Topic 8

Question 1

Label the location of the major endocrine organs in the human body

Answer 1

• Hypothalamus
• Pituitary gland
• Pineal gland
• Thyroid gland
• Adrenal glands
• Pancreas
• Ovaries and testes

Question 2

Describe the role of circulating (blood) and local hormones

Answer 2

Hormones are secreted by endocrine glands to regulate and coordinate a range of bodily functions. Most hormones are released in short bursts. However, some hormones take long periods of time to stimulate permanent change (puberty). Hormones only affect specific target cells by chemically binding to receptors.
Circulating hormones travel around the body in the blood (adrenaline and testosterone)
Local hormones act on neighbouring cells without entering the bloodstream and are usually inactivated quickly (glucagon and serotonin)

Question 3

Explain how circulating hormone levels are regulated

Answer 3

Hormones are regulated by complex feedback loops. Regulated by chemical changes within extra cellular fluid (blood)
EX> insulin/ high blood glucose levels stimulate insulin from pancreas
EX>glucagon/ Low blood glucose levels stimulate release of glucagon
- Signals from the nervous system, once the substance reaches a certain level, it sends signals to stop further release of subatstances. EX> adrenaline/ release due to the fight or flight response through autonomic nervous system.
Endocrine glands release hormones when stimulated by hormones released by other endorcrine glands
EX> growth hormones/ stressors stimulate GHRH release from hypothalamus, which in return stimulates pituitary glands to release GH

Question 4

Explain the relationship between the hypothalamus and the pituitary gland