Endocrine 2: Hormones and the Hypothalamus

Question 1

the mechanism of thyroxine is a ___feedback loop

Answer 1

negative

Question 2

when thyroxine is high in the blood, negative feedback is sent to the brain which stops the production of ___ and therefor stops the production of thyroxine

Answer 2

RH

Question 3

when iodine is completely absent from the diet, ___ cannot be made

Answer 3

thyroxine

Question 4

what causes a Goiter?

Answer 4

iodine not present in the blood so thyroxine cannot be made, so when the pituitary continues to secrete TSH, it builds up and forms the loiter

Question 5

breastfeeding is a ____feedback loop that will result in the continuous secretion of ____ until the baby stops feeding

Answer 5

positive; oxytocin

Question 6

where is the hypothalamus located?

Answer 6

at the base of the brain, just below the thalamus and above the pituitary

Question 7

the hypothalamus is attached to the pituitary by the __

Answer 7

infundibulum

Question 8

the _____ senses any unbalance in the body and secretes hormones into the blood to maintain homeostsatisi

Answer 8

hypothalamus

Question 9

there are two groups of ____ cells in the hypothalamus

Answer 9

neuroendocrine

Question 10

stimulating and inhibitory hormones are secreted by the ___ pituitary

Answer 10

anterior

Question 11

anti-diuretic hormone and oxytocin are secreted by the ___ pituitary

Answer 11

posterior

Question 12

the anterior and posterior pituitary secrete hormones in response to

Answer 12

signals from the hypothalamus

Question 13

the anterior pituitary is also called the ___

Answer 13

Adenhypophysis

Question 14

the posterior pituitary is also called the ___

Answer 14

neurohypophysis

Question 15

secretion from the anterior pituitary is controlled by the ___ hormones secreted by the hypothalamus and reach the pituitary through the ____ vessels

Answer 15

hypothalamic releasing and inhibitory; portal

Question 16

secretion from the posterior pituitary is controlled by ___ that start in the hypothalamus and terminate in the posterior pituitary

Answer 16

nerve signals

Question 17

between the two lobes of the pituitary, there is a small vascular zone called the ___

Answer 17

pars intermedia

Question 18

the pars intermedia is almost ___ in humans, but is much more ___ in other animals

Answer 18

absent; large/functional

Question 19

t/f the two lobes of the pituitary secrete different hormones and have different functions

Answer 19

t

Question 20

the ____ pituitary is vital to fertility and contributes significantly to a variety of critical functions ranging from growth and development to general well being

Answer 20

anterior

Question 21

the ___ pituitary is important for the body osmoregulation and breastfeeding

Answer 21

posterior

Question 22

the ___ pituitary is often referred to as the master gland bc it controls the activity of most other hormone-secreting glands

Answer 22

anterior

Question 23

the posterior pituitary is actually an extension of the ___ of the hypothalamus

Answer 23

neurosecretory cells

Question 24

the cell bodies of the neurosecretory cells rest in the __ and their axons can be found in the ___

Answer 24

hypothalamus; posterior pituitary

Question 25

does the posterior pituitary make hormones?

Answer 25

no!

Question 26

the function of the posterior pituitary is to store and release 2 neurohormones that act on ___ target tissues

Answer 26

non-endocrine

Question 27

what are the 2 neurohormones secreted by the posterior pituitary?

Answer 27

antidiuretic hormone, oxytocin

Question 28

what is the function of the ADH?

Answer 28

acts on kidney to promote water reabsorption

Question 29

what is the function of oxytocin?

Answer 29

stimulates smooth muscle contractions in uterine and mammary tissue regulate labor and milk production and letting

Question 30

plasma osmolarity is maintained within a narrow range by employing mechanisms that regulate both ___ and ___

Answer 30

water intake and output

Question 31

____ sense changes in plasma osmolarity and changes of ___mOsm/kg induce action

Answer 31

hypothalamic osmoreceptors; 2-3

Question 32

the control os plasma osmolarity involves control of the blood water level, which is secrete by the __ hormone

Answer 32

antidiuretic

Question 33

control of hormone synthesis in the hypothalamus is at the level of ___

Answer 33

gene transcription

Question 34

what is the hormonal response to thirst?

