3. Endocrine System

Question 1

Endocrinology

Answer 1

1. Hormone structure/secretion
2. Pituitary: the “master” gland
3. Mechanisms of hormone action
4. Chemical messengers

Question 2

Endocrine system: Major organs

Answer 2

• Adrenal glands: cortex, medulla
• Gonads: male, female
• Hypothalamus
• Pancreas
• Parathyroid gland
• Pineal gland
• Pituitary gland: anterior, posterior
• Thyroid

Question 3

Three major chemical classes of hormones

Answer 3

1. Amines
2. Peptides and proteins
3. Steroids

Question 4

Three control mechanisms for hormone secretion

Answer 4

1. Mineral ions or organic nutrients
   e. g. glucose, Na+, water
2. Neural control by neurotransmitters
3. Hormonal control (by hormones)

Question 5

Which structure(s)/hormone(s) contribute to hormonal and neural control?

Answer 5

Adrenal cortex - hormonal control 
Adrenocorticotropic hormone (ACTH) - hormonal control 

Adrenal medulla - neural control
Sympathetic innervation - neural control

Question 6

Hypothalamo-hypophysial Axis

Answer 6

Close relationship between hypothalamus and pituitary gland

Question 7

Anterior Pituitary Hormones

Answer 7

1. FSH (follicular stimulating hormone)
2. LH (lutenizing hormone)
3. GH (growth hormone)
4. TSH (thyroid stimulating hormone)
5. Prolactin
6. ACTH (adrenocortico tropic hormone)

Question 8

Hypothalamus hormones

Answer 8

1. GnRH (gonadotropin releasing hormone)
2. GHRH (growth hormone releasing hormone)
3. SS (somatostatin)
4. TRH (thyrotropin releasing hormone)
5. DA (dopamine)
6. CRH (corticotropin releasing hormone)

Question 9

Chemical Messengers: Signal Transduction

Answer 9

• For cell-to-cell communication

- Specificity

Question 10

Signal Transduction Pathways

Answer 10

1. intracellular receptors (for lipid-soluble hormones)

2. plasma membrane receptors (for water-soluble hormones)

Question 11

Intracellular Receptors (hydrophobic hormones)

Answer 11

• Steroids

- T4

Question 12

Plasma Membrane Receptors (hydrophilic hormones)

Answer 12

• Peptides
• Proteins
• Amines

Question 13

Membrane Receptors

Answer 13

• Transmembrane protein

- Contains extracellular domains

Question 14

Classification of Receptors

Answer 14

a. Ligand-gated ion channels
b. Function as enzymes
(receptor kinase)
c. Receptor activates
cytoplasmic janus kinase
d. G-protein coupled
receptors

Question 15

Effects of caffeine on cAMP

Answer 15

1) adenylate cyclase

2) phosphodiesterase