Endocrine System

Question 1

Peptide hormone

Answer 1

Polar molecules composed of amino acids (prehormone –> prohormone –> hormone); synthesized in the rough ER; can travel freely in the bloodstream; promotes intracellular signaling cascade (2^nd messenger system)

• Growth hormone
• Insulin
• ANP
• Oxytocin
• ADH
• PTH

Question 2

Steroid hormones

Answer 2

Non-polar molecules derived from cholesterol (most ends with -ol, -one, -en); modified from cholesterol in the smooth ER; transported thru carrier proteins; diffuse via cell membrane and alter transcription of DNA sequences

• Glucocorticoids
• Mineralocorticooids
• Cortical sex hormone

Question 3

Amine hormones

Answer 3

Derivated from tyosine or tryptophan

• Catecholamines
• Serotonin
• Thyroid hormones

Question 4

Homeostasis is primarily maintained by which feedback mechanism?

Answer 4

Negative feedback

Question 5

Hypothalamus

Answer 5

• Secretes chemicals that control the release of hormones from the anterior pituitary
• Also produces 2 posterior pituitary hormones, ADH and oxytocin
• The hypothalamus is connected to pituitary via the hypophyseal portal system

(Hormones that are secreted from the anterior pituitary are also synthesized there; post. pit. hormones are synthesized in the hypothalamus)

Question 6

Portal system and endocrine function

Answer 6

A portal system is a circulatory structure in which one capillary bed drains into another

• The hypophyseal portal system allows hormones to be transported from the hypothalamus to the pituary gland

Question 7

Hormones from the anterior pituitary

Answer 7

• FSH (tropic)
• LH (tropic)
• ACTH (tropic)
• GH
• TSH (tropic)

Question 8

Endocrine function of thyroid gland

Answer 8

Releases thyroid hormones (T₃ & T₄), which controls metabolism

Also secretes calcitonin (involved in helping to regulate levels of calcium and phosphate in the blood, opposing the action of parathyroid hormone)