The pituitary gland and its disorders Flashcards
Describe the anatomy of the pituitary gland
How many lobes?
Where does it lie?
How does it form?
- Two lobes
- Lies below the sella turcica
- the anterior lobe is derived from the imagination of the roof the embryonic oropharynx knows as Rathke’s pouch
- A notochordal projection forms the pituitary stalk, which connects the gland to the brain and also to the posterior lobe of the pituitary
Describe the blood supply of the pituitary gland
It has a dual blood supply:
Via long and short pituitary arteries and the second via hypophyseal portal circulation. This begins as a capillary plexus around the arc
Pituitary cells were originally classified by their standing characteristics with acid and basic dyes
Describe the primary, secondary and tertiary signalling of endocrine hormones
Primary = end organ
secondary = pituitary
Tertiary = hypothlamaus
What does a tumour in the pituitary cause?
- Hormone hypersecretion
- Space occupying lesion causing headache, visual loss, cavernous sinus invasion
- Hormone deficiency states causing interference with surround normal pituitary
What does excess Gh cause?
Acromegaly
What does to much ACTH cause?
Cushing’s disease
What does to much TSH cause?
Secondary thyrotoxicosis
What does too much LH/ FSH cause?
Non-functioning pituitary tumour -
What does too much PRL?
Prolactinoma
What causes the release of GH?
What causes a negative feedback pathway?
How does the growth hormone influence fat and muscle?
Somatostatin and GHRH cause the release of growth hormone acting on muscles and liver, this releases IG-1 and IGFBP-3 release form the liver causing the chondrocytes to grow causing the growth.
IG-1 causes a negative feedback pathway
Growth hormone reduces body fat, traps energy in muscle
What are the symptoms of Acromegaly?
The tongue is too large-stop breathing
large hands, feet, wrist, compression of radial nerve
sweaty hands
jaw comes forward
teeth separate and fall out
diabetes
cardiomyopathy
hypertension
bowel polyps
colonic cancer
multinodular goitre
hypogonadism
Arthropathy - an overgrowth of cartilage - changes the pressure
OSA
What does cortisol do?
Increase glucose levels
Increase lipolysis
Proteins are catabolised
Na and water retention
anti-inflammatory
Describe cushing syndrome
On previous lecture
What is a prolactinoma?
Increase the release of DA inhibits PRL release
What does a non-functioning pituitary tumour cause?
How can we treat it?
Reduce space in the brain causes headaches, visual defects. nerve palsies
cause deficiency of other hormones
Surgery and radiotherapy
no effective medical treatment
