13.5- Brainstem

Question 1

What does the brainstem connect?

Answer 1

Cerebrum, diancephalon, and cerebellum.

Question 2

Midbrain- other name

Answer 2

Mesencephalon- superior portion of the brain stem

Question 3

Cerebral peduncle- location

Answer 3

Anterolateral surface of midbrain

Motor tracts

Question 4

Superior cerebral peduncles

Answer 4

Connect the midbrain to the cerebellum.

Question 5

Substantia Nigra

Answer 5

Bilaterally symmetric nuclei in the midbrain.
Almost black appearance due to melanin pigmentation
Houses cluster os neurons that produce the neurotransmitter dopamine (which controls movement, emotional response, and ability to experience pleasure and pain)
Degeneration here is connected to Parkinson’s.

Question 6

Tegmentum

Answer 6

Sandwiched between the substantial nigra and the periaquiductal gray matter.
Pigmented red nuclei and reticular formation.
Red is due to blood vessel density and iron pigmentation
Integrates info from cerebrum and cerebellum and issues involuntary motor commands to the erector spinae muscles of the back.
Maintains posture, standing, bending at the waist, and walking.

Question 7

Cerebral aqueduct

Answer 7

Extend through the midbrain.
Connects the third and fourth ventricles
Surrounded by periaquiductal gray matter.
Houses the nuclei of the oculomotor (III) and trochlear (IV) nerves.

Question 8

Tectum

Answer 8

Most posterior region of the midbrain.
Contains the superior and inferior colliculi (called tectal plate)
Relay stations in the pathway of visual and sensory auditory input.

Question 9

Superior colliculi

Answer 9

Visual reflex centers

Help track moving objects and control reflexes like turning eyes and head in response to visual stimulus

Question 10

Inferior colliculi

Answer 10

Auditory reflex centers

Control reflexes that turn head and eyes toward source of loud.

Question 11

Pons

Answer 11

Bulging part of the brain stem

Contains sensory and motor tracts

Question 12

Middle cerebral peduncles

Answer 12

Transverse axons that connect the pons the the cerebellum.

Question 13

Pontine respiratory center

Answer 13

Respiratory center housed in the pons. Controls skeletal muscle breathing.
Regulates smooth transition between inhalation and exhalation.

Question 14

Superior olivary nuclei

Answer 14

Located in the inferior portion of the pons.

Receives auditory input and is responsible for sound localization.

Question 15

What other nerves do the pons house?

Answer 15

trigeminal V, abducens VI, facial VII

Question 16

Mudula oblongata

Answer 16

Most inferior part of the brain stem.

All communication between brain and spinal cord involve tracts that pass thought this region.

Question 17

Pyramids

Answer 17

Two ridges on the anterior side of the medulla oblongata.

House motor projection tracts

Question 18

Decussation of the pyramids

Answer 18

Anterior point in the medulla where most of the axons of the pyramidal tract cross to the opposite side of the brain.
This is why the brain controls opposite sides of the body.

Question 19

Olive

Answer 19

Bulge immediately lateral to the pyramids

Contains large folds of gray matter called the inferior olivary nucleus.

Question 20

Olivary nucleus

Answer 20

Relay ascending nerve signals- especially proprioreceptive info the the cerebellum.

Question 21

Inferior cerebral peduncles

Answer 21

Paired with olivary nuclei-tracts that connect the medulla oblongata to the cerebellum.

Question 22

Medullary respiratory center

Answer 22

Made up of ventral and dorsal respiratory groups.
Groups influence by the pontine respirator center.
Causes breathing.
This area also controls coughing, sneezing, salivation, gaging, and vomiting reflexes.

Question 23

What cranial nerves does the medulla oblongata contain?

Answer 23

Vistibulocochlear VIII, glossopharyngeal IX, vagus X, accessory XI, and hypoglossal XII.

Question 24

Nucleus cuneatus and nucleus gracilis.

Answer 24

Contained in the Medulla