Sensory and Reflex Pathways In the head and neck regionregionregionregion

1. Reflex

1.1. Eye

1.1.1. Accommodation Reflex

1.1.1.1. Light from distant or near object

1.1.1.1.1. Photoreceptor cells on retina

1.1.2. Pupillary light reflex

1.1.2.1. Rapid change of light intensity

1.1.2.1.1. stimulation of photoreceptors

1.2. Swallowing Reflex

1.2.1. Voluntary part 1: Pushing of food by tongue into oropharynx

1.2.2. Involuntary part 2: Afferent: Trigeminal, facial, glossopharyngeal, vagus nerve

1.2.2.1. To Nucleus Tractus Solitarii

1.2.2.1.1. Efferent: Trigeminal, facial, glossopharyngeal, vagus, accessory, hypoglossal nerves

1.2.3. Involuntary part 3: Efferent: Vagus nerve from swallowing center

1.2.3.1. Upper esophageal sphincter relaxes

1.2.3.1.1. Food moves from pharynx to esophagus

1.3. Mouth

1.3.1. Gag Reflex

1.3.1.1. sensory receptor receives an environmental stimulus

1.3.1.1.1. afferent nerve to CNS vis CN IX

2. Sensory

2.1. Pain And Temperature

2.1.1. Kruse end bulb ==> Carried by nerve endings==> dorsal ganglion ==> interneuron ==> enter spinal cord and decussate ==> ascend to LSTT ==> thalamus (VPLN) ==> cerebrum (primary and secondary area)

2.2. Light touch and Crude touch

2.2.1. Meissner's corpuscles ==> dorsal root ganglion ==> lamina VI-VII ==> cross anterior white commisure ==> ventral spinothalamic tract ==> thalamus ==> cerebellum

2.3. Discriminative touch

2.3.1. Pacinian/Meissner's corpuscle ==> dorsal ganglion ==> fasciculus gracilis ==> Nucleus gracilis ==> decussation at lower medulla ==> medial lemniscus ==> Thalamus ==> cerebrum

2.4. Concious proprioception

2.4.1. Posterior funiculus ==> fasciculuss gracilis ==> nucleus of gracilis ==> decissatoin ==> thalamus ==> cerebelum