TOPIC 1- 10. Macroscopy of the brainstem and the cerebellum

The most inferior portion of the brain, that connects the spinal cord to the diencephalon

What is the brainstem?

- Information transfer between the hemispheres, spinal cord and cerebellum

- Origin of most of the cranial nerves

What is the function of the brainstem?

- Mesencephalon

- Pons

- Medulla oblongata

How can you macroscopically divide the brainstem?

- Control movements of the eye

- Process auditory and sensory information

Main functions of the mesencephalon?

- Tectum

- Cerebral peduncle

What are the main parts of the mesencephalon?

Tectum

Superior colliculus

Relay station for visual reflexes

Function of superior colliculus

Inferior colliculus

Relay station for audio pathway

Function of the inferior colliculus

Cerebral peduncles

Cerebral peduncles

- Tegmentum

- Cerebral crus

What does cerebral peduncles consist of?

Cerebral crus

Contain fibers that transfer information between the brainstem and the thalami

What is the function of the cerebral peduncles?

- Arnold´s pathway

- Türk pathway

- Pyramidal pathway

Which pathways go through the cerebral peduncles?

Superior medullary velum

Superior medullary velum

Superior medullary velum

Structure of white matter between the superior cerebellar peduncles?

The 4th ventricle

What is between the brainstem and the cerebellum?

Frenulum of the superior medullary velum

- Oculomotor nerve

- Trochlear nerve

Which cranial nerves exit in the mesencephalon?

Trochlear nerve

Below inferior colliculus, above superior medullary velum

Where does the trochlear nerve originate?

Rhomboid fossa

- Upper triangular part

- Intermediate part

- Lower triangular part

Which are the three parts of the rhomboid fossa?

- Medial eminences (facial colliculus)

- Locus coeruleus

- Upper part of the vestibular area

Which are the different parts of the upper triangular part?

Medial eminence

Facial colliculus

What does the medial eminence overlie?

- Motor nucleus of abducent nerve

- Axons of facial nucleus

Which structures does the facial colliculus overlie?

- Lower portion of the vestibular area

- Hypoglossal trigone

- Vagal trigone

- Obex

Which are the different parts of the lower triangular part?

Posterior median sulcus

Sulcus limitans

- Posterior median sulcus

- Sulcus limitans

Which sulcuses are the borders of the medial eminence?

Contains melanin cells

Why is the locus coeruleus gey-bluish in color?

Locus coeruleus

Chemo-receptor zone

- blood control analysis

What is the function of locus coeruleus?

Vestibular area

Vestibular nuclei

Which structure does the vestibular area overlie?

Medullary striae of the fourth ventricle

Leading auditory fibers

Function of the medullary stria?

Lower triangular part

Which part of the rhomboid fossa is located in the medulla oblongata?

Hypoglossal trigone

Dorsal nuclei of the hypoglossal nerve

What is the hypoglossal trigone formed by?

Vagal trigone

Dorsal nuclei of the 9th, 10th and 11th cranial nerve/nucleus ambiguus

What is the vagal trigone formed by?

Obex

The opening of the central canal

What is the obex?

Area postrema

Center of vomiting

Function of area postrema

Gracile tubercle

Gracile fasciculus

Cuneate tubercle

Cuneate fasciculus

Trigeminal tubercle

Lateral funiculus

Habenular trigone

Pineal gland

Release melatonin

Function of the pineal gland

The cerebellum is a part of the motor system

- cannot initiate conscious movements by itself, but is responsible for unconscious coordination and fine control of the muscle actions

Functions of the cerebellum?

- Cerebellar hemispheres

- Vermis

What does the cerebellum consist of?

Each hemisphere consist of three lobes:

- Anterior lobe

- Posterior lobe

- Flocculonodular lobe

What does each hemisphere consist of?

Vermis

Through the superior, middle and inferior cerebellar peduncles

Through what is the cerebellum in contact with the brainstem?

Superior cerebellar peduncle

A

Middle cerebellar peduncle

B

Inferior cerebellar peduncle

C

Connecting cerebellum and the brainstem and convey information

Function of the cerebellar peduncles?

Primarily efferent

Which way does the superior cerebellar peduncle convey information?

Primarily afferent

Which way does the inferior cerebellar peduncle convey information

Anterior lobe of the cerebellum

Flocconodular lobe

Superior cerebellar peduncle

Superior medullary velum

Middle cerebellar peduncle

Cerebellar tonsil

Inferior cerebellar peduncles

Posterior lobe of the cerebellum

Inferior medullary velum

Fourth ventricle

Floccular lobe

Vermis

Nodule of vermis

Pyramidal decussation

Accessory nerve

Choroid plexus of the fourth ventricle

Flocculus

Medullary pyramids

Olivary nuclei

Hypoglossal nerve

Vagus nerve

Glossopharyngeal nerve

Vestibulocochlear nerve

Facial nerve

Abducens nerve

Trigeminal nerve

Pons

Temporal lobe

Trochlear nerve

Oculomotor nerve