Endocrine System

Question 1

What are the 3 categories of hormones?

Answer 1

1. Peptides
2. Steroids
3. Amino acid derivatives

Question 1

What are peptide hormones?

Answer 1

chains of amino acids

Question 2

Because peptide hormones are ____________ and cannot pass through the plasma membrane, they must bind to an _________________ receptor

Answer 2

charged; extracellular

Question 3

What is the first and second messenger?

Answer 3

• first messenger: the peptide hormone
• second messenger: the second signal that is triggered when the peptide hormone binds to the receptor

Question 4

What is a signaling cascade?

Answer 4

connection between the hormone at the surface and the effect brought about by second messengers within the cell

Question 5

What are 3 common second messengers?

Answer 5

cAMP (cyclic adenosine monophosphate), IP3 (Inositol trisphosphate), and calcium

Question 6

The effects of peptide hormones are usually _________ but _______-_______

Answer 6

rapid; short-lived

Question 7

Because peptides are generally __________-___________, peptide hormones can travel freely in the blood stream without a carrier (unlike steroid hormones)

Answer 7

Water-soluble

Question 8

What are steroid hormones?

Answer 8

Hormones derived from cholesterol and primarily produced in the gonads and adrenal cortex

Question 9

what is dimerization?

Answer 9

pairing of two receptor homone complexes

Question 10

The effects of steroid hormones are ___________ but ______-________ than peptide hormones because steroid hormones participate in gene regulation

Answer 10

Slower; longer lived

Question 11

Hormones are generally ___________ when attached to a carrier protein

Answer 11

Inactive

Question 12

What are amino acid derivative hormones? And what are some examples?

Answer 12

Hormones that are made from a few modifications of one or two amino acids; epinephrine, norepinephrine, triiodothyronine, and thyroxine

Question 13

What are direct and trophic hormones?

Answer 13

-direct: secreted and then act directly on a target tissue
-trophic: require an intermediary to act

Question 14

What are the 8 endocrine glands?

Answer 14

1. hypothalamus
2. pituitary
3. thyroid
4. parathyroid glands
5. adrenal glands
6. pancreas
7. gonads (testes and ovaries)
8. pineal gland

Question 15

What is Negative Feedback?

Answer 15

When a hormone later in the pathway inhibits hormones earlier in the pathway

Question 16

What is the blood vessel system that connects the hypothalamus to the anterior pituitary?

Answer 16

Hypophyseal portal system

Question 17

What are the 4 tropic hormones that the hypothalamus release and what does the anterior pituitary release in response?

Answer 17

1. GnRH (gonadrotropin-releasing hormone)–>FSH (folliicle stimulating hormone) and LH (Luteinizing hormone)
2. GHRH (growth hormone releasing hormone) –> GH
3. TRH —> TSH
4. CRF —> ACTH

Question 18

Each of the trophic hormones then causes the release of _______ ________ from an endocrine gland that has negative feedback effects.

Answer 18

Another hormone

Question 19

How does the hypothalamus interact with the posterior pituitary?

Answer 19

neurons in the hypothalamus send axons down the pituitary stalk into the posterior pituitary which release oxytocin and antidiuretic hormone

Question 20

What do oxytocin and antidiuretic hormone do?

Answer 20

-Oxytocin - stimulates uterine contracts and milk letdown during lactation
- Antidiuretic hormone (ADH): increases reabsorption of water in the collecting ducts of the kidney

Question 21

What are the 7 hormones that the anterior pituitary gland secretes (4 trophic, 3 direct)?

Answer 21

FLAT PEG (FLAT =trophic; PEG = direct)
1. FSH
2. LH
3. ACTH
4. TSH
5. Prolactin
6. Endorphins
7. GH

Question 22

What are the functions of the 3 direct hormones secreted by the anterior pituitary gland?

Answer 22

-prolactin: more important in females than males; stimulates milk production in the mammary glands
-endorphins: decrease the perception of pain
GH: promotes growth of bone and muscle; stimulates breakdown of fatty acids; requires large amound of energy and glucose

Question 23

What happens if there is an excess or deficit of GH?

Answer 23

-excess = gigantism
-deficit = dwarfism

Question 24

What are the 2 hormones of the posterior pituitary?

Answer 24

ADH and oxytocin

Question 25

Why are ADh and oxytocin secreted?

Answer 25

-ADH: in response to low blood volume or increased blood osmolarity; results in greater water retention to counteract
oxytocin: secreted during childbirth for coordinated contractions of uterine smooth muscle; runs on a positive feedback loop which spirals forward

Question 26

What hormones controls the thyroid? What are teh 2 main functions of the thyroid?

Answer 26

Thyroid stimulating hormone
1. setting basal metabolic rate (through T3 and T4)
2. promoting calcium homeostasis (through calcitonin)

Question 27

What are T3 and T4?

Answer 27

• Hormones produced by the iodination of the amino acid tyrosine in the follicular cells of the thyroid
• capable of resetting the metabolic rate by making energy production more or less efficient

Question 28

What can a deficiency or excess of thyroid hormone result in?

Answer 28

deficiency: hypothyroidism (fatigue, lower body temp, slowed respiration and heart
rate, cold intolerance, weight gain)
excess: hyperthyroidism (higher activity level and body temp, higher respiration and BPM, heat intolerance, weight loss)

Question 29

What is the function of calcitonin?

Answer 29

decreases plasma calcium levels in three ways:
1. increase calcium excretion from kidneys
2.decreasing calcium absorption from the gut
3. increasing storage of calcium in bones