Answer 34

hypothalamic osmoreceptors stimulate secretion of ADHand turn on gene machine to increase ADH expression on mRNA in magnocellular neurons

Question 35

ADH hormones are first made as large ___, then are enzymatically processed to produce the ___ and 2 ___

Answer 35

preprohormones; mature hormone and 2 byproducts

Question 36

what ae the 2 byproducts of ADH synthesis?

Answer 36

neurophysin and glycopeptide

Question 37

the mature form of ADH is transported by ___ to the posterior pituitary along ___ tracks

Answer 37

neurosecretory vesicles; microtubule

Question 38

ADH vesicle transport increases when synthesis is ___ and stops when stimulus is __

Answer 38

stimulated; removed

Question 39

ADH activates ____receptors, leading to ____mediated activation of __, which will phosphorylate ___and lead to their insertion in the cell membrane

Answer 39

V2 GPCR; cAMP; PKA; Aquaporin 2

Question 40

what is the function of inserting AQ2 channels in the cell membrane ?

Answer 40

reabsorb water

Question 41

tropic neurohormones are carried from the hypothalamus to the anterior pituitary by ___

Answer 41

portal vessels

Question 42

tropic hormones from the hypothalamus act on ___ cells in the anterior pituitary which will then release ___ into a second set of capillaries for distribution through the body

Answer 42

endocrine; peptides

Question 43

what are the 5 types of cells that secrete hormones in the anterior pituitary and what are the hormones they secrete? and what % of AP cells are they?

Answer 43

1. somatotropes--> human growth hormone (GH) 30-40% 2. thyrotropes-->TSH 3-5% 3. Corticotropes--> adrenocorticotropin hormone (ACTH) 20% 4. gonadotropes --> gonadotropic hormones (LH, FSH) 5. lactotropes --> prolactin (PRL) 3-5%

Question 44

with the exception of ____, all anterior pituitary hormones are collectively referred to as tropic hormones bc they turn on/off the function of other hormones

Answer 44

GH

Question 45

which AP hormone is not tropic?

Answer 45

GH

Question 46

all AP hormones act on ____ receptors except GH

Answer 46

GPCR

Question 47

the GH is also called ___ or ____

Answer 47

somatotropin hormone; somatotropin

Question 48

GH is a small protein of around ___aa

Answer 48

200

Question 49

unlike tropic hormones, GH does not function on a ___, but rather exerts its effects by ___

Answer 49

acting directly on all (or almost) tissues of the body

Question 50

GH also acts through an intermediate substance called ___ or ___

Answer 50

insulin-like growth factor or somatomedin

Question 51

which of the 2 (GH/IGF) attaches weakly to transporters for a short time and which attaches strongly for a long time?

Answer 51

GH weak and short, IGF strong and long

Question 52

IGF-1 is activated by ___ and supports the ___, ___ and ___ of many tissues, ranging from muscle and immune cells to nervous and immune systems

Answer 52

GH; bioenergetic prossesses, metabolism, and growth

Question 53

IGF-1 regulates GH through negative feedback loops at the level of the ___, where it activates the release __

Answer 53

hypothalamus; growth hormone inhibitory hormone (GHIH)

Question 54

GH binds to GH receptors which undergo___ and then interact with ___ that activate the receptor by the phosphorylation of ___ on GH receptors

Answer 54

dimerization; janus kinase (JAK), tyrosine residues

Question 55

the GH JAK complex interacts with the ____- that gets phosphorylated by JAK causing its dimerization and movement into the nucleus where it induces the transcription and production of ___

Answer 55

signal transducer and activator of transcription (STAT); IGF-1

Question 56

list some things that may cause abnormalities in GH secretion

Answer 56

GH deficiency, GH receptor mutation, IGF deficiency, IGF receptor mutation, TH deficiency, insulin/insulin receptor defects, nutrition deficiency

Question 57

hyper secretion of GH before puberty causes

Answer 57

giantism

Question 58

hyper secretion fo GH acter puberty causes

Answer 58

acromegaly

Question 59

what is the treatment for hypersecetion of GH?

Answer 59

somatostatin analogues (Octreotide)