Hypothalamus & Pituitary

Question 1

What is the most common cause of pituitary disease?

Answer 1

Pituitary tumour

Question 2

How do pituitary tumours cause problems?

Answer 2

Over production of pituitary hormone

Inadequate production of other remaining hormones

Local effects of antomically related structures

Question 3

How are hormones released in the anterior pituitary?

Answer 3

Produced in arcuate, ventromedial, preoptic
Nucleus. Cells bodies and neurone secrete the hormones, they pass down portal vessels and reach capillary bed which controls secretion

Question 4

In the posterior pituitary oxytocin and vasopressin are produced but what are the nuclei called?

Answer 4

Paraventricular and supra optic

Question 5

For each of the cell types name the anterior pituitary hormone produced: somatotrphs, lactotrophs, corticotrophs, thyrotrophs, gonadotrophs

Answer 5

1) somatotropin - GH
2) prolactin
3) corticotropin - adenocorticotropin hormone ACTH
4) thyrotropin - thyroid stimulating hormone TSH
5) luteinizing hormone LH, follicle stimulating hormone FSH

Question 6

Define Tropic and trophic

Answer 6

Tropic: affecting activity of an endocrine gland

Trophic: promote growth, tissue integrity

Question 7

What is GH’s direct action and how does it effect lipolysis and glucose?

Answer 7

Metabolism

Increased lipolysis
Increase aa uptake and protein synthesis
Increase hepatic glucose output and decreases glucose uptake

Question 8

What is GH’s indirect mode of action and how does IGF-I effect cells?

Answer 8

Promote growth by releasing growth factors from liver and other cells

IGF-I: stimulate protein synthesis and increase cell size, stimulate cell division, increase cell number and promote skeletal growth

Question 9

What are the symptoms of GH deficiency?

Answer 9

Physiological changes 
Malaise, tiredness, anxiety and depression 
Osteoporosis
Poor muscular tone and less body mass 
Impaired hair growth 
Increase in adipose tissue

Question 10

What is excess GH called

In adults and children, what are the symptoms and how is it treated?

Answer 10

Adults- acromegaly
Children- gigantism

Coarsening of facial features 
Enlarged hands and feet 
Headaches, bison disturbances 
Sleep apnoea, general tiredness 
Hypertension , cardiomegaly 
Glucose intolerance 

Surgery or radiotherapy
Somatostatin analogues

Question 11

What is the most common cause of hyperprolactinaenia, what are the symptoms and how is it treated?

Answer 11

Cause: prolactinoma
Symptoms: loss of fertility, libido and galactorrhoea
Treatment: dopamine receptor agonist or surgery/ radiotherapy

Question 12

What is arginine vasopressin also known as, how is it stimulated and what are its actions?

Answer 12

ADH
stimulated: increase in body fluid osmolality, fall in b volume/ pressure and stress

Actions: vasoconstriction via V1 receptors,increase permeability and reabsorption of water in DCT and CD, stimulate ACTH release

Question 13

Deficiency of ADH cause diabetes insipidus what are the two forms and how are they treated?

Answer 13

Pituitary DI: inadequate release of ADH causing large volumes of dilute urine and polydipsia
Treated by desmopressin

Nephrogenic DI: lack of response of CD to ADH causing polyuria and polydipsia treated with diuretics

Question 14

What is SIADH and how is it treated?

Answer 14

Excess ADH - syndrome of inappropriate ADH secretion
Retention of water causing small volume of urine, highly concentrated and hyponatraemia
Treat by restricting water intake and V2 receptor antagonist

Question 15

What stimulated oxytocin, is it positive or negative feedback and what are its actions?

Answer 15

By suckling and cervical stimulation
Positive
Actions: stimulate expression of breast milk, uterine smooth muscle contraction

Question 16

What are the two areas of the pituitary called and which is neurohypophysis and which is adenohypophysis?

Answer 16

Posterior - neuro

Anterior - adenohypophysis