The Brainstem and blood supply to the brain

Question 1

What are the 3 main arteries that Supply the brain ?

Answer 1

1. Anterior cerebral artery - supplies the middle part (medial branch)
2. middle cerebral artery - supplies the majority of brain and outer bits
3. Posterior cerebral artery - supplies the bottom part of the brain, important for vision

Important for classifying strokes

Question 2

What is the Homunculus ?

Answer 2

Shows the tomography of the parts of the brain are being activated by.

Question 3

How does the ACA get to the middle of the brain?

Answer 3

It wraps around the corpus callous

Question 4

What is the Corpus Callosum ?

Answer 4

Corpus callous is in middle part of the brain. Linked with memory and houses the Singlet of Gyrus. 4 parts. The Genu, splenium, Rostrum and Body

Low yield, used to connect the 2 sides of the brain together

Question 5

What are the 3 main parts of the brainstem ?

Answer 5

1. Medulla oblongata - bottom part
2. Pons - Middle part
3. Midbrain - Top part

Question 6

What does the medulla do/ include ?

Answer 6

The opening just before spinal cord.

Main features -
Olives

Corticospinal tract

Inferior cerebellar peduncles

Anterior and posterior median

Question 7

What does the pons do/ include ?

Answer 7

Middle cerebellar peduncles - connects the pons to the cerebellum

Question 8

What does the midbrain do/ include ?

Answer 8

Superior cerebelar peduncles - connects the midbrain to the cerebellum

Includes the substantia nigra.

Tectum and Tegmentum - protrusions that hold inferior and superior colliculi. They make up the rectum

Superior - eye movement in one direction
Inferior - houses all descending fibres for hearing
They are linked because when you hear something need to be able to look in the direction

Question 9

What is the Rubrospinal tract ?

Answer 9

Only intervals upper limbs and doesn’t go to the finger tips, it changes sides similar to the corticospinal tract

Includes red nucleus which is found in the midbrain.

Ends at the C5 level (cervical spine )

Question 10

what is somatosensory ?

Answer 10

Genreal sensory is going from the muscle to the brainstem.

Motor innervation goes from the brainstem down towards the mUSCLE

Question 11

What are the different types of sensation ?

Answer 11

General sensory - touch (crude touch and discriminative touch), temperature, vibration, pain (C fibres) and Proprioception. They are split into different tracts

Answer 12

Primary afferent nerones- takes info from the surroundings

Secondary order neutron takes info from spinal cord up to thalamus and also desiccates onto opposite side where they synapse.

Thalamic neutron takes info from thalamus to cerebral cortex.

Question 13

What are the 2 main types of tracts ?

Answer 13

1. Spiniothalamic tract - for detecting info like temperature, pain, crude touch. It decisates at eh same point of its innervation
2. Dorsal column/ Medial lemiscus when in brainstem - Travels up dorsal side of Proprioception, vibration, discriminative touch.

Question 14

What is the main difference of the Spinothalamic tract and Dorsal column ?

Answer 14

STT - desiccates at same level of spinal cord (its second order neurone )

DC - First order neurone continues travelling up and only desiccates at the medulla, at medulla it synapses

Question 15

What is the blood supply of the spinal cord ?

Answer 15

Spinal cord has an anterior and posterior artery

Anterior - supplies majorly of spinal cord, supplies everything apart from dorsal column meniscus.

Question 16

What is the journey of the CSF

Answer 16

Goes from lateral ventricle to 3rd ventricle to 4th ventricle.

Choriod plexus is in the lateral ventricle which makes the CSF

Lv -> 3rd Interventricular foramen
3rd -> 4th Cerebral aqueduct

Question 17

What is Syringomyelia ?

Answer 17

This is damage to the spinal cord

A syrinx - a fluid filled. cavity in the central canal of the spinal cord that can appear. Will affect the spinothalamic tract

Question 18

What does the cerebral aqueduct connect ?

Answer 18

Cerbral aqueduct connects 3rd and 4th ventricle. Can be blocked and cause hydrocephalus, can cause enlargement of ventricles.

Question 19

What is the Corticospinal tract?

Answer 19

Corticospinal tract - main descending tract of the brain, allows intricate movement, goes all the way to your fingertips and such. At the open medulla it desiccates to contralateral side to become the lateral corticospinal tract (happens at lowest part of medulla). Originates from cerebral cortex

Question 20

What are the Inferiror cerebellular penduncles?

Answer 20

Inferior cerebellar peduncles - connects the medulla to the cerebellum

Question 21

What are the anterior and posterior median sulcus?

Answer 21

Anterior and posterior median sulcus - the line that goes through the brainstem

Question 22

What is the substantia nigra?

Answer 22

Includes the substantia nigra - It is where Parkinsons takes place. The degradation of substance nigra. It is where the main nuclei that produces dopamine for the pathway is produced.

Question 23

What are the Olives of the Medulla?

Answer 23

Olives (inferior olivary nuclei) - send information via climbing fibres towards the cerebellum, important for recorrecting movement Sends info to inf cerebellar peduncle in order to get to the cerebellum