Endocrine anatomy

Question 1

What is the pituitary gland and where is it located?

Answer 1

• an extension of the hypothalamus

- located in the sella turcica

Question 2

What is the infundibulum?

Answer 2

pituitary stalk –> connects the hypothalamus and the pituitary

Question 3

What is the posterior lobe, what does it secrete?

Answer 3

posterior lobe = neurohypophysis

• a downgrowth of the hypothalamus
• secretes ADH and oxytocin

Question 4

What is the anterior lobe, what does it secrete?

Answer 4

anterior lobe = adenohypophysis

• made up of glandular tissue
• secretes ACTH, TSH, LH, FSH, PRL, GH and MSH

Question 5

Describe the connection between the hypothalamus and the posterior pituitary.

Answer 5

• Neural connection
• connected by 2 cell bodies:
  1. supraoptic nuclei - secretes ADH
  2. paraventricular nuclei - secretes oxytocin

Question 6

Describe the connection between the hypothalamus and the anterior pituitary.

Answer 6

• blood connection
• ICA –> superior hypophyseal artery –> into the infundibulum –> becomes primary plexus (in hypothalamus) –> hypophyseal portal vein to anterior pituitary –> becomes the secondary plexus –> efferent hypophyseal vein branches off and goes to cavernous sinus

Question 7

what % of intracranial tumours are pituitary tumours?

Answer 7

10-15%

Question 8

What are the effects of a tumour secreting LH/FSH?

Answer 8

• irregular periods

- reduced libido

Question 9

What are the effects of a tumour secreting prolactin?

Answer 9

• abnormal periods

- abnormal milk production

Question 10

What are the effects of a tumour secreting GH?

Answer 10

• gigantism (children)

- acromegaly (adults)

Question 11

What are the effects of a tumour secreting TSH?

Answer 11

• hyperthyroidism = reduced weight, increased HR, tremors

Question 12

What are the effects of a tumour secreting ACTH?

Answer 12

• abnormal cortisol production = Cushing’s symptoms

Question 13

What effects can a pituitary tumour have on vision?

Answer 13

1. Bitemporal hemianopia/loss of peripheral vision due to compression of optic chiasm
2. Progressive ophthalmoplegia due to compression of CN III, IV and VI

Question 14

What is the main treatment for pituitary tumours?

Answer 14

Removal via surgery (keep as much normal tissue as possible)

May require hormone replacement after

Question 15

Where are the adrenal glands located?

Answer 15

between superomedial aspect of kidney and crura of diaphragm

Question 16

What are the layers of the adrenal cortex, and what is secreted from each layer (outside –> inside)?

Answer 16

1. Zona granulosa = aldosterone
2. Zona fasciculata = cortisol
3. Zona reticularis = androgens

Question 17

What is secreted from the adrenal medulla?

Answer 17

Adrenaline and noradrenaline

Question 18

Compare the right and left adrenal glands.

Answer 18

Right:

• pyramidal shaped
• contract with liver and IVC

Left:

• crescent shaped and larger
• contact with spleen, stomach and pancreas

Question 19

Describe the blood supply of the adrenal glands.

Answer 19

• superior suprarenal arteries (6-8) –> branch of the inferior phrenic artery (supplies top of adrenal gland)
• middle suprarenal artery –> branch abdominal aorta near SMA
• inferior suprarenal artery –> branch of renal artery
• large suprarenal vein
• -> right suprarenal drains to IVC
• -> left suprarenal –> left renal –> IVC

Question 20

At what levels does the thyroid gland lay?

Answer 20

C5-T1

Question 21

What is the structure connecting the right and left lobes of the thyroid gland called?

Answer 21

Isthmus

Question 22

Describe the blood supply of the thyroid gland.

Answer 22

• gland sits between the common carotids
• superior thyroid artery descends from the bifurcation of common carotids –> supplies the thyroid
• inferior thyroid artery is a branch of the thyrocervical artery
• thyroid can have an IMA that supplies the isthmus
• superior and middle thyroid veins drain into the internal jugular veins
• inferior thyroid veins and internal jugular veins drain into the brachiocephalis
• brachiocephalic drains into the IVC

Question 23

How many parathyroid glands are there? Where are they in relation to the thyroid gland?

Answer 23

4 - 2 superior, 2 inferior

- lie posterior to thyroid gland

Question 24

What is the role of the parathyroid glands?

Answer 24

Regulate serum calcium levels

- when activated they increase calcium level s

Question 25

What structures must be avoided when performing a thyroidectomy? what is the result of damage to these structures?

Answer 25

1. recurrent laryngeal = dysphonia 2. Ima artery = post-op haemorrhage and compression fo trachea 3. parathyroid glands = tetany (intermittent muscular spasms)

Question 26

Describe the blood supply to the pnacreas.

Answer 26

- comes from celiac trunk and SMA - splenic artery supplies the spleen - has a branch (transverse pancreatic) supplies the tail, body and neck of pancreas - common hepatic artery --> branch called gastroduodenal --> gives off the superior pancreaticoduodenal artery --> supplies head of pancreas - inferior pancreaticoduodenal artery (from SMA) that supplies the head and uncinate process

Question 27

What is the effect of gall stones in the body of the gallbladder?

Answer 27

asymptomatic

Question 28

What is the effect of gall stones in the neck of the gallbladder/cystic duct?

Answer 28

stops bile flow from the gallbladder but not the liver = pain after meal (biliary colic)

Question 29

What is the effect of gall stones in the common bile duct?

Answer 29

stop flow of bile from the gallbladder and the liver = 1. jaundice 2. biliary colic

Question 30

What is the effect of gall stones in the sphincter of Oddi/hepatoduodenal ampulla?

Answer 30

stop bile flow and pancreatic enzymes = 1. biliary colic 2. jaundice 3. pancreatitis