Major Structures of the Brain Stem

Question 1

Medulla

Answer 1

The most posterior region of the brain stem; the myelencephalon; its major structures include the pyramids, olives, medullary reticular formation, and the nuclei that contribute axons to cranial nerves 9, 10, 11, and 12.

Question 2

Pyramids

Answer 2

Two large bulges, one left nad one right, on the ventral surface of the medulla; they contain the pyramidal tracts, which carry signals for voluntary movement from the cerebral hemispheres to the motor circuits of the spinal cord.

Question 3

Olives

Answer 3

The pair of large olive-shaped cluster of nuclei that are visible as bulges on the lateral surfaces of the medulla, one on each side; they are connected to the cerebellum.

Question 4

Reticular formation

Answer 4

A complex network of nuclei and short interconnecting tracts that is located in the core of the brainstem, from the medulla to the midbrain; its nuclei play a role in controlling many vital body functions and in the promotion of arousal, attention, and sleep.

Question 5

Cerebellum

Answer 5

The large striped metencephalic structure that is situated just dorsal to the pons; it plays a role in the coordination of movement.

Question 6

Cerebellar penduncles

Answer 6

Three of large pairs of tracts (inferior, middle, and superior) that connect the cerebellum. to the rest of the brain stem

Question 7

Pons

Answer 7

The ventral portion of the metencephalon; its major structures include the fourth ventricle, the metencephalic portion of the reticular formation, many ascending and descending tracts,and the nuclei of cranial nerves 5, 6, 7, and 8.

Question 8

Superior colliculi (kuh-LIK-yu-lee)

Answer 8

The more anterior of the two pairs of the nuclei that constitute the mammalian tectum; they play a role in vision.

Question 9

Inferior colliculi

Answer 9

The more posterior of the two pairs of nuclei that constitute mammalian tectum; they play a role in audition.

Question 10

Red nuclei

Answer 10

A pair of tegmental nuclei, one on the left and one on the right; they have a pinkish appearance and are important structures of the sensorimotor system.

Question 11

Periaqueductal gray

Answer 11

The tegmental gray matter that is located around the cerebral aqueduct; it plays a role in the suppression of pain and in defensive behavior.

Question 12

Substantia nigra

Answer 12

A pair of tegmental sensorimotor nuclei, one on the left and one on the right; they are so named because many of the neurons contain a dark pigment.

Question 13

Thalamus

Answer 13

The two-lobed diencephalic structure at the top of the brain stem, one lobe on each side of the third ventricle; several of its nuclei relay sensory information to the appropriate regions of the cerebral cortex.

Question 14

Lateral geniculate nuclei

Answer 14

The thalamic nuclei that relay visual information to the cerebral cortex.

Question 15

Ventral posterior nuclei

Answer 15

The thalamic nuclei that rely tactual information to the cerebral cortex.

Question 16

Internal lamina

Answer 16

The layers of white matter in each lobe of the thalamus.

Question 17

Medial geniculate nuclei

Answer 17

The thalamic nuclei that relay auditory information to the cerebral cortex.

Question 18

Hypothalamus

Answer 18

The diencephalic structure that is located just beneath the anterior end of the thalamus; the pituitary gland is suspended from it.

Question 19

Ventromedial nuclei

Answer 19

The pair of hypothalamic nuclei, one on the left and one the right, that plays a role in regulating the conversion of blood glucose to body fat; they are located near the midline in the ventral part of the hypothalamus.

Question 20

Suprachiasmatic nuclei

Answer 20

The pair of hypothalamic nuclei, one on the left and one on the right, that play a role in the timing of 24-hour biological rhythms; they are located just dorsal to the optic chiasm.

Question 21

Mammillary bodies (MAM-i-lair-ee)

Answer 21

The pair of hypothalamic nuclei, one on the left and one on the right, that are part of a system that plays an important role in emotion; they are visible on the inferior surface of the hypothalamus as a a pair of bumps just behind the pituitary.

Question 22

Preoptic area

Answer 22

The most anterior area of the hypothalamus; it plays a role in sexual behavior.

Question 23

Anterior pituitary

Answer 23

The anterior portion of the pituitary; it releases tropic hormone in response to hypothalamic releasing hormones.

Question 24

Posterior pituitary

Answer 24

The posterior portion of the pituitary; it releases vasopressin and oxytocin from neuron terminals that have cell bodies in the hypothalamus.

Question 25

Pituitary stalk

Answer 25

The stalk from which the anterior and posterior pituitary are suspended fro the hypothalamus.

Question 26

Paraventricular nuclei

Answer 26

One of the two pairs of hypothalamic nuclei that contain neurons whose axons terminate in the posterior pituitary; this pair is located on the dorsal surface of the hypothalamus on each side of the third ventricle.

Question 27

Supraoptic nuclei

Answer 27

One of the two pairs of hypothalamic nuclei that contain neurons whose axons terminate in the posterior pituitary; this pair is located above the optic chiasm, just posterior to the suprachiasmatic nuclei.