3. Hypothalamus/ Pituitary 2

Question 1

What is the name for a decrease in secretion of all anterior pituitary hormones?

Answer 1

Panhypopituitarism

Question 2

What are the causes of panhypopituitarism?

Answer 2

Congenital
Pituitary tumour
Pregnancy (infarction of portal vessels

Question 3

What does a deficiency of AP hormones in childhood result in?

Answer 3

Panhypopituitary dwarfism
Greatly decreased rate of development
Person never passes through puberty

Question 4

What are the symptoms of panhypopituitarism in the adult?

Answer 4

Hypothyroidism
Decreased production glucocorticoids
Loss of sexual function

Question 5

How is panhypopituitarism in the adult treated?

Answer 5

Adrenocortical and thyroid hormones

Question 6

What type of hormone is growth hormone?

Answer 6

Peptide

191 amino acids

Question 7

What 5 factors influence a person’s final height?

Answer 7

Growth hormone
Genes
Diet
Stressfulness of environment
Thyroid and sex hormones

Question 8

What is the most abundant hormone produced by the anterior pituitary?

Answer 8

Growth Hormone

Question 9

What are the target organs of GH?

Answer 9

Adipose tissue
Skeletal muscle
Liver

Question 10

What are the metabolic effects of GH?

Answer 10

Increases mobilisation of fatty acids from adipose
Decreases glucose utilisation
Increases rate of protein synthesis

Question 11

What are somatomedins?

Answer 11

Stimulated by GH
Structurally and functionally similar to insulin
IGFs

Question 12

What is a major source of circulation IGF-1?

Answer 12

Liver

Question 13

What effect does GH have on bone growth?

Answer 13

Increases rate of osteoblasts
Increases division of chondrocytes
Older chondrocytes expand
When these die, osteoblasts fill the space with bone

Question 14

What stimulates GH secretion?

Answer 14

GHRH

Question 15

What inhibits GH release?

Answer 15

GHIH/somatostatin

High blood levels IGF-1

Question 16

What factors can influence GH secretion?

Answer 16

Diurnal rhythm
Exercise
Stress
Low blood glucose
High protein meal
Low blood fatty acids

Question 17

What can cause a deficiency in GH?

Answer 17

Hypothalamic dysfunction
Pituitary defect
Mutations in GH receptor

Question 18

What is dwarfism?

Answer 18

Hyposecretion of GH as a child
Short stature
Poorly developed muscles
Excess subcutaneous fat

Question 19

What is Laron Dwarfism?

Answer 19

Abnormal GH receptors on tissues

Question 20

What is the defect in African pygmies?

Answer 20

Lack IGF-1

Question 21

What does a GH deficiency in adults result in?

Answer 21

Reduced skeletal mass and strength
Decreased bone density
Increased risk of heart failure

Question 22

How is GH deficiency treated?

Answer 22

Recombinant GH

Question 23

What are the causes of GH excess?

Answer 23

Tumour of GH producing cells in anterior pituitary

Defect in GH secreting mechanisms

Question 24

What does overproduction of GH result in in a child?

Answer 24

Gigantism
Rapid growth in height
Hyperglycaemia

Question 25

What does hypersecretion of GH after adolescence result in?

Answer 25

Thickening of bones Skin and connective tissue proliferates Acromegaly Possible insulin resistance and hyperglycaemia

Question 26

How is GH excess measured?

Answer 26

Glucose Loading Test

Question 27

How is GH excess treated?

Answer 27

Somatostatin mimetics

Question 28

Who is recombinant GH approved for use in?

Answer 28

GH deficient children Adults with pituitary tumours AIDS patients with muscle wasting Shortest 1.2% of children

Question 29

What are the disadvantages of extended or excessive use of GH?

Answer 29

Increases likelihood of: diabetes, kidney stones, high BP, headaches, joint pain, carpal tunnel, cancer Expensive

Question 30

How long does it take for PRL levels to decline if a mother does not nurse?

Answer 30

3-6 weeks

Question 31

How long do PRL levels remain elevated if a mother breastfeeds?

Answer 31

8-12 weeks

Question 32

How is PRL secretion regulated?

Answer 32

PIH/Dopamine and PRH | Short loop feedback

Question 33

What are the biological effects of PRL?

Answer 33

1. Branching of ducts in breasts (puberty) 2. Development of lobules for milk production (pregnancy) 3. Milk synthesis and secretion (after parturition) 4. Excess stops release of GnRH 5. Prevents mother's immune system from attacking foetus

Question 34

What is the cause of a deficiency of PRL?

Answer 34

Destruction of the anterior pituitary

Question 35

What are the symptoms of a lack of PRL?

Answer 35

Inability to lactate

Question 36

What are the causes of an excess of PRL?

Answer 36

Hypothalamic dysfunction | Pituitary tumours

Question 37

What are the symptoms of PRL excess in women?

Answer 37

Infertility Complete loss of menses Lactation Decreased libido

Question 38

What are the symptoms of PRL excess in men?

Answer 38

Decreased testosterone Decreased sperm production Breast development and lactation Libido decreased

Question 39

How is a lactotroph tumour treated?

Answer 39

Removal of tumour | Administration of dopaminergic drugs

Question 40

What are the functions of oxytocin?

Answer 40

Milk ejection | Contraction of uterus

Question 41

What increases secretion of oxytocin?

Answer 41

Reflexes (suckling infant, birth canal)

Question 42

What is the function of vasopressin?

Answer 42

Water retention | Contraction of arteries

Question 43

What influences ADH secretion?

Answer 43

1. Osmotic and volume stimuli 2. Decreased blood volume of BP 3. Pain, emotional stress, heat 4. Age 5. Alcohol (inhibits secretion)

Question 44

What is the most common form of ADH deficiency?

Answer 44

Diabetes Insipidus

Question 45

What causes hypothalamic DI?

Answer 45

Deficiency in ADH from PP Tumours of hypothalamus Autoimmune disease Head trauma

Question 46

What causes nephrogenic DI?

Answer 46

Kidney is unable to respond to ADH Renal disease Mutations in ADH receptor Drugs

Question 47

What are the major symptoms of DI?

Answer 47

Polyuria Polydipsia Nocturia

Question 48

How is hypothalamic DI treated?

Answer 48

Exogenous ADH

Question 49

What is the name of the condition where ADH is secreted in excess?

Answer 49

Syndrome of Inappropriate ADH Secretion | SIADH

Question 50

What are the symptoms of SIADH?

Answer 50

Hyponatraemia (low Na+) | Lethargy, anorexia, nausea, muscle cramps, drowsiness, confusion, seizures, coma

Question 51

What are the causes of SIADH?

Answer 51

CNS damage Drugs Infection

Question 52

How is SIADH treated?

Answer 52

Fluid restriction | ADH antagonists