Endocrine

Question 1

What do hormones control?

Answer 1

– Reproduction
– Growth and development
– Mobilization of body defenses
– Maintenance of much of homeostasis
– Regulation of metabolism

Question 2

Hormones are classified chemically as what?

Answer 2

Proteins, peptides, amines, also known as proteins, fat, and steroids

Question 3

When hormones arouse cells or alter cellular activity what can happen? (5 options)

Answer 3

1. Change plasma membrane permeability or membrane
   potential by opening or closing ion channels
2. Activate or inactivate enzymes
3. Stimulate or inhibit cell division
4. Promote or inhibit secretion of a product
5. Turn on or turn off transcription of certain genes

Question 4

What two mechanisms do hormones act by?

Answer 4

1. Direct gene activation
2. Second-messenger system

Question 5

Explain direct gene activation

Answer 5

1. Steroid hormone diffuses through the plasma
   membrane of target cells
2. Once inside the cell, the hormone enters the nucleus
3. Then, the hormone binds to a specific protein within
   the nucleus
4. Hormone-receptor complex binds to specific sites on
   the cell’s DNA
5. Certain genes are activated to transcribe messenger
   RNA
6. New proteins are synthesized

Question 6

Explain second-messenger system

Answer 6

1. Hormone (first messenger) binds to a receptor
   protein on the plasma membrane
2. Activated receptor sets off a series of reactions that
   activates an enzyme
3. Enzyme catalyzes a reaction that produces a
   second-messenger molecule (such as cyclic AMP,
   known as cAMP)
4. Second messenger molecule oversees additional
   intracellular changes to promote a specific response
   in the target cell

Question 7

What are hormone levels in the blood maintained by?

Answer 7

Negative feedback systems

Question 8

What are the groups of stimuli that activate endocrine glands?

Answer 8

1. Hormonal
2. Humoral
3. Neural

Question 9

What is a hormonal stimuli?

Answer 9

Endocrine organs are activated by other hormones

Question 10

What is a humoral stimuli?

Answer 10

Changing blood levels of certain ions and nutrients stimulate hormone release.

Question 11

What is a neural stimuli?

Answer 11

Nerve fibers stimulate hormone release.

Question 12

Name the MAJOR endocrine organs.

Answer 12

Hypothalamus
* Pituitary gland
* Pineal gland
* Thyroid gland
* Parathyroid glands
* Thymus
* Adrenal glands
* Pancreas
* Gonads (testes and ovaries)

Question 13

What is the master endocrine gland and why?

Answer 13

Pituitary gland, because it controls activities of so many other endocrine glands

Question 14

Other organs that are generally nonendocrine in function but also secrete hormones are…

Answer 14

– Stomach
– Small intestine
– Kidneys
– Heart
– placenta

Question 15

What is Calcitonin?

Answer 15

Decreases blood calcium by causing
deposition of calcium into bone from thyroid gland

Question 16

What is thyroid hormone?

Answer 16

Major metabolic hormone, controls rate of oxidation of glucose for body heat and formation of ATP from the thyroid gland

Question 17

What is Insulin?

Answer 17

Released from the pancreas when blood glucose levels are high to increase uptake and metabolism of glucose.

Question 18

What is Glucagon?

Answer 18

Released from pancreas when blood glucose levels are low, stimulates liver to release glucose to the blood

Question 19

What is thymosin?

Answer 19

-Released from the Thymus
– Matures some types of white blood cells
– Important in developing the immune system