brainstem structure and cn nuclei

Question 1

brainstem components

Answer 1

Midbrain, pons, medulla
A brain stem cross section is usually the area posterior to the ventricle, area anterior to it and the additional anterior structures

Midbrain: Posterior- tectum, Ant- tegmentum, very ant- substantia nigra and then cerebral peduncle

Pons- small tectum, tegmentum, basal pons

Medulla: Tegmentum, inferior olivary nucleus, pyramid

Question 2

brainstem functions

Answer 2

integrative functions are performed by a diffuse nucleus within the core of the brainstem- reticular formation

Reticular formation regulates consciousness and contains respiratory and cardiovascular centers

The brainstem is a conduit for ascending sensory and descending motor tracts

Corticospinal tract- voluntary movement of limbs, spinothalamic tract- transmits sensory info (pain and temp), posterior column/medial leminiscus system- transmits sensory information (touch vib, prop)

Cranial nerves function: cell bodies of neurons clustered in nuclei throughout the brainstem serve as the origins of motor CNs or as the terminations of sensory CNs. Nuclei are bilateral, and are arranged in functional columns

Question 3

Brainstem cn nuclei are organized into cell columns

Answer 3

NS develops from neural tube, Neural tube has basal plate (motor) and alar plate (sensory) divided by sulcul limitans. Brainstem development is similar to sp cd development

motor systems more in the middle
sensory systems end up on the lateral

Question 4

somatic motor CN nuclei

Answer 4

functions- innervate sk muscles in the head and neck that are derived from mytomes

Brain stem nuclei- oculomotor (3), trochlear (4), abducens (6), hypoglossal (12)

Question 5

branchial motor nuclei

Answer 5

innervate skeletal muscles derived from branchial arches: muscles of mastication, facial expression, pharynx, larynx, middle ear, trapezius

Motor nucleus of V (5), facial nucleus (VII), nucleus ambiguus (9 and 10), spinal accessory nucleus (in spinal cord 11)

Question 6

visceral motor

Answer 6

preganglion parasympathetic innervation to cardiac m., smooth m., and glands

Edinger Westphal n. (3), Salivatory (7), Inferior Salivatory (9), Dorsal motor nucleus of X (10)

Question 7

visceral sensory

Answer 7

special- tastes; rostral nucleus solitarius/gustatory nucleus (7,9, 10)

General-control of CV, Resp, and digestive function, Caudal nucleus solitarius- (CV and resp, 9 and 10)

Question 8

somatic sensory

Answer 8

convey touch pain temp position and vibration from skin, muscles and joints of the head

Trigeminal nucleus

V, 7, 9 10

Question 9

Special sensory

Answer 9

Hearing: cochlear nucleus VIII

Balance: vestibulat nuclei VIII

Question 10

blood vessels in the region of the midbrain

Answer 10

Basilar a., superior cererbellar a, posterior cerebral a, posterior communicating a

The corticospinal tract (in the middle of crus cerebri) is supplied by the PCA and superior cerebellar a

Occlusion of the PCA–> Webers syndrome

Question 11

Blood vessels in the region of the pons

Answer 11

Basilar, AICA, superior cerebellar a

Basilar a suplies the pontine nucle, medial lemniscus, and corticospinal tract

occusion of basilar a–> medial pontine syndrome

occlusion of superior cerebellar a–> lateral pontine syndromes

Question 12

Blood vessels in the region of the medulla

Answer 12

Vertebral a, PICA, anterior spinal a (medial), posterior spinal a (lateral

occlusion of vertebral a or PICA–> lateral medullary syndrome (of Wallenberg)

Anterior spinal a supplies medullary pyramid

occlusion of anterior spinal a–> medial medullary syndrome