Salmonella is an illness caused by a bacterium. Salmonella is often found in raw egg or poultry. It typically presents with gastrointestinal discomfort, diarrhea, and fever. It can be treated with antibiotics, but rarely becomes serious unless it is present in the old, the young, or the immunocompromised. 

The correct answer is the lower esophageal sphincter. In "heartburn," a patient's lower esophageal sphincter, which separates the distal esophagus from the proximal stomach, transiently relaxes its tone, inappropriately allowing food/digestive contents that have been acidified for digestion in the stomach to travel backwards into the distal esophagus. In patients with normal lower esophageal sphincter tone, i.e. without GERD, digestive contents that have passed to the stomach remain in the stomach without traveling backwards and causing an acidic, burning sensation in the esophagus. 

The other answers are incorrect for the following reasons:

The epiglottis prevents food from being swallowed into the airway by closing off the airway temporarily during swallowing.  It does not separate the esophagus from the stomach.

The upper esophageal sphincter is located proximally in the esophagus and opens to allow food to enter the esophagus from the pharynx. It does not separate the esophagus from the stomach.

The ileocecal valve is located distally in the small intestine, separating the ileum from the cecum of the colon. It functions to prevent colo-ileal reflux, but not gastro-esophageal reflux.

The left mainstem bronchus does not play any role in digestion of food or acid reflux, as it is part of the more distal respiratory tract.

Thiamine is a vitamin required for the metabolism of carbohydrates and amino acids. Deficiency of this vitamin results in beriberi, a disease typically of the malnourished. Symptoms of this disease manifest in many different ways such as heart failure, neuropathy, and leg swelling.

Celiac disease is an autoimmune response in which the body attacks the brush border of the small intestine and therefore prevents proper nutrient absorption. The small intestine's brush border is made of many small protrusions called villi and microvilli, which increase surface area in order to increase absorption area. Without these areas of absorption, the body cannot absorb a sufficient amount of necessary nutrients from the diet.

Acute diverticulitis: left lower quadrant

Acute pancreatitis: epigastric, can radiate to back, poorly localized, leaning forward may help alleviate pain, laying supine aggravates. May have positive Grey Turner's sign and Cullen's sign.

Acute cholecystitis: Right Upper Quadrant, Positive Murphy Sign, may radiate into right shoulder and scapula

Peptic ulcer: epigastric, may radiate to back, wakens patient at night, possible relief with certain foods, gnawing/aching pain, heartburn

The affected dermatome is supplied by the spinal root C3.

This is a matter of simple memorization of dermatomes in the body. Each dermatome is innervated by a single spinal nerve, which is responsible for sensation in the area. The neck is supplied mostly by C3, with C4 and C5 supplying parts of the posterior neck.

C2 supplies the back of the skull. C6 supplies the lateral aspect of the arm and forearm. T2 supplies the upper chest and medial aspect of the arm. T4 is a common landmark dermatome as it supplies the nipples. Another landmark is T10, which supplies the umbilical cord.

You suspect that the trigeminal nerve (CN V) is compromised and would expect there to be sensory deficits in the face.

To approach this problem, we need to think about a few things:

1. If the blink reflex is absent, what cranial nerves are involved?

The afferent part of the blink reflex is supplied by the trigeminal nerve (V), while the efferent action is from the facial nerve (VII).

2. The patient is able to make different facial expressions and shut her eyes tightly. Which cranial nerve is involved in facial expressions?

The facial nerve innervates muscles of facial expressions. The patient's ability perform these actions tells us the facial nerve is intact; thus, the trigeminal nerve must be the part of the blink reflex that is deficient.

3. What other function does the trigeminal nerve have?

The trigeminal nerve provides sensation to the face and scalp, and also innervates the muscles of mastication.

Absent gag reflex can be due to deficits in the glossopharyngeal nerve (IX, afferent portion) or vagus nerve (X, efferent portion). Lack of eye movement can be due to occulomotor (III), trochlear (IV), and/or abducens (VI) cranial nerves. Inability to turn the head is a result of sternocleidomastoid deficiency, which is innervated by the accessory nerve (XI). An impaired sense of smell suggests olfactory nerve (I) deficit.

The biceps brachii is innervated by C5 and C6 nerve roots. So, in the presence of a C5 nerve root irritation, biceps tendon reflexes may be diminished. the triceps brachii is innervated by C7 and C8 nerve roots, and the lower extremity muscles are innervated by L2 through S2 nerve roots, so testing these muscles would not tell us anything about a C5 nerve irritation.

The Romberg test involves maintaining an upright stance with feet together, which tests the vestibular portion of the vestibulocochlear nerve. The accessory nerve controls shoulder girdle and neck movement, the olfactory nerve provides the sense of smell, the hypoglossal nerve controls tongue movement, the facial nerve controls the muscles of facial expression (amon other functions) and the trigeminal nerve controls the muscles of mastication (among other functions). Thus, the Romberg test would not test any of these functions

The triceps brachii deep tendon reflex tests the C7 and C8 nerve roots, so testing it would not provide any information about a lumbosacral nerve root pathology. The cremasteric reflex tests the T12 and L1 nerve roots, the Achilles deep tendon reflex tests the S1 and S2 nerve roots, the anal wink reflex tests the S2, S3, and S4 nerve roots, and the patellar deep tendon reflex tests the L3 and L4 nerve roots.