Hypothalamic-Pituitary Relationships and Biofeedback Pt. I

Question 1

what is another name for the pituitary gland?

Answer 1

hypophysis

Question 2

what is another name for the anterior pituitary gland?

Answer 2

adenohypophysis

Question 3

what is the anterior pituitary made up of?

Answer 3

epithelium

Question 4

what is the posterior pituitary made up of?

Answer 4

neural tissue

Question 5

what is the connection between the hypothalamus and the pituitary gland?

Answer 5

the hypophyseal stalk

Question 6

Due to the anatomical location, tumors in the pituitary expand and put pressure on what?

Answer 6

the optic nerves

Question 7

the connection between the hypothalamus and the posterior pituitary is what type of signal?

Answer 7

neural signal

Question 8

what are the two areas in the hypothalamus that house the cell bodies that will extend their axons down to the posterior pituitary?

Answer 8

supraoptic nucleus and the paraventricular nucleus

Question 9

what do the axons in the supraoptic nucleus and the paraventricular nucleus secrete?

Answer 9

ADH and oxytocin

Question 10

the connections between the hypothalamus and the anterior pituitary are what type of signal?

Answer 10

both neuronal and hormonal

Question 11

Hypothalamic neurons produce what type of hormones that target the anterior pituitary?

Answer 11

releasing or release-inhibiting hormones

Question 12

how do the releasing or release-inhibiting hormones get to the anterior pituitary?

Answer 12

via the hypothalamic-hypophyseal portal blood vessels

Question 13

what do corticotrophs secrete?

Answer 13

ACTH

Question 14

what do thyrotrophs secrete?

Answer 14

TSH

Question 15

what do gonadotrophs secrete?

Answer 15

FSH and LH

Question 16

what do somatotrophs secrete?

Answer 16

GH

Question 17

what do lactotrophs secrete?

Answer 17

PRL (prolactin)

Question 18

What positively targets thyrotrophs in the anterior pituitary?

Answer 18

TRH

Question 19

what positively targets corticotrophs in the anterior pituitary?

Answer 19

CRF (corticotropin releasing factor)

Question 20

What positively targets the gonadotrophs in the anterior pituitary?

Answer 20

GnRH

Question 21

What positively targets the somatotrophs in the anterior pituitary?

Answer 21

GHRH (growth hormone releasing hormone)

Question 22

What negatively targets the somatotrophs in the anterior pituitary?

Answer 22

somatostatin (GHIH)

Question 23

what negatively targets the lactotrophs in the anterior pituitary?

Answer 23

PIF (prolactin inhibiting factor) (dopamine)

Question 24

what positively targets the lactotrophs in the anterior pituitary?

Answer 24

TRH (elevated levels)

Question 25

primary disorders are classified how?

Answer 25

defects in the peripheral gland (e.g. the thyroid)

Question 26

secondary disorders are classified how?

Answer 26

they are associated with altered hormone levels due to a defect in the pituitary gland

Question 27

tertiary disorders are classified how?

Answer 27

they are associated with altered hormone levels due to a defect in the hypothalamus

Question 28

what is the HPG axis?

Answer 28

hypothalamic-pituitary-gonado axis

Question 29

what is the hypothalamic hormone that is released in the HPG axis?

Answer 29

GnRH

Question 30

what could affect the pulsatile release of GnRH from the hypothalamus?

Answer 30

anorexia/starvation, extremem exercise/ very low body fat, or depression

Question 31

in males what does LH target?

Answer 31

Leydig cells in the testes

Question 32

in males, what does FSH target?

Answer 32

Sertoli cells in the testes

Question 33

when LH acts on the leydig cells in the testes what happens?

Answer 33

it stimulates the production of testosterone

Question 34

when FSH acts on the sertoli cells in the tests what happens?

Answer 34

it stimulates them to be responsive to androgens--> aids in the process of spermatogenesis

Question 35

what do the sertoli cells produce that act as a negative feedback?

Answer 35

inhibin, which acts on the anterior pituitary to limit FSH production

Question 36

in females, what does LH target?

Answer 36

theca cells in the ovaries

Question 37

in females, what does FSH target?

Answer 37

granulosa cells in the ovaries

Question 38

what happens when LH acts on theca cells in the ovaries?

Answer 38

there will be a production of androgen, which is then converted by granulosa cells to estrogens and progestins

Question 39

what happens when FSH targets granulosa cells?

Answer 39

synthesis of estrogens--> allows for follicle development during the reproductive cycle

Question 40

what occurs at the mid-cycle of a female?

Answer 40

a positve feedback pathway

Question 41

what is the purpose of the positive feedback pathway?

Answer 41

it allows the oocyte to mature- produces an LH surge right around the time of ovulation

Question 42

what is acromegaly?

Answer 42

the overgrowth of soft tissues, cartilages, and bone in the face, hands, and feet

Question 43

what causes acromegaly?

Answer 43

excessive growth hormone

Question 44

what could excessive growth hormone also cause besides acromegaly?

Answer 44

increase in blood glucose and hyperinsulemia

Question 45

what are the direct targets of growth hormone (somatotropin) released by the anterior pituitary?

Answer 45

bone and liver

Question 46

how will the bone and liver cells that respond to growth hormone (somatotropin) respond? (mechanism)

Answer 46

tyrosine-kinase associated pathway called JAK STAT pathway

Question 47

what happens when the JAK STAT pathway is activated?

Answer 47

there will be a production and secretion of a protein known as insulin-like growth factor 1

Question 48

what affect does IGF-1 have?

Answer 48

negative feedback on the anterior pituitary and hypothalamus; growth stimulating effects on tissues including bone, muscle, and adipose tissue

Question 49

when is GH secretion the highest?

Answer 49

during sleep and it peaks with exercise

Question 50

what causes stimulation of GH?

Answer 50

fasting/hunger/starvation, hypoglycemia, puberty, exercise, sleep, stress

Question 51

excess growth hormone before the closure of the bone epiphyses due to IGF-1 stimulated long bone growth causes what?

Answer 51

gigantism

Question 52

excess growth hormone after closure of bone epiphyses due to promotion of growth of deep organs and cartilaginous tissue causes what?

Answer 52

acromegaly

Question 53

increased GH has a negative feedback where?

Answer 53

to the hypothalamus that causes decreased GHRH

Question 54

increased levels of IGF-1 has a feedback loop where?

Answer 54

negative feedback loop to the anterior pituitary (so less GH secretion). but a positive feedback loop to the hypothalamus that causes an increase in GHIH from the hypothalamus

Question 55

an increase in the amount of GH levels would cause suspicion of what?

Answer 55

primary endocrine disorder/ growth hormone insensitivity

Question 56

if GH and IGF-1 were absent what type of disorder would it be?

Answer 56

secondary deficiency

Question 57

if GHRH, GH, and IGF-1 were all missing, what type of disorder would it be?

Answer 57

tertiary deficiency

Question 58

what happens if you have a high carb diet but a low protein diet?

Answer 58

GH is inhibited and the liver will not produce IGF-1 (weight gain)

Question 59

what happens if you have a decreased carb diet and an increased protein diet?

Answer 59

increased GH levels and increased IGF-1 (ketogenic metabolism)

Question 60

what is the main regulation of prolactin?

Answer 60

through inhibition using dopamine

Question 61

what does increased levels of prolactin cause?

Answer 61

a negative feedback on GnRH from the hypothalamus