Lecture 26 -- Endocrine System III

Question 1

LO1: relate steroid hormone structure to that of cholesterol. Give examples.

name all the steroid hormones and where they are produced

Answer 1

adrenal cortex:
- mineralocorticoids (aldosterone)
- glucocorticoids (cortisol)
- androgens

gonads:
- testosterone
- estrogen

Question 2

LO1: relate steroid hormone structure to that of cholesterol. Give examples.

how are steroid hormones synthesized?

what do all the steroid hormones have in common?

how do the steroid hormones differ?

Answer 2

synthesized from cholesterol

they all have a 4-ringed steroid backbone

they differ in the functional groups attached to the 4-ringed steroid backbone

Question 3

LO2: how are steroid hormones transported in blood?

Answer 3

steroids are hydrophobic –> must bind to hydrophilic transport proteins

Question 4

LO2: how are steroid hormones transported in blood?

what are examples of the hydrophilic transport proteins?

Answer 4

albumins and globulins –> synthesized by liver

Question 5

LO2: how are steroid hormones transported in blood?

what do the hydrophilic transport proteins do?

Answer 5

increase steroid half lives

protect steroids from:
- enzymes
- being filtered out of blood by kidneys

Question 6

LO3: describe target cell stimulation by steroid-H:

how do most steroids stimulate target cells? What do they do?

Answer 6

steroids = hydrophobic
pass thru cell mb directly to nucleus

genomic effects –> affects transcription

Question 7

LO3: describe target cell stimulation by steroid-H:

exception to this rule

Answer 7

glucocorticoids –> bind to cytosol instead

LH –> non-steroid but is also lipid soluble and can enter cell as well

Question 8

LO4: give examples of hormones w/ monoamine structure and indicate their amino acid precursor

what are monoamines made of?

Answer 8

amino acids

Question 9

LO4: give examples of hormones w/ monoamine structure and indicate their amino acid precursor

examples of monoamines and their aa precursor

Answer 9

catecholamines (synthesized from tyrosine):
- dopamine –> synthesized from tyrosine
- epinephrine –> synthesized from tyrosine
- norepinephrine –> synthesized from tyrosine

melatonin –> synthesized from tryptophan

thyroid hormone (TH) –> synthesized from tyrosine
- thyroxine (T4) –> synthesized from tyrosine –> lipid soluble
- triiodothyronine (T3) –> synthesized from tyrosine

Question 10

LO5: give examples of peptide hormones:

what are they made of? How are they synthesized?

Answer 10

made up chains of amino acids

synthesized the same way as any other protein

Question 11

LO5: give examples of peptide hormones:

give examples of peptide hormones and where they are produced:

Answer 11

releasing hormone (RH) and inhibiting hormone (IH) –> produced by hypothalamus

most hormones of anterior pituitary gland are polypeptides or glycoproteins

insulin

growth hormone

oxytocin

antidiuretic hormone (ADH)

Question 12

LO6: describe the following steps applying to peptide-H and monoamines:

Answer 12

1) peptide-H and monoamines synthesized and stored in secretory vesicles until stimulus is received

2) transportation: peptide-H and monoamines are hydrophilic –> travel freely in blood

3) binding and effects: hormones can’t cross membrane so bind to cell-surface receptors –> signal transduction pathway (2nd messengers – CAMP, DAG, IP3)

hormone doesn’t always employ the same 2nd messenger

Question 13

LO7: summarize the cyclic AMP signaling pathway

Answer 13

1) hormone binds to receptor

2) activates G protein –> activates adenylate cyclase

3) activate adenylate cyclase converts ATP into cAMP
cAMP gets broken down by phosphodiesterase (PDE)

4) cAMP activates protein kinase (PK) –> PK attaches phosphates to other molecules

5) PK phosphorylates enzymes (activates/deactivates)

6) altered protein (enzyme) –> causes cell response

Question 14

LO7: summarize the cyclic AMP signaling pathway

example of glucagon:

Answer 14

cAMP leads to activation of enzymes that hydrolyze glycogen stored in cell

Question 15

LO8: summarize the DAG-IP3 signaling pathway

Answer 15

1) hormone binds to receptor –> activates G protein

2) activated G-protein binds to and activates phospholipase (PLC) enzyme

3) phospholipase splits a membrane phospholipid into 2 fragments –> DAG and IP3 (2nd messengers)

Question 16

LO8: summarize the DAG-IP3 signaling pathway

what does the pathway do?

