Brain Anatomy Lecture 1

Question 1

What are the different components of the brain?

Answer 1

1 - Forebrain = Prosencephalon
(Cerebrum)
–> Telencephalon
–> Diencephalon

2 - Midbrain = Mesencephalon

3 - Hindbrain = Rhombencephalon

 - -> Pons
 - -> Medulla = Myelencephalon 
 - -> Cerebellum = Metencephalon

Question 2

What is the composition of the brainstem?

Answer 2

• Midbrain = Mesencephalon
• Pons
• Medulla = Myelencephalon

+ sometimes includes Cerebellum = Metencephalon

Question 3

What are the 3 axes of the brain?

Answer 3

–> similar to rest of body

- Lateral-medial
- Dorsal-ventral
- Rostral-caudal (anterior-posterior
mouth to tail)

Question 4

What are the 2 anatomical axes of the human brain?

What is this due to?

Answer 4

Axis A
–> Forebrain

Axis B
–> Brainstem, cerebellum and spinal cord

This is due to the flexure in the brain at that point (not so pronounced in other vertebrates)

Question 5

How many flexures are there in the vertebrate brain? What do they separate?

Answer 5

2 flexures separating:

• forebrain from midbrain
• midbrain from hindbrain

Question 6

What are the main planes of section?

Answer 6

- Horizontal
(separates top of brain from bottom)
- Sagittal
(separates left from right side)
- Transverse/frontal/coronal
(Separates front from back)

• Oblique
  (rarer)

Question 7

Meninges: what are the main layers and their characteristics?

Answer 7

From in to out:
1 - Pia Mater

2 - Arachnoid Mater

3 - Dura Mater
     --> lines the skull cavity
     --> formed into folds (Falx cerebri and Tentorium 
          cerebelli)
     -->  tough, smooth, & fibrous

Question 8

How many ventricles are there?

What do they contain?

Answer 8

• 2 lateral ventricles: large and associated with telencephalon
• 3rd ventricle associated with diencephalon
• 4th ventricle associated with brainstem

–> all contain cerebro-spinal fluid (CSF)

Question 9

What connects the third and fourth ventricles?

Answer 9

cerebral aqueduct

Question 10

Where do the majority of cranial nerves emerge from?

Answer 10

brainstem

Question 11

What are cerebellar connections points called?

Answer 11

peduncles

–> two stalks that attach the cerebrum to the brainstem

Question 12

What is the cerebellum attached to?

Answer 12

the pons

Question 13

Describe the arrangement of grey and white matter in the cerebellum?

Answer 13

deep cerebellar nuclei in centre

• -> bits of grey matter in white matter
• -> on outside: cerebellar cortex

Question 14

Where is the brainstem/cerebellum positioned in the skull?

Answer 14

Posterior cranial fossa

Question 15

How many cranial fossas are there/what are they called?

Answer 15

three:

• Anterior cranial fossa
• Middle cranial fossa
• Posterior cranial fossa

Question 16

What do you call the fold of the dura mater?

Answer 16

Tentorium cerebelli

–> an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes

Question 17

How many cranial nerves are there?

Answer 17

12 cranial nerves

• some are sensory (e.g. CN1, 2, 8)
• some are motor (e.g. CN3, 4, 6, 11, 12)
• some are mixed = contain both motor and sensory fibres (e.g. CN5, 7, 9, 10)

Question 18

What is the diencephalon composed of?

Answer 18

• Thalamus
• Epithalamus
• Hypothalamus
• Pineal (epiphysis)
• Pituitary (hypophysis)

Question 19

Where does the optic nerve (cranial nerve 2) originate?

Answer 19

From the hypothalamus in the diencephalon

Question 20

How many principle lobes are there in the cerebral cortex? Name them

Answer 20

Four principle lobes:

• frontal lobe
• parietal lobe
• temporal lobe
• occipital lobe

Question 21

What are the main fissures/sulci of the cerebral cortex?

Answer 21

Fissures separate lobes:

• Longitudinal cerebellar fissure (down middle from front to back of brain)
• Central sulcus (separates frontal lobe from parietal lobe)
• Lateral sulcus (temporal lobe)
• Parieto-occipital sulcus (separates parietal and occipital lobes)

Question 22

What are the “valleys” and “hills/ridges” of the cerebral cortex called?

Answer 22

valleys = sulci
ridges = gyri

Question 23

What are the deep cerebral ganglia?

Answer 23

• Deep cerebral grey matter within the white matter
• Various names describe groupings of these nuclei: basal ganglia, corpus striatum etc…
• Associated with movement disorders: Parkinson’s disease and Huntington’s disease

Question 24

What is the circle of Willis?

Answer 24

A circular anastomosis of
arteries from which almost all
the brain’s blood is supplied

Question 25

What are the three main arteries in the brain?

Answer 25

• Anterior Cerebral Artery
• Middle Cerebral Artery
• Posterior Cerebral Artery