L11

Question 1

growth hormone is antagonistic to _____ and similar to ______

Answer 1

Antagonistic to insulin;
similar to glucagon

Question 2

GH released in response
to insulin-induced_______

Answer 2

hypoglycemia

Question 3

role of estrogen and androgen in bone growth (5)

Answer 3

– Stimulates fracture healing through receptor mediated mechanism
– Modulates release of a specific inhibitor of IL-1active at puberty
– initial growth spurt (hormones stimulate osteoblasts)
– masculinization or feminization (affects shape of bone)
– later, cause epiphyseal plate to close

Question 4

two functions of thyroid hormones (thyroxine and triiodothyronine)

Answer 4

• stimulate osteoclastic bone resorption
• modulates activity of cells in
  response to GH to ensure proper proportions of the skeleton

Question 5

how do glucocorticoids cause increased osteoclastic bone
resorption

Answer 5

Inhibit calcium absorption from the gut causing increased PTH and therefore increased osteoclastic bone
resorption

Question 6

Intermittent exposure of parathyroid Hormone (PTH) and PTH-like peptide stimulates _______

Answer 6

osteoblasts –> increased bone formation

Question 7

another name for IGF-1 is _______

Answer 7

Somatomedin C

Question 8

Inadequate supply of vitamin D results in _______ and ______

Answer 8

rickets and osteomalacia

Question 9

what happens to bones in the absence of vitamin D?

Answer 9

In its absence, excess osteoid accumulates –> repression of osteoblastic collagen synthesis.

Question 10

3 main factors affecting bone growth

Answer 10

genetics, nutrition (vitamin C and D), hormones

Question 11

why is vitamin D necessary for bones?

Answer 11

Necessary for absorption of calcium from intestines

Question 12

vitamin C is necessary for bone growth for ______

Answer 12

collagen synthesis by osteoblasts

Question 13

vitamin C deficiency leads to ____

Answer 13

scurvy

Question 14

explain osteomalacia

Answer 14

soft bones. osteoid is produced but inadequately mineralized. caused by insufficient dietary calcium or vitamin D

Question 15

_____ is the children’s form of osteomalacia

Answer 15

rickets

Question 16

signs of rickets

Answer 16

bowed legs, and deformities of the pelvis, ribs, and skull.

Question 17

thyroid hormones needed for setting _______ and for ______

Answer 17

setting metabolic rate; differentiation

Question 18

[growth/thyroid hormone] stimulates secretion of [growth/thyroid hormone]

Answer 18

thyroid hormones stimulate GH secretion

Question 19

name a condition caused by thyroid hormone deficiency and describe it (causes, effects)

Answer 19

cretinism - primarily caused by iodine deficiency, which is crucial for thyroid hormone development. causes stunted growth, mental retardation, potential deaf-mutism, etc.

Question 20

true or false: thyroid hormone replacement therapy can allow for catch-up growth

Answer 20

true

Question 21

what is adrenarche?

Answer 21

period btwn ages 6-8 where androgen secretion increases (androstenedione, DHEA, DHEAS), regulated by ACTH

Question 22

what’s the order of growth in puberty?

Answer 22

hands/feet –> arms/legs –> trunk

Question 23

what main hormone is released during puberty and in what manner? release is correlated with ________

Answer 23

GnRH from hypothalamus in a pulsatile manner. release is correlated with critical body composition

Question 24

how is puberty the great equalizer?

Answer 24

if it starts early –> final percentile is less
if it starts late –> final percentile is more

Question 25

Kisspeptin neurons may act as central processors for relaying signals from _____ to ______

Answer 25

the periphery to GnRH neurons

Question 26

Androgens and Estrogens promote __________, terminating adolescent growth spurt

Answer 26

epiphyseal fusion

Question 27

estrogens and androgens stimulate ____ secretion

Answer 27

GH

Question 28

what effect does leptin have on the Kiss1 neuron?

Answer 28

leptin stimulates Kiss1 neurons --> the neurons synapse on terminals of GnRH neurons --> release of GnRH

Question 29

positive stimulators of GnRH neurons (2)

Answer 29

leptin and sex steroids

Question 30

at what concentration is estrogen stimulatory for growth? when is it inhibitory?

Answer 30

stimulatory at very low concentrations, inhibitory at high concentrations

Question 31

childhood obesity is associated with [early/late] signs of puberty in girls

Answer 31

early

Question 32

what is the critical weight/fat hypothesis

Answer 32

A minimum body weight/fat is needed for menarche

Question 33

______ is a protein that negatively regulates muscle growth

Answer 33

Myostatin

Question 34

______ is an age-related condition characterized by the gradual loss of muscle mass, strength, and function

Answer 34

Sarcopenia

Question 35

true or false: the number of secretions of GH decreases with age

Answer 35

false; number is about the same but the volume of those secretions is lowered

Question 36

Overexpression of IGF-1 results in (2):

Answer 36

sustained hypertrophy and regeneration in senescent skeletal muscle

Question 37

transcription factor associated with maintaining muscle satellite cells

Answer 37

pax7

Question 38

how does injury/exercise affect muscle satellite cells?

Answer 38

pax7 expression decreases --> satellite cell activated --> differentiate into myoblasts/myofibers

Question 39

how does myostatin kickstart its pathway?

Answer 39

myostatin binds to a receptor which causes smad activation --> smad suppresses muscle proliferation

Question 40

what does a primary endocrine disorder mean?

Answer 40

dysfunction of peripheral gland

Question 41

what does a secondary endocrine disorder mean? what are the exceptions to this (2)?

Answer 41

usually pituitary dysfunction projected to peripheral gland exceptions: Secondary hyperaldosteronism = response of adrenal cortex to rennin hyperactivity Secondary hyperparathyroidism = response of PTH to low plasma Ca2+

Question 42

what does a tertiary endocrine disorder mean?

Answer 42

rarely used term for hypothalamic dysfunction

Question 43

methods for assessing endocrine function that require antibodies (3)

Answer 43

radioimmunoassay (RIA), immunoradiometric assays (IRMA), and enzyme-linked immunosorbent assays (ELISA)

Question 44

key component of elisa

Answer 44

enzyme-labeled antibody that can change the substrate color

Question 45

what is a way of quantifying hormonal activity?

Answer 45

bioassay --> standard curve

Question 46

explain immunoaffinity chromatography

Answer 46

affinity chromatography that uses antibodies as the stationary phase. The target molecule binds specifically to the antibody, while other molecules in the sample pass through or are washed away.

Question 47

true or false: one-time blood sample collection is a sufficient procedure for a majority of hormones

Answer 47

true

Question 48

2 examples of hormones with diurnal variability

Answer 48

cortisol, GH