Answer 16

can open Ca channels in the plasma mb or in the ER

Ca2+ binds to calcium-dependent cytoplasmic enzymes that alter cell metabolism

Question 17

LO9: identify the 3 types of stimuli for hormone secretion

are hormones secreted at steady rates?
do they have constant levels in bloodstream throughout the day?

Answer 17

no

no

Question 18

LO9: identify the 3 types of stimuli for hormone secretion

neural (describe)

Answer 18

nerve fibers supply some endocrine glands and elicit the release of their hormones

Question 19

LO9: identify the 3 types of stimuli for hormone secretion

humoral (describe)

Answer 19

blood-borne stimuli

Question 20

LO9: identify the 3 types of stimuli for hormone secretion

hormonal (describe)

Answer 20

1 hormone stimulates the secretion of another hormone

Question 21

LO9: identify the 3 types of stimuli for hormone secretion

key ideas and concepts about hormone receptors:

hormone receptors are ___ or ___ located on the ___, in the ___, or in the ___

Answer 21

proteins or glycoproteins

located on the plasma mb, in the cytoplasmic, or in the nucleus

Question 22

LO9: identify the 3 types of stimuli for hormone secretion

key ideas and concepts about hormone receptors:

not all cells express the same ___

Answer 22

receptors

Question 23

LO9: identify the 3 types of stimuli for hormone secretion

key ideas and concepts about hormone receptors:

most cells are sensitive to more than one ___

Answer 23

hormone

Question 24

LO9: identify the 3 types of stimuli for hormone secretion

key ideas and concepts about hormone receptors:

hormone stimulate only those cells that have ___ for them (their target cells)

Answer 24

receptors

Question 25

LO9: identify the 3 types of stimuli for hormone secretion key ideas and concepts about hormone receptors: the same type of ___ may be located on cells in different body tissues, and trigger somewhat ___ responses

Answer 25

receptor different

Question 26

LO9: identify the 3 types of stimuli for hormone secretion key ideas and concepts about hormone receptors: receptors exhibit ___ and ___

Answer 26

specificity saturation

Question 27

LO9: identify the 3 types of stimuli for hormone secretion key ideas and concepts about hormone receptors: define specificity

Answer 27

the receptor for one hormone will not bind other hormones

Question 28

LO9: identify the 3 types of stimuli for hormone secretion key ideas and concepts about hormone receptors: define saturation

Answer 28

condition in which all the receptor molecules are occupied by hormone molecules -- adding more hormone cannot produce any greater effect

Question 29

LO9: identify the 3 types of stimuli for hormone secretion key ideas and concepts about hormone clearance: most hormones are taken up and degraded by the ___ and ___ and then excreted in the ___ or ___

Answer 29

liver --> bile kidneys --> urine

Question 30

LO9: identify the 3 types of stimuli for hormone secretion key ideas and concepts about hormone clearance: some hormones are degraded by their ___

Answer 30

target cells

Question 31

LO9: identify the 3 types of stimuli for hormone secretion key ideas and concepts about hormone clearance: define metabolic clearance rate (MCR):

Answer 31

the rate of hormonal removal

Question 32

LO9: identify the 3 types of stimuli for hormone secretion key ideas and concepts about hormone clearance: define half life (t 1/2):

Answer 32

the length of time required to clear 50% of the hormone from the blood

Question 33

LO10: explain how target cells regulate their sensitivity to circulating hormones:

