Anatomy of the pituitary gland

Question 1

In what region of the brain are the thalamus and hypothalamus found?

Answer 1

Diencephalon

Question 2

What is the diencephalon?

Answer 2

This forms the core of the cerebrum with connections to both the right and left cerebral hemispheres and midbrain

Question 3

What connects the pituitary gland to the hypothalamus?

Answer 3

Infundibulum (Pituitary stalk)

Question 4

Describe the location of the pituitary gland on the cranial vault floor

Answer 4

It is found in the sella turcica, within the pituitary fossa of the sphenoid bone

Question 5

What are the 2 main lobes of the pituitary gland?

Answer 5

Anterior pituitary
Posterior pituitary

Question 6

What is the other name given to the anterior pituitary lobe?

Answer 6

Adenohypophysis

Question 7

What is the other name given to the posterior pituitary lobe?

Answer 7

Neurohypophysis

Question 8

What are the 3 regions of the anterior pituitary?

Answer 8

• Pars distalis
• Pars tuberalis
• Pars intermedia

Question 9

What is the function of the anterior pituitary gland?

Answer 9

This is responsible for synthesis and release of most pituitary hormones, including growth hormone, TSH, ACTH, FSH, LH and PRL

Question 10

What is the main region of the posterior pituitary lobe?

Answer 10

Pars nervosa

Question 11

What is the function of the posterior pituitary lobe?

Answer 11

This is an extension of the brain and releases ADH and oxytocin, which are synthesised in the hypothalamus

Question 12

What are the 2 regions of the retina?

Answer 12

Temporal retina
Nasal retina

Question 13

What are the 2 regions of the visual field?

Answer 13

Left and right

Question 14

Where will light from the left visual field hit?

Answer 14

Left nasal retina
Right temporal retina

Question 15

Where will light from the right visual field hit?

Answer 15

Right nasal retina
Left temporal retina

Question 16

What is the name of cross over between the optic nerves?

Answer 16

Optic chiasm

Question 17

Where will signals from the left nasal and right temporal retina travel?

Answer 17

To the right side of the brain

Question 18

Where will signals from the right nasal and left temporal retina travel?

Answer 18

To the left side of the brain

Question 19

Describe the route of the nerves from the eye to the brain

Answer 19

2 x Optic nerves =>
1 x Optic chiasm =>
2 x Optic tracts =>
4 x Geniculocalcarine tracts (Optic radiations)
Visual cortex of the occipital lobe

Question 20

How can pituitary gland tumours affect the visual pathway?

Answer 20

They can cause bitemoral hemianopia, in which only one half of the visual field can be seen

Question 21

Where on the optic pathway do pituitary gland tumours affect in bitemporal hemianopia?

Answer 21

In the case of bitemporal hemianopia, the lesion will occur not in the optic nerve, as light is still being seen, but in the optic chiasm, where the crossing over of the visual field is seen

Question 22

What are the two forms of access to the pituitary gland for surgery?

Answer 22

• Trans-cranial access
• Trans-sphenoidal access

Question 23

How is trans-cranial access to the pituitary gland gained?

Answer 23

Trans-cranial access is gained sub-frontally, in which access is made just under the frontal lobe of the brain, above the orbital fossa

Question 24

How is trans-cranial access to the pituitary gland gained?

Answer 24

Trans-sphenoidal access is gained up through the nose and through the sphenoidal sinus

Question 25

What are some structures at risk during pituitary gland surgery?

Answer 25

Optic chiasm Occulomotor nerve Trochlear nerve Trigeminal nerve Abducens nerve Cavernous sinus Internal carotid artery Dura mater

Question 26

What will occur if the optic chiasma is damaged during pituitary gland surgery?

Answer 26

Bitemporal hemianopia

Question 27

What will occur if the oculomotor nerve is damaged during pituitary gland surgery?

Answer 27

Several eye movement deficits Dilated pupils

Question 28

What will occur if the Trochlear nerve is damaged during pituitary gland surgery?

Answer 28

Difficulty looking inferiorly and laterally

Question 29

What will occur if the trigeminal nerve is damaged during pituitary gland surgery?

Answer 29

Parasthesia of the face Difficulty masticating

Question 30

What will occur if the abducens nerve is damaged during pituitary gland surgery?

Answer 30

Difficulty abducting the eye

Question 31

What will occur if the cavernous sinus is damaged during pituitary gland surgery?

Answer 31

Venous haemorrhage

Question 32

What will occur if the internal carotid artery is damaged during pituitary gland surgery?

Answer 32

Catastrophic haemorrhage

Question 33

What will occur if the dura mater is damaged during pituitary gland surgery?

Answer 33

Cerebrospinal fluid leak

Question 34

What are the paranasal sinuses?

Answer 34

air-filled spaces within the bones surrounding nasal cavities

Question 35

What are some examples of paranasal sinuses?

Answer 35

- Frontal sinuses - Frontal bone - Maxillary sinuses - Maxillae - Ethmoidal air cells - Sphenoid bone - Sphenoid sinuses - Sphenoid bone

Question 36

What surrounds the inside of the paranasal sinuses?

Answer 36

Mucus-secreting respiratory mucosa

Question 37

What are some functions of the paranasal sinuses?

Answer 37

- Secretion of mucus, which drains into nasal cavities through the ostia (Bony drainage holes) - Reduce weight of skull - Add resonance to voice

Question 38

What structure lines the entire floor of the cranial vault?

Answer 38

Dura mater

Question 39

What is the tentorium cerebelli?

Answer 39

The tentorium cerebelli is a tough sheet of dura mater tenting over the cerebellum in the posterior cranial fossa, but which a centra gap to permit the brainstem to pass through

Question 40

What is the diaphragma sellae?

Answer 40

The diaphragma sellae is a tough sheet of dura mater forming a roof (Diaphragm) over the pituitary fossa

Question 41

What are the dural venous sinuses?

Answer 41

These are venous channels within the dura mater that drain most of the venous blood from the cranial cavity (Including the brain) into the internal jugular veins at the jugular foraminae in the floor of the posterior cranial fossa

Question 42

What dural venous sinuses surround the pituitary gland?

Answer 42

Left and right cavernous sinuses Anterior and posterior inter cavernous sinuses