Midbrain

Question 1

What are the surfaces of the midbrain?

Answer 1

Anterior
Posterior

Question 2

What are the divisions of the midbrain?

Answer 2

Two halves each called cerebral peduncle

Question 3

Which nerve arises from the medial border of the peduncle?

Answer 3

Oculomotor Nerve

Question 4

What is the posterior surface of the midbrain called?

Answer 4

Tectum

Question 5

What structures are formed from the tectum?

Answer 5

2 Superior Colliculi
2 Inferior Colliculi

Question 6

Which nerve originates from the posterior surface of the tectum?

Answer 6

Trochlear Nerve

Question 7

How is each Cerebral Peduncle divided?

Answer 7

Substantia Nigra divides peduncle into Crus Cerebri anteriorly and Tegmentum posteriorly

Question 8

Crus Cerebri
Varying of the Crus Cerebri structure throughout the midbrain

Answer 8

Same structure throughout

Question 9

Crus Cerebri
Fibers of the anterior part of the Crus Cerebri

Answer 9

Corticospinal fibers
Corticopontine fibers

Continue descending downwards converging at the pons

Question 10

Substantia Nigra
Varying of the Substantia Nigra structure throughout the midbrain

Answer 10

Same structure throughout

Question 11

Substantia Nigra
Structure

Answer 11

Lamina of grey matter formed of melanin pigmented nerve cells which synthesize dopamine

Question 12

Substantia Nigra
Location

Answer 12

Behind the Crus Cerebri

Question 13

Substantia Nigra
The Substantia Nigra is connected to the …

Answer 13

… Caudate Nucleus and Putamen of Basal Ganglia

Question 14

Substantia Nigra
Damage to the Substatia Nigra causes …

Answer 14

… loss of dopamine secreting neurons leading to Parkinson’s Disease

Question 15

Tegmentum
Location

Answer 15

Posterior to Substantia Nigra

Question 16

Tegmentum
Components

Answer 16

Ascending Tracts
Nuclei

Question 17

Tegmentum
Part of Tegmentum behind the aqueduct is called …

Answer 17

… Tectum

Question 18

Tegmentum
Purpose of the Superior Colliculi

Answer 18

Reflex centres of vision

Question 19

Tegmentum
Purpose of the Inferior Colliculi

Answer 19

Reflex centres of hearing

Question 20

Tegmentum: Lower Midbrain at Inferior Colliculus
Structures

Answer 20

Nuclei
Ascending Tracts

Question 21

Tegmentum: Lower Midbrain at Inferior Colliculus
Nuclei Names

Answer 21

Inferior Colliculus
Trochlear Nerve Nucleus
Mesencephalic Nucleus of Trigeminal
Decussation of Superior Cerebellar Peduncles

Question 22

Tegmentum: Lower Midbrain at Inferior Colliculus
What fibers does the Inferior Colliculus Nucleus receive?

Answer 22

Ascending Auditory Fibers

Question 23

Tegmentum: Lower Midbrain at Inferior Colliculus
Where do the fibers of the Inferior Colliculus Nucleus run?

Answer 23

In the Lateral Lemniscus

Question 24

Tegmentum: Lower Midbrain at Inferior Colliculus
Location of the Trochlear Nerve Nucleus

Answer 24

Anterior to Cerebral Aqueduct

Question 25

**Tegmentum: Lower Midbrain at Inferior Colliculus** Trochlear Nerve Nucleus fiber pathway

Answer 25

Cross to opposite sides and emerge from back of midbrain

Question 26

**Tegmentum: Lower Midbrain at Inferior Colliculus** What does the Trochlear Nerve Nucleus supply?

Answer 26

Superior Oblique Muscle

Question 27

**Tegmentum: Lower Midbrain at Inferior Colliculus** What fibers does the Mesencephalic Nucleus of Trigeminal receive?

Answer 27

Proprioceptive fibers from Facial and Extra-Ocular Muscles and Muscles of Mastication

Question 28

**Tegmentum: Lower Midbrain at Inferior Colliculus** What is the Decussation of Superior Cerebellar Peduncles

Answer 28

Fibers of each peduncle cross to opposite sides in the central part of Tegmentum

Question 29

**Tegmentum: Lower Midbrain at Inferior Colliculus** Names of Ascending Tracts

Answer 29

Medial Lemniscus Spinal Lemniscus Trigeminal Lemniscus Lateral Lemniscus Anterior Spinocerebellar Tract

Question 30

**Tegmentum: Lower Midbrain at Inferior Colliculus** What is the Medial Lemniscus

Answer 30

Ascending fibers carrying prioperioceptive sensations from the opposite side of the body

Question 31

**Tegmentum: Lower Midbrain at Inferior Colliculus** The Medial Lemniscus is an upward continuation of ...

Answer 31

... the Gracial and Cuneate tracts of the opposite side

Question 32

**Tegmentum: Upper Midbrain at Superior Colliculus** Nuclei Names

Answer 32

Superior Colliculus Oculomotor nerve motor nucleus Pretectal nucleus

Question 33

**Tegmentum: Upper Midbrain at Superior Colliculus** Superior Colliculus location

Answer 33

Upper part of tectum in midbrain

Question 34

**Tegmentum: Upper Midbrain at Superior Colliculus** Superior Colliculus nucleus is the centre of what impulses?

Answer 34

Visual Reflexes

Question 35

**Tegmentum: Upper Midbrain at Superior Colliculus** Oculomotor Nerve Nucleus Location

Answer 35

Anterior to aqueduct of midbrain

Question 36

**Tegmentum: Upper Midbrain at Superior Colliculus** Where do fibers of Oculomotor Nerve Nucleus emerge from?

Answer 36

Medial surface of crus cerebri

Question 37

**Tegmentum: Upper Midbrain at Superior Colliculus** What does the Oculomotor Nerve Nucleus supply?

Answer 37

Extra-ocular muscles of eye ## Footnote Except for superior and lateral rectus muscles

Question 38

**Tegmentum: Upper Midbrain at Superior Colliculus** Pretectal Nucleus location

Answer 38

Dorsal to Superior Colliculus

Question 39

**Tegmentum: Upper Midbrain at Superior Colliculus** Pretectal Nucleus has connections with ...

Answer 39

... parasympathetic nucleus of oculomotor nerves of both sides (Edinger-Westphal nucleus)

Question 40

**Tegmentum: Upper Midbrain at Superior Colliculus** Ascending Tract names

Answer 40

Medial Lemniscus Spinal Lemniscus Trigeminal Lemniscus Anterior Spinocerebellar Tract

Question 41

Which blood vessels supply the Medial Parts of the Crus Cerebri and Tegmentum?

Answer 41

Branches of Basilar Artery and Posterior Cerebral Artery

Question 42

Which blood vessels supply the Lateral Parts of the Crus Cerebri and Tegmentum?

Answer 42

Branches of Posterior Cerebral and Superior Cerebellar