Answer 33

target cells can adjust their sensitivity to a hormone by changing the number of receptors for it up-regulation -- increase receptor density --> increase sensitivity --> stronger response - ex. late pregnancy --> uterus produces oxytocin receptors down-regulation -- decrease receptor density --> decrease sensitivity --> diminished response - ex. in response to long-term exposure to a high hormone

Question 34

LO11: differentiate the types of hormone-hormone interactions:

Answer 34

antagonistic -- one opposes the other additive -- synergistic hormones work together. effects may be additive or complementary permissive -- one hormone is required before target cell can respond to another hormone

Question 35

LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS: define stress

Answer 35

situation that upsets homeostasis physical or emotional causes

Question 36

LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS: how does the body respond to stress?

Answer 36

stress response or general adaptation syndrome (GAS) mediated by endocrine and sympathetic NS increase cortisol and epinephrine

Question 37

LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS: describe 3 stages of GAS: stage 1 is called the ___ how does it occur? what does it do? what is it mediated by? what are the hormones involved?

Answer 37

alarm reaction -- "fight or flight" stressor upsets homeostasis or cellular balance increased mental alertness mediate mainly by sympathetic stimulation mostly epinephrine, some norepinephrine

Question 38

ge LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS: describe 3 stages of GAS: stage 2 is called the ___ what is it marked by? what is the main priority? what happens? what hormone gets released and what does it do?

Answer 38

stage of resistance or adaptation body fights back by adjusting to stress glycogen reserves become exhausted. priority --> provide alternative fuels for metabolism gluconeogenesis occurs in liver --> breakdown of fat and protein cortisol --> inhibits glucose uptake by most organs --> glucose-sparing effect --> saves glucose for brain

Question 39

LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS: describe 3 stages of GAS: stage 3 is called the ___ what is it marked by? when does stage of exhaustion set in? what is the result of stage of exhaustion? describe the energy sources...

Answer 39

stage of exhaustion lack of adaptation response sets in when fat is depleted (months) stress overwhelms homeostasis --> rapid decline --> death no more glycogen --> no more fat --> body relies on protein breakdown --> difficult to maintain glucose homeostasis --> infections failure to maintain adequate fluid and electrolyte balance

Question 40

LO13: infer the type of short-distance signaling that chemicals can use for communication what are the 3 types of signaling?

Answer 40

paracrine --> signal to nearby cells in same tissue or organ contact-dependent --> must be in contact to signal, (e.g. gap junctions) autocrine --> signal stimulates same cell that secretes them

Question 41

LO13: infer the type of short-distance signaling that chemicals can use for communication T or F: single chemical can be considered a hormone, paracrine, autocrine, or neurotransmitter depending on location and circumstance

Answer 41

true

Question 42

LO14: explain what eicosanoids are and how they are produced eicosanoids are... they are produced by...

Answer 42

signaling molecules made by oxidation of FA 20-carbon backbones derived from the FA arachidonic acid

Question 43

LO14: explain what eicosanoids are and how they are produced give examples of eicosanoids

Answer 43

a type of eicosanoid is prostanoids 3 types of prostanoids: - prostaglandins - prostacyclin - thromboxane a type of eicosanoid is leukotrienes: - leukotrienes help regulate bronchoconstriction and mucus secretion

Question 44

LO15: describe the physiological roles of prostanoids in: GI mucosa

Answer 44

NSAID: COX-1 gastric protection side effects (COX inhibition): - peptic ulcers - GI bleeding

Question 45

LO15: describe the physiological roles of prostanoids in: kidney

Answer 45

NSAID: COX-1&2 greater sodium and water excretion said effects (COX inhibition): - Na and water retention - hypertension - kidney injury

Question 46

LO15: describe the physiological roles of prostanoids in: cardiovascular

Answer 46

NSAID: COX-1&2 COX2 > COX1 inhibition: - stroke - myocardial infarction