Endocrine System Test

Question 1

what does the endocrine system consist of ?

Answer 1

endocrine glands

secreting cells in organs

Question 2

hormones

Answer 2

diffuse from interstitial fluid to bloodstream & eventually to other cells called TARGET CELLS

Question 3

Characteristics of endocrine system

what do hormones affect? what do they contain? receptors?

Answer 3

hormones affect target cells that respond to a specific hormone

• contain SPECIFIC RECEPTORS (proteins or glyoproteins)
• ‘site specific’ (only accept 1 type of hormone)

Question 4

Hormone types (2)

Answer 4

non-steroid (water-soluble)

steroid (lipid-soluble)

Question 5

non-steroid includes what?

Answer 5

amines, peptides, proteins, glycoproteins

Question 6

steroid includes?

Answer 6

steroid hormones, thyroid hormones, nitric oxide (NO)

Question 7

lipid-soluble (steroid) hormones

Answer 7

insoluble in water- but soluble in other lipids (EASY to enter cell membrane)
all derived from cholesterol
takes longer to act, but generally effects last longer than non-steroid hormones
-EX) puberty takes longer to act but lasts longer

Question 8

action of steroid hormones

Answer 8

hormones transported in blood by transport proteins

diffuse through cell membrane (lipid bilayer) & bind to receptors within target cells

Question 9

water soluble (non-steroid) hormones

Answer 9

composed of amine acids
cant diffuse through lipid-bilayer
bind to receptors on target cell surface
act faster, but effects are more short-lived than steroid hormones
EX) scared, heart rate increase (fight or flight)

Question 10

Steroid hormone action (how steroid hormones work)

Answer 10

1) lipid soluble steroid hormone enters the target cell directly through cell membrane and binds to specific receptor (activation).
2) Activated hormone-receptor complex binds to specific genes of target cell’s DNA & causes these genes to be expressed.
3) mRNA from hormone-activated genes leaves nucleus & starts to make new proteins
4) new proteins alter cell’s activity in some specific way

Question 11

Non-steroid hormone action (how non-steroid hormones work)

Answer 11

1) Water-soluble non-steroid hormone = first chemical message. Binds to specific receptor ON cell membrane of target cell (activation)
2) Hormone receptor complex stimulates formation of a SECOND messenger inside cell (cAMP). cAMP made from ATP by enzyme adenylate cyclase.
3) cAMP activates protein kinase enzymes -> activate other proteins by phosphorylation (adding phosphate)
4) many phosphorylated proteins alter cell’s activity to elicit physiological responses
5) cAMP only lasts for short time before degraded

Question 12

non-steroid vs steroid hormones

Answer 12

steroid: enters cell membrane, insoluble in water (transport proteins, receptors in target cell)
derived from cholesterol
long to act, effects last long
non-steroid: can’t diffuse through lipid-bilayer (already has proteins, receptor on membrane)
composed of amino acids
act fast, short effects

Question 13

Affect of aging on what 5 glands?

Answer 13

pituitary
pineal
thymus
kidneys
pancreas

Question 14

affects of aging on thymus gland

Answer 14

thymus gland shrinks significantly causing decreased immune cell production & decreased resistance to disease

Question 15

affects of aging on pituitary gland

Answer 15

hGH secretion decreases, leading to muscle atrophy and weakness

Question 16

affects of aging on kidneys

Answer 16

calcitriol secretion diminishes

Question 17

affects of aging on pineal gland

Answer 17

secretion of melatonin is reduced w/ age, disrupts normal sleep-wake cycles

Question 18

affects of aging on pancreas

Answer 18

insulin secretion and sensitivity of target tissue diminishes, affects changes in blood glucose ; increases = faster & return to normal glucose levels = more slowly

Question 19

3 ways /methods hormones are controlled by the body

Answer 19

1. signals from NERVOUS SYSTEM
2. Chemical changes in BLOOD
3. act on OTHER HORMONES

Question 20

Describe how hormones are controlled by the signals from the nervous system

Answer 20

nervous system -> endocrine gland -> target cells-> action

Question 21

Describe how hormones are controlled by the chemical changes in the blood

Answer 21

blood -> endocrine gland -> target cells -> action

Question 22

Describe how hormones are controlled by other hormones acting on each other?

Answer 22

hypothalamus -> ant. pituitary -> peripheral endocrine gland-> target cells -> action

Question 23

how are hormonal secretions controlled in general?

Answer 23

controlled using negative feedback

1. Secretion triggered by internal/external stimulus
2. Rising hormone levels inhibit further hormone release in target organ

Question 24

negative feedback of insulin

Answer 24

blood sugar level is high -> insulin is secreted, the change in blood glucose levels is detected, hypothalamus stops stimulating insulin production

Question 25

negative feedback of glucagon

Answer 25

blood sugar level is low -> glucagon is secreted, the increase in blood glucose levels is detected, hypothalamus stops stimulating glucagon production

Question 26

where is insulin and glucagon made? effect on body?

Answer 26

made in- pancreas
insulin-secreted by beta cells in pancreas, lowers blood glucose
glucagon- secreted by alpha cells in pancreas, raises blood glucose

Question 27

explain how nervous & endocrine system work together?ex of hormone and effect when stimulated? how messages are sent?

Answer 27

• nervous system receives internal/external stimulus ie physical harm, body temp, etc
• stimulus is sent to brain for interpretation
• bc hypothalamus is link btwn nervous & endocrine systems, it stimulates the pituitary gland to produce certain hormones that are then sent to an endocrine gland w/ target cells
• EX) you’re asleep & house catches on fire.
• change in body temp alerts nervous system
• stimulus sent to brain
• interpreted as “danger”
• hypothalamus stimulates pituitary gland
• pituitary secretes ACTH
• ACTH travels through blood stream & stimulates adrenal glands to release epinephrine & norepinephrine which allows increased focus and mobility to get out of the house as a flight or fight response