Endocrine System -13.1

Question 1

What two body systems facilitate cellular communication and control?

Answer 1

Endocrine System and Nervous System

Question 2

What are endocrine glands?

Answer 2

Glands that secrete chemical messengers called hormones into the blood stream

• Bloodstream transports hormones throughout the body

Question 3

What are hormones?

Answer 3

Chemical messengers sent to many parts of the body to produce a specific effect on a target cell of organ.

Question 4

Describe the action of the pancreas

Answer 4

The pancreas secretes hormone - insulin - into the blood stream

Insulin affects target cells (adipose tissue, liver) - makes them more permeable to glucose

Question 5

What makes up the endocrine system?

Answer 5

The Endocrine Glands and the hormones that they release

Question 6

What does homeostasis depend on?

Answer 6

The close relationship between the nervous system and the endocrine system.

Question 7

What chemical functions as both a neurotransmitter and a hormone?

Answer 7

Epinephrine

Question 8

Why is epinephrine considered both a neurotransmitter and a hormone?

Answer 8

• It acts as a neurotransmitter between certain neurons in the nervous system
• Acts a hormone released by the adrenal glands in the flight or fight response

Question 9

What regulates the nervous system and endocrine system?

Answer 9

Negative feedback loops

Question 10

Who had the first experiment to test the link between hormones and their activity on target cells?

Answer 10

Arnold Adolph Berthold

Question 11

What did Arnold Adolph Berthold do?

Answer 11

Removed testes from rooster - became a capon
- did not fight, did not mate, did not crow, did not grow plumage like other roosters

Question 12

What caused the developmental changes in the bird?

Answer 12

The lack of the hormone testosterone

Question 13

What is the concentration of hormones in the blood stream?

Answer 13

10-8 to 10-12 mol/L

Question 14

What can trigger a hormone release?

Answer 14

• Environmental factors
• may follow a pattern repeated over hours, weeks, or every year

Question 15

What has allowed scientists to look at glands, hormones, and target cell membranes in great detail?

Answer 15

• Nuclear scanning devices (like PET)
• High powered microscopes

Question 16

How are fluorescent stains used to see hormones and glands?

Answer 16

Fluorescent stains are used to colour different hormones in a tissue sample

Question 17

How are endocrine glands viewed in a living body?

Answer 17

A capsule containing a small amount of radioactive material is ingested (same amount as that someone would receive from standard x ray)

Radioactive material accumulates in a specific gland - easy to see on PET or other nuclear scanning devices

Question 18

How does each hormone work with its target cell?

Answer 18

Each hormone fits with its receptor protein like a lock and key - each hormone has a unique molecular shape that fits into a receptor proteins on its target cell

Question 19

What target cells does hgH interact with?

Answer 19

liver, muscles, and bone cells

Question 20

What are hormones composed of?

Answer 20

Lipids or amino acids

Question 21

What hormones can easily diffuse through the lipid layer of the cell membrane?

Answer 21

Steroid hormones:

Testosterones, estrogen, cortisol

Question 22

Where do the steroid hormones bind to their protein receptors?

Answer 22

Inside the target cell

Question 23

How do steroid hormones affect target cell?

Answer 23

Activates specific genes - causing changes in the cell -

Question 24

What are water soluble hormones?

Answer 24

Epinephrine, insulin, thyroxine, hgh - amino based - cannot diffuse across cell membrane

Question 25

How do water soluble hormones cause reactions then?

Answer 25

They bind to protein receptors on the surface of the target cell - which starts a cascade of reactions inside the target cell

Question 26

What happens once a hormone has been delivered?

Answer 26

Enzymes inactivate the hormone - as lingering affects can be disruptive

Question 27

How does a negative feedback loop work?

Answer 27

When a certain blood concentration of hormone has been reached

When target cells have responded to specific hormone - endocrine gland releasing the hormone is inhibited (hormone stops coming out)

Question 28

What hormones regulate water reabsorption by the kidneys?

Answer 28

Antidiuretic hormone and aldosterone

Question 29

What is the process of ADH being released (blood concentration)

Answer 29

Blood plasma becomes to concentrated

Receptors in blood plasma become to concentrated

Receptors in hypothalamus detect this and send neural signals to pituitary gland to release ADH

Question 30

How does ADH work on target cell?

Answer 30

ADH targets the nephrons of kidneys - tubules become more permeable to water

More water is reabsorbed - body excretes less (but more concentrated urine) - blood pressure increases

Hypothalamus detects this - signals posterior pituitary to stop releasing ADH

Question 31

What is the result of an inability to produce ADH?

Answer 31

Diabetes insipidus - person produces large volumes of urine - resulting loss of ions from the body

Question 32

What is a name given to hypothalamus and the anterior pituitary hormones?

Answer 32

Tropic hormones - their targets are other endocrine glands

Question 33

What do tropic hormones do?

Answer 33

Stimulate endocrine glands to release other hormones