Introduction to the endocrine system

Question 1

Which cell signalling is transported via the blood stream?

Answer 1

Endocrine

Question 2

Which cell signalling is via a local mediator into target cells nearby?

Answer 2

Paracrine

Question 3

Which cell signalling involves neurons binding at a synapse?

Answer 3

Neuronal

Question 4

Which cell signalling releases a signal to act on itself?

Answer 4

Autocrine

Question 5

Which glands are ductless?

Answer 5

Endocrine glands

Question 6

What are the major endocrine glands?

Answer 6

Hypothalamus
Pineal gland
Pituitary
Thyroid
Parathyroid
Thymus
Adrenal
Pancreas
Ovaries
Testes

Question 7

Which is the pituitary gland also known as?

Answer 7

Hypophysis

Question 8

How is the pituitary gland connected to the hypothalamus?

Answer 8

Via the pituitary stalk (infundibulum)

Question 9

Which gland controls almost all pituitary secretions?

Answer 9

Hypothalamus

Question 10

How many hormones are secreted in the pituitary?

Answer 10

Anterior - 6
Posterior - 2

Question 11

Answer 11

Question 12

Which functions does the pituitary gland regulate?

Answer 12

Question 13

What is acromegaly and what can cause it?

Answer 13

Dysfunction of the pituitary gland.
Increased growth hormone in adults = bigger bones

Question 14

What is gigantism and what can cause it?

Answer 14

Increased growth hormones in children before bone fusion, leads to abnormal height and bone growth.
Caused by pituitary gland dysfunction.

Question 15

The parathyroid glands are involved in which ion?

Answer 15

Calcium concentration

Question 16

What hormones does the pancreas release?

Answer 16

Insulin (beta cells) and Glugagon
Also secretes digestive enzymes into GI tract

Question 17

Where are the adrenal glands located?

Answer 17

Above kidneys

Question 18

Answer 18

Question 19

What does the medulla of the adrenal glands secrete?

Answer 19

Adrenaline and noradrenaline in response to SS

Question 20

What does the cortex of the adrenal glands secrete?

Answer 20

Corticosteroids - synthesised from cholesterol

Question 21

Which syndrome is caused by too much cortisol?

Answer 21

Cushings syndrome

Question 22

Which condition is caused by too much aldosterone?

Answer 22

Hyperaldosteronism - leads to HTN

Question 23

Can peptide hormones cross the cell membrane?

Answer 23

No as they’re hydrophilic, they bind to cell surface receptors instead

Question 24

Hormones can be stored in cells until required as what?

Answer 24

Prohormones (inactive) –> get cleaved into active hormones via enzymes

Question 25

Can steroids cross the cell membrane?

Answer 25

Yes as they are hydrophobic

Question 26

Which type of hormones cannot be stored in cells?

Answer 26

Steroids, but they can be rapidly synthesised

Question 27

What are steroids synthesised from?

Answer 27

Cholesterol

Question 28

What is the pathway of Tyrosine to thyroid hormones?

Answer 28

Tyrosine --> 3-lodo-L-tyrosine --> 3-5-lodo-L-Tyrosine --> Thyroxine or Triiodothyronine

Question 29

What is the pathway of tyrosine to adrenaline?

Answer 29

Tyrosine --> Dopamine --> Noradrenaline --> Adrenaline

Question 30

Which type of hormones have a short half life, short duration of action and a rapid onset of action?

Answer 30

Peptide hormones

Question 31

Which type of hormones have a slow onset of action, a long plasma half life and a long duration of action?

Answer 31

Steroid and thyroid hormones

Question 32

Which type of hormones are not orally active?

Answer 32

Peptides. Steroids and thyroid hormones are orally active.

Question 33

What are steroid and thyroid hormones transported in the blood with?

Answer 33

Plasma proteins. Peptide hormones are not bound and can freely circulate.

Question 34

What are three primary receptor classes?

Answer 34

GPCR Tyrosine kinase receptors Steroid hormone receptors

Question 35

Which receptor does adrenaline bind to?

Answer 35

G-protein a-adrenergic receptors (Gaq)

Question 36

What is the GPCR Gaq pathway?

Answer 36

PLC activated --> PIP2 cleavage into DAG and IP3 --> Ca2+ influx, cAMP activation --> protein phosphorylation

Question 37

What is the pathway of a tyrosine kinase receptor?

Answer 37

Question 38

What is the pathway of steroid hormone receptors?

Answer 38

1 - enters through cell membrane due to small size and hydrophobic nature 2 - steroid hormone binds with cytoplasmic receptor forming hormone receptor complex (HRC) 3 - HRC enters the nucleus and cytoplasmic receptor aspect of the HRC binds to DNA 4 - HRC binding to genes is able to turn genes on or off 5 - cell undergoes transcription and protein synthesis

Question 39

When is serum TSH at it's highest throughout the day?

Answer 39

At night - there is diurnal variation, TSH then reduces during the day

Question 40

What is the pathway of the hypothalamus-pituitary-adrenal (HPA) axis?

Answer 40

- hypothalamus secretes corticotropin releasing hormone (CRH) - CRH binds to anterior pituitary gland causing release of adrenocorticotropic hormone (ACTH) - ACTH is released into blood and binds to adrenal cortex - adrenal cortex releases glucocorticoids (cortisol) - glucocorticoids bind to pituitary gland and hypothalamus, inhibits further release of glucocorticoids

Question 41

What type of receptor class would insulin bind to?

Answer 41

Cell surface receptor

Question 42

What type of receptor class would thyroid hormones bind to?

Answer 42

Cytosolic receptors