Introduction to Endocrinology

Question 1

Endocrine vs Exocrine

Answer 1

Without ducts - Endocrine

With ducts - Exocrine

Question 2

Define paracrine action

Answer 2

Acts on adjacent cells

Question 3

Define Autocrine

Answer 3

Substances released by the cell will act on that cell

Question 4

Difference in transport of water soluble and fat soluble hormones

Answer 4

Unbound - Water

Bound - fat

Question 5

Difference in cell interaction of water soluble and fat soluble hormones

Answer 5

Water - bind to surface receptor

Fat - Diffuse into cell

Question 6

Difference in Half-life of water soluble and fat soluble hormones

Answer 6

Water - short

Fat - long

Question 7

Difference in clearance of water soluble and fat soluble hormones

Answer 7

Water - Fast

Fat - slow

Question 8

Where are peptides stored

Answer 8

Vesicles

Question 9

Are steroids stored

Answer 9

No, they are synthesised on demand

Question 10

What two structures do peptides come in

Answer 10

Linear or ringed

Question 11

How many chains do peptide hormones have

Answer 11

2

Question 12

Three characteristics of peptides

Answer 12

Stored in secretory granules
Hydrophilic
Water soluble

Question 13

What form are peptide hormones synthesised as

Answer 13

Preprohormone -> prohormone (cleaved) at ribosomes
Packaged: Prohormone -> hormone
Released: hormone

Question 14

What kind of hormone are amines

Answer 14

Water souble

Question 15

Where are amine derived from

Answer 15

Phenylalanine

Question 16

Describe the path of production of epinephrine

Answer 16

L-phenylalanine -> L-tyrosine -> L-DOPA -> DOPAMINE -> Norephinephrine -> Epinepherine

Question 17

How does epinephrine act on receptors

Answer 17

Binds to alpha-adrenoceptor :

1. Receptor linked to Gq
2. IP3 produced

Question 18

What are thyroid hormones bound to

Answer 18

Albumin

Question 19

What proportion of T3 in circulation is secreted directly by thyroid

Answer 19

20%

Question 20

Property of vitamin D

Answer 20

Fat-Soluble

Question 21

Describe the production of vitamin D

Answer 21

7-dehydrocholesterol -> Cholecalciferol -> Unfinished

Question 22

Describe steroid action

Answer 22

1. Steroid diffuses into cell
2. Receptor-hormone complex forms
3. Complex bins to GRE
4. Transcription of gene to mRNA

Question 23

What is basal secretion of hormones

Answer 23

Continuous or pulsatile secretion by cells

Question 24

What is the rhythmic secretion of hormones

Answer 24

The amount of hormone secreted depends on the time of day (GH and TSH)

Question 25

Role of inhibiting factors in steroid secretion

Answer 25

Increased secretion of one hormone inhibits secretion of another

Question 26

Define synergism

Answer 26

Combined effects of two hormones amplified

Question 27

Define antagonism

Answer 27

One hormone opposes another

Question 28

What is hormone receptor induction

Answer 28

Induction of LH receptors by FSH

Question 29

What is hormone down-regulation

Answer 29

Hormone secreted in large quantities causes down regulation of its target receptors

Question 30

Where are hormones produced in the posterior pituitary gland

Answer 30

Hypothalamus by the paraventricular nucleus OR supraoptic nucleus

Question 31

What is the blood supply to the posterior pituitary gland

Answer 31

Inferior hypophyseal artery

Question 32

Where are hormones released by the posterior pituitary gland stored

Answer 32

Axon terminals

Question 33

What stimuli causes increased vasopressin secretion

Answer 33

When blood volume falls (e.g. during shock )

Question 34

What is oxytocin responsible for

Answer 34

Uterine contractions

Question 35

What simulates oxytocin release other than labour

Answer 35

Suckling by myoepithelial cells

Question 36

What simulates oxytocin release other than labour

Answer 36

Suckling by myoepithelial cells

Question 37

Signs of a pituitary dysfunction

Answer 37

Tumour mass effects (will compress surrounding structures like the third, fourth and sixth cranial nerves which control eye movement and fifth which controls eye sensation) Excess blood hormone levels Hormone deficiency

Question 38

Where is GH produced

Answer 38

Anterior pituitary gland

Question 39

What does GH act on

Answer 39

Causes release of IGFs Fat metabolism Carbohydrate metabolism Increased protein synthesis

Question 40

What stimulates release of GH

Answer 40

GNRH released by the hypothalamus

Question 41

Where is TRH produced

Answer 41

Hypothalamus

Question 42

What does TRH do

Answer 42

Causes secretion of TSH from the anterior pituitary gland

Question 43

Functions of the thyroid hormones

Answer 43

1. Accelerates food metabolism 2. Increases protein synthesis 3. Stimulates carb metabolism 4. Increases fat metabolism 5. Increase Ventilation rate 6. Increase CO and HR 7. Growth rate accelerated 8. Brain development during foetal life

Question 44

What is the half life of T4

Answer 44

5-7 days

Question 45

Half life of T3

Answer 45

1 day

Question 46

What happens to T4 in the periphery sites

Answer 46

Converted to T3 which then activates the nucleus (most active form)

Question 47

What causes release of ACTH

Answer 47

CRH b the hypothalamus

Question 48

What does ACTH act on

Answer 48

Adrenal glands tor please Cortisol

Question 49

Where in the adrenal gland is cortisol secreted from

Answer 49

Zona fasciculata

Question 50

What is secreted from the Zona glomerulosa

Answer 50

Aldosterone

Question 51

What is secreted from the Zona reticularis

Answer 51

Androstenedione | DHEA

Question 52

Describe the Renin-angiotensin system

Answer 52

Check book

Question 53

What is secreted by the adrenal medulla

Answer 53

Adrenaline