretomotor supply of the parotid gland?

A) Cranial nerve V (Trigeminal nerve)

B) Cranial nerve VII (Facial nerve)

C) Cranial nerve IX (Glossopharyngeal nerve)

D) Cranial nerve X (Vagus nerve)

**Answer: C) Cranial nerve IX (Glossopharyngeal nerve)**

**Question 2:**

The secretomotor fibers for the parotid gland synapse in:

A) Submandibular ganglion

B) Ciliary ganglion

C) Otic ganglion

D) Pterygopalatine ganglion

**Answer: C) Otic ganglion**

**Question 3:**

Which branch of the mandibular nerve carries postganglionic parasympathetic fibers to the parotid gland?

A) Infraorbital nerve

B) Maxillary nerve

C) Buccal nerve

D) Auriculotemporal nerve

**Answer: D) Auriculotemporal nerve**

**Question 4:**

Activation of the secretomotor fibers of the glossopharyngeal nerve leads to:

A) Constriction of the pupil

B) Increased heart rate

C) Secretion of saliva from the parotid gland

D) Increased blood pressure

**Answer: C) Secretion of saliva from the parotid gland**

**Question 5:**

The otic ganglion is located near which cranial nerve foramen?

A) Foramen rotundum

B) Foramen lacerum

C) Foramen ovale

D) Foramen magnum

**Answer: C) Foramen ovale**

**Question 6:**

Which of the following is a branch of the trigeminal nerve (CN V)?

A) Otic nerve

B) Auriculotemporal nerve

C) Hypoglossal nerve

D) Accessory nerve

**Answer: B) Auriculotemporal nerve**

**Question 7:**

The auriculotemporal nerve carries postganglionic fibers to the parotid gland from the:

A) Otic ganglion

B) Pterygopalatine ganglion

C) Submandibular ganglion

D) Ciliary ganglion

**Answer: A) Otic ganglion**

**Question 8:**

The parasympathetic stimulation of the parotid gland results in the release of:

A) Gastric juice

B) Insulin

C) Tears

D) Saliva

**Answer: D) Saliva**

**Question 9:**

What response is triggered by activation of the glossopharyngeal nerve's secretomotor fibers?

A) Pupillary dilation

B) Bronchoconstriction

C) Sweating

D) Salivary secretion

**Answer: D) Salivary secretion**

**Question 10:**

The secretomotor supply of the parotid gland contributes to which physiological process?

A) Digestion

B) Vision

C) Hearing

D) Muscle movement

**Answer: A) Digestion**

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