General Endocrinology

Question 1

What is Endocrinology?

Answer 1

Study of hormones

Question 2

What are 4 forms of intercellular communication?

Answer 2

• direct cell-cell
• paracrine/autocrine
• neural
• endocrine

Question 3

What are the differences between the nervous and endocrine signals?

Answer 3

• speed
• duration
• specificity

Question 4

How does speed differ between nervous and endocrine signals?

Answer 4

Nerves are faster

Question 5

How does duration differ between nervous and endocrine signals?

Answer 5

• nerves have brief duration
• hormones can have permanent consequences

Question 6

How does specificity differ between nervous and endocrine signals?

Answer 6

• nerves very specific
• hormones have a widespread action (not specific)

Question 7

What is a hormone?

Answer 7

• chemical substance
• synthesised + secreted by a specific gland
• secreted in small amounts into bloodstream
• acts at a site distant from site of secretion
• acts on specific receptors to give a specific physiological effect

Question 8

Give an example of a hormone and it’s specifities.

Answer 8

• adrenaline
• from adrenal medulla
• <10 ng/ml at rest
• acts on heart
• stimulates receptors to increase heart rate

Question 9

List the endocrine glands of the body.

Answer 9

(Brain): Hypothalamus
Pituitary
(Throat): Thyroid
Parathyroids
(Lungs): Thymus
(Kidneys): Adrenals
Pancreas
Ovaries
Testes

Question 10

What do hormones do?

Answer 10

• reproduction
• growth & development
• maintenance of internal environment
• regulation of digestion & energy availability

Question 11

What are the types of hormone molecules?

Answer 11

• peptides (proteins)
• amine derivatives
• lipid based (steroids)

Question 12

What is the solubility property of hormones?

Answer 12

peptide & amine derivatives:
- water soluble

(lipid based) steroid & thyroid:
- lipid soluble

Question 13

How much storage do hormones have in cells?

Answer 13

peptide & amine derivatives:
- substantial storage

(lipid based) steroid & thyroid hormones:
- minimal storage

Question 14

How are hormones transported in blood?

Answer 14

peptide/protein/amino derivative:
- dissolve in plasma

steroid & thyroid hormones:
- bind to carrier proteins

Question 15

How are hormone molecules catabolised and excreted?

Answer 15

peptide & amine derivatives:
- broken down by proteases (in bloodstream/tissues)
- excreted in urine

steroid & thyroid hormones:
- modified in liver to become water soluble
- excreted in bile/urine

Question 16

What is the ‘half-life’ of hormones?

Answer 16

peptide & amine derivatives:
- short (mins)

(lipid based) steroid & thyroid hormones:
- long (hrs)

Question 17

Where is the ‘site of action’ for hormones?

Answer 17

peptide & amine derivatives:
- plasma membrane

(lipid based) steroid & thyroid hormones:
- nucleus

Question 18

Where is the ‘cell binding site’ for hormones?

Answer 18

peptide & amine derivatives:
- cell surface receptor

(lipid based) steroid & thyroid hormones:
- cytoplasmic/nuclear receptor

Question 19

How long is the course of action for hormones?

Answer 19

peptide & amine derivatives:
- rapid onset
- short duration

(lipid based) steroid & thyroid hormones:
- long latency + duration
- may be permanent

Question 20

How do hormones act on target cells?

Answer 20

• act on specific receptors
• regulate activity of target cell
• mechanism of action depends on nature of hormone

Question 21

What hormones cannot enter the cell?

Answer 21

• peptides
• catecholamines

Question 22

What hormones can enter the cell?

Answer 22

• steroids
• thyroid hromones

Question 23

How is hormone secretion controlled/regulated?

Answer 23

• neural regulation
• endocrine & neuroendocrine regulation
• non-neural/non-endocrine regulation
• positive & negative feedback
• bioavailability