3.3 - Endocrine System Continued

Question 1

What does the thyroid gland do?

Answer 1

Affects metabolism, among other things

Question 2

What does the pituitary gland do?

Answer 2

Secretes many different hormones, some of which affect other glands

Question 3

What does the hypothalamus do?

Answer 3

Brain region that controls the pituitary gland

Question 4

What do parathyroids do?

Answer 4

Help to regulate level of calcium in the blood

Question 5

What do adrenal glands do?

Answer 5

Help trigger the fight-or-flight response

Question 6

What does the pancreas do?

Answer 6

Regulates the level of sugar in the blood

Question 7

What are tropic hormones?

Answer 7

Hormones with the job of stimulating OTHER ENDOCRINE organs to make a different hormone.

Question 8

What are the two componenets of the pituitary gland?

Answer 8

• Anterior pituitary (the actual gland/front portion: produces and secretes the 7 pituitary hormones (TSH, LH, FSH, ACTH, PRL, GH, MSH under control of the hypothalamus))
• Posterior pituitary (extension of the hypothalamus/back portion: stores and releases the 2 hypothalamus produced hormones (ADH and Oxytocin))

Question 9

What is the process that causes a release in sex hormones for spermatogenesis/oogenesis?

Answer 9

• Hypothalamus stimulates anterior pituitary hormone production
• Anterior pituitary stimulates gonad hormone production
  FSH and LH
• Gonadal hormones downregulate hypothalamus and anterior pituitary
• Testosterone and inhibin
  Estrogen, progesterone, and inhibin

Question 10

What is the negative feedback loop in spermatogenesis?

Answer 10

High levels of both Testosterone and Inhibin work on Pituitary and Hypothalamus to REDUCE production of FSH and LH, and thus LOWER sperm and testosterone production  NEGATIVE FEEDBACK

Question 11

Beyond sperm production, how is testosterone important in males?

Answer 11

Testosterone is important for developing and maintaining male primary and secondary sexual characteristics:

• Growth of penis
• Development of testes
• Growth and changes in bone and muscle mass/distribution
• Sex drive
• Change in voice
• Hair development

Question 12

What is andropause?

Answer 12

Reduction in sex hormone production in later life for men:
- reduced fertility and sex-drive
- loss of muscle and bone mass

• Male menopause

Question 13

How is the regulation of female hormones cyclical?

Answer 13

High levels of ESTROGEN ↓ FSH ( – fdbk) and ↑LH (+ feedback).

High levels of INHIBIN ↓ FSH ( – feedback) .

High levels of PROGESTERONE ↓FSH and ↓LH ( – feedback).

When both ESTROGEN AND PROGESTERONE levels drop (end of cycle), triggering ↑FSH to restart the process.

Question 14

How are hormones during the follicular phase (pre-ovulation): days 1-14?

Answer 14

• FSH causes follicle to mature and secrete estrogen (peaks at day 14)
• Estrogen stimulates endometrial preparation and LH release
• LH peak triggers ovulation and transition of follicle into corpus luteum

Question 15

How are hormones during the luteal phase (post-ovulation): days 15-28?

Answer 15

Corpus luteum secretes progesterone to continue preparation of endometrial lining

Question 16

How does fertilization change the hormone levels during oogenesis?

Answer 16

• If fertilization does not occur dropping hormone levels lead to menstruation aka shedding of uterine lining = cycle restarts
• If fertilization does occur, hormone production taken over by placenta

Question 17

Beyond oocyte and endometrial lining production, how is estrogen important in females?

Answer 17

Estrogen is important for developing and maintaining female primary and secondary sexual characteristics

• Development of external genitalia
• Growth and changes in bone and muscle mass/distribution
• Sex drive (aided by testosterone)
• Change in voice (less dramatic than males)
• Hair development
• Breast development

Question 18

What is menopause?

Answer 18

With age ovaries become less sensitive to FSH and LH, leading to dysregulation of the uterine cycle aka MENOPAUSE
- Menstrual cycles become irregular, eventually ceasing
- Reduced sex-drive
- Loss of muscle and bone mass

Question 19

What are the general associations with brain masculinization?

Answer 19

• Increased sex drive
• Increased aggression
• Increased spatial faculties but decreased fine motor skill tuning

Question 20

What are the general associations with brain feminization?

Answer 20

• Increased empathy
• Increased fine motor skill tuning but decreased spatial faculties
• Increased verbal fluency

Question 21

Why is the pancreas a mixed gland?

Answer 21

The pancreas is a mixed gland because it has both endocrine (directly into bloodstream) and exocrine (travelling via duct) functions

Question 22

What is the exocrine function of the pancreas?

Answer 22

-Production of digestive enzymes, buffers
- 99% of pancreas by volume

Question 23

What is the endocrine function of the pancreas?

Answer 23

Occurs in special patches called ISLETS of LANGERHANS/PANCREATIC ISLETS
- Approximately 2 million pancreatic islets scattered between exocrine cells
- 1% of all pancreatic cells
- Major hormones: INSULIN and
GLUCAGON (Glucose metabolism)

Question 24

When is insulin produced?

Answer 24

Insulin is produced when the pancreas detects high levels of glucose in the blood (ex: after eating)

Question 25

How does the liver respond to insulin being produced?

Answer 25

In response to insulin, the liver takes glucose out of the blood to build glycogen

Question 26

When is glucagon produced?

Answer 26

Glucagon is produced when the pancreas detects low levels of glucose in the blood (ex: after fasting)

Question 27

How does the liver respond to glucagon being produced?

Answer 27

In response to glucagon, the liver breaks apart glycogen and releases glucose into the blood

Question 28

What is Type 1 Diabetes?

Answer 28

Deficiency (often genetic) in pancreatic cells so they do not produce sufficient insulin

Treatment: Provide insulin injections based on blood glucose levels to get the liver to do what it’s supposed to

• Langerhans don’t produce insulin anymore, Beta cells are destroyed by immune system

Question 29

What is Type 2 Diabetes?

Answer 29

Often related to lifestyle diet, liver gets desensitized to insulin and doesn’t respond properly

Treatment: Provide higher amounts of insulin to provide sufficient stimulation to the liver to behave as it should

Loss of insulin sensitivity in TARGET CELLS aka insulin resistance

• Beta cells still produce insulin, but target cells are “blind” to it so glucose remains in blood and cells think they